hash stringlengths 32 32 | doc_id stringlengths 7 13 | section stringlengths 3 121 | content stringlengths 0 2.2M |
|---|---|---|---|
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.1 General description | 6. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.1 General description | This subclause intends to describe a High Level NP solution when all involved Networks, at call set-up, has access to a Number Portability Database as outlined in figure 13 below. The Originating Network makes a DB query on the dialled CdPN to retrieve a Routeing Number to address the Recipient Network, routes the call towards the Recipient Network either directly or via Transit Network(-s). The Routeing Number indicates either Recipient Network only or optionally also Point of Interconnection. Transit Network(-s) receives the incoming call, makes a DB query again to retrieve a Routeing Number to Recipient Network, then it routes the call towards the Recipient Network either directly or via another Transit Network(-s). Again the Routeing Number indicates either Recipient Network only or optionally also Point of Interconnection. The Recipient Network receives the incoming call, makes a DB query again to retrieve a Routeing Number to Recipient Exchange, then it routes the call towards the Recipient Exchange. b) IAM a1 ) IAM a2 ) IAM Originating Network D onor Network Rec ipient Network C alled S ubsc riber Transit Network(-s) D B Lasting Re latio n Te m po rary R elatio n C alling Subsc riber D B D B Figure 13: All call Query by all involved Networks As can be seen in figure 13, all involved networks have access to a Number Portability Data Base, this opens the possibility of not needing to transfer NP related Routeing information between networks. As also can be seen in the figure, the Donor Network is not involved in call set-up at all. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.2 Interaction with supplementary services | No interactions with supplementary services are foreseen since DB query is made, prior call set-up, by all involved Networks, i.e. calls to ported-out numbers is routed as efficient as for calls to non ported numbers. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.3 Interaction with IN based services | No interference/impact identified. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.4 Interaction with carrier selection | If calling party has requested carrier selection then Originating Network would not need to do any NP DB query, instead the call would be routed directly to a Transit Network which then is responsible for further Routeing towards recipient, figure 11 is the relevant figure for this case. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.5 Interaction with statistical counters | Interactions with statistical counters is depending on the first Routeing step and are described in previous subclauses. TR 101 118 V1.1.1 (1997-11) 31 |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.6 Required forward information transfer between networks | Routeing information need not, but might optionally, be sent over Network borders. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.7 Required backward information transfer between networks | No new NP related information is identified in the backward direction for call Routeing purposes. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.8 NP routeing loop detection issues | Some loop cases are identified, since this solution involves retrieval of Routeing information several times, for a call over Network borders. Only one retrieval is required if Originating and Recipient Networks are the same. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.9 Pros | The main advantages with this solution are that: a) it allows the Donor Network to discontinue maintaining data for subscriber numbers no longer in response of; b) as efficient utilization of Network resources, as for calls to non ported numbers; c) all supplementary services will work, as for calls to non ported numbers, thanks to no dependency on other networks (than used for other calls) to set up the call to recipient; d) originating Network has full control over call Routeing; f) statistical circuit quality counters will work as today thanks no release involved prior redirection; e) donor Network will not need to consider processing capacity for incoming calls to ported-out numbers; f) equal treatment of calls to both ported and not ported subscribers; g) calls to really vacant subscribers are trapped already in Originating, this saving load (in both Transit and Donor) and possible accounting costs (in Originating) for non successful calls; j) no interference with Carrier Selection; j) robust network since no dependency on other networks in getting Routeing information for calls to ported-out numbers; k) network operators need not inform others when making changes in their internal network, i.e. privacy of network internals is maintained; l) not mandatory to introduce Routeing Number transfer between networks; o) Routeing can be based on Routeing number only, i.e. current Routeing scheme can be removed; p) routeing number allocation can be network internal business if RN is not sent between networks. |
63690b205142be3574b7b253769796a3 | 101 118 | 6.7.10 Cons | The main disadvantages with this solution are that: a) might be longer call set-up time for calls to not ported subscribers, than in the onward Routeing, Query on Release and Drop-back cases; b) additional processing capacity (the query) is needed for all calls in all involved networks; c) large processing capacity required in DB since all calls will require DB query; d) all networks required to invest in DB techniques. TR 101 118 V1.1.1 (1997-11) 32 7 Examples of locations of number portability data base(-s) within networks 7.1 General description Depending on the evolutionary level in a particular Network the NP data base will be located in different places of the Network or possibly even external to the Network, the following principles of NP data storing have been identified, described and evaluated: a) exchange based (distributed) solutions; b) exchange external (centralized) solutions. The following options for NP data query places have been identified, described and evaluated: 1) originating Local Exchange; 2) gateway Exchange(-s); 3) transit or Gateway Exchange(-s); 4) donor Local Exchange(-s). All combinations of the above could exist, as described in the following subclauses. Regardless of data storing place, the Exchange/Network can act according to different NP principles, e.g. Onward Routeing the call, Dropping back the Re-routing information or even acting as a database and responding a query with Re-routing information. The emphasis in this subclause is on network internal options which not are subjects for standardization but desired options need still to be described to support the development of NP standards allowing multivendor solutions. NOTE 1: Despite figures show Local, Transit or Gateway Exchanges it should be understood that it is the functionality of these Exchanges that is intended, i.e. it shall be assumed that the functionality of Local, Transit and Gateway Exchanges can reside in the same physical Network Element. Incoming calls from other networks might very well be received directly to Transit or even Local Exchanges if this has been agreed on by bilateral agreements. NOTE 2: The emphasis on the location of exchange external DB is from where the DB access is performed and what triggered the DB access. Despite the figures show the location of the DB within the domain of a particular Network it shall be understood that the DB might very well be located outside that domain, e.g. commonly maintained by a third party. TR 101 118 V1.1.1 (1997-11) 33 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.2 Network overview for geographic numbers | The figure 14 below shows an overview of an evolved Network supporting NP. LE TE GW GWMSC NP DB MSC- VLR NP DB NP DB TE LE GW GW Netw 1 Netw 2 Netw 3 Portability domain Non Portability domain NP DB = Number Portability Data Base. Transport Network Figure 14: Network overview for number portability. One should understand that it is up to each of the Network providers if the NP DB is located in a separate Network Element or replicated (i.e. NP DB in LE, TE or GW) in each of the nodes, e.g. this collocation might be the case for small Network providers. The inclusion of Network 3 in the figure should be understood in such a way that despite the Network is not being part of the portability domain it could still maintain an own number portability database this to allow cost effective Routeing to right Network for its outgoing calls. It shall however be understand that Network 3 might or might not be part of an other portability domain than the one shared between Networks 1 and 2. The inclusion of the Non portability domain should be understood in such a way that calls originated from this Network is allowed to be routed to the Networks 1 or 2 depending on the historical number series allocation, i.e. to Donor Network. The gateway in the call receiving Network will then trap this call and make a database query to retrieve Routeing information. Despite not shown, one should keep in mind that the principals outlined in the figure 14 above will exist once per portability domain, i.e. the GW might be differing depending on geographic area, the service level of called subscribers etc. TR 101 118 V1.1.1 (1997-11) 34 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3 NP re-routing data stored in donor network | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.1 NP re-routing data stored in donor local exchange | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.1.1 General description | The principle to store the Number Portability information in the Donor Local Exchange, as outlined in figure 15 below, is often the first solution proposed since at low portability level, no extra Network elements are needed to support NP. In this solution calls to ported-out numbers should first be routed to the Donor Local Exchange before the Routeing Information can be obtained. D o n o r N e tw o rk P o rte d a w a y S u b s c rib e r D a ta B a s e s o lu tio n s in D B L E T E G W Figure 15: NP data stored in the donor local exchange This DB location might be used for many of the high level solutions, e.g.: a) incoming Call to ported-out subscriber is Onward Routed by Donor LE; b) incoming Call to ported-out subscriber is Dropped-back to TE or GW, with Re-routing information. Please note that the Drop-back might be restricted to the domain of the Donor Network, i.e. in that case the Donor Network would still, in a high level architecture, act as an Onward Routeing Network. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.1.2 Interaction with supplementary services | The service level is dependent on Donor LE, there will be interaction, i.e. the call will fail, with essential services if the connection to the Donor exchange is of lower functionality level than the incoming interconnection used to the GW/TE. No additional interworking is foreseen for non essential services. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.2 NP re-routing data stored in donor network transit exchan | ges |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.2.1 General description | The principle to store the Number Portability information in the Donor Transit Exchange(-s), as outlined in figure 16, is a possible enhancement compared storing data in Donor LE since calls to ported-out numbers do not necessarily need to reach the Donor local exchange before the Routeing Information can be obtained, i.e. if these calls are trapped in the transit level of Donor Network and then after retrieval of Routeing information routed to the correct Recipient Network/Exchange either by onward Routeing or Drop-back (to GW) principles. Still no extra Network element(-s) are needed to support NP. TR 101 118 V1.1.1 (1997-11) 35 L E L E L E D B G W P o rte d in /o u t S u b s c rib e r(-s ) D a ta B a s e s o lu tio n s in T E D o n o r N e tw o rk Figure 16: NP data stored in the donor transit exchange(-s) An alternative to trapping the calls to ported-out numbers in TE is trapping these calls by Donor LE and then release them to TE according to QoR principles, i.e. TE only retrieves data after receiving a release indicating "ported". This DB location might be used for many high level NP solutions, e.g.: a) calls to ported-out subscribers are trapped and onward routed by Donor TE; b) call Drop-back to GW, with Re-routing information, from TE; c) query on Release (QoR), from LE. The incoming calls are routed to the Transit Exchange(-s), so that the DB can be queried and call be re-routed to correct destination. The Originating calls to ported-out numbers are e.g. handled in the following way: 1) first a check is made if called subscriber is defined/connected in own LE; 2) a) if so, the call is connected according to existing procedures; b) if not, the call is redirected to transit exchange. optionally with a special indication (e.g. a prefix) to simplify next step; 3) the transit exchange traps the call and makes the DB query; 4) the call is re-routed to correct destination. At least two options exist to indicate that the subscriber has been ported out: i) the ported-out number is marked as "ported" and only calls to "ported" subscribers are routed to TE; ii) the ported-out number is marked as "vacant" and all calls to "vacant" subscribers are routed to TE, used if no data about ported-out numbers are stored in Donor LE. A not so efficient option is to always route the Originating calls to transit Network and then trombone or drop them back to the LE, i.e. no try is made to connect the call locally first. The procedures in the Originating LE discussed here are of course valid/defined per number block, i.e. the procedure is not needed in number blocks not opened for portability. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.2.2 Interaction with supplementary services | The service level is no longer dependent on Donor Local Exchange. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.3 NP re-routing data stored in donor network GW exchanges | Number portability data could theoretically be stored internally in Donor Network GW exchange(-s), but this is probably not yet a feasible/desirable solution due to amount of required data. TR 101 118 V1.1.1 (1997-11) 36 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4 Re-routing data stored exchange external in donor network | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.1 General description | A further evolution of NP data management is that the data is stored centrally, i.e. Exchange external, this to simplify management. The following different origination's of NP database queries have been identified: a) query by the Donor Local Exchange; b) query by transit exchange next to the Donor Local exchange; c) query by gateway exchange(-s). More than one principle can be applied in a certain Network at the same time, depending on evolution of the Network/exchange in question. Please note that the "central database" can actually be several databases according to replicated or load sharing methods or both, e.g. two databases (mated pair) could serve a number of number series and two other DBs could serve other number series. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.2 Query to central database by donor local exchange | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.2.1 General description | The principle of performing a DB query, as outlined in figure 17, in the Donor LE has advantages, compared to Local Exchange internal stored data, mainly with respect to simplified data management and also that it can easily be scaled up to other query methods (e.g. by Transit or Gateway exchanges). D o n o r N e tw o rk P o rte d in /o u t S u b s c rib e r(-s ) D a ta B a s e s o lu tio n s in L E T E D B G W L E L E Figure 17: NP data stored exchange external and queried by donor local exchange(-s) The same NP functions, as for Exchange internal data, are supported by this solution. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.2.2 Interaction with supplementary services | Same as for Donor LE Exchange Internal NP DB. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.3 Query to central database by donor transit exchange(-s) | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.3.1 General description | The principle of performing a DB query, as outlined in figure 18, in Donor TE, has advantages, compared to Query by Donor Local Exchange, mainly because it results in that calls to ported out subscribers do not reach the Donor local exchange, i.e. these calls are trapped in the transit level of Donor Network and then routed to the correct Recipient Network/Exchange. TR 101 118 V1.1.1 (1997-11) 37 D o n o r N e tw o rk P o rte d in /o u t S u b s c rib e r(-s ) D a ta B a s e s o lu tio n s in L E D B G W L E L E T E Figure 18: NP data stored switch external and queried by the donor transit exchange(-s) |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.3.2 Interaction with supplementary services | The interactions with supplementary services are the same as when NP DB is Donor TE Internal. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.4 Query to central database by both donor local, transit | and gateway exchange(-s) |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.4.1 General description | The principle of performing a DB query, as outlined in figure 19, by all Donor Exchanges, has advantages, compared to other methods, mainly because it results in that calls to ported out subscribers do not reach the Donor local exchange, i.e. these calls are trapped in the transit level (or even at Gateway) of Donor Network and then routed to the correct Recipient Network/Exchange. D o n o r N e tw o rk P o rte d in /o u t S u b s c rib e r(-s ) D a ta B a s e s o lu tio n s in L E G W L E L E T E D B Figure 19: NP data stored exchange external and queried by all donor exchange(-s) |
63690b205142be3574b7b253769796a3 | 101 118 | 7.3.4.4.2 Interaction with supplementary services | The service level is no longer dependent on Donor Local/Transit Exchange, i.e. incoming calls to ported-out numbers can be trapped already in GW Exchange. TR 101 118 V1.1.1 (1997-11) 38 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.4 NP re-routing data stored/ accessed in transit network | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.4.1 NP re-routing data stored/accessed in transit network gat | eway exchange(-s) Number portability data could theoretically be stored Exchange internal in a Transit Network, but this is probably not yet a feasible/desirable solution nor is advantages with this identified. |
63690b205142be3574b7b253769796a3 | 101 118 | 7.4.2 NP re-routing data stored/accessed centrally and accessed | by transit network |
63690b205142be3574b7b253769796a3 | 101 118 | 7.4.2.1 General description | A further evolution of NP data management is that the data is not only stored/available in the Donor Network, instead also stored in e.g. Transit Networks, as outlined in figure 20, or stored centrally commonly accessible by all involved Networks. Examples for management of NP data to several networks can be found in other subclauses. The main advantage here is a more efficient Routeing of calls and that call set-up no longer is depending on Donor Network only. T ra n s it N e tw o rk (-s ) D a ta B a s e s o lu tio n s in D B G W (1 ) G W (n ) Figure 20: NP data stored exchange external and queried by transit network exchange(-s) This location of NP DB can be used for several of the high level solutions, e.g.: a) always query method, the Transit Network GW (or optionally also a TE) receives an incoming call traps the call being destined to a number series that is opened for NP makes a NP DB query to obtain a RN towards Recipient Network. Finally it routes the call with the use of RN; b) Query on Release (QoR), the Transit Network GW (or optionally also a TE) receives a Release message indicating that the called number has been ported-out, makes a NP DB query to obtain a RN towards Recipient Network. Finally it routes the call with the use of RN. An option to the above is that instead of using the RN to route the call onward towards recipient, the Transit network can return the RN to the previous network according to Drop-back principles. Drop-back could also be used within Transit Network in case QoR is performed in e.g. GW(n) and call is dropped back to GW(1). TR 101 118 V1.1.1 (1997-11) 39 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.5 NP re-routing data stored in originating network | |
63690b205142be3574b7b253769796a3 | 101 118 | 7.5.1 NP re-routing data stored centrally and accessed by origi | nating network |
63690b205142be3574b7b253769796a3 | 101 118 | 7.5.1.1 General description | A further evolution of NP data management is that the data is not only stored/available in the Donor Network, instead also stored in e.g. Originating, as outlined in figure 21, or stored centrally commonly accessible by all involved Networks. Examples for management of NP data to several networks can be found in other subclauses. In this case the data is also stored/available within the Originating Network. The main advantage here is equally efficient Routeing for calls to ported and not ported numbers and that call set-up is not depending on other Networks more than for non NP calls. O rig in a tin g N e tw o rk( s) D a ta B a s e s o lu tio n s in L E L E TE D B G W Figure 21: NP data stored exchange external and queried by transit network exchange(-s) As can be seen in figure 21 Local, Transit and Gateway Exchanges have access to the NP DB, however one of the LEs do not have this capability. This location of NP DB can be used for several of the high level solutions, e.g.: a) always query method, the Originating Network LE, TE or GW receives a call originating within the network, traps the call being destined to a number series that is opened for NP makes a NP DB query to obtain a RN towards Recipient Network. Finally it routes the call with the use of RN; b) Query on Release (QoR), the Originating Network LE, TE or GW receives a Release message indicating that the called number has been ported-out, makes a NP DB query to obtain a RN towards Recipient Network. Finally it routes the call with the use of RN. Drop-back can also be used within the Originating Network e.g. in case QoR is performed in the GW and call is dropped back to Originating LE or TE. The NP DB access from the TE can be used in case some of the LE do not have any access to the NP DB. The TE will trap incoming calls to numbers opened for NP, but do not have any RN, make a NP DB query to obtain a RN towards Recipient Network. Finally TE routes the call with the use of RN. TR 101 118 V1.1.1 (1997-11) 40 |
63690b205142be3574b7b253769796a3 | 101 118 | 7.6 NP re-routing data stored in recipient network | The Recipient Network might need to access NP DB for several reasons: a) receiving an incoming call to a ported-in number, without any RN or with incomplete RN, to obtain complete RN to Recipient Exchange, b) in a "Query on Release" case for an originating call to a ported-in number,: this case is covered as an originating case. c) in a "all call query" case for an originating call to a ported-in number. This case is covered as an originating case. NP DB access in a Recipient Network (when acting as such) is only of interest in either GW Exchanges or TE since there is no need to access it if already in Recipient LE, see figure 22. The main reason for accessing "own" NP DB for an incoming call to a ported-in number is not to expose network internal structure to other network operators, i.e. have privacy. R e c ip ie n t N e tw o rk P o rte d in S u b s c rib e r(-s ) D a ta B a s e s o lu tio n s in L E G W L E L E T E D B Figure 22: NP data stored exchange external and queried by recipient GW or TE TR 101 118 V1.1.1 (1997-11) 41 8 High level evolutionary model for np and sccp using services to geographic numbers |
63690b205142be3574b7b253769796a3 | 101 118 | 8.1 Background information | Some services (e.g. CCBS, CCNR) make use of non-circuit related signalling. Within ITU-T Signalling System No.7, non-circuit related signalling is supported almost exclusively by the SCCP layer. SCCP allows messages to be addressed with Global Titles (GT), which may contain ITU-T Recommendation E.164 [1] numbers, including ITU-T Recommendation E.164 [1] numbers which are subject to portability. Where a called GT in an SCCP message contains a ported number the SCCP message should be delivered to the recipient network, and to the appropriate node within the recipient network. Traditionally, SCCP GT Translation (GTT) functions and data have been implemented as distinct from the call control routeing functions and data, and have also typically only required to a few hundred entries. With the advent of services which use ITU-T Recommendation E.164 [1] numbers as GTs, and particularly with the introduction of number portability, such GTT capability is insufficient. Hence solutions should be found which allow the correct delivery of SCCP messages addressed with ITU-T Recommendation E.164 [1] numbers, including ported numbers. An example to highlight the problem, the CCBS/CCNR (as standardized by ETSI), uses the called party number (CdPN), as dialled by user, as Global Title, then SCCP will, in the Global Title Analysis (GTA) route the message, to the destination exchange, according to which number block the dialled number is part of. This e.g. means that the 4 last digits of the CdPN need not be analysed to determine destination Network and Exchange neither need data exist for the 4 last digits in the GTA, i.e. this reduces the amount of data in GTA by 10.000 (if called party number is part of a 10.000 number block). The use of Called Party Number (CdPN), as entered by the calling subscriber, as Global Title, might no longer lead to the right local exchange since a particular dialled subscriber number, part of a certain 10.000 number block, might be relocated/ported to another operators Exchange. One should not forget the impact on CCBS/CCNR requests initiated from an ISDN PBX (ISPBX), in this case the CCBS request is, from the Local Exchange point of view, handled transparently without any relation to the previously busy/no response call, i.e. either the Local Exchange or SS no. 7 network should be able to (re-)route these SCCP messages to the right destination Local Exchange with some new functionality. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.2 Requirements on solutions for routeing of SCCP messages | The routeing of SCCP messages should be achieved by the SCCP, and data available to the SCCP, without reference to the application part providing the service. This is required because an end to end service supported by originating and terminating networks should be available even if the service application is not supported by the donor or transit networks. The integrity of services provided by the SCCP layer should be maintained also in a NP environment. The main services provided by the SCCP are: a) connectionless message service with sequencing not guaranteed; b) connectionless message service with sequencing guaranteed; c) notification of failure to deliver a connectionless message; d) basic connection oriented service; e) connection oriented service with flow control. NOTE: Currently defined inter-operator non-circuit related services utilize only connectionless service. TR 101 118 V1.1.1 (1997-11) 42 Solutions should be easy to maintain and keep consistent with chosen solutions for calls to ported numbers. The maintenance of large GTT tables is a new function for most Network Operators, and solutions should aim to minimize the effort required for this activity. Inconsistency between GTT data and call routeing data could lead to incomplete service being offered to customers with ported numbers or customers calling these numbers. Inconsistency between the GTT data held by different Network Operators may lead to circular routeing of messages. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.3 Proposal for solutions | In all architectures identified for circuit related signalling, there exists one or more databases which assist the routeing of calls to a ported number. These Number Portability databases may be internal to an exchange (for example, in the donor exchange) or may be external to any exchange. It is proposed to allow using these databases also to assist the routeing of SCCP messages. The database would be queried during execution of the GTT function for ITU-T Recommendation E.164 [1] numbers. The result of the query would be a modified GT which will be reanalysed within the SCCP to determine how to subsequently route the message. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4 General introduction to described models | The following subclauses describes a number of possible high level solutions to support supplementary services (e.g. CCBS, CCNR, etc.) using Global Title based Routeing in a NP environment. Three main approaches are identified, i.e. that a Routeing Global Title (RGT) is retrieved and used: a) by Donor Network that reroute the TCAP/SCCP message to correct destination; b) by Originating LE; c) by a SCCP Transit node, e.g. a SPR. This case can also be evolved to use same NP DB (and data) as used for Routeing of calls. For all solutions several techniques could be used. TR 101 118 V1.1.1 (1997-11) 43 |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.1 SCCP routeing solutions in donor network/exchange | |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.1.1 General description | In this NP solution for Routeing of TCAP/SCCP messages to the Recipient Exchange, the Donor Network/Exchange maintains all the data, e.g. a Routeing Global Title (RGT), for ported-out numbers. The NP DB is located either exchange internal or external of the LE. As outlined in figure 23, the Originating Network/Exchange routes the TCAP/SCCP message according to the historical location of the Number Series that the called party Directory Number is part of. C a llin g S u b s c r ib e r D o n o r N e tw o r k R e c ip ie n t N e tw o r k P o r te d S u b s c r ib e r D B O r ig in a tin g N e tw o r k L a s t in g R e l at i o n T e m p o r a r y R e l at io n S S N o . 7 L E L E L E Figure 23: DB query and TCAP/SCCP message redirection performed by donor LE The Donor Network (e.g. Local Exchange) detects that the called number has been ported-out, makes a DB query to retrieve a Routeing Global Title and replaces the received GT with this. Thereafter the TCAP/SCCP message is Onward routed towards the Recipient Exchange. The Recipient Network need not make an own DB query since call is routed directly to Recipient Exchange. This solution for Routeing of connection less services can be compared with the "onward Routeing" solution for ordinary call set-up as outlined in subclause 6.2.1. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.1.2 Pros | The main advantages with this solution are that: a) only the Donor Network/Exchange needs to maintain NP data for ported-out numbers; b) no impact when addressing not ported subscribers. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.1.3 Cons | The main disadvantages with this solution are that: a) the recipient network(-s) should inform donor networks when modifying network internal structure, i.e. it does not allow for privacy for Network Operators; b) impacts TCAP and SCCP layer if not two transaction ID are consumed per CCBS request. TR 101 118 V1.1.1 (1997-11) 44 |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.2 SCCP routeing solutions in originating network/exchange | |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.2.1 General description | In this NP solution, for Routeing of TCAP/SCCP messages to the Recipient Exchange, the Originating Network/Exchange has access to NP data for Portable Numbers. As outlined in figure 24, the Originating Network/Exchange makes a DB query, to retrieve a Routeing Global Title prior Routeing the TCAP/SCCP message towards the Recipient Exchange. The Recipient Network need not make an own DB query since complete Routeing information is received at once. C a llin g S u b s c r ib e r D o n o r N e tw o r k R e c ip ie n t N e tw o r k P o r te d S u b s c r ib e r O r ig in a tin g N e tw o r k L a s t in g R e l at i o n T e m p o r a r y R e l at io n S S N o . 7 L E L E L E D B Figure 24: DB query and SCCP redirection performed by Originating LE DB query made, to retrieve a Routeing Global Title (RGT), by Originating LE prior sending out the TCAP/SCCP message. This principle is not backwards compatible to (Originating) Local Exchanges (e.g. outside NP domain) not intended/upgraded for Number Portability since required to have NP DB query capabilities. As also can be seen in the figure, the Donor Network is not involved in call set-up at all. This solution for Routeing of connection less services can be compared with the "all call query" Routeing solution for ordinary call set-up as outlined in subclause 6.4.3. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.2.2 Pros | The main advantages with this solution are that: a) the CCBS supplementary service is not dependent on the Donor Network/Exchange; b) only one transaction ID is used per CCBS request; c) efficient SCCP Routeing. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.2.3 Cons | The main disadvantages with this solution are that: a) the principle is not backwards compatible to (Originating) Local Exchanges not intended or not upgraded for Number Portability; b) the donor network should inform all other networks when modifying internal network structure, i.e. it does not allow for privacy for Network Operators. TR 101 118 V1.1.1 (1997-11) 45 8.4.3 SCCP routeing solutions in originating and recipient network/exchange |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.3.1 General description | In the solution outlined in figure 25, the NP DB query is made firstly at Signalling Gateway (SPR) level of Originating Network, i.e. the SCCP level traps, by analysing the received Global Title, TCAP/SCCP messages directed towards number series that are allowed for Number Portability makes a DB query, alternative a, to obtain a Routeing Global Title to Recipient Network, modifies the Global Title and routes the message onward to Recipient Network. The SPR of the Recipient Network traps the incoming TCAP message and makes a new DB query, alternative c, to obtain the Routeing GT of recipient Exchange) and routes the TCAP/SCCP message onward to Recipient Exchange. S S N o . 7 S P R S P R C a llin g S u b s c r ib e r D o n o r N e tw o r k R e c ip ie n t N e tw o r k P o r te d S u b s c r ib e r O r ig in a tin g N e tw o r k L as t in g R e lat i o n Te m p o r ar y R e l ati o n D B L E L E L E D B a b c S P R : S i g n al li n g P o in t w i th R e l ay f u n c ti o n s Figure 25: DB query and SCCP redirection performed at STP level The solution above also allows for cases where some Local Exchange, see alternative b in figure 25, perform the NP DB query according to figure 24 but other LEs leaves this task to the Originating (or even a Transit) SPR of the SS no.7 network. As also can be seen in the figure, the Donor Network is not involved in call set-up at all. The DB could very well coexist in every (or some of) the SPR, i.e. the NP data being replicated into the GTT for load sharing reasons. A variant of this solution is that the NP DB triggering point, i.e. the SPR, could also be enhanced to be collocated with a SSP/Service Control Point (SCP) or Service Switching and Control Point (SSCP), i.e. allowing IN techniques to be used to obtain the Routeing Global Title This would also allow the use of same NP DB for both call and connection less service Routeing, retrieving the same or differing Routeing information. This solution for Routeing of connection less services can be compared with the two step "all call query" Routeing solution for ordinary call set-up as outlined in subclause 6.6.1 and figure 12. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.3.2 Pros | The main advantages with this solution are that: a) network operators need not inform others when main changes in their internal network, i.e. privacy of network internals is maintained; b) thanks to "a" less administrative procedures between Networks. |
63690b205142be3574b7b253769796a3 | 101 118 | 8.4.3.3 Cons | The main advantages with this solution are that: a) several (at least two) DB queries are needed per TCAP/SCCP message to portable numbers, i.e. regardless number is ported-out or not (only one query needed if the called number is served by the Originating Network). TR 101 118 V1.1.1 (1997-11) 46 9 Proposed generic distributed functional entity model for number portability |
63690b205142be3574b7b253769796a3 | 101 118 | 9.1 General information | A functional structure is needed to ease allocation of the different NP related tasks required, the figure 26 below is a proposal of a generic Distributed Functional Entity Model for Number Portability. This subclause addresses only Routeing related aspects. The figure also depicts the functional entities and their relationship. CCF CCPF NPCF M-NPMF NPMF1 Network (1) Network (n) NPMFn CCF Call Control Functions CCPF Call Control Portability Functions NPCF NP Control Functions NPDF NP Data Functions NPMF NP Management Functions M-NPMF Master NPMF Real time functional entities Non Real time functional entities NPDF Figure 26: Functional entity model for number portability The definition of the functional entities (CCF, Call Control Portability Functions (CCPF), Number Portability Control Functions (NPCF), Number Portability Data Functions (NPDF), Number Portability Management Functions (NPMF) and M-NPMF), with respect to Service Provider Portability (NP) for both Geographic (GNP) and Non Geographic Number Portability (NGNP) is found in the following subclauses. Both Routeing and NP data management aspects of each functional entity is addressed, however no attempt is made to limit an individual Network Operators implementation of the functionality associated with each of the functional entities. In the scenario of e.g. an exchange internal "onward Routeing" solution by Donor LE: a) the CCF would have a trigger, e.g. a line category, on the ported-out number which would cause the CCPF interacting with NPCF; b) the NPCF would then interact with the NPDF to obtain the Routeing Information and then instruct the CCPF to introduce it into CCF Routeing data; c) the task of NPMF is then to: 1) load the translation table in NPDF; 2) set the triggering condition in CCF/CCPF; 3) maintain the NP control logic in the NPCF (if manageable). In the scenario of e.g. an "all call query" NP solution by Donor LE: a) the CCF would have triggers on number blocks allowing NP, which would cause calls to numbers part of these blocks cause the CCPF interacting with NPCF; TR 101 118 V1.1.1 (1997-11) 47 b) the NPCF would then interact with the NPDF to obtain the Routeing Information and then instruct the CCPF to introduce it into CCF Routeing data; c) the task of NPMF is then to: 1) load the translation table in NPDF; 2) set the triggering condition in CCF/CCPF; 3) maintain the NP control logic in the NPCF (if manageable). |
63690b205142be3574b7b253769796a3 | 101 118 | 9.2 Call Control Functions (CCF) | Call Control Functions (CCF), provides the functions for processing and control of Routeing of calls and services according to definitions in ITU-T recommendation Q.71. In a Number Portability environment it also provides call trap and triggering functionality to access Number Portability Functionality for calls to portable/ported numbers, depending on type of trigger.. |
63690b205142be3574b7b253769796a3 | 101 118 | 9.3 Call Control Portability Functions (CCPF) | CCPF which, associated with the CCF, provides a set of additional call control related functions that are required for the interaction between the CCF and the NPCF. It: a) extends the logic of the CCF to include recognition of Number Portability control triggers; b) extends the logic of the CCF to enable interaction with the NPCF; c) modifies call processing data, i.e. the Routeing Information, under the control of NPCF; d) interfaces and interacts with the NPCF; e) interfaces and interacts with the CCF; f) interfaces and interacts with the NPMF. |
63690b205142be3574b7b253769796a3 | 101 118 | 9.4 Number Portability Control Functions (NPCF) | NPCF provides functions that are required to command CCF, via CCPF, in the processing of a call to a ported number. It: a) contains the Number Portability logic and processing capability to obtaining Routeing Information for calls to portable/ported numbers; b) interfaces and interacts with the CCPF; c) interfaces and interacts with the NPDF; d) interfaces and interacts with the NPMF. |
63690b205142be3574b7b253769796a3 | 101 118 | 9.5 Number Portability Data Functions (NPDF) | NPDF contains a data mapping table, for real time access, giving Routeing Information for ported Numbers. The table is loaded and managed by NPMF. Other functions that are required: a) to ensure that only authorized access to NP data is given; b) interfaces and interacts with the NPCF; c) interfaces and interacts with the NPMF. TR 101 118 V1.1.1 (1997-11) 48 |
63690b205142be3574b7b253769796a3 | 101 118 | 9.6 Number Portability Management Functions (NPMF) | NPMF controls the management of Number Portability Data within the domain of a Network. NPMF also possibly adds and or modifies some NP data before data is distributed to the different Network Elements (NPDF). NPMF also requires that possible NP data replicated into more than one NE is kept consistent. In addition it also controls the setting of NP traps/triggers in CCPF and management of NP control logic in NPCF. 9.7 Master Number Portability Management Functions (M- NPMF) Master Number Portability Management Functions (M-NPMF), controls the management of Number Portability Data within one or several Number Portability Domains. This management function may only be needed in case NP data is centrally managed on a national or European Telephony Numbering Space (ETNS) numbers level. It also controls: a) the down loading of NP data to concerned Networks; b) that only authorized access to NP data is given; c) authentication of users; d) shadowing of stored data not to be distributed. 10 Service Provider Portability for Non-Geographic Numbers (NGNP) In principle the same problems, architectures and solutions are valid/possible for NGNP as for Geographic Number Portability (GNP) but the main difference is that NP Routeing Number cannot indicate any Recipient Exchange instead only Recipient Network, this since the recipient Exchange is determined by the Non Geographic Service Number itself and by the Recipient Network. This means that NP related procedures, for non geographic numbers, ends when Recipient Network is reached. 11 Concatenation of service provider portability for Non- Geographic Numbers (NGNP) and Geographic Numbers (GNP) It should be remembered that a Geographic Number might very well be the output after executing the NGN Service, this Geographic Number (GN) could in turn be ported, i.e. this means the concatenation of NGNP and GNP is a possible traffic case. This case is both applicable for call based Routeing and service (SCCP based) Routeing. TR 101 118 V1.1.1 (1997-11) 49 12 High Level examples for management of NP information |
63690b205142be3574b7b253769796a3 | 101 118 | 12.1 General Description | Management of Number Portability Data Base(-s) differ in complexity depending on Network solution, e.g. depending on if the NP data for a certain ported number only exists within the domain of Donor Network or if NP data is replicated over a number of Networks. Number portability domains could e.g. be structured to: a) all national Geographic Numbers; b) national Geographic Numbers but per NDC; c) all national non geographic numbers; d) national non geographic numbers per type of service; e) all national Mobile Station ISDN (MSISDN); f) ETNS numbers. NOTE: One should not forget that both call based Routeing and SCCP based Routeing need to be managed and that a least one of the managed network Elements stores the NP data that is accessed in real time. |
63690b205142be3574b7b253769796a3 | 101 118 | 12.2 NP data is donor network internal business | Despite the case that NP data is not distributed beyond Donor Network there still exists a number of Management options, i.e. one per type of NP DB distribution within the Donor Network. See figure 27 for a principal Network layout for management of NP data when data maintained within Donor Network only. A dm inistrativ e N um be r D a ta B a s e N e tw ork E le m ents (-s ) N e tw ork E le m ent M ana ge m ent Func tions D a ta B ase e.g. X .25 M F N E e.g. X .25 D on or N etw ork Figure 27: Principal network layout for management of np data when data is maintained within donor network only From a management architecture point of view minor modifications are needed when introducing NP and NP data is stored within Donor LE but on the other hand more advanced solutions might be used as well e.g. that NP DB is located TR 101 118 V1.1.1 (1997-11) 50 Exchange external. Regardless location of NP DB, modifications are still needed to allow storage of the NP Routeing Information. Despite NP data is maintained Donor network internally there are needs to have bilateral agreements on the content of NP DB e.g. the structure of Routeing Number. However no new interconnections to management systems are needed since down loading of NP information, from network external DB, is not needed in this case. This NP management solution supports only the "onward Routeing" and "Drop-back" NP solutions. This architecture supports the "Onward Routeing" case only. TR 101 118 V1.1.1 (1997-11) 51 |
63690b205142be3574b7b253769796a3 | 101 118 | 12.3 NP data is centrally managed per portability domain | In the case that NP data is managed per e.g. NDC or charging zones and also that NP data is replicated in several different network data bases a management architecture according to figure 28 can be foreseen. D a ta B as e D o m ain B D a ta B as e D o m ain N D a ta B as e D o m ain A A dm inis tra tiv e N um be r D a ta B a s e (-s ) N e tw ork E le m e nts N e tw ork E le m e nt M a na g e m e nt Fu nc tion s e .g . X .2 5 M F M F M F N E N E N E e .g . X .2 5 O pe ra to r 1 O pe ra to r 2 O pe ra to r n M F e .g . X .2 5 M -M F M F M F e .g . X .2 5 M F M a na g e m e nt Fu nc tion s M a s te r N um be r M a na g e m e nt Fu nc tion s Figure 28: Network layout for management of NP data when data is maintained nationally, per portability domain and when NP data is replicated in each of involved operators network From a management point of view this scenario brings in new interfaces/interconnections to networks for management of the Number portability data. This solution allows each of the Network providers to manage, e.g. distribute, data within their network. This NP management solution supports all described NP solutions, but is not needed in case of "onward Routeing" and "Drop-back" solutions. TR 101 118 V1.1.1 (1997-11) 52 |
63690b205142be3574b7b253769796a3 | 101 118 | 12.4 NP data is centrally managed on national level | In the case that Master NP data is managed centrally on national level, and distributed to networks according to figure 29, all networks have access to the same data regardless portability domains being part of. This means less interconnections for networks involved in many portability domains. N E e . g . X . 2 5 N E N E M F M F M F A d m in is tr a tiv e D ir e c to r y N u m b e r A g e n c y D a ta B a s e N e tw o r k E le m e n t M a n a g e m e n t F u n c tio n s D a t a B a s e O p e ra to r 1 O p e ra to r 2 O p e ra to r n N e tw o r k E le m e n t(s ) e . g . X . 2 5 M -M F e . g . X . 2 5 M a s te r M a n a g e m e n t F u n c tio n s , N a tio n a l L e v e l Figure 29: Network layout for management of NP data when data is maintained nationally, and when NP data is replicated in each of involved operators network This NP management solution supports all described NP solutions, but is not needed in case of "onward Routeing" and "Drop-back" solutions. |
63690b205142be3574b7b253769796a3 | 101 118 | 12.5 NP data is centrally managed on European level | The ETNS is probably best management as an own NP domain, i.e. separated from national portable numbers, since data is managed on European level. For further information see TR "Number Portability for pan-European services". TR 101 118 V1.1.1 (1997-11) 53 Annex A A.1 Current proposals on solutions for Number Portability A.1.1 Introduction There exist a number of different proposals for implementing number portability in the public switched telephony network (PSTN) and the Integrated Services Digital Network (ISDN). Note, the vocabulary within this annex does not always follow the one used in the main report, instead the vocabulary used reflects the publicly discussed solution. The proposals can be divided in the following main types: - central Database; - drop-back from donor; - call Forwarding by donor; - non-Geographic Number. In the Central Database solutions the databases contain the relationship between the subscriber directory number and a routeing number used for routeing in the network. The actual routeing number can be the subscriber number prefixed with some kind of operator or even exchange identity or be a pure routeing number, like the Roaming Number used in the GSM network and in the ETSI CTM drafts. The Drop-back solutions make use of the 'drop back' feature in the signalling network. When an exchange analyses the called number and detects that the number has been ported out from the exchange, the call is released with some information that can be used by a proceeding exchange that performs necessary re-routing. The Call Forwarding solution makes use of the Call Forwarding Unconditional function in the exchange from where the number has been ported. The forwarded to number is the address to the current serving network or even exchange of the ported subscriber. This solution has the mayor drawback of impacting a lot of Supplementary Services. The Non-Geographic Number solution requires that when a subscriber is ported for the first time he/she should change to a non Geographic (e.g. Personal) number. After this the subscriber can keep the number at any future porting. New subscribers can immediately receive a non-geographic number like e.g. an UPT number or PN. This solution then requires a number portability solution for non geographic numbers only. This solution has not been further elaborated in this report as it initially will force subscribers to change the directory number. This solution is used in Finland for nation wide NP. Several solutions/methods have been proposed for providing number portability, the different methods can be grouped as follows: Call Forwarding methods: - Simple Call Forwarding Unconditional (CFU); - Remote Call Forwarding (RCF). Drop-back methods: - Query on Release (QoR); - Return to Pivot (RTP). Central Database methods: - Call Completion to Portable Number (CCPN); TR 101 118 V1.1.1 (1997-11) 54 - Local Area Number Portability (LANP); - Carrier Portability Code (CPC); - Network Routeing Prefix (NRP); - Generic Routeing Method (GRM); - Query on Release (QoR). A.1.2 Simple Call Forwarding Unconditional (CFU) In the described example the Call Forwarding Unconditional (CFU) function is used to reroute the call from the donor exchange to the recipient network or/and exchange. The additional problem with this solution, compared to Remote Call Forwarding, is that the CLI as presented to called party might indicate the called party number since this is the number that caused the forwarding in the donor exchange. Depending on Call Forwarding parameters used also some Supplementary services (e.g. U-U-1) might not work, i.e. it is an option weather or not U-U-1 shall be transported at call forwarding. Problem areas are otherwise similar as the ones for RCF. This solution is only regarded as a very interim such. A.1.3 Remote Call Forwarding (RCF) In the Remote Call Forwarding differs from the Call Forwarding function in the way that it allow for correct presentation of CLI and does not restrict supplementary services being forwarded transparently to recipient exchange/network (it can be compared with Onward routeing in the main report). The main drawbacks are that since the donor exchange is involved, the service level of the call is depending on the one available on the used interconnection protocols and the donor exchange. One should also consider services that normally do not work over operator borders are e.g. (Carrier Selection (CS), CUG, U-U. The CUG and U-U services might result in call being released at the interconnection point due to service requirements, e.g. CUG without outgoing access or U- U-1 essential. Regarding the CS we might have legal problems since CS decision might be wrong by the donor, it can also be questioned if the donor network is allowed to be routed through at all if CS tells else. One can here consider the case that originating and destination network operators have agreements on transfer/inter- networking for CLIP, COLP, CUG, CS and U-U but the same agreements do not exist between donor and recipient network, i.e. the service level would differ for calls to ported subscribers compared to calls to non ported subscribers. One can also assume that cost effective routeing can not be performed with this type of solution, the call might in worst case be trombone back to originating network. The solution is in service in UK and is planned for Germany. Both UK and Germany forward the call by using a prefix 5xxxxx and Dxxx respectively but without modifying the NOA. France intend to use x0xxx as identification of a routeing number. A.1.4 Return To Pivot (RTP) This is a method originally proposed by Pacific Bell but already exists as different variants in a number of markets, this is the method that usually is referred to as Drop-back. RTP uses extended switching capabilities to accomplish portability. Calls using RTP will attempt to complete, as they presently do, to a switch that is assigned the dialled number serie. If the dialled number has been ported from the switch, the call will be released back to a previous switch (Pivot switch) in the call path for re-routing to its new location. The re-routing information (RI), obtained from a central database or locally stored in the switch, are included in the release message sent back in the network to be able to reach the new location from the re-routing exchange. The Pivot switch indicates to succeeding exchanges with information (CI) sent in set-up message that it is Pivot capable and thus drop-back is possible. TR 101 118 V1.1.1 (1997-11) 55 This method is not seen as a long term solution for the introduction of service provider portability since it favours the incumbent service providers. Even though a subscriber has been ported to another service provider all calls will first be directed to the donor service provider which then will have control over the call. This also means that the donor service provider will be favoured since resources are used in its domain and accounts has to be settled which then favours the donor service provider. The method also prohibits the service provider of the originating switch to perform optimal routeing in its own network before eventually breaking out to another service providers network. As a rule, a service provider would like to keep the call within its own network as long as possible to avoid unnecessary settlements of accounts between operators. This method could though be used for location portability, but when the number of ported subscribers increases this will cause inefficient routeing and bad utilization of network resources. A.1.5 Query on Release (QoR) This is a method originally proposed by Nortel. This feature is very similar as Return To Pivot. When using QoR the initiating switch sets a QoR attempt indicator and routes the call to the donor service providers switch. The switch determines whether it serves the called user. If it does not serve the called user and the call request contains the QoR attempt indicator, it releases the call back to the originating switch with an indication that the user is no longer served on the donors switch. The donors switch handles all other calls using existing procedures. Based on the release information, the initiating switch obtains a network routeing number for the called user's terminating switch, clears the QoR attempt indicator, and completes the call. The network routeing number can be obtained by the originating switch by interrogating a database located either internally in the switch or external from the switch. A.1.6 Call Completion to Portable Number (CCPN) This is a method originally proposed by AT&T, and is in US considered the best long-term solution for the wireline networks in US. AT&T has also a proposal for wireless networks which uses the AT&T LRN scheme for call set-up. As it seems now, US will go for the CCPN solution and work is already being done in ANSI T1S1 to include the CCPN method in the ANSI standard. In this method, each portable number is associated with a Network Routeing Number (NRN) for this switch. When a number is dialled by a calling subscriber to reach the intended subscriber, the first switch that can query a number portability database will do so. The response will be the NRN which is the node address to the switch were the called subscriber is served. The method proposes an modification of the ISUP signalling system, so that the NRN will be included as CdPN in the set up message to be sent off and used for further routeing in the network. The dialled digits will be included in Generic Number (in US called Generic Address Parameter, GAP) with a new number qualifier. A new field in Forward Call Indicator will be set to indicate if a database query has been performed, this to prevent several queries to be made. The terminating switch will substitute the NRN included in CdPN with the actual dialled digits stored in Generic Number parameter and do a seizure attempt towards the called subscriber. The Service Management aspects include both updates of the database as well as updating of GTT data. This means that there is a need for each ported subscriber to have an update in the Signalling Transfer Point (STP), translation data, for some subscriber services such as CCBS, CCNR and SMS services. This means that the updates to the database and the GTT data should be synchronized and handled within one transaction to maintain consistency. The subscriber line allocation/de-allocation is not taken into consideration. This is also valid for the next method described. A proposal exists to also solve the SCCP using services by use of same database(-s), this by introducing a QoR procedure in the SCCP. SCCP shall then make the DB query in the case a SCCP message is rejected (by donor). The retrieved data is optionally also stored in the GTA, i.e. GTT will then be self provisioning. After this procedure the SCCP message is re-routed to recipient exchange. TR 101 118 V1.1.1 (1997-11) 56 The main drawbacks with this solution are that the SCCP tables will after a while be enormous and that donor exchange/network is loaded with failing SCCP messages a period after that a subscriber is ported out. A.1.7 Local Area Number Portability (LANP) This is a method originally proposed by U.S Intelco, Stratus Computer and Electric Lightwave Inc. The LANP method is functionally a superset of LRN, the main difference between the CCPN and LANP methods is that the LANP only defines the inter-work interfaces in the network, but does not mandate or constrain the internal implementation in switches of the NP functionality amongst competing carriers. The LANP method uses two "domains" of 10-digit numbers to route telephone calls to customer that have transferred the numbers to new carriers or new geographic locations. Specifically, LANP assigns a ten-digit customer number address (CNA) to each subscriber; this is the number that callers would dial to place telephone calls to the particular subscriber. It also assigns each customer a 10-digit network address (NNA) that identifies where in the telephone network to reach the particular subscriber. Both the CNA and NNA are stored in routeing databases so that carriers can determine from the dialled number where in the network to reach the called party. The LANP method does not mandate how a specific NNA is interpreted in the terminating switch of a ported line, either the CNA or NNA values may be used to translate the incoming call to the intended subscriber facilities. In other words, the LANP is functionally a superset of CCPN, as the NNA can be assigned the NRN value and CNA can be used to locate the subscribers facilities in the same way as in the CCPN method. The method proposes the same modification of the signalling system as the CCPN method. A.1.8 Carrier Portability Code (CPC) This is a method originally proposed by MCImetro. CPC is a method that uses a Number Portability database to obtain the routeing information necessary to terminate calls to subscribers that have been ported. Each service provider are assigned a unique three-digit Carrier Portability Code (CPC) in each number portability area (within a LATA). To be noticed is that CPCs and NPAs are not allowed to overlap which then also means that CPCs can be reused in another portability area i.e. LATA. As can be seen from this method is that the called party number is destroyed since the NPA part of the NANP number is replaced with the CPC. One of the reasons for this is that the number length in US is always 7 or 10 digits. If the CPC just would be prefixed to the called party number this would most probably cause major impact on existing switching systems in US. The CPC method does not require any updates of the signalling systems, both the Multi-Frequency (MF) and Signalling System 7 (SS7) can be used. The CPC method is related to the Network Routeing Prefix (NRP) solution, the main difference is that in NRP solution a prefix is added to the called party number which means that the dialled number is not destroyed which is the case for CPC. A.1.9 Network Routeing Prefix (NRP) The main principle is the same as the LRN (the use of a central database) and CPC (routeing principle) methods, The NRP method is based on using a central database to administer all the addresses and have the relation between a subscriber directory number and the address to which node the subscriber resides on in form of a Network Routeing Prefix (NRP). No new signalling information is required compared to both LRN and NRA. The NRP might either indicate the receiving operators network (gateway) or indicate the full address to the recipient exchange. An other difference is that it proposes using the Type Of Number (TON) to indicate that the CdPN contains NRP + Called Party Number, this saves digits in the CdPN, e.g. the starting 5 and 7 in the UK and German solutions can be omitted in transmissions. The method also allows for several TON values to be used, e.g. one value indicating NRP being a Network ID and an other telling Exchange ID. TR 101 118 V1.1.1 (1997-11) 57 When a call is made towards a subscriber, the dialled digits are analysed in the originating local exchange and a query is done towards a central database to get the NRP. The NRP is added as a prefix before the called subscriber number. NRP is then used for routeing the call to the called party network or to the recipient switch if the called party is within home network. In the recipient LE the NRP is recognized as "own" and removed, thereafter the number is used for performing the call set up according to existing principles. The NRP can optionally be removed, in the gateway exchange prior leaving to other network, in case the other network uses an own DB for its network internal routeing. This then results in no extra information being sent on operator borders. The method does not require any modifications of the signalling systems. A specific value of the TON is used to indicate the existence of NRP and implicitly also that a database query has been performed. The Service Management aspects includes only SMS updates of the portability database. It is assumed that the number series are defined in the LE by ordinary LE management systems. This leaves the update of moved subscribers in the database to the SMS system. The database Query could optionally be performed in the first transit exchange in the originating Network. A.1.10 Generic Routeing Method (GRM) This solution has originally been proposed by KPN. The Generic Routeing Method is very similar to CCPN solution, the main difference is that the database query is only performed either prior to leaving the originating network or as a QoR procedure. The NRN is not sent over operator borders. This solution has some advantages since it does not involve the donor network. It requires similar modifications in the signalling protocols as the NRN solution. TR 101 118 V1.1.1 (1997-11) 58 History Document history V1.1.1 November 1997 Publication ISBN 2-7437-1815-3 Dépôt légal : Novembre 1997 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 1 Scope | The term PCI stands for Programmable Communication Interface, sometimes also referred to as Programming Communication Interface. A PCI presents a specialized Application Program Interface (API) that is related to the communications aspects of software. The present document deals with the requirements of PCIs for multimedia applications, i.e. digital applications that combine independent isochronous and asynchronous media types together. Multimedia applications can be interactive or not. They may use and/or present different types of media either in context, or simultaneously or in loose conjunction with each other. Different types of applications and different types of media like audio, video, voice or images, impose different requirements onto the terminal equipment and the underlying communications networks. The impact of those applications and media, and the abilities of the communications networks are studied thoroughly. The demands of the (human) users are considered carefully. The present document analyses the different requirements by applying different viewpoints, which illuminate the viewpoint-specific impacts and demands. The summary of the results form a general list of requirements for PCIs for multimedia applications. Those requirements are then compared against existing PCIs. As result a detailed list of requirements for each type of PCI is obtained. Moreover, the present document structures the existing and future PCIs in accordance with existing PCI models and discusses briefly the need for future extension or creation of specific PCIs. The general title of the present document reads "Generic PCI for multimedia applications". Since this title might mislead the reader in the sense that possibly one - and only one - PCI might exist that covers all the applications needs, the reader should note that the complexity of multimedia applications disallows this approach. Several - in nature completely different - PCIs will be needed to cover the world of multimedia applications. This becomes even more apparent, if it is considered that future multimedia applications will probably extend to run in new kinds of terminal equipment that is not even yet available. The present document identifies the Programmable Communication Interfaces (PCIs) needed for today and future multimedia aware applications. It points out: - what kind of PCIs are needed; - what kind of features those PCIs shall provide; - what kind of suitable PCIs are already defined (or standardized) by standardization bodies; - how existing definitions of those PCIs should be extended to cover the needs of multimedia aware applications. TR 101 170 V1.1.1 (1998-05) 7 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 2 References | The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, subsequent revisions do apply. A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. [1] TCR-TR 026 (1994): "Terminal Equipment (TE); Multimedia Project Plan". [2] ITU-T Recommendation F.581 (1993): "Guidelines for Programming Communication Interfaces (PCIs) definition: service Recommendation". [3] ITU-T Recommendation I.374 (1993): "Framework Recommendation on network capabilities to support multimedia services". [4] ITU-T Recommendation I.112 (1988): "Vocabulary of terms for ISDNs". [5] ETR 173 (1995): "Terminal Equipment (TE); Functional model for multimedia applications". [6] ETR 225 (1995): "Terminal Equipment (TE); Application Programming Interface (API) and script representation for MHEG; Requirements and framework". [7] ETR 084 (1993): "Terminal Equipment (TE); Multimedia & Hypermedia Information Retrieval Services (M&HIRS), Investigation of candidate architectures for M&HIRS". [8] ETR 181 (1995): "Terminal Equipment (TE); Multimedia portfolio; A compilation of multimedia applications and services provided by ETSI members". [9] ETR 368: "Terminal Equipment (TE); General architecture for Programming Communication Interfaces (PCIs)". [10] ETS 300 243-1 (1995): "Terminal Equipment (TE); Programmable Communication Interface (PCI) APPLI/COM for facsimile group 3, facsimile group 4, teletex and telex services Part 1: ITU- T Recommendation T.611 (1992) [modified]". [11] ITU-T Recommendation T.611 (1994): "Programmable Communication Interface (PCI) APPLI/COM for facsimile group 3, facsimile group 4, teletex, telex, E-mail and file transfer services". [12] ETS 300 325 (1994): "Integrated Services Digital Network (ISDN); Programming Communication Interface (PCI) for Euro-ISDN". [13] ETS 300 325 second edition (June 1995): "Integrated Services Digital Network (ISDN); Harmonized Programming Communication Interface (PCI) for ISDN". [14] WinISDN, An Open Specification for ISDN voice and data communications under Microsoft Windows. Internet: http://www.microsoft.com [15] ITU-T Recommendation I.211 (1993): "B-ISDN service aspects". [16] ETS 300 382 (1995): "Terminal Equipment (TE); Videotex Enhanced Man Machine Interface service (VEMMI)". [17] ITU-T Recommendation T.122 (1993): "Multipoint communication service for audiographics and audiovisual conferencing service definition". TR 101 170 V1.1.1 (1998-05) 8 [18] ITU-T Recommendation T.123: "Network specific data protocol staks for multimedia conferencing". [19] ITU-T Recommendation T.124 (1994): "Generic conference control". [20] ITU-T Recommendation T.125 (1994): "Multipoint communication service protocol specification". [21] ITU-T Recommendation T.126 (1994): "Multipoint still image and annotation protocol". [22] ITU-T Recommendation T.127 (1994): "Multipoint binary file transfer protocol". [23] ITU-T Recommendation T.434 (1992): "Binary file transfer format for the telematic services". [24] ITU-T Recommendation H.261 (1993): "Video codec for audiovisual services at p x 64 kbit". [25] ITU-T Recommendation G.711 (1988): "Pulse Code Modulation (PCM) of voice frequencies". [26] ITU-T Recommendation G.722 (1993): "7 kHz audio-coding within 64 kbit/s". [27] ITU-T Recommendation G.728 (1992): "Coding of speech at 16 kbit/s using low-delay code excited linear prediction". [28] ISO/IEC 13522 (1995): "Information Technology - Coding of Multimedia and Hypermedia Information" Part 1: "MHEG Object Representation, Base notation (ASN.1)". Part 2: "Alternate notation (SGML)". Part 3: "MHEG Extension for Scripting Language Support". Part 4: "Registration Procedure for Format Identifiers". Part 5: "MHEG Subset for Base Level Implementation". [29] Internet Draft (1995): "HTML 2.0". [30] ETR 296: "Multimedia; Standardization areas to be covered". [31] Microsoft MAPI specifications (1995). Internet: http://www.microsoft.com [32] Microsoft TAPI specifications (1995). Internet: http://www.microsoft.com [33] TRIBUNE Application Programming Interface - Framework document. Internet: http://www.cellware.de [34] ITU-T Recommendation T.50 (1992): "International reference alphabet". [35] ITU-T Recommendation T.51 (1992): "Latin based coded character sets for telematic services". [36] ITU-T Recommendation T.52 (1993): "Non-latin based coded character sets for telematic services". [37] ISO/IEC 11172 (1993): "Coding for moving pictures and associated audio for storage media up to about 1,5 Mbit/s". [38] ISO/IEC 13818 (1994): "Generic coding of moving pictures and associated audio information". [39] ISO/IEC 10918 (1989): "Digital compression and coding of continuous-tone still images". [40] ITU-T Recommendation H.320 (1993): "Narrow-band visual telephone systems and terminal equipment". [41] ITU-T Draft Recommendation H.32Y: "Adaptation of H.320 terminals to B-ISDN". [42] ETS 300 383 (1995): "Integrated Services Digital Network (ISDN); File transfer over the ISDN EUROFILE transfer profile". TR 101 170 V1.1.1 (1998-05) 9 [43] ETS 300 388 (1995): "Integrated Services Digital Network (ISDN); File Transfer Access and Management (FTAM) over ISDN based on simple file transfer profile". [44] RFC 959 (1985): "File Transfer Protocol". [45] ITU-T Recommendation T.522 (1992): "Communication application profile BT1 for document bulk transfer". [46] ITU-T Recommendation T.435: "Document Transfer and Manipulation (DTAM) - Services and protocols - Abstract service definition and procedures for confirmed document manipulation". [47] ITU-T Recommendation T.436: "Document Transfer and Manipulation (DTAM) - Services and protocols - Protocol specifications for confirmed document manipulation". [48] ISO/IEC 8613 (1989): "Information processing - Text and office systems - Office Document Architecture (ODA) and interchange format". Part 1: Introduction and general principles. Part 2: Document structures. Part 3: Abstract interface for the manipulation of ODA documents. Part 4: Document profile. Part 5: Office Document Interchange Format (ODIF). Part 6: Character content architectures. Part 7: Raster graphics content architectures. Part 8: Geometric graphics content architectures. Part 9: Audio content architectures. Part 10: Formal specifications. Part 11: Tabular structures and tabular layout. Part 12: Identification of document fragments. Part 14: Temporal structures and non-linear structures". [49] ITU-T Recommendation X.224 (1993): "Information technology - Open Systems Interconnection - Protocol for providing the OSI connection-mode transport service". [50] ITU-T Recommendation X.400 (1993): "Message Handling Service (MHS) System and Service Overview". [51] RFC 822 (1982): "Standard for the format of ARPA Internet text messages". [52] ETS 300 072 (1990): "Terminal Equipment; Videotex presentation layer protocol Videotex presentation layer data syntax". [53] ETS 300 073 (1990): "Videotex presentation layer data syntax Geometric display (CEPT Recommendation T/TE 06-02, Edinburgh 1988)". [54] ETS 300 074 (1990): "Videotex presentation layer data syntax; Transparent data (CEPT Recommendation T/TE 06-03, Edinburgh 1988)". [55] ETS 300 075 (1994): "Terminal Equipment (TE); Processable data File transfer". [56] ETS 300 076 (1994): "Terminal Equipment (TE); Videotex Terminal Facility Identifier (TFI)". [57] ETS 300 177 (1995): "Terminal Equipment (TE); Videotex Photographic Syntax". [58] ETS 300 149 (1992): "Terminal Equipment (TE); Videotex Audio Syntax". [59] ETS 300 223 (1993): "Terminal Equipment (TE); Syntax-based Videotex Common end-to-end protocols". [60] ETS 300 079 (1991): "Integrated Services Digital Network (ISDN); Syntax-based videotex End- to-end protocols, circuit mode DTE-DTE". [61] ETS 300 222 (1993): "Terminal Equipment (TE); Framework of Videotex terminal protocols". [62] RFC 793 (1981): "Transport Control Protocol". TR 101 170 V1.1.1 (1998-05) 10 [63] RFC 791 (1981): "Internet Protocol". [64] ETR 227 (1995): "Multimedia Applications and Services; Inband and outband signalling protocols; A survey". [65] Windows Sockets 2 Application Programming Interface (1995): "An Interface for Transparent Network Programming Under Microsoft Windows Revision 2.0.8". [66] Windows Sockets 2 Service Provider Interface (1995): "A Service Provider Interface for Transparent Network Programming under Microsoft Windows Revision 2.0.8". [67] Windows Sockets 2 Protocol-Specific Annex (1995): "Revision 2.0.1". [68] RFC 1738 (1994): "Uniform Resource Locators (URL)". [69] ITU-T Recommendation Q.931 (1988): "ISDN user-network interface layer 3 specification for basic call control". [70] ITU-T Recommendation H.221 (1993): "Frame structure for a 64 kbit/s to 1920 kbit/s channel in audiovisual teleservices". [71] IMTC GCC API (1995). Internet: ftp://ftp.imtc-files.org/pub/AP-AG/TECH/CD/GCC_API/ [72] IMTC MCS API (1995). Internet: ftp://ftp.imtc-files.org/pub/AP-AG/TECH/CD/MCS_API/ [73] ITU-T Draft Recommendation T.XAPI (1995): "eXtensive Application Programming Interface" [under preparation in ITU-T SG8 Q1, Q8, Q10, Q15]. [74] ITU-T Draft Recommendation X.434 (1996): "CMC 2.0" [under preparation in ITU-T SG7]. [75] EIA/TIA Standard (1990): "Asynchronous Facsimile DCE Control Standard". [76] ITU-T Recommendation T.31 (1995): "Asynchronous facsimile DCE control - Service class 1". [77] ITU-T Recommendation T.32 (1995): "Asynchronous facsimile DCE control - Service class 2". [78] ISO/IEC 8879 (1986): "Standard Generalized Markup Language (SGML)". [79] ISO/IEC 9070 (1990): "Registration procedures for public text owner identifiers". [80] TC-TR 004: "Interworking between Videotex and Internet: Retrieval aspects of Hypertext Markup Language (HTML) documents". [81] Sun Microsystems JAVA specifications (1995). [82] RFC 147 (1971): "Definition of a socket". [83] ITU-T Recommendation Q.922 (1992): "ISDN data link layer specification for frame mode bearer services". [84] ITU-T Recommendation V.14 (1993): "Transmission of start-stop characters over synchronous bearer channels". [85] ITU-T Recommendation V.34 (1994): "A modem operating at data signalling rates of up to 33 600 bits for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuits". [86] ITU-T Recommendation X.21 (1992): "Interface between Data Terminal equipment (DTE) and Data Circuit-terminating Equipment (DCE) for synchronous operation on public data networks". [87] ITU-T Recommendation X.21bis (1992): "Use on public data networks of Data Terminal Equipment (DTE) which is designed for interfacing to synchronous V-series modems". TR 101 170 V1.1.1 (1998-05) 11 [88] ITU-T Recommendation X.25 (1992): "Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit". [89] ITU-T Recommendation I.430 (1993): "Basic user-network interface - Layer 1 specification". [90] ITU-T Recommendation I.431 (1993): "Primary rate user-network interface - Layer 1 specification". [91] ITU-T Recommendation X.31 (1993): "Support of packet mode terminal equipment by an ISDN". [92] ITU-T Recommendation R.140 (1988): "Definitions of essential technical terms in the field of telegraph transmission". [93] IEEE MultiMedia Journal, 1070-986X/95 (Fall 1995): "Network Evolution and Multimedia Communication", by Heinrich J. Stüttgen, IBM European Networking Center. [94] Diplomarbeit of Sandra Hornig and Ralf Kupper, Deutsche Telekom, Fachhochschule Dieburg (1995): "Optimierung von Benutzerschnittstellen für Multimedia-Anwendungen unter ergonomischen Aspekten". [95] IEEE 802. [96] PC Professionell (German Edition, October 95), Page 72: "Standards für Videokonferenzsysteme". [97] ITU-T Recommendation G.703 (1991): "Physical/electrical characteristics of hierarchical digital interfaces". [98] ITU-T Recommendation I.365 (1993): "Frame relaying service specific convergence sublayer (FR- SSCS)". [99] ITU-T Recommendation X.36 (1993): "Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for public data networks providing frame relay data transmission service by dedicated circuit". [100] ITU-T Recommendation I.361 (1993): "B-ISDN ATM layer specification". [101] ITU-T Recommendation I.363 [Rev. 2] (1994): "B-ISDN ATM adaptation layer (AAL) specification". [102] ETS 300 217 (1992): "Connectionless Broadband Data Service (CBDS)". [103] TS GSM 05.01: "European digital cellular telecommunications system (Phase 1); Physical Layer on the Radio Path (General Description)". [104] TS GSM 07.01: "European digital cellular telecommunications system (Phase 1); General on Terminal Adaptation Functions for MSs". |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 3 Definitions, symbols and abbreviations | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 3.1 Definitions | For the purposes of the present document the following definitions apply. In case the definition is taken from another source, the reference to the source is indicated in square brackets at the end of the definition. asynchronous: Unrestricted transmission delay for each message [93]. isochronous: Constant transmission delay for each message [93]. NOTE: The official ITU definition is much more complicated and can be found in [92]: TR 101 170 V1.1.1 (1998-05) 12 isochronous: Pertaining to a signal or a time-varying phenomenon characterized by significant instants separated by time intervals having a duration theoretically equal to the duration of a unit interval or to an integral multiple of this duration. medium: A means by which information is perceived, expressed, stored or transmitted [3]. multimedia application: A digital application that combines independent isochronous and asynchronous media types together. The multimedia application can be interactive or otherwise. multimedia: The property of a piece of information, an application, a user equipment, to handle several types of data [3]. provider: The abstract entity that offers one or more (tele-)communications services [9]. synchronous: Bounded transmission delay for each message [93]. user: The abstract entity of a communication system that uses one or more (tele-)communications services [9]. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: AAL ATM Adaptation Layer ADSL Asymmetrical Digital Subscriber Line API Application Program Interface, sometimes also referred to as Application Programming Interface ATM Asynchronous Transfer Mode AVI Microsoft Audio Video Interleaved B-ISDN Broadband Integrated Services Digital Network BFT Binary File Transfer BMP Windows Device-Independent Bitmap CAD Computer Aided Design CATV Community Antenna TV or Cable TV CBDS Connectionless Broadband Data Service CD Compact Disc CD-ROM Compact Disc - Read Only Memory CGM Computer Graphics Metafile CODEC Coder-Decoder CSPDN Circuit-Switched Public Data Network DAVIC Digital Audiovisual Council DCE Data Communications Equipment DCT Discrete Cosine Transform DSM-CC Digital Storage Media Control Command DTMF Dual Tone Modulation Frequency DTAM Document Transfer and Manipulation DTAM-BT-NM Document Transfer and Manipulation - Bulk Transfer - Normal Mode DTE Data Terminal Equipment DVB Digital Video Broadcasting DVI Intel Digital Video Interactive ETR ETSI Report ETS European Telecommunications Standard FDDI Fibre Distributed Data Interface FR-SSCS Frame relaying service specific convergence sublayer FTAM File Transfer, Access and Management FTP File Transfer Protocol GCC Generic Conference Control GIF CompuServe Graphics Interchange Format GSM Global System for Mobile communications HCI Human Computer Interface HDSL High bitrate Digital Subscriber Line HDTV High Definition Television HTML Hyper Text Markup Language TR 101 170 V1.1.1 (1998-05) 13 HTTP Hyper Text Transfer Protocol IEC International Electrotechnical Commission IETF Internet Engineering Task Force IMTC International Multimedia Teleconferencing Consortium IP Internet Protocol IPX Internetwork Packet eXchange protocol (Novell Inc.) IPng Internet Protocol Next Generation ISDN Integrated Services Digital Network ISO International Standards Organization ITU-T International Telecommunications Union - Telecommunications sector JPEG Joint Photographic Experts Group JBIG Joint Bi-level Image Experts Group LAN Local Area Network LLC Link Layer Control MAC Media Access Control MAN Metropolitan Area Network MAPI Messaging Application Programming Interface MCS Multipoint Communications Service MCU Multipoint Control Unit MHEG Multimedia and Hypermedia Experts Group MHS Messaging Handling System MIDI Musical Instruments Digital Interface MIME Multipurpose Internet Mail Extension MJPEG Moving JPEG MBFT Multipoint Binary Filetransfer MPEG Moving Picture Experts Group N-ISDN Narrowband Integrated Services Digital Network NDIS Network Device Interface Specification ODA Open Document Architecture ODI Open Datalink Interface OS Operating System OSI Open System Interconnection PBX Private Branch Exchange PCI Programmable Communication Interface, sometimes also referred to as Programming Communication Interface PCM Pulse Code Modulation PDU Protocol Data Unit POTS Plain Old Telephone Service PSPDN Packet-Switched Public Data Network PSTN Public Switched Telephone Network QoS Quality of Service RFC Request For Comment SBV Syntax-Based Videotex SCF Synchronization and Convergence Function SGML Standard Generalized Markup Language SMDS Switched Multimegabit Data Service SPI Service Provider Interface SPX Sequenced Packet eXchange protocol (Novell Inc.) SSL Secure Sockets Layer TAPI Telephony Application Programming Interface or TRIBUNE Application Programming Interface TCP Transport Control Protocol TIA Telecommunications Industries Association TIFF Tagged Image File Format TSAPI Telephony Services Application Programming Interface UNI User Network Interface URL Uniform Resource Locator VDSL Very high bandwidth Digital Subscriber Line VEMMI Videotex Enhanced Man-Machine Interface VoD Video on Demand WAN Wide Area Network TR 101 170 V1.1.1 (1998-05) 14 WAV Windows audio WAVeform file format WMF Windows MetaFile WOSA Windows Open System Architecture WWW World Wide Web XAPI eXtensive Application Programming Interface X/OPEN the X/Open Company, Ltd. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 4 Reader's guideline | The creation of the present document was facilitated by the existence of several recommendations, reports or surveys from various sources that present multimedia models and summarize different aspects of multimedia applications To guide the reader quickly through the most important sources for the present document, a (non-exhaustive) list of the documents providing those overall aspects is given in table 1. Table 1: Documents dealing with overall aspects of multimedia applications Document Reference Title ITU-T Recommendation I.211 [15] B-ISDN service capabilities ETR 173 [5] Functional model for multimedia applications ETR 181 [8] Multimedia Portfolio; A compilation of multimedia applications and services provided by ETSI members ETR 227 [64] Multimedia Applications and Services; Inband and outband signalling protocols; A survey ETR 296 [30] Multimedia; Standardization areas to be covered The remainder of the present document is structured into four logical sections as shown in table 2. Table 2: Logical sections of the present document Section which comprises… that… 1st logical section clause 5 (5 Methodology) …presents the description of the methodology chosen, 2nd logical section clause 6 (6 PCI aspects) …briefly introduces the PCI model and summarizes existing and future PCIs that are under development, 3rd logical section clause 7 (7 Summary of results) …contains the "management summary", i.e. the summary of the results obtained, 4th logical section clauses 8…13 …holds the detailed information, requirements and demands that lead to the results summarized in clause 0. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5 Methodology | For the purpose of the present document it is essential to apply a methodology that ensures a complete analysis of requirements and demands put onto PCIs for multimedia applications. Since the world of multimedia applications is complex, the present document cuts it down into manageable pieces. Different viewpoints are applied to the terminal equipment that runs the multimedia applications. Like in a beam of a torch the viewpoints are illuminated and the specific requirements are isolated. Figure 1 depicts this method and shows the viewpoints applied. Because the material used is huge and wide spread, it is a fair hope that all the important aspects of multimedia applications are considered. TR 101 170 V1.1.1 (1998-05) 15 Network View Media View Application Class View Service View 3&,IRU 0XOWLPHGLD User View Figure 1: Viewpoints applied to structure requirements of the PCI for multimedia applications |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5.1 Application class view | Multimedia applications are structured into classes. The individual requirements of each application class are isolated and studied. Clause 8 presents the application class view in detail. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5.2 User view | Users of multimedia applications belong to one of these three classes: information producer, information manager and information consumer. Clause 9 presents the user view in detail. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5.3 Media view | The transport, coding and synchronization aspects of the possible media are studied. The requirements imposed are filtered out and analysed. Clause 10 presents the media view in detail. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5.4 Service view | Multimedia application specific services, such as teleconferencing or other multipoint control services are studied and the requirements are carefully pondered. The consideration of the service view takes most attention, since implementations are rare and thorough experience with this new kind of services is not yet widely available. Clause 11 presents the service view in detail. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 5.5 Network view | Existing and prospected networks and architectures are summarized. From this, requirements regarding parameters for controlling and accessing the communications network are derived. Clause 12 presents the network view in detail. TR 101 170 V1.1.1 (1998-05) 16 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6 PCI aspects | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.1 PCI model | The present document regards a PCI as a sort of API, located within a terminal equipment that deals with the communications aspects of an application. For multimedia applications the definition of the term PCI needs careful consideration. At a first glance, two interpretations seem possible: 1) the definition of the PCI describes communications network and communications hardware related issues, of course considering special conditions of the specific environment like synchronization of data streams and bandwidth requirements. Those PCIs are called network related PCIs; 2) the definition of the PCI is oriented towards the user’s application and tries to encapsulate and to encompass the communications aspects of the software. Such a PCI is (telecommunications) service related rather than network or protocol related. In some cases it might cover even several, distinct services. Those PCIs are called application related PCIs. For monomedia environments, theses interpretations are well known. They are discussed in ITU-T Recommendation F.581 [2] and in ETR 368 [9]. In terms of the OSI Model (ITU-T X.200 Series of Recommendation): - a network related PCI could be said to cover OSI layers 1-3, preferably offering the interface on top of layer 3 (network layer); - an application related PCI could be said to cover OSI layer 7 (and the layers below), offering the interface somewhere within layer 7. The characteristics mentioned cannot be used carelessly. Firstly, some data communications are not conforming to OSI at all (e.g. ITU-T Recommendation T.30); secondly, some applications might need to circumvent OSI layers because of performance or bandwidth demands. Especially in multimedia environments, a third type of PCI can be identified. This type is dealing with transport and presentation protocols and is furthermore concerned with the internal communication of the modules related to multimedia presentation and interaction. For the purpose of the present document, those PCIs are called (transport and presentation) protocol related PCIs. In terms of the OSI Model, they can be said to be located between layer 3 and 7. The three modelled types of PCIs are depicted in figure 2. TR 101 170 V1.1.1 (1998-05) 17 Application related PCI Layer 7 Layer 1 Protocol related PCI Network related PCI Figure 2: PCI types modelled |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.1.1 Application related PCIs | PCIs related to application aspects provide an interface that allows applications to access one or several communications services independently of an underlying network. Here the PCI fulfils at least two requirements: - it hides the network and abstracts the access to it; - it provides for easy access of a communications aware application in a way that minimum knowledge about the communications peculiarities is needed by the application. An example of such a PCI is ETS 300 243-1 [10] that provides access to several telematic services independent of the underlying network. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.1.2 Network related PCIs | PCIs related to network aspects provide access to hardware that connects the terminal equipment to the network. It is clear that such an interface, and the PCI provided by that interface, has to fulfil certain requirements like: - ability to support all or most capabilities the network provides; - ability to allow data and control transfer at full speed the network is capable of; - ability to shelter the network from unqualified access, i.e. access that could harm the network operation. An example of such a PCI is ETS 300 325 [12], which defines a PCI for access to Euro-ISDN and to the hardware providing that access. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.1.3 Protocol related PCIs | Protocol related PCIs are concerned with internal communication of the modules related to multimedia transport, presentation and interaction. Such PCIs ideally have the following abilities: - they provide unified access to certain network services; - they provide transportation of all network specific parameters; - they account for signalling peculiarities of specific networks. TR 101 170 V1.1.1 (1998-05) 18 Protocol related PCIs do not necessarily appear to the application as a "complete" interface covering all application needs. They rather provide access to certain aspects of the communication, but this in a way that abstracts underlying hardware access. An example is the IMTC MCU API defines access to a Multipoint Control Unit (MCU) for teleconference applications. Another example is the forthcoming definition of the eXtensive Application Programming Interface (XAPI) [73] that is suited for teleconferencing and corporate document handling applications. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.2 Commonalties of PCIs | The following issues are general and common to all kind of PCIs: - PCIs have local impact only; - use of a standardized PCI is not necessary to participate in a communications service; - any approach taken to define a PCI can be suitable, as long as the basic requirements of the communications service are respected. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3 Existing PCIs | Several PCIs already exist for monomedia or telematic services. To a certain extent these PCIs are also capable to transport multimedia information. An example is the Winsock interface [65], a protocol related interface that makes available the sockets interface RFC 147 [82] for the TCP/IP protocol stack RFC 793 [62] and RFC 791 [63]. The PCIs considered by the present document are listed in table 3. TR 101 170 V1.1.1 (1998-05) 19 Table 3: List of existing PCIs considered Name/Title Primary source Additional sources Type Description Facsimile Class 1 interface TIA TR29 EIA/TIA-578 [75] ITU ITU-T Rec. T.31 [76] network related DTE-DCE interface for control of facsimile communication (ITU-T Rec. T.30) within a Modem Facsimile Class 2/Class 2.0 interface TIA TR29 ITU ITU-T Rec. T.32 [77] network related DTE-DCE Interface for control of facsimile communication ETS 300 325 Ed.2 [13] + ETS 300 325 [12] ETSI -- network related N-ISDN interface WinISDN [14] Microsoft -- network related N-ISDN interface NDIS Microsoft -- network related Network Device Interface Specification for the Windows operating system ODI Novell -- network related Open Datalink Interface for the Novell environment Sockets Interface [82] BSD X/OPEN protocol related Interface for access to TCP/IP protocol stack WinSock 2 Application Programming Interface [65] Intel, Microsoft, Stardust -- protocol related Interface for access to various protocol stacks WinSock 2 Service Provider Interface [66] Intel, Microsoft, Stardust -- protocol related Service Provider Interface for provision of various protocol stacks XAPI [73] ITU ITU-T Draft T.XAPI DAVIC protocol related eXtensive API; Teleconference and Corporate Document Handling transport interface IMTC GCC API [71] IMTC -- protocol related IMTC Generic Conference Control interface IMTC MCS API [72] IMTC -- protocol related IMTC Multipoint Control Unit interface ITU-T Rec. T.611 [11] (APPLI/COM) ITU ETSI ETS 300 243 [10] application related Operating system independent telematic interface CMC v2.0 mail interface Lotus, Microsoft ITU ITU-T Draft X.434 [74] application related Operating system independent mail interface MAPI [31] Microsoft -- application related Mail interface for the Windows operating system TAPI [32] (NOTE) Microsoft -- application related Telephony interface for the Windows operating system TSAPI Novell -- application related Telephony Services API for the Novell environment NOTE: TAPI also stands as acronym for the TRIBUNE Application Programming Interface [33] that is described in subclause 6.3.3.3. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.1 Network related interfaces | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.1.1 Facsimile Class 1, Class 2 and Class 2.0 interface | The interfaces considered are concerned with facsimile group 3 control and binary file transfer (BFT, ITU-T Recommendation T.434 [23]) only. The facsimile Class 1 interface [75, 76] defines the control procedures to be applied to the data communications equipment (DCE) to manipulate the facsimile protocol (ITU-T Recommendation T.30) and the data transfer. The handling of the ITU-T Recommendation T.30 protocol and the preparation of ITU-T Recommendation T.4 images must be carried out by the data terminal equipment (DTE) entirely. Facsimile Class 2 interface and the Class 2.0 interface [77] assume that the manipulation of the facsimile protocol is entirely performed within the DCE. Only the preparation of the T.4 images is left to the DTE. Consequently, TR 101 170 V1.1.1 (1998-05) 20 programming the Class 2 (Class 2.0) interfaces is carried out in a easier way, relieving the programmer of critical timing considerations. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.1.2 ETS 300 325 and ETS 300 325 edition 2 | ETS 300 325 [12] and ETS 300 325 Edition 2 [13] provide access to ISDN. The PCI is designed in an operating system independent way. Mappings to popular operating systems are provided in the standard. Typically, the interface is provided directly or indirectly by the hardware implementation, i.e. the ISDN card, in the operating system compliant way. ETS 300 325 [13] is, by definition, restricted to access to Euro-ISDN, whereas the successor, edition 2 of ETS 300 325 - the harmonized PCI for ISDN - provides access to ISDN in general, including national variants and Private Branch eXchanges (PBXs). Currently both definitions provide access on top of OSI layer 3, being able to select and support various layer 3 and layer 2 protocols for the user channels (B-channel). The access to signalling is aiming to N-ISDN, using ITU-T Recommendation Q.931 as guidance for that access. A variant (one could say an implementation) of ETS 300 325 [13] is presented by the TRIBUNE Application Programming Interface [33]. The TRIBUNE application programming interface provides for access to B-ISDN, especially to the ATM adaptation layer. Unfortunately, its acronym TAPI is also used for the much more known microsoft telephony API (see subclause 6.3.3.3). However, both PCIs should not be confused. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.1.3 WinISDN | WinISDN [14] defines an interface to ISDN for the microsoft windows environment. Access to ISDN is achieved by provision of a dynamic link library (DLL) called "WinISDN.DLL". Like it is the case with ETS 300 325 [13], this DLL shall be provided by the provider of the ISDN-hardware, i.e. the ISDN card. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.2 Protocol related interfaces | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.2.1 Sockets and winsock interfaces | The Berkley socket interface RFC 147 [82] has been defined early in the year 1971 for the unix environment. It defines an entity (a socket) through which IP packets can be exchanged. The WinSock 2 interface definitions [65, 66], created by a consortium consisting of intel, microsoft, stardust and others, reuse the definition of a socket and provide a windows operating system dependent means to access various protocol stacks over various (communications) network platforms. Those protocol stacks and platforms comprise: • TCP/IP protocols; • Novell IPX/SPX protocols;(see Note) • DECNet protocols; • OSI protocols; • Secure Sockets Layer protocol (SSL); • wireless networks; • ATM offering networks. NOTE: IPX/SPX are the hardware independent lower layer protocols of the Novell NetWare LAN-based network operating system. TR 101 170 V1.1.1 (1998-05) 21 To achieve this independence, the winsock 2 specifications consist of three parts: - the windows sockets 2 Application Programming Interface (API) [65]; - the windows sockets 2 Service Provider Interface (SPI) [66]; - the windows sockets 2 Protocol-Specific annex [67]. The relationship between these definitions and the winsock 2 architecture, which is compliant to the Windows Open System Architecture (WOSA), is depicted in figure 3. WinSock 2 Application WinSock 2 Application Transport Service Provider Name Space Service Provider Transport Service Provider WinSock 2 API WinSock 2 Transport SPI Name Space Service Provider Transport Functions Name Space Functions The WinSock 2 DLL WS2-16.DLL (16 bit) - WS2-32.DLL (32 bit) WinSock 2 Name Space SPI NOTE: This figure has been taken from the Windows Sockets 2 Application Programming Interface [65] Figure 3: WinSock 2 architecture |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.2.2 XAPI interface | The definition of the eXtensive Application Programming Interface (XAPI) [73] is an ongoing work that takes place in ITU-T SG8 Q1, Q8, Q10 and Q15. The primary goal of the XAPI is to provide a connection-oriented interface for teleconference and corporate document handling applications, as described in the ITU-T T.120 and T.190 series of Recommendation. The mechanisms used in the XAPI are derived from the XTI API that has been defined by the X/OPEN group. However, XAPI is not just an extension of XTI. It rather uses the basic mechanisms of XTI for provision of a new interface for point-to-point and point-to-multipoint communications. Similar to the winsock 2 concept, it provides unified transport of data over various protocol stacks and (communications) networks. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.2.3 GCC and MCS interfaces | The GCC and MCS interfaces are provided by the International Multimedia Teleconferencing Consortium (IMTC). The GCC interface presents an API for implementations of ITU-T Recommendation T.124 [19] for Generic Conference Control (GCC). TR 101 170 V1.1.1 (1998-05) 22 The MCS interface presents an API for implementations of ITU-T Recommendations T.122 [17] and T.125 [20] that are dealing with Multipoint Communication Services (MCS) and the related protocol. Both interfaces are highly, but not exclusively, related to the windows operating system. The relationship of the APIs is shown in figure 4. T.124 GCC User Application(s) T.122/T.125 MCS T.123 Transport Stack(s) T.122 - Service Definition T.125 - Protocol Specification X.214 - Service Definition NOTE: This figure has been taken from the IMTC MCS API [72] Figure 4: Relationship of GCC and MCS API |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.3 Application related interfaces | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.3.1 ITU-T Recommendation T.611 (APPLI/COM) | ITU-T Recommendation T.611 [11] and its ETSI version ETS 300 243-1 [10] present a uniform, high level interface for telematic services. Currently facsimile (group 3 and 4), telex, teletex, X.400 and file transfer services are covered. The PCI is designed in an operating system independent way. Mappings to popular operating systems are provided in the present document. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.3.2 CMC v2.0 and MAPI interfaces | CMC v2.0 [74] and MAPI [31] present e-mail interfaces. CMC, which stands for Common Messaging Call, is operating system independent and has also been adopted by ITU as ITU-T Recommendation X.434 [74]. MAPI presents the microsoft e-mail interface for the windows operating system. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 6.3.3.3 TAPI interface | TAPI [32] stands for Telephony API and presents the Microsoft API for telephone applications under the Windows operating system. There exists also another interface called TAPI [33]. There TAPI stands for TRIBUNE Application Programming Interface. TR 101 170 V1.1.1 (1998-05) 23 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7 Summary of results | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.1 Requirements for PCIs in a multimedia environment | A multimedia environment may - and probably will - impose many APIs. However, the requirements for a PCI need to be focused on the communications aspects and demands of the multimedia environment. Derived from the demands listed in clause 0, tables can be computed that summarize the requirements dependent of the type of interface. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.1.1 Requirements of network related interfaces | If applicable, a network related interface ideally supports the following features: Table 4: Features supported by an ideal network related interface Classification Features Importance General aspects • Operating system independence • Extendibility Connection type • Connection oriented and connectionless • Point-to-point connection support • Point-to-multipoint connection support Information interchange • Demand of bandwidth • Dynamic allocation of bandwidth • Support of synchronization • Support of flow control • Transparent exchange of objects • Multiplex capabilities • Transparent data compression Connectability • Optional codec capabilities • Quality of service parameters (QoS) Security • Authentication • Signature • Partial encryption Supplemental services • Provision of charging information (Network) • Provision of charging information (Provider) • Support of network specific abilities |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.1.2 Requirements of protocol related interfaces | If applicable, a protocol related interface ideally supports the following features: Table 5: Features supported by an ideal protocol related interface Classification Features Importance General aspects • Operating system independence • Extendibility Connection type • Transport of connection oriented and connectionless parameters • Point-to-point connection support • Point-to-multipoint connection support Information interchange • Transport information interchange specific parameters of underlying network interfaces Connectability • Transport of codec parameters • Transport of quality of service parameters Security • Transport of security related parameters Supplemental services • Transport of charging and network specific parameters TR 101 170 V1.1.1 (1998-05) 24 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.