Chapter 2 Advanced Routing for FortiOS 5.0 : Routing Information Protocol (RIP) : Troubleshooting RIP : Routing Loops : Routing loops’ effect on the network
  
Routing loops’ effect on the network
In addition to this “traffic jam” of routed packets, every time the routing table for a router changes that router sends an update out to all of the RIP routers connected to it. In a network loop, its possible for a router to change its routes very quickly as it tries and fails along these new routes. This can quickly result in a flood of updates being sent out, which can effectively grind the network to a halt until the problem is fixed.