endpoints on a point-to-point serial link. The example for Singapore to Kuala Lumpur is configured as follows: Singapore(config)#interface serial 0
Singapore(config-if)#ip address 192.168.10.137 255.255.255.252 KualaLumpur(config)#interface serial 1
KualaLumpur(config-if)#ip address 192.168.10.138 255.255.255.252
Content 1.2 RIP Version 2 1.2.1 RIP history The Internet is a collection of autonomous systems (AS). Each AS is generally administered by a single entity. Each AS will have its own routing technology, which may differ from other autonomous systems. The routing protocol used within an AS is referred to as an Interior Gateway Protocol (IGP). A separate protocol, called an Exterior Gateway Protocol (EGP), is used to transfer routing information between autonomous systems. RIP was designed to work as an IGP in a moderate-sized AS. It is not intended for use in more complex environments. RIP v1 is considered an interior gateway protocol that is classful. RIP v1 is a distance vector protocol that broadcasts its entire routing table to each neighbor router at predetermined intervals. The default interval is 30 seconds. RIP uses hop count as a metric, with 15 as the maximum number of hops. If the router receives information about a network, and the receiving interface belongs to the same network but is on a different subnet, the router applies the one subnet mask that is configured on the receiving interface: RIP v1 is a popular routing protocol because virtually all IP routers support it. The popularity of RIP v1 is based on the simplicity and the universal compatibility it demonstrates. RIP v1 is capable of load balancing over as many as six equal-cost paths, with four paths as the default. RIP v1 has the following limitations: RIP v1 is simple to configure, as shown in Figure .
Content 1.2 RIP Version 2 1.2.2 RIP v2 features RIP v2 is an improved version of RIP v1 and shares the following features: RIP v2 provides prefix routing, which allows it to send out subnet mask information with the route update. Therefore, RIP v2 supports the use of classless routing in which different subnets within the same network can use different subnet masks, as in VLSM. RIP v2 provides for authentication in its updates. A set of keys can be used on an interface as an authentication check. RIP v2 allows for a choice of the type of authentication to be used in RIP v2 packets. The choice can be either clear text or Message-Digest 5 (MD5) encryption. Clear text is the default. MD5 can be used to authenticate the source of a routing update. MD5 is typically used to encrypt enable secret passwords and it has no known reversal. RIP v2 multicasts routing updates using the Class D address 224.0.0.9, which provides for better efficiency.
Content 1.2 RIP Version 2 1.2.3 Comparing RIP v1 and v2 RIP uses distance vector algorithms to determine the direction and distance to any link in the internetwork. If there are multiple paths to a destination, RIP selects the path with the least number of hops. However, because hop count is the only routing metric used by RIP, it does not necessarily select the fastest path to a destination. RIP v1 allows routers to update their routing tables at programmable intervals. The default interval is 30 seconds. The continual sending of routing updates by RIP v1 means that network traffic builds up quickly. To prevent a packet from looping infinitely, RIP allows a maximum hop count of 15. If the destination network is more than 15 routers away, the network is considered unreachable and the packet is dropped. This situation creates a scalability issue when routing in large heterogeneous networks. RIP v1 uses split horizon to prevent loops. This means that RIP v1 advertises routes out an interface only if the routes were not learned from updates entering that interface. It uses holddown timers to prevent routing loops. Holddowns ignore any new information about a subnet indicating a poorer metric for a time equal to the holddown timer. Figure summarizes the behavior of RIP v1 when used by a router. RIP v2 is an improved version of RIP v1. It has many of the same features of RIP v1. RIP v2 is also a distance vector protocol that uses hop count, holddown timers, and split horizon. Figure compares and contrasts RIP v1 and RIP v2. Lab Activity Lab Exercise: Review of Basic Router Configuration with RIP In this lab, the students will setup an IP addressing scheme using Class B networks and configure Routing Information Protocol (RIP) on routers. Lab Activity e-Lab Activity: Review of Basic Router Configuration including RIP In this lab, the students will review the basic configuration of routers. Interactive Media Activity Checkbox: RIP v1 and RIP v2 Comparison When the student has completed this activity, the student will be able to identify the difference between RIP v1 and RIP v2.
Content 1.2 RIP Version 2 1.2.4 Configuring RIP v2 RIP v2 is a dynamic routing protocol that is configured by naming the routing protocol RIP Version 2, and then assigning IP network numbers without specifying subnet values. This section describes the basic commands used to configure RIP v2 on a Cisco router. To enable a dynamic routing protocol, the following tasks must be completed: RIP v2 uses multicasts to communicate with other routers. The routing metric helps the routers find the best path to each network or subnet. The router command starts the routing process. The network command causes the implementation of the following three functions: The network command is required because it allows the routing process to determine which interfaces will participate in the sending and receiving of routing updates. The network command starts up the routing protocol on all interfaces that the router has in the specified network. The network command also allows the router to advertise that network. The router rip version 2 command specifies RIP v2 as the routing protocol, while the network command identifies a participating attached network. In this example, the configuration of Router A includes the following: The interfaces on Router A connected to networks 172.16.0.0 and 10.0.0.0, or their subnets, will send and receive RIP v2 updates. These routing updates allow the router to learn the network topology. Routers B and C have similar RIP configurations but with different network numbers specified. Figure shows another example of a RIP v2