Avoiding Instability during Graceful Shutdown of OSPF

Abstract—Many recent router architectures decouple the routing engine from the forwarding engine, so that packet forwarding can continue even when the routing process is not active. This opens up the possibility of using the forwarding capability of a router even when its routing process is down, thus avoiding the route flaps that normally occur when the routing process goes down. Unfortunately, current routing protocols, such as BGP, OSPF and IS-IS do not support this behavior. In this paper, we describe an enhancement to OSPF, called the IBB (I’ll Be Back) capability, that enables other routers to use a router whose OSPF process is inactive for forwarding traffic for a certain period of time. The IBB capability can be used for avoiding route flaps that occur when the OSPF process is brought down in a router to facilitate protocol software upgrade, operating system upgrade, router ID change, AS and interface renumbering, etc. When the OSPF process in an IBB-capable router is in...

• Type: Conference
• Year: 2002
• Where: INFOCOM
• Authors: Aman Shaikh, Rohit Dube, Anujan Varma
• Keywords: Communications, INFOCOM 2002, OSPF, OSPF Process, Routers