Route Protocol:RIP

RIP: Routing Information Ptotocol.

OVERVIEW

RIP is one of the oldest distance-vector routing protocol.距离向量
RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination.The maximum number of hops allowed RIP is 15,which limits the size of networks that RIP can support.A hop count of 16 is considered an infinite distance and the route is considered unreachable.RIP implements the split horizon ,route posioning and holdown mechanisms to prevent incorrect routing information from being propagated.

• Originally, each RIP router transmitted full updates every 30 seconds.
• There are three versions of Routing Information Protocol:RIPv1、RIPv2、RIPng(RIP next generation)
• RIP defines two types of messages
  • Request Message,the command value is 0x01
  • Response Message,the command value is 0x02

RIP FRAME FORMAT

RIP uses the User Datagram Protocol(UDP) as its transport protocol, and is assigned the reserved port number 520.