H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 156)

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RIPv1, a classful routing protocol, supports message advertisement via broadcast only. RIPv1 protocol
messages do not carry mask information, which means it can only recognize routing information of
natural networks such as Class A, B, and C. That is why RIPv1 does not support discontiguous subnets.
RIPv2 is a classless routing protocol, and has the following advantages over RIPv1.
• Supports route tags. Route tags are used in routing policies to flexibly control routes.
• Supports masks, route summarization and Classless Inter-Domain Routing (CIDR).
• Supports designated next hops to select the best ones on broadcast networks.
• Supports multicasting routing updates to reduce resource consumption. Only RIPv2 routers can
receive these update messages.
• Supports 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
A RIP message consists of a header and up to 25 route entries. (A RIPv2 authentication message uses the
first route entry as the authentication entry, leaving 24 available.)
RIPv1 message format
Figure 52 RIPv1 Message Format
Header description:
• Command—Type of message. 1 indicates request, which is used to request all or part of the routing
information from the neighbor; 2 indicates response, which contains all or part of the routing
information. A response message consists of up to 25 route entries.
• Version—Version of RIP, 0x01 for RIPv1.
• Must be zero—This field must be zero
• 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
RIPv2 message format
The format of RIPv2 message is similar to RIPv1.