RIPv2 Introduction

Routing Information Protocol

RIPv2

• Interior Gateway Protocol (IGP) subset
• Protocol & Port: UDP, 520
• Distance Vector (Bellman-Ford) algorithm
• Classless Routing Protocol, support CIDR (Classless Inter-Domain Routing，無類域間路由)
• Metric: Hop count, max up to 15 of each single route, value 16 as unreachable / inifinite

Packet Frame

Timer / Intervals

All mentioned as default:

• Update Timer: 30 secs
• Invalid Timer: 180 secs
• Hold-Down Timer: 180 secs
• Flush Timer: 240 secs

Figure 1: image not reproduced here (source: n-study.com).

Authentication

1. Simple Password
   With authentication key of up to 16 characters included in the packet, if password doesnt match, then discard the packet.
   This method provides very little security level, which is posiible to learn the key through by sniffer RIP packets.

2. MD5 algorithm
   By using MD5 method to create a crypto checksum of a RIP packet and an authentication key with up to 16 characters.
   The transmitted packet doesn’t contain the authentication key itself but a crypto checksum, called the digest

Ref: https://sc1.checkpoint.com/documents/R81/WebAdminGuides/EN/CP_R81_Gaia_Advanced_Routing_AdminGuide/Topics-GARG/RIP-v2.htm