ID
int64 1
1.96k
| Split
stringclasses 1
value | Domain
stringclasses 4
values | SubDomain
stringclasses 24
values | Format
stringclasses 1
value | Tag
stringclasses 2
values | Language
stringclasses 1
value | Question
stringlengths 15
717
| A
stringlengths 1
292
| B
stringlengths 1
232
| C
stringlengths 1
217
| D
stringlengths 1
192
| Answer
stringclasses 4
values | Explanation
stringlengths 21
1.43k
⌀ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1,270
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What role does a router play in a network? ()
|
Connecting two different networks
|
Provide network security
|
Provide network storage
|
Control network traffic
|
A
| null |
1,271
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What are the characteristics of the RIP protocol? ()
|
Protocol based on link-state
|
Distance Vector-based Protocol
|
UDP-based protocol
|
Protocol Based on MAC Address
|
B
| null |
1,272
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
In an IPv6 address, how is a multicast address represented? ()
|
Starts with FF
|
Starts with FE
|
Starts with FD
|
Starts with FC
|
A
| null |
1,273
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What information does the protocol field in an IP datagram indicate? ()
|
The specific data carried by the datagram is of which protocol.
|
Total length of the datagram
|
Destination IP address of the datagram
|
Source IP address of the datagram
|
A
| null |
1,274
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the length of an IPv6 address in bits? ()
|
32-bit
|
64-bit
|
96-bit
|
128-bit
|
D
| null |
1,275
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the function of NAT technology? ()
|
Improve network performance
|
Mitigate the consumption of IP addresses
|
Enhancing Network Security
|
Enhancing Network Reliability
|
B
| null |
1,276
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the function of the ARP protocol? ()
|
Translate IP address to MAC address
|
Convert MAC address to IP address
|
Translate domain names into IP addresses
|
Convert IP address to domain name
|
A
| null |
1,277
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the main function of the RARP protocol? ()
|
Convert MAC address to IP address
|
Translate IP address to MAC address
|
Translate domain names into IP addresses.
|
Convert IP address to domain name
|
A
| null |
1,278
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the main application of the ICMP protocol? ()
|
Datagram Transmission
|
Error Message Report
|
Broadcast transmission
|
Multicast transmission
|
B
| null |
1,279
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What does stability mean in the requirements of routing algorithms? ()
|
The algorithm aims to produce results that are as simple as possible.
|
The algorithm can adapt to network changes.
|
The algorithm is capable of maintaining balance.
|
Algorithms can persist over time.
|
B
| null |
1,280
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the standard for measuring paths in the RIP protocol? ()
|
Bandwidth
|
Hop count
|
latency
|
Packet size
|
B
| null |
1,281
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The BGP protocol operates between what? ()
|
Router and Switch
|
Host and Router
|
between ASes
|
Within the same AS (Autonomous System)
|
C
| null |
1,282
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
How many bits does the header length field of an IP datagram occupy? ()
|
4
|
8
|
12
|
16
|
A
| null |
1,283
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What are the main functions of the network layer? ()
|
Data Transparent Transmission
|
Power Management
|
Signal Amplification
|
Data Compression
|
A
| null |
1,284
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
In an IPv6 address, how many bits are used for host identification? ()
|
32-bit
|
64-bit
|
96-bit
|
128-bit
|
C
| null |
1,285
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the role of a router in a network? ()
|
Connecting two different networks
|
Provide network security
|
Provide power management
|
Control network traffic
|
A
| null |
1,286
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What are the characteristics of the RIP protocol? ()
|
Based on the distance-vector protocol
|
Link State Protocol based
|
Protocol Based on MAC Address
|
UDP-based protocol
|
A
| null |
1,287
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the main function of the Traceroute application? ()
|
Test network bandwidth
|
Tracing the Path of IP Datagrams
|
Test Network Failure
|
Control network traffic
|
B
| null |
1,288
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The primary purpose of the network layer is ( ).
|
Data packet transmission between adjacent nodes
|
Reliable datagram transmission between adjacent nodes
|
Data packet transmission between any two nodes
|
Reliable datagram transmission between any two nodes
|
C
| null |
1,289
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The heterogeneous networks connected by a router refer to ( ).
|
The network topology is different.
|
Computers in the network have different operating systems.
|
The data link layer and the physical layer are both different.
|
The data link layer protocols are the same, but the physical layer protocols differ.
|
C
| null |
1,290
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Congestion has occurred in the network, according to ()
|
As the load on the communication subnet increases, the throughput also increases.
|
The number of packets received and transmitted by network nodes is decreasing.
|
The number of packets received and transmitted by network nodes is increasing.
|
As the load on the communication subnet increases, the throughput actually decreases.
|
D
| null |
1,291
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
(Without using CIDR) When an IP packet is delivered directly, it is required that the sender and the destination have the same ( ).
|
IP address
|
Host number
|
Port number
|
Subnet Address
|
D
| null |
1,292
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The network layer of the Internet contains four important protocols, which are ().
|
IP, ICMP, ARP, UDP
|
TCP, ICMP, UDP, ARP
|
IP, ICMP, ARP, RARP
|
UDP, IP, ICMP, RARP
|
C
| null |
1,293
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
In the IPv4 packet header, there are two fields related to length: the header length and the total length, where ( ).
|
The header length field and the total length field are both measured in units of 8 bits.
|
The header length field is measured in 8-bit units, while the total length field is measured in 32-bit units.
|
The header length field is measured in units of 32 bits, while the total length field is measured in units of 8 bits.
|
The header length field and the total length field are both measured in 32-bit units.
|
C
| null |
1,294
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The checksum field in an IP packet covers the range of ().
|
The entire IP packet
|
Only inspect the header of the packet.
|
Only check the data section.
|
All of the above are checked
|
B
| null |
1,295
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The following description of the fragmentation and reassembly of IP packets is incorrect ( )
|
The fields in the IP packet header related to fragmentation and reassembly are: Identification, Flags, and Fragment Offset.
|
The maximum length specified for an IP packet is 65535B.
|
The MTU of Ethernet is 1500B.
|
The unit of offset is 4B.
|
D
| null |
1,296
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Among the following addresses, the one that is a unicast address is ( )
|
172.31.128.255/18
|
10.255.255.255
|
192.168.24.59/30
|
224.105.5.211
|
A
| null |
1,297
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Every host accessing the internet needs to be assigned an IP address (assuming the default subnet mask is used). The following IP address that can be assigned to a host is ( )
|
192.46.10.0
|
110.47.10.0
|
127.10.10.17
|
211.60.256.21
|
B
| null |
1,298
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Subdividing an IP network into subnets offers the benefit of ( ).
|
Increase the size of the collision domain.
|
Increase the number of hosts
|
Reduce the size of the broadcast domain.
|
Increase the number of networks
|
C
| null |
1,299
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The function of CIDR technology is ( ).
|
Aggregate small networks into a large supernet.
|
Divide a large network into smaller subnets.
|
Addressing the issue of insufficient address resources
|
Multiple hosts share the same network address.
|
A
| null |
1,300
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
To address the issue of IP address exhaustion, the following measures can be adopted, among which the fundamental solution is ( ).
|
Subnetting
|
Adopting Classless Inter-Domain Routing (CIDR)
|
Adopt Network Address Translation (NAT)
|
Adopt IPv6
|
D
| null |
1,301
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Host A and Host B have IP addresses of 216.12.31.20 and 21.13.32.21, respectively. To enable A and B to work within the same IP subnet, the subnet mask that should be assigned to them is ( ).
|
255.255.255.0
|
255.255.0.0
|
255.255.255.255
|
255.0.0.0
|
D
| null |
1,302
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Compared to IPv4, IPv6( )
|
Using a 32-bit IP address
|
Increased the number of header fields
|
Does not provide QoS assurance.
|
No checksum field provided
|
D
| null |
1,303
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The protocol used for inter-domain routing is ( ).
|
RIP
|
BGP
|
OSPF
|
ARP
|
B
| null |
1,304
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
In RIP, a distance value of 16 to a certain network signifies ( ).
|
The network is unreachable.
|
Existence of routing loops
|
This network is a direct connect network.
|
To reach that network, it must pass through 15 hops.
|
A
| null |
1,305
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
The Ethernet multicast MAC address that the multicast IP address 224.215.145.230 should be mapped to is ().
|
01-00-5E-57-91-E6
|
01-00-5E-D7-91-E6
|
01-00-5E-5B-91-E6
|
01-00-5E-55-91-E6
|
A
| null |
1,306
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Among the following addresses, () is a multicast address.
|
10.255.255.255
|
228.47.32.45
|
192.32.44.59
|
172.16.255.255
|
B
| null |
1,307
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Mobile IP assigns two IP addresses to a mobile host: a primary address and a secondary address, ().
|
Both of these addresses are fixed.
|
These two addresses change dynamically with the movement of the host.
|
The main address is fixed, while the auxiliary address changes dynamically.
|
The main address changes dynamically, while the auxiliary address remains fixed.
|
C
| null |
1,308
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Routers mainly implement the function of ( ).
|
Data Link Layer, Network Layer, and Application Layer
|
Network Layer and Transport Layer
|
Physical layer, Data Link layer, and Network layer
|
Physical Layer and Network Layer
|
C
| null |
1,309
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
Among the following network devices, the one with the longest transmission delay time is ( )
|
Local Area Network (LAN) Switch
|
Bridge
|
router
|
Hub
|
C
| null |
1,310
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Knowledge
|
English
|
In the routing table, to set a default route, the destination address and subnet mask should respectively be set to ( ).
|
192.168.1.1, 255.255.255.0
|
127.0.0.0, 255.0.0.0
|
0.0.0.0, 0.0.0.0
|
0.0.0.0, 255.255.255.255
|
C
| null |
1,311
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In the structure of multiple local area networks interconnected by routers, each local area network is required to ( ).
|
The physical layer protocols can differ, while the data link layer and higher-level protocols above it must be the same.
|
The physical layer and data link layer protocols can differ, while the higher-level protocols above the data link layer must be the same.
|
The protocols for the physical layer, data link layer, and network layer can be different, while the higher-level protocols above the network layer must be the same.
|
Physical layer, data link layer, network layer, and higher-level protocols can all differ.
|
C
|
Routers are layer 3 devices that hide the specifics of the lower layers from the transport layer and above, so the protocols for the physical layer, data link layer, and network layer can be different. However, routers cannot process the protocol data above the network layer, so the higher-level protocols above the network layer must be the same. It is easy to mistakenly choose option B, mainly because the TCP/IP protocol suite is widely used in the current internet, and IPv4 is commonly used at the network layer, leading to the misconception that the network layer protocols must be the same. In reality, using specific routers to connect IPv4 and IPv6 networks is a typical example of different network layer protocols being used to achieve connectivity.
|
1,312
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In the Internet, a router's routing table typically contains ( )
|
Destination network and the complete path to reach the destination network
|
All destination hosts and the complete paths to reach those destinations.
|
Destination network and the IP address of the next router on the path to that destination network.
|
The MAC address of the destination network and the next router on the path to that destination network.
|
C
|
A router is a network layer device, whose task is to forward packets. Each router maintains a routing table to determine the forwarding of packets. The routing table typically contains the destination network and the IP address of the next router on the path to that destination network.
|
1,313
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In the Internet, the transmission of IP packets requires passing through the source host and intermediate routers to reach the destination host, typically ( ).
|
The source host and intermediate routers are both aware of the complete path that an IP packet must traverse to reach the destination host.
|
The source host and intermediate routers are unaware of the complete path that an IP packet must traverse to reach the destination host.
|
The source host is aware of the complete path that an IP packet must traverse to reach the destination host, while intermediate routers are not.
|
The source host does not know the complete path that an IP packet must traverse to reach the destination host, while intermediate routers are aware of it.
|
B
|
The transmission of IP packets requires passage through the source host and intermediate routers to reach the destination host. Typically, neither the source host nor the intermediate routers know the complete path that the IP packets must traverse to arrive at the destination host.
|
1,314
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following protocols, the one that is a network layer protocol is ( ) I. IP II. TCP III. FTP IV.CMP
|
I and II
|
II and III
|
III and IV
|
I and IV
|
D
|
TCP is a transport layer protocol, FTP is an application layer protocol, and only IP and ICMP belong to the network layer protocols.
|
1,315
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following descriptions, () is not a characteristic of Software-Defined Networking (SDN).
|
Separation of Control and Forwarding Functions
|
Centralization of control level
|
Interface Open Programmable
|
OpenFlow replaces routing protocols.
|
D
|
The characteristics of Software-Defined Networking (SDN) include the separation of control and forwarding functions, centralized control plane, and open programmable interfaces. OpenFlow is a network protocol used to control switches in SDN, not to replace routing protocols.
|
1,316
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The main difference between dynamic routing and static routing is ( ).
|
Dynamic routing requires the maintenance of the entire network's topological structure information, while static routing only needs to maintain partial topological structure information.
|
Dynamic routing can adaptively adjust to changes in network traffic or topology, whereas static routing requires manual adjustment of relevant routing information.
|
Dynamic routing is simple and incurs low overhead, while static routing is complex and incurs high overhead.
|
Dynamic routing uses routing tables, while static routing does not use routing tables.
|
B
|
Static routing involves the use of manually configured routing information, which is simple and incurs low overhead. It requires the maintenance of the entire network's topology information but cannot adapt to changes in network status in a timely manner. Dynamic routing, on the other hand, automatically discovers and maintains routing information through routing protocols, can adapt to changes in network status promptly, and is complex with high overhead. Both dynamic and static routing use routing tables.
|
1,317
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following descriptions of routing algorithms, ( ) is incorrect.
|
Static routing is sometimes also referred to as a non-adaptive algorithm.
|
The routing selection used by static routing cannot be modified once it is initiated.
|
Dynamic routing, also known as adaptive algorithm, changes routing decisions based on network topology changes and traffic fluctuations.
|
Dynamic routing algorithms require real-time acquisition of network status.
|
B
|
Static routing, also known as a non-adaptive algorithm, does not estimate traffic and topology to adjust its routing decisions. However, this does not mean that the route selection cannot be changed; in fact, users can configure the routing table at any time. Dynamic routing, also referred to as an adaptive algorithm, requires real-time acquisition of the network's state and adjusts routing decisions timely based on the network's status.
|
1,318
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Regarding the description of the link-state protocol, ( ) is incorrect.
|
Only adjacent routers need to exchange their respective routing tables.
|
The topology databases of all routers in the network are consistent.
|
Adopt flooding technique to update link change information.
|
with the advantage of rapid convergence
|
A
|
In the link-state routing algorithm, each router floods the link-state information to other routers in the network when its own link state changes. The transmitted link-state information includes the adjacent routers of that router and the status of all adjacent links, so option A is incorrect. The link-state protocol has the advantage of rapid convergence; it can immediately recalculate routes when the network topology changes and promptly send the latest link-state information to other routers, ensuring that the link-state tables of all routers are as consistent as possible, making options B, C, and D correct.
|
1,319
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In distance-vector routing protocols, ( ) are most likely to cause routing loops.
|
Due to network bandwidth limitations, some routing update datagrams have been dropped.
|
Because the router does not have the information on the entire network topology, when it receives a routing update, it sends the update back to the router from which it received the routing information.
|
When a router detects that one of its directly adjacent links has gone down, it fails to report this change to other routers.
|
Slow convergence results in routers receiving invalid routing information.
|
D
|
In distance-vector routing protocols, "good news travels fast, while bad news travels slow." This leads to a situation where, when routing information changes, not all routers become aware of the change in a timely manner, and the outdated information may still be propagated among routers. This is known as the "slow convergence" phenomenon. Slow convergence is the fundamental cause of routing loops.
|
1,320
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following statements about router delivery, the incorrect one is ( ) I. Routing selection is divided into direct delivery and indirect delivery II. For direct delivery, the two machines do not need to be in the same physical network segment III. Indirect delivery does not involve direct delivery IV. During direct delivery, routers are not involved.
|
I and II
|
II and III
|
III and IV
|
I and IV
|
B
|
Routing selection is divided into direct delivery and indirect delivery. Direct delivery is used when the sending station and the destination station are in the same network segment; otherwise, indirect delivery is used. Therefore, I is correct, II is incorrect. The last router in indirect delivery must use direct delivery. Incorrect direct delivery occurs within the same network segment, hence it does not involve a router, so IV is correct.
|
1,321
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following descriptions of hierarchical routing, ( ) is incorrect.
|
After adopting hierarchical routing, routers are divided into areas.
|
Each router not only knows how to route packets to destination addresses within its own area, but also knows how to route to other areas.
|
After adopting hierarchical routing, different networks can be interconnected.
|
For large networks, multi-level hierarchical routing may be required for management.
|
B
|
After adopting hierarchical routing, routers are divided into areas, and each router knows how to route packets to destination addresses within its own area but is completely unaware of the structure within other areas. When different networks are interconnected, each network can be treated as an independent area, which has the advantage that routers within one network do not need to know the topological structure of other networks.
|
1,322
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
If an IPv4 packet is too large, it will be fragmented during transmission, and the fragments will be reassembled at the ( ).
|
Intermediate Router
|
Next-hop router
|
Core Router
|
Destination host
|
D
|
After a datagram is fragmented, each fragment is transmitted independently to the destination, potentially taking different paths, and only at the destination host can the fragments be reassembled.
|
1,323
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of the basic method of IP packet fragmentation is incorrect ( ).
|
When the IP packet length exceeds the MTU, fragmentation must be performed.
|
When DF=1 and the length of the packet exceeds the MTU, the packet is discarded without reporting back to the source host.
|
The MF value of 1 for a fragment indicates that the received fragment is not the last one.
|
Fragments belonging to the same original IP packet have the same identifier.
|
B
|
If the packet length exceeds the MTU, then when DF=1, the packet is discarded, and an ICMP error message is sent to the source host; when DF=0, fragmentation occurs, with MF=1 indicating that there are more fragments to follow.
|
1,324
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following addresses, the address that belongs to the subnet 86.32.0.0/12 is ()
|
86.33.224.123
|
86.79.65.126
|
86.79.65.216
|
86.68.206.154
|
A
|
The network prefix of the CIDR address block 86.32.0.0/12 is 12 bits, indicating that the higher-order bits of the second byte are in the second byte with the binary form of 32 being 00100000. The first 8 bits of the four given addresses are the same, and the first 4 bits of the second byte are respectively 0010, 0100, 0100, 0100, so the answer to this question is A.
|
1,325
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Without considering NAT, in the Internet, an IP datagram may need to pass through multiple networks and routers from the source node to the destination node. Throughout the entire transmission process, the ( ) in the header of the IP datagram.
|
The source and destination addresses will remain unchanged.
|
The source address may change while the destination address remains unchanged.
|
The source address will not change while the destination address may change.
|
The source and destination addresses are both subject to change.
|
A
|
In the Internet, an IP datagram may need to pass through multiple networks and routers from the source node to the destination node. When a router receives an IP datagram, it selects the next hop address based on the routing table for the destination address, without changing the value of the source address. Even when the IP datagram is fragmented during transmission, the source address of the original datagram is copied to the header of each fragment. Therefore, the source address in the header of the IP datagram remains unchanged throughout the entire transmission process.
|
1,326
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
A network segment with the network number 198.90.10.0/27 can be divided into ( ) subnets, and each subnet can have up to ( ) valid IP addresses.
|
8, 30
|
4, 62
|
16, 14
|
32.6
|
A
|
From the problem, it is known that there are 5 bits for the host number. If only 1 bit is used for the host number, then there are no valid IP addresses available for allocation (excluding 0 and 1, there would be none left), so at least 2 bits are needed to represent the host number. Therefore, there are 3 bits left to represent the subnet number, which means that up to 2^3=8 subnets can be created. When all 5 bits represent the number of hosts, that is, when there is only 1 subnet, each subnet can have a maximum of 2^5-2=30 valid IP addresses (excluding all 0s and all 1s).
|
1,327
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Routing table errors and software faults can cause data in the network to form transmission loops, resulting in packets being forwarded indefinitely. The method that the IPv4 protocol uses to solve this problem is ( ).
|
Message Fragmentation
|
Set the lifespan
|
Add checksum
|
Add option field
|
B
|
Set a Time to Live (TTL) for each IP packet. The TTL is decremented by 1 each time the packet passes through a router. When the TTL reaches 0, the router will no longer forward the packet. This prevents packets from circulating indefinitely within the network.
|
1,328
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following descriptions of IP packet fragmentation and reassembly, the correct one is ( )
|
IP packets can be fragmented by the source host and reassembled at intermediate routers.
|
IP packets can be fragmented by routers along the path and reassembled at the destination host.
|
IP packets can be fragmented by routers along the path and reassembled at intermediate routers.
|
IP packets can be fragmented by routers along the path and reassembled at the router of the final hop.
|
B
|
When a router is ready to send an IP packet onto a network that cannot transmit the entire packet at once, the router must fragment the packet so that its length meets the network's packet length restrictions. IP fragments can be sent independently through different paths, and fragmentation can still occur during transmission (as different networks may have different MTUs), hence they cannot be reassembled by intermediate routers. The fragmented IP packets are only reassembled upon reaching the destination host, and they may not even arrive in the original order. Therefore, the receiving host is required to support reassembly capabilities.
|
1,329
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
A certain unit has been allocated a Class B address and plans to divide its internal network into 35 subnets, with the possibility of adding 16 more subnets in the future. Each subnet should support close to 800 hosts. The feasible mask scheme is ( ).
|
255.255.248.0
|
255.255.252.0
|
255.255.254.0
|
255.255.255.0
|
B
|
Before subnetting, a Class B address has 16 bits for the host portion. Since there is a need to create 35+16=51 subnets, 2^5<51<2^6, it is necessary to allocate 6 bits from the host portion for the subnet number, leaving 10 bits for hosts, which allows for 2^{10}, or 1024 hosts, meeting the requirements of the problem. Therefore, a viable mask scheme is 255.255.252.0.
|
1,330
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The subnet mask of a certain subnet is 255.255.255.224, and IP addresses have been allocated to 4 hosts. One of the hosts has a communication failure due to improper IP address allocation. The IP address of this host is ( ).
|
202.3.1.33
|
202.3.1.65
|
202.3.1.44
|
202.3.1.55
|
B
|
Under the conditions of this question, a host not being able to communicate normally means that its IP address is not in the same subnet as the other three hosts. The subnet mask 255.255.255.224 can be divided into 8 subnets, and the address ranges of the first three subnets are 202.3.1.0-202.3.1.31, 202.3.1.32-202.3.1.63, and 202.3.1.64-202.3.1.95, respectively. Therefore, the IP address of this host should be within the range of 202.3.1.32-202.3.1.63, which corresponds to option B.
|
1,331
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
When hosts in different subnets communicate with each other, the correct statement among the following is ( )
|
When forwarding IP datagrams, a router re-encapsulates the source and destination hardware addresses.
|
When a router forwards an IP datagram, it re-encapsulates the source IP address and the destination IP address.
|
When a router forwards an IP datagram, it re-encapsulates the destination hardware address and the destination IP address.
|
The source site can directly perform ARP broadcast to obtain the hardware address of the destination site.
|
A
|
An IP datagram header contains both the source IP address and the destination IP address, but routing decisions are made based solely on the destination IP address during communication. As the IP datagram travels through the network, the source IP address and destination IP address in the header remain unchanged when passing through routers. ARP broadcasts are only propagated within a subnet; since the communicating hosts are not on the same subnet, the destination station's hardware address cannot be obtained directly through ARP broadcasts. Hardware addresses are only locally significant, so each time a router forwards an IP datagram to a specific network, it must re-encapsulate the source hardware address and the destination hardware address. Note: Upon receiving a packet, the router strips off the data link layer protocol header of that packet and then adds a new data link layer protocol header before the packet is forwarded.
|
1,332
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following situation requires initiating an ARP request: ( )
|
The host needs to receive information, but there is no mapping between the source IP address and the MAC address in the ARP table.
|
The host needs to receive information, but the ARP table already contains a mapping relationship between the source IP address and the MAC address.
|
The host needs to send information, but there is no mapping between the destination IP address and the MAC address in the ARP table.
|
The main requirement is to send information, but the ARP table already contains a mapping relationship between the destination IP address and the MAC address.
|
C
|
When the source host wants to send an IP datagram to a host on the local LAN, it first checks its ARP cache for a mapping of the destination IP address to a MAC address. If there is a mapping, the hardware address is written into the MAC frame, which is then sent to the destination hardware address through the LAN. If there is no mapping, an ARP request packet is broadcasted first, and after receiving the ARP reply packet from the destination host, the mapping of the destination host's IP address to its hardware address is written into the ARP cache. If the destination machine is not on the local LAN, the IP packet is sent to the router on the local LAN, and of course, the mapping of the router's IP address to its hardware address must be obtained in the same way.
|
1,333
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following statements about ICMP messages, the incorrect one is ( )
|
ICMP messages are encapsulated in data link layer frames for transmission.
|
ICMP messages are used to report errors in sending IP datagrams.
|
ICMP messages are encapsulated within IP datagrams for transmission.
|
ICMP messages that contain errors will not be processed further.
|
A
|
ICMP messages belong to the network layer protocol and are sent out as IP datagrams, with the data header added to the IP layer data.
|
1,334
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of ICMP is incorrect ( )
|
IP lacks error control mechanisms.
|
IP lacks mechanisms for host and network management queries.
|
ICMP messages are divided into two categories: error reporting and query.
|
As a supplement to IP, ICMP messages are directly encapsulated in Ethernet frames.
|
D
|
ICMP is a network layer protocol, but its messages still need to be encapsulated in IP packets for transmission.
|
1,335
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of ICMP error messages is incorrect ()
|
For packets that already carry ICMP error messages, no further ICMP error messages are generated.
|
For already fragmented packets, only the first fragment generates an ICMP error message.
|
The error message PING utilizes ICMP error messages.
|
For multicast packets, no ICMP error messages are generated.
|
C
|
ICMP is a network layer protocol, but its messages still need to be encapsulated in IP packets for transmission.
|
1,336
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following descriptions of IPv6, the incorrect one is ( )
|
The header length of IPv6 is fixed.
|
IPv6 does not allow fragmentation.
|
IPv6 adopts a 16B address, which will not be exhausted in the foreseeable future.
|
IPv6 does not use a header checksum to ensure the correctness of transmission.
|
D
|
The header length of IPv6 is fixed, so there is no need for a header length field. IPv6 has eliminated the checksum field, thereby speeding up the processing of datagrams by routers.
|
1,337
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of autonomous systems is incorrect ( )
|
The benefit of dividing an autonomous system into areas is that it confines the scope of exchanging link-state information using the flooding method to each area, rather than the entire autonomous system.
|
The method of hierarchical partitioning increases the variety of information exchanged and also simplifies the OSPF protocol.
|
The OSPF protocol subdivides an autonomous system into several smaller scopes, known as areas.
|
Routers within a region only know the network topology of their own region and are unaware of the network topology of other regions.
|
B
|
The method of hierarchical area division has increased the types of information exchanged and also made the OSPF protocol more complex. However, this approach significantly reduces the communication of routing information exchange within each area, thereby enabling the OSPF protocol to be used in very large autonomous systems.
|
1,338
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In computer networks, the functions of routing protocols do not include ( ).
|
Exchange network status or path information
|
Select the optimal path to the destination.
|
Update the routing table
|
Discover the physical address of the next hop.
|
D
|
Discovering the physical address of the next hop is generally achieved through other means (such as ARP), and is not a function of the routing protocol.
|
1,339
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In RIP, if router X and router K are two adjacent routers, and X tells K, "My distance to destination network Y is N," then K, upon receiving this information, knows that "If I choose X as the next router to network Y, then my distance to network Y is ()" (assuming N is less than 15).
|
N
|
N-1
|
1
|
N+1
|
D
|
RIP stipulates that the distance (hop count) increases by 1 each time it passes through a router.
|
1,340
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of RIP is incorrect ( )
|
RIP is based on the distance-vector routing selection algorithm.
|
RIP requires internal routers to broadcast their routing information about the entire AS.
|
RIP requires internal routers to broadcast routing information to all routers within the AS.
|
RIP requires internal routers to broadcast routing information at regular intervals.
|
C
|
RIP requires internal routers to send routing information to their adjacent routers, rather than to all routers within the entire AS.
|
1,341
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
Among the following statements about the RIP and OSPF protocols, the incorrect one is ( )
|
RIP and OSPF protocols are both network layer protocols.
|
During the exchange of routing information, routers in RIP only send information to their adjacent routers, while routers in the OSPF protocol send information to all routers within their own autonomous system.
|
During the exchange of routing information, routers in RIP send the entire routing table, while routers in the OSPF protocol only send a part of the routing table.
|
Routers in RIP do not know the topology of the entire network; routers in the protocol are aware of the topology of their own area.
|
A
|
OSPF is a network layer protocol, while RIP is an application layer protocol.
|
1,342
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The most accurate description of the OSPF protocol is ( )
|
The OSPF protocol calculates the optimal route based on the link-state method.
|
The OSPF protocol is an exterior gateway protocol used between autonomous systems.
|
The OSPF protocol cannot dynamically change routes based on network communication conditions.
|
The OSPF protocol is only suitable for small-scale networks.
|
A
|
The OSPF protocol calculates the optimal route based on the link-state method. The OSPF protocol is an interior gateway protocol used within an autonomous system. The OSPF protocol dynamically changes routes according to network communication conditions. The OSPF protocol is suitable for medium to large-sized networks.
|
1,343
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of the characteristics of the OSPF protocol is incorrect ( )
|
The OSPF protocol divides an autonomous system into several areas, with a special area known as the backbone area.
|
Domains are interconnected through area border routers.
|
In an autonomous system, there are 4 types of routers: intra-area routers, backbone routers, area border routers, and autonomous system boundary routers.
|
The backbone router cannot function as an area border router.
|
D
|
In the backbone area, routers used to connect the backbone area to other lower-level areas are called Area Border Routers (ABR). Any router located within the backbone area is referred to as a backbone router; hence, a backbone router can also function as an Area Border Router.
|
1,344
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of the multicast concept is incorrect: ()
|
In unicast routing selection, a router can only forward the received packet from one of its interfaces.
|
In multicast routing selection, a router can forward the received packets from its multiple interfaces.
|
Simulating a multicast with multiple unicasts requires more bandwidth.
|
When simulating a multicast using multiple unicasts, the delay is essentially the same.
|
D
|
Multiple unicasts can simulate multicast, but the bandwidth required for a multicast is less than the sum of the bandwidths for multiple unicasts; when simulating a multicast with multiple unicasts, the delay of the router will be significant, whereas the delay for processing a multicast packet is very small.
|
1,345
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
In the design of multicast routing, in order to avoid routing loops, ()
|
Horizontal partitioning technique has been adopted.
|
Constructing multicast forwarding trees
|
IGMP is adopted.
|
Through the Time to Live (TTL) field
|
B
|
Due to the characteristic of trees not having cycles, constructing a multicast forwarding tree allows the broadcast group to be delivered to every host within the group while avoiding loops. Horizontal splitting is used to prevent the count-to-infinity problem in distance vector routing. The TTL field is used to prevent multicast packets from circulating indefinitely in the network due to loops.
|
1,346
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The following description of the basic working principle of Mobile IP is incorrect ( )
|
The basic working process of Mobile IP can be divided into four stages: Agent Discovery, Registration, Packet Routing, and Deregistration.
|
When a node communicates using Mobile IP, a tunnel needs to be established between the home agent and the foreign agent.
|
Upon arriving at a new network, the mobile node notifies the foreign agent of its new reachability information through the registration process.
|
The packet routing of Mobile IP can be divided into unicast, broadcast, and multicast.
|
C
|
Option C updates the mobile node's new reachability information (Care-of Address) to the home agent. Thus, the home agent can tunnel the packets destined for the mobile node to the Care-of Address (foreign agent), which then delivers them to the mobile node.
|
1,347
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
A host has moved to another LAN. If a packet arrives at its original LAN, then the packet will be forwarded to ().
|
Mobile IP's local agent
|
Mobile IP Foreign Agent
|
Host
|
Discard
|
A
|
When a packet arrives at the user's local LAN, it is forwarded to a router connected to the local LAN. The router looks for the destination host, at which point the local agent responds to the request, encapsulating these packets into the payload of some new packets, and sends the new packets to the foreign agent. The foreign agent then extracts the original packets and hands them over to the mobile host.
|
1,348
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
If a host has an IP address of 160.80.40.20/16, then when it moves to another network that is not part of the 160.80/16 subnet, it will ( ).
|
Can directly receive and send packets without any impact.
|
Cannot directly receive packets, nor can it directly send packets.
|
Packets cannot be sent directly, but can be received directly.
|
Packets can be sent directly, but cannot be received directly.
|
B
|
Since all routers arrange routing based on subnets, all packets destined for host 160.80.40.20/16 will be sent to the 160.80/16 subnet. When the host leaves this subnet, it can neither directly receive nor send packets, but it can indirectly receive and send packets through a forwarding address.
|
1,349
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
To control broadcast storms on the network, the method that can be adopted is ( ).
|
Segmenting a network using a bridge.
|
Segmenting a network with a router.
|
Convert the network to 10Base-T.
|
Use a network analyzer to track the computer that is broadcasting information.
|
B
|
Bridges and switches are layer 2 devices that can segment collision domains but cannot segment broadcast domains. Routers are layer 3 devices that do not forward global broadcasts (destination 255.255.255.255), thus they can segment broadcast domains.
|
1,350
|
Test
|
Computer Network
|
Network Layer
|
Multiple-choice
|
Reasoning
|
English
|
The routing table of a router typically contains ( )
|
The information must include complete path details to reach all hosts.
|
The information must include the complete path to the destination network.
|
The information must include the next-hop path to the destination network.
|
The information should include the next-hop paths to reach all hosts.
|
C
|
The routing table contains the next-hop path information to the destination network. It is impossible for a router to contain the next-hop information to reach all hosts, otherwise, routing forwarding would be inconceivable.
|
1,351
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
What kind of service does the TCP protocol provide? ()
|
Connection-oriented reliable transmission
|
Connectionless Unreliable Transmission
|
Connectionless Reliable Transmission
|
Connection-oriented unreliable transmission
|
A
| null |
1,352
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
What mechanism is commonly used for error detection at the transport layer? ()
|
Checksum
|
CRC Checksum
|
Abstract Algorithm
|
Parity Check
|
A
| null |
1,353
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Which field is the calculation of the checksum based on? ()
|
Header
|
Data Section
|
Port number
|
Identifier
|
B
| null |
1,354
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the goal of congestion control? ()
|
Increase network throughput
|
Reduce network latency
|
Avoid network congestion
|
Increase network bandwidth
|
C
| null |
1,355
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
In the implementation of congestion control, the commonly used algorithm is? ()
|
TCP Tahoe
|
UDP Vegas
|
IP Reno
|
ICMP Cubic
|
A
| null |
1,356
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Which protocol in the transport layer provides security? ()
|
SSL/TLS
|
HTTP
|
UDP
|
ICMP
|
A
| null |
1,357
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
How does the SSL/TLS protocol achieve data encryption? ()
|
Symmetric encryption and public key encryption
|
Asymmetric encryption
|
Hash function
|
Abstract Algorithm
|
A
| null |
1,358
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
What is the range of port numbers at the transport layer? ()
|
0-255
|
256-511
|
512-1023
|
0-65535
|
D
| null |
1,359
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
The protocol data unit of the transport layer is called? ()
|
Data packet
|
frame
|
Segment or Packet
|
Data segment
|
C
| null |
1,360
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Which of the following does not belong to the communication subnet? ( )
|
Physical Layer
|
Data Link Layer
|
Network Layer
|
Transport Layer
|
D
| null |
1,361
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
In the TCP/IP reference model, the primary function of the transport layer is to establish a ( ) for sessions between peer entities of the source and destination hosts on the internet.
|
Operational Connection
|
Point-to-point connection
|
Control Connection
|
End-to-end connection
|
D
| null |
1,362
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
The following ( ) can uniquely determine a process communicating on the Internet.
|
Hostname
|
IP address and MAC address
|
MAC address and port number
|
IP address and port number
|
D
| null |
1,363
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Port numbers within the ( ) range are referred to as "well-known port numbers" and are restricted for use. This means that these port numbers are reserved for commonly used application layer protocols such as FTP, HTTP, etc.
|
0~127
|
0-255
|
0~511
|
0~1023
|
D
| null |
1,364
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Regarding TCP and UDP ports, the correct statement is ( )
|
TCP and UDP each have their own port numbers, and they do not interfere with each other, allowing them to coexist on the same host.
|
TCP and UDP each have their own port numbers, but they cannot coexist on the same host.
|
TCP and UDP ports have no essential difference, but they cannot coexist on the same host.
|
When a TCP connection is established, they do not interfere with each other and cannot coexist on the same host.
|
A
| null |
1,365
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
The following statement is incorrect ( ).
|
The Transport Layer is the fourth layer of the OSI reference model.
|
The transport layer provides point-to-point data transmission between hosts.
|
TCP is connection-oriented, while UDP is connectionless.
|
TCP performs flow control and congestion control, while UDP does neither flow control nor congestion control.
|
B
| null |
1,366
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
UDP datagrams provide additional ( ) services compared to IP datagrams.
|
Flow Control
|
Congestion Control
|
Port Function
|
Routing and Forwarding
|
C
| null |
1,367
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
The UDP datagram header does not include ( ).
|
UDP source port number
|
UDP checksum
|
UDP destination port number
|
UDP datagram header length
|
D
| null |
1,368
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
Length field in the UDP datagram ( )
|
Length of data not recorded
|
Record only the length of the header.
|
Only record the length of the data portion.
|
The length including the header and data part
|
D
| null |
1,369
|
Test
|
Computer Network
|
Transport Layer
|
Multiple-choice
|
Knowledge
|
English
|
The following description of UDP is correct ( )
|
Sequential delivery of data
|
Multiplexing is not allowed.
|
Possessing a flow control mechanism
|
is connectionless
|
D
| null |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.