RIP routing table limitations
by David Sudjiman ~ July 3rd, 2006. Filed under: Cisco.From http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/rip.htm#xtocid9
Up to 25 occurrences of the AFI, Address, and Metric fields are permitted in a single IP RIP packet. That is, up to 25 routing table entries can be listed in a single RIP packet. If the AFI specifies an authenticated message, only 24 routing table entries can be specified. Given that individual table entries aren’t fragmented into multiple packets, RIP does not need a mechanism to resequence datagrams bearing routing table updates from neighboring routers.