CCNA: Routing Protocols And Concepts: Chapter 7

The field that was added to the RIP message header by RFC 1723 to add support for VLSM and CIDR is the subnet mask. The subnet mask is used to determine which part of an IP address represents the network address and which part represents the host address. By including the subnet mask in the RIP message header, routers are able to accurately determine the network prefixes and perform routing accordingly, supporting Variable Length Subnet Masks (VLSM) and Classless Inter-Domain Routing (CIDR).

The maximum network diameter permitted by the default metric of RIPv2 is 15 hops. This means that RIPv2 will not consider routes that are more than 15 hops away as valid paths to reach a destination network. The metric is used to determine the best path for routing packets, and a hop refers to each time a packet is passed from one network device to another. Therefore, any routes that require more than 15 hops will be considered unreachable by RIPv2.

The command "Router2(config-router)# version 2" will allow Router1 to learn about the 192.168.0.0/20 network. This command is used to specify the version of the routing protocol being used. By setting it to version 2, Router2 is indicating that it is using a newer version of the routing protocol which may include updates or improvements that Router1 needs to be aware of in order to learn about the 192.168.0.0/20 network.

RIP version 2 supports VLSM, which stands for Variable Length Subnet Masking. This allows for more efficient use of IP addresses by allowing the use of different subnet mask lengths within a network. RIP version 2 also supports routing update authentication, which provides a level of security by allowing routers to verify the authenticity of routing updates received from neighboring routers.

RIPv1 does not support Variable Length Subnet Masking (VLSM), which allows for the use of different subnet masks within a network. This means that RIPv1 can only advertise routes using the default subnet mask for the network, which may cause issues when trying to communicate between routers with different subnet masks. In this scenario, both routers can ping each other's serial interfaces, indicating that the physical connectivity is fine. However, since they are not dynamically learning routes from each other, it suggests that the problem lies with the lack of support for VLSM in RIPv1.

RIP version 2 will auto summarize routes by default. This means that when RIP version 2 advertises routes, it will automatically summarize them at the classful network boundary. In this case, the network 192.168.1.32/27 falls within the classful network 192.168.1.0/24. Since RIP version 2 auto summarizes routes, it will not advertise the more specific network 192.168.1.32/27, resulting in no route for that network in the routing table.

The router responds with an error because the network address for Loopback1 overlaps with an already configured interface address. This means that the IP address 192.168.6.62 is already being used by another interface on the router, and therefore cannot be assigned to the loopback interface. It is important to use unique IP addresses for each interface to avoid conflicts and ensure proper network functionality.

When the network administrator enters the command "default-information originate" on Router1, it will propagate the default route to all routers in the network. This means that all routers in the network will be aware of the default route and can use it to forward traffic to destinations that are not directly connected. This command is useful when there is a need for a default route to be advertised throughout the network, ensuring that all routers have a route to forward traffic to unknown destinations.

The users on the LAN of each router are unable to access the remote LANs because RIPv1 is unable to route to discontiguous subnets of a major network. This means that RIPv1 cannot route traffic between networks that are not directly connected and have different subnets within the same major network. In this case, the network statements are configured correctly, but RIPv1 is unable to handle the routing for the discontiguous subnets.

The network administrator can use the IP address ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 from RFC 1918. These ranges are reserved for private networks and are not routable on the internet. Using these IP address ranges ensures that the company's internal network is secure and isolated from the public internet.

Entering the command "no version 2" on the routers will cause the routers to receive both version 1 and version 2 updates, but it will not send out version 2 updates. This means that the routers will be able to understand and process both versions of the updates, but they will only send out version 1 updates.

The output in the exhibit suggests that the "no auto-summary" command has not been configured on the router. This command is used to disable automatic summarization of routes at network boundaries. Since this command has not been configured, it indicates that the router is performing automatic summarization, which can lead to less efficient routing and potential routing issues.

The CHI router will install a route to the 192.168.0.0/16 network in its routing table. This is because the command "network 192.168.0.0" is entered in the RIP configuration of the CHI router. This command tells the router to advertise the specified network in its routing updates. Therefore, the CHI router will include the 192.168.0.0/16 network in its routing table.

RIP v1 and RIP v2 are similar to one another in three ways. Firstly, they both use hop count as a metric to determine the distance between networks. Secondly, they both have the same metric value for infinite distance, meaning that if a network is unreachable, it is assigned the maximum metric value. Lastly, they both utilize split horizon, a technique that prevents routing loops by not advertising routes back to the same interface from which they were learned.

The given commands configure Router1 to send only version 2 updates to the multicast address 224.0.0.9. This means that Router1 will only send RIP version 2 updates to its neighboring routers that are listening to the multicast address 224.0.0.9. It will not send any updates to the broadcast address 255.255.255.255 and it will not send any version 1 updates.

When a loopback interface with an address of 10.16.1.129/27 is configured on router B, a connected route to the 10.16.1.128/27 network will be added to the routing table of router B. This means that router B will now have a direct connection to the 10.16.1.128/27 network, allowing it to send and receive traffic to and from that network without needing to go through any other routers.

The possible solution to the problem of Router CHI and Router ORL not being able to reach the 192.168.1.16/28 network is to configure RIPv2 on the routers. This is because RIPv2 is an enhanced version of RIP that supports classless routing and can advertise subnet masks along with network addresses. By configuring RIPv2 on the routers, the 192.168.1.16/28 network will be included in the routing updates and properly advertised to Router CHI and Router ORL, allowing them to reach the network.

The network command is used to identify which networks will be included in the routing updates. It allows the administrator to specify which networks should be advertised to other routers in the network. Additionally, the network command determines which interfaces can send and receive routing updates. This helps control the flow of routing information and ensures that only the desired interfaces participate in the routing process.

Based on the exhibit, Router1 will install a route to 192.168.0.0/20 because it has a directly connected interface in that network. However, Router1 will not install a route to 192.168.0.0/24 because it does not have a directly connected interface in that network. Router1 will also install a route to 192.168.16.0/24 because it has a directly connected interface in that network. On the other hand, Router2 will not install a route to 192.168.16.0/20 because it does not have a directly connected interface in that network.

The command "Router1(config-router)# network 192.168.16.0" is the correct answer because it allows Router1 to advertise the 192.168.16.0/28 network to its neighbors. This command tells the router to include the specified network in its routing updates, allowing Router2 to learn about it.