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8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.3.4 Roles | The satellite link can play different roles in the network: • Last mile connections: End users are directly connected to the satellite to provide direct forward and return links. Traffic sources connect to the satellite feeder or hub stations through the Internet, tunneling, dial-up links, etc. The connection is basica... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.4 Session management | The text in this clause is based on IETF RFC 3170. Session management is one of the most misunderstood services with respect to multicast. Most application developers assume that multicast will provide services like security, encryption, reliability, session advertisement, monitoring, billing, etc. In fact, multicast i... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.5 Caching | Caching is a technique, which can dramatically improve performance, whilst simultaneously reducing the traffic load on the network. A cache is a place where temporary copies of objects are kept. Once data has been cached, subsequent requests for it will be given the cached copy. Some Web browsers also implement their o... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.6 Edge- and data-casting | Edge casting is a particular application of multicasting, where data is multicast and stored at the destination location. We would normally assume that there is a storage unit associated with the destination location, where the content can be retrieved at a later time. However, edge-casting may also be done "live", wit... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.6.1 Edge casting to gateways | Edge-casting enables data like live video and audio to be up-linked to a satellite network in order to bypass a congested Internet backbone. Edge casting may be used, for instance, to distribute data to a number of gateways, or local access points, where it can be stored for local access. For instance, there is a produ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 5.6.2 Edge- and data-casting to terminals | Edge casting to terminals builds upon the same philosophy as edge casting to gateways. Edge casting to terminals could also imply transmitting corporate data to the edge of the corporate network. For instance would possible an auto-manufacturer be interested in edge casting the latest parts- and service manual for thei... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6 Satellite multicasting issues | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.1 Introduction | Different satellite systems exhibit a number of relative differences, which may present a challenge for harmonizing multicast standards. Such differences should preferably be taken into account for future standards, as they should allow for differences in technology. Some satellite system differences relevant for multi... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.2 Multicast via Broadcast | Broadcast implies sending the data to every user in the network. Thus if there is a single subscriber somewhere on the satellite network the multicast message would be broadcast to all receivers in the network. The individual receivers must then sort out if the message is intended for them. Multicast via broadcast impl... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.3 BSM multicast capability issues | With respect to multicasting there are a number of application-issues that is worth considering when designing a satellite multicast system. Some of the most relevant are discussed below: • Reliability, implying if every host needs to receive the data and if that information needs to be fed back to the network. - Usual... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4 Satellite multicast architectures | The basic reference figure 16 is applicable for different satellite network architectures. In consistency with TR 101 984 [4], satellite architectures are initially divided into mesh and star networks. There may be a number of hosts connected to one and the same satellite receiver. This is an important observation, and... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.1 Star networks | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.1.1 Single gateway/hub | For convenience we repeat the star network reference architecture from TR 101 984 [4], to show how it maps onto the multicast reference network architecture. ETSI ETSI TR 102 156 V1.1.1 (2003-04) 49 Remote terminal Satellite Hub terminal Network Control Centre IP router BSM node End Systems (destination) End Systems (s... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.1.2 Multiple gateways | When there are multiple gateways, an immediate issue becomes the choice of which gateway should be used to transfer the multicast content to the end receiver (and host). This consideration applies both when more than one gateway can reach a given receiver and when only one of the gateways can. Choices of which gateway ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.1.3 Internal source | If the source is internal then the content must be tunneled to a/the gateway. Once it reaches a gateway then the above considerations apply. There may be restrictions as to if the source shall be made available outside of the satellite system. |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.2 Mesh networks | Figure 25 shows the BSM mesh network figure from TR 101 984 [4]. The basic difference is the emphasis on inter- terminal communication without the need of going via a gateway, which is beneficial when a large portion of the networks traffic is between terminals on the same system, etc. Satellite terminal Satellite Sate... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.2.1 Single gateway | The same terrestrial routing arguments as for the bent-pipe satellite is valid, except that in addition a regenerative satellite able to replicate data could do with one uplink even for multiple spot-beams, as the replication could be done in the satellite. In this case, one would save uplink capacity, as it would not ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.2.2 Multiple gateways | Basically the same arguments are valid here as in the case for bent-pipe satellite systems. If there are several gateways then there must be a mechanism that chooses which gateway shall be used to reach which terminals. A possible additional issue would be that with a mesh network most gateways accessing the same satel... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.2.3 Internal source | A mesh network with the underlying OBP capability can in principle support multicast with one terminal as source and other terminals as recipients (for instance distance learning or corporate multicast). It is however worth noting that there are systems with OBP capabilities that cannot support direct multicasting, so ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.3 Forward and return channels | An interactive satellite system will in principle have two channels, one forward and on return. In DVB-RCS the interaction channel is defined as a duplex channel in addition to the forward DVB channel, but in most cases the forward interaction channel will be physically combined with the forward (DVB TV) channel. |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.3.1 Forward channels | A traditional satellite system consists of one or more geo-stationary satellites with a bent-pipe payload operating in a global beam environment. In a one-hub scenario, all users can be accessed via the same uplink beam, although they may be tuned to separate downlink carriers. Some satellite systems use multiple spot-... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.4.3.2 Return channels | Return channels can be used in multicast when reliable multicast is required, but they are not mandatory. Satellite multicast delivery may or may not require a return channel, and the return channel, if present, may or may not be via satellite. If it is via satellite, it may even be over a different satellite from that... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5 User traffic forwarding functions | This plane would compare to the U-plane. BSM multicast would base the traffic at the link and physical layers on whatever technology was used also for unicast. This domain would be in the satellite dependent region of the protocol stack. In BSM multicast some of the issues involved would which protocols to use (UDP wil... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1 Satellite multicast replication concepts | Every multicast message must be replicated to every relevant downlink carrier (which in general would be one per relevant spotbeam). If all downlink carriers are addressed via one and the same gateway in a bent-pipe satellite system, then replication and mapping onto relevant carriers can take place there. If the satel... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.1 Replication externally | External replication will involve a number of messages sent as unicast or point-to-point within the satellite system. The replication can in this case be assumed to take place outside of the gateway(s) in the system. In this case a challenge for the satellite system would be on the resource optimization side, if at all... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.2 Replication in a gateway | This is a very relevant scenario. Replication in the gateway would be a common scenario for satellite multicast, and in particular for a bent-pipe satellite. • The gateway would need to maintain a host/beam mapping and replicate the message once for every beam where there is a receiver for the multicast message. • The ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.2.1 Replication in a satellite terminal | A terminal may have a number of hosts connected to it, forming a home network, or a customer premises network. There is a chance that more than one of the connected hosts subscribe to the same multicast group, in particular that may be the case on a closed network (that may be part of a corporate network). If more than... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.2.2 Replication in a multicast entry point | When the source is external to the BSM network, it has to enter the BSM network via one ore more Multicast Entry Points (MEP) somewhere. The same consideration applies for also points to point source, with the potential difference that it always would enter at one single place (the Network Entry Point, NEP). A multicas... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.3 Replication in satellite | For any satellite system, the optimal configuration in the spectrum sense is if the message can only be up-linked once, and then reach all destination receivers either directly or via replication in the satellite. This can be the case for a global beam system with one gateway. For a spot-beam system, the most efficient... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.3.1 Replication at MAC layer | If the satellite replicates the message at the MAC layer it will basically copy the content of the up-linked frame to different beams. The satellite may in general need to buffer the content, if it cannot copy it instantly to other beams. This would depend on the traffic load and the RRM of the satellite, but in genera... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.1.3.2 Replication at IP layer | With replication at the IP layer, the satellite would be able to recognize a multicast message, and keep track of the group management. This is the most powerful solution in terms if preserving the spectrum resources, but probably also the most challenging in terms of complexity, processing and storage. With a one-sate... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.2 Replication and routing summary | A key issue in BSM multicast is how to route and where to replicate the content. As has been seen from the discussion above on different satellite architectures, many factors influence routing and replication. Replication should as a general rule be done as close to the host receiver as possible. Not looking at the arc... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.3 Reliable multicast in BSM | It may seem a lot to request reliable multicast when using UDP as a transport layer protocol, since UDP is a connectionless protocol, unlike its counterpart Transmission Control Protocol (TCP) which is connection oriented. TCP offers a reliability we may desire in multicast, but the drawback is the overhead involved. I... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.3.1 Totally reliable multicast (file transfer) | This can be accomplished by coding, ARQ or other means, but the important thing is that the users can rely upon the satellite system to deliver the content. If it has been detected that it has not been receiver, the content will always be retransmitted. For BSM systems there may be a need to define a maximum loss rate ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.3.2 Semi-reliable multicast (audio, video) | Semi-reliable multicast will offer a very low packet loss (according to QoS contract) rate but no re-transmissions (ARQ) at the link layer. For real-time applications a retransmission will in any case not have any value. For BSM systems there may be a need to define a maximum loss rate (at a low level), and power, codi... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.3.3 Acknowledgements | Reliable multicast messages may request acknowledgements. For a satellite network the resource handling associated with this in a large group is undesirable, and it is then best avoided. For very small groups, however, it may be implemented. Acknowledgements can be returned from a gateway if required, as long as the ga... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.3.4 FEC for increased reliability | Perhaps of particular interest if there is no return channel available for multicast purposes, additional FEC can be applied to the message to increase the reliability to the desired level. Messages can of course also be duplicated, but that may serve little purpose if the reason for not receiving the content has not g... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.5.4 Receiver synchronization | Some applications may require that the receiver are synchronized in such a way that all messages are received at the same time. This could for instance be the case when stock quotes are multicast or in gaming or betting situations. More generally, it could be the case for any application that would require a quick resp... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6 Multicast control functions | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6.1 Satellite multicast routing | Satellites are inherently good for multicasting. For a spot beam satellite network the problem of how to deliver multicast messages is a mix of using broadcast channels, as in one spot beam, and routing, as in selecting spot beams and carriers. Clearly, if there are subscribers in a spot beam a multicast message needs ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6.1.1 User and terminal mobility | Satellite systems can support mobile and/or nomadic users. Further, users may be mobile across fixed terminals via e.g. a SIM-card. As a consequence, a satellite system can not rely on a fixed beam location nor a fixed physical terminal if multicast is to be supported on a user basis. If multicast is to be supported on... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6.2 IP multicast addressing | IP multicast provides a method of using a unique class D address to transport data to multiple destination stations using a single IP packet. As class D address range includes IP addresses between 224.0.0.0 and 239.255.255.255, concurrent multicast groups can exist over the same IP network yet remain logically independ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6.3 MAC layer multicast addressing | The address space in the L2 (MAC) layer may vary between different satellite systems. With a large number of spot-beams and many multicast groups in addition to other types of traffic the address space of the satellite system must be considered. In DVB and DVB-RCS it is for example common to use (Packet ID) PID for add... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.6.4 Satellite multicast group management | There are several options for group management depending on the requirements in question. For a satellite network where the spectrum resources are limited and should be used carefully, it is of importance to take this into account when designing satellite group management system. A multicast router periodically sends q... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.7 Multicast management functions | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.7.1 Capacity requirements and resource management | A RRM scheme will have to allocate terminals that shall receive the same multicast content to the same carrier in a spot beam, if several are present. The RRM system will also have to make sure the terminals either listen to the timeslots where the multicast content is sent, unless they listen to all content. |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.7.2 Traffic management | Multicast group management and link layer protocols requiring retransmissions and using acknowledgements may be extremely challenging to handle if the concept is not properly designed. Traffic management and congestion control on the forward channel from a gateway may not be of the highest importance, as the gateway it... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.7.3 Physical and Link Layer issues | It is on the physical layer the satellite multicast may differ from other technologies for delivering multicast content in that it truly is a shared physical resource. Granted, it is so for a number of other physical layers, such a radio networks and shared cable networks. However, none of these can boast the same cove... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.7.4 Performance and QoS issues | In the long term QoS must be supported by BSM multicast systems. In the short term QoS for multicast is not used (as of March 2003). Multicast QoS classification can be seen as: • Best effort, with no user specifications and no network guarantees. A best-effort routing protocol (e.g. PIM-SM) sets up a layer-3 routing t... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 6.8 Security in satellite multicast | There is work in progress on security in the ETSI BSM WG, and basic BSM security will be discussed there. Multicast applications are no different than unicast applications with respect to their need for security, and they require the same basic security services: user authentication, data integrity, data privacy and us... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7 Other multicast standards work | This clause identifies other relevant standardization work related to IP multicasting over satellite networks. The majority of the work has been done by the IETF, but the ITU is also doing relevant and interesting work. Not noted here, but also of possible interest, are the numerous projects, both national and internat... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.1 DVB | It is not known that the DVB project is working specifically on multicast work, but certainly there has been work on multicast over DVB. DVB-S with MPE is a layer 2 multicast capable protocol. One of the addressing options is to adapt to the multicast MAC address scheme specified by IETF RFC 1112 [7]. This mapping uses... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.2 IETF multicasting standardization work | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.2.1 TCP/IP network model | Although the OSI model is widely used and often cited as the standard, TCP/IP protocol has been used by most Unix workstation vendors. TCP/IP is designed around a simple four-layer scheme. It does omit some features found under the OSI model. Also it combines the features of some adjacent OSI layers and splits other la... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.2.2 Relevant IETF Working Groups | This clause lists some of the most relevant IETF workgroups. Please see the IETF website for detailed charters and work item status. • Inter-Domain Multicast Remnants (IDMR) deals with IGMP, and also with DVMRP. • Protocol Independent Multicast remnants (PIM) deals with PIM and is chartered to standardize and promote t... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.2.3 Multicast or satellite related RFC documents | A search in the RFC database for satellite and multicast gives a large number of hits. Some of those considered most relevant are listed below. Best current practice • draft-ietf-pilc-link-design-12.txt (July 2002) - This document provides advice to the designers of digital communication equipment, link-layer protocols... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3 ITU multicasting standardization work | In a March 2002 presentation titled "Multicast Delivery of Broadband Multimedia Applications and Services", Seok Joo Koh, Editor of X.606 in Q.8/17, informs about ITU work related to multicasting. Claims for status: • Intra-domain routing protocols are stable, and deployed in private and local Internet. • Inter-domain ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.1 Activities and work items in ITU-T Q.8/17 | ECTP (Enhanced Communications Transport Protocol) • ECTP-1 (X.606): Reliable Multicast, Approved (2001.10). • ECTP-2 (X.606.1): Multicast QoS Management (To be approved 2002). GMP (Group Management Protocol) • X.gmp: Session/membership Management. RTM (Relayed Transport for Multicast) • X.rtm: Hybrid delivery of broadb... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.1.1 ECTS definition | ITU-T Recommendation X.605 ISO/IEC 13252: "INFORMATION TECHNOLOGY - ENHANCED COMMUNICATIONS TRANSPORT SERVICE DEFINITION". This Recommendation defines an enhanced transport services for the next-generation Internet, named ECTS (Enhanced Communications Transport Service), which provides for a multicast data transfer cap... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.1.2 Multi-peer framework | ITU-T Draft Recommendation X.601: " MULTI-PEER COMMUNICATIONS FRAMEWORK. This Recommendation provides the basic framework to specify services and protocols for multi-peer communications. The scope of this Recommendation is to define the basic concepts of group and various aspects of group communication, which are neede... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.1.3 Simplex multicast transport | ITU-T Draft Recommendation X.606 | ISO/IEC 14476-1: "INFORMATION TECHNOLOGY - ENHANCED COMMUNICATIONS TRANSPORT PROTOCOL: SPECIFICATION of SIMPLEX MULTICAST TRANSPORT". This Recommendation | International Standard specifies the Enhanced Communications Transport Protocol (ECTP), which is a transport protocol designed to... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.1.4 QoS for simplex multicast transport | ITU-T Draft Recommendation X.606.1 | ISO/IEC 14476-2: "INFORMATION TECHNOLOGY - ENHANCED COMMUNICATIONS TRANSPORT PROTOCOL: SPECIFICATION of QoS MANAGEMENT FOR SIMPLEX MULTICAST TRANSPORT". This second part of ECTP defines the QoS management functions for the simplex multicast case. Further parts of ECTP will define re... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 7.3.2.1 Next Generation Networks (NGN) | SG13 decided in Feb. 2002 to start the preparation of a new ITU Project on NGN, with the objective to respond to the demand from the market for standards, on a worldwide basis. NGN (Next Generation Network) is a concept widely used by network designers to describe future networks which should cope with the emerging sit... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8 BSM multicast discussion | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.1 Gap analysis | The IETF has done and is doing a considerable amount of work on multicasting, and is likely to be the main standards body where multicast standards are developed also in the future. The ITU is doing work related to multicast, and claims are that more work is needed on the transport protocol layer, i.e. layer 2. There a... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.2 BSM multicast key findings | Subnetworks using shared channels (like satellite) are especially suitable for native multicasting, and should make every effort to support it. This involves designating a section of the subnetwork's own address space for multicasting. Satellite multicast specifications must scale gracefully with the number of users an... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.3 Source group table management | For every source there will a group that is associated with it. For every group there will be a routing table. The table will need to track the following entries in the general case (for some systems not all parameters may be relevant), assuming the multicast source enters the BSM network at some point and is destined ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.4 Address space management | It is likely that multicast replication will be done at layer 2, and transport will be based on L2 addresses. If for instance all multicast groups shared the same PID or L2 address, then all groups would be replicated even if they were not requested, and filtering would be done in the receivers. However, this would be ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5 Brief BSM Multicast Proxy description | A BSM Multicast Proxy (BSM-MP) should take advantage of the specific satellite systems strong features at the various layers, yet making different satellite system architectures basically invisible to the outside world. BSM-MP will know both the specifics of the underlying satellite system as well as the requirements o... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5.1 Basic needs and optional features | This clause will discuss BSM multicast basic needs, the desirable features, things that are optional, things that should not be done. The basic needs consist of: • The availability of a multicast source and knowledge of where it is connected and the intended "scope" i.e. where in the network it is intended to be delive... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5.2 BSM Multicast Networks | A multicast implementation relies upon a receiver-based protocol and multicast-aware/enabled switches and routers to replicate a single stream to multiple destinations. The architecture of the BSM multicast network is important, and it must also be seen in relating to the customer premises network. For a significant pa... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5.3 BSM multicast protocols | It is proposed to use an interworking function at the IGMP level for consumer terminals. A draft version of the protocol stack is illustrated below. The use of multicast proxies in a satellite network implies that multicast messages are intercepted, and handled by one or more multicast proxies in the satellite network.... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5.4 Performance measurement | Multicast performance measurement is usually straight-forward, as illustrated in IETF RFC 1889 [11] (Real-time Transport Protocol). A set of measurement hosts send small probe packets to a particular multicast session. It will also receive packets from the session in order to determine session transfer (network) perfor... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.5.5 Use case concepts | Technically, BSM-MP can work like this when it is at the edge of the network, and the satellite is a bent pipe type: A host connected to a terminal wishes to receive a source and subscribe to a multicast group. It informs the nearest router, residing in the terminal, which relays the message to its gateway. When a host... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6 BSM multicast operation | Broadband satellite multimedia systems will all differ with each other with respect to satellite packet regeneration and supported network topologies, star, multi-satellite, mesh, etc. But the most interesting difference between BSM satellite systems affecting multicast may be the number of addressable downlink spot be... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.1 General operation | BSM multicast operation can occur on demand or be scheduled by the source. For on-demand operation, multicast setup is triggered by data flow or customer premises protocol. For scheduled operation, multicast setup is based on time triggers configured by an NSP and NCC interaction. Multicast operation can also have stat... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.2 Preconditions and Assumptions | The following preconditions are assumed for the multicast scenarios: • Security has provided the appropriate authorization information to the ST from the NCC for the multicast. Note that conditional access and key distribution are beyond the scope of the present document. • The coordination of senders and receivers in ... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3 Scenario description | |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.1 Setup of scheduled multicast sessions | The Network Service Provider (NSP) is the owner of multicast sessions that are scheduled for satellite terminals (ST) participation. The NSP provides the NCC with the session details and the NCC uses those details to determine whether or not to set up the multicast session. This scenario is shown below. After the NSP h... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.2 Setup of on-demand multicast sessions | This scenario shows an example of how a multicast session can be set up on demand by an end user. The on-demand multicast session can be stimulated by IP data with a multicast class IP address or by a signalling request to set up multicast. The origination ST must be configured with the appropriate classification rules... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.3 Dynamic join | Figure 50 shows one of several cases of multicast setup when the receivers are joining dynamically. A multicast session is already active when the destination host requests to join the multicast session. When an end host requests a multicast via IGMP, the ST at that end receives the IGMP or a multicast routing protocol... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.4 Dynamic leave | For sessions that allow dynamic membership, any participant may leave the session while it is active. Upon leaving the session, the current multicast configuration dictates whether or not this affects the distribution tree. If other STs in the multicast session are still active in the satellite beam, for example, multi... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.5 Multicast teardown | A multicast session can be terminated either by reaching the end of a scheduled duration, by signalling from the session owner that the multicast session has ended, or, for sessions that have no duration, when no data has been sent for a configurable amount of time. The NCC signals the release of the multicast to all t... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 8.6.3.6 Configuration parameters | For on-demand multicast sessions, the following parameters should be configured in all potential source STs: • Rate. • Class D Multicast ID. • Multicast Group ID. • Classification Rules. For scheduled multicast sessions, a time profile (start time, duration, and schedule) should also be configured in source ST: For mem... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 9 Recommendations | TS1: Multicast Architecture TS10: Multicast Management TS20: Multicast Contrl And handling (proxy) TS 30: Multicast Data Transport TS 11: General Management TS 31: Multicast Transport Reliable Multicast TS21: Session Handling TS22: Group Management Address Management TS 23: IGMP Spoofing TS 32: Multiple Source Mulicast... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 9.1 Specification topics and draft scope | The following set of specifications topics are proposed, with a draft scope given below each one. It may not be essential to prepare the specifications as individual document, as they can also form separate chapters/volumes of a multi-part BSM multicast specification. The topics' priority is to be considered outside th... |
8f4fe51f2c92e0bc31f3d83583a5f46f | 102 156 | 9.2 Brief discussion on concept | The above recommendations indicate that ETSI should develop a (set of) BSM multicast standard(s) that is based on using a multicast proxy manager concept. There are benefits in having a standard way of how a BSM satellite system interacts with the outside world, both from the terminal and from the gateway side. However... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 1 Scope | The present document identifies the users' requirements regarding the standardization needs in Local Area Network Interconnection as seen through a survey carried out by the ETSI User Group in 1998. |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 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. • Fo... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 3 Definitions and abbreviations | |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: repeater: a device connecting two LAN segments at the Physical layer (layer 1) of the OSI Reference Model. bridge: a device interconnecting two LANs at the Data Link layer (layer 2) of the OSI Reference Model. router: an inter-networki... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: ANSI American National Standards Institute ATM Asynchronous Transfer Mode BGP Border Gateway Protocol CMIP Common Management Information Protocol COS Corporation for Open Systems DECnet Digital Equipment Corporation proprietary protocol DNA Di... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 4 Standards Applicable to LAN Interconnection | The standards applicable to LAN interconnection over WANs are in three areas: interfaces, protocols and management. Standards come in many forms: de facto, de jure, International, European, proprietary, etc. |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 4.1 Standards Bodies involved in LAN Interconnection | There are many standards bodies involved in the LAN interconnection over WANs. Listed here are the major ones. ANSI American National Standards Institute ATM Forum Asynchronous Transfer Mode Forum COS Corporation for Open Systems ECMA European Computer Manufacturers Association GOSIP Government Open Systems Communicati... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 4.2 Interfaces used in LAN Interconnection | Interfaces are used to connect a system to the media carrying the data traffic. The interface standards used in interconnect are generally well known and well specified. Examples of such interfaces are: T1/E1 1,544 Mb/s (North America) / 2,048 Mb/s (Europe) time-multiplexed connection (defined in ITU-T Recommendations ... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 4.3 Protocols used in LAN Interconnection | Protocols are the defined procedures or rules by which systems communicate with each other. The following protocols are widely used in LAN interconnect: 4.3.1 Communications (Lower Level) Protocols used in LAN Interconnection ATM Asynchronous Transfer Mode DECnet Digital Equipment Corporation proprietary protocol IPX/S... |
7a11a89a63fc40c7ca0f712d7e551b2b | 102 101 | 4.3.3 Network Management Protocols used in LAN Interconnection | CMIP Common Management Information Protocol SNMP Simple Network Management Protocol ETSI TR 102 101 V1.1.1 (1999-03) 8 5 Users' views on the need for Standards in the LAN Interconnect Arena This clause contains a selection of views obtained from a survey of the User community. 5.1 User 1: A Telecom Consultant specialis... |
70dd98e0a973606fff72ddda06b980b6 | 102 100 | 1 Scope | The present document is part A of the ETSI SRC6 report [1] dealing with the European Information Infrastructure (EII). It comprises a number of recommendations indicating the need to develop standards in the area of interworking between a number of existing and emerging access networks and core network types. In partic... |
70dd98e0a973606fff72ddda06b980b6 | 102 100 | 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. • Fo... |
70dd98e0a973606fff72ddda06b980b6 | 102 100 | 3 Definitions and abbreviations |
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