RIP-2
RIP version 2 (RIP-2) is a classless routing protocol. Figure 1 shows the format of a RIP-2 packet.
Compared with RIP-1, RIP-2 has the following advantages:
Supports external route tags and uses a routing policy to flexibly control routes based on the tag.
Supports route summarization and classless inter-domain routing (CIDR) by adding mask information to RIP-2 packets.
Supports next hop specification so that the optimal next hop address can be specified on the broadcast network.
Supports Update packets transmission along multicast routes. Only the routers that support RIP-2 can receive RIP-2 packets, which reduces resource consumption.
Provides three packet authentication modes: simple text authentication, Message Digest 5 (MD5) authentication and HMAC-SHA256 authentication. For the sake of security, using the HMAC-MD5 authentication is recommended.