RIPv2 is a classless routing protocol. Compared with RIPv1, RIPv2 has the following
advantages.
Supporting route tags. Route tags are used in routing policies to flexibly control
routes.
Supporting masks, route summarization and Classless Inter-Domain Routing (CIDR).
Supporting designated next hops to select the best next hops on broadcast networks.
Supporting multicast routing update to reduce resource consumption.
Supporting plain text authentication and MD5 authentication to enhance security.
Note
：
RIPv2 has two types of message transmission: broadcast and multicast. Multicast is the default
type using 224.0.0.9 as the multicast address. The interface working in the RIPv2 broadcast
mode can also receive RIPv1 messages.
RIP Message Format
1)
RIPv1 message format
A RIPv1 message consists of a header and up to 25 route entries. The following figure shows
the format of RIPv1 message.
Figure 10-27 RIPv1 Message Format
The detailed explanations of each field are stated as following:
Command: Type of message. 1 indicates request, and 2 indicates response.
Version: Version of RIP, 0x01 for RIPv1.
AFI: Address Family Identifier, 2 for IP.
IP Address: Destination IP address of the route. It can be a natural network, subnet or a
host address.
Metric: Cost of the route.
2)
RIPv2 message format
The format of RIPv2 message is shown as the following figure. It is similar to RIPv1.
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