N/APosted on - 04/02/2012
I'm currently studying CISCO 2 right now and so far, I only have a few knowledge on OSPF protocol.
I've been wondering what the IS-IS protocol has that is not found in the OSPF protocol.
What is the difference between these two routing protocols?
Difference between OSPF and IS-IS
Hi Mr. Alvaldez,
OSPF routers can fit in to numerous areas and can sustain virtual links. IS-IS routers, on the other hand, fit in to exactly one area and cannot sustain virtual links since it rides L2 directly.
IS-IS Routes calculated involving L2 to L2 routes in IS-IS are link-state / SPF computation. L1 routers have no straight outer area connection. OSPF Like routes (non-local) inside OSPF are distance vector computation.
OSPF sustains NBMA as well as point-to-multipoint links. On the other hand, IS-IS is not capable to sustain these.
IS-IS traverses openly over layer two, against on IP akin to OSPF, which might propose a security gain (IS-IS hits can’t be routed).
OSPF opts for a DR and BDR that can’t be pre-empted, for the broadcast networks. While IS-IS opts for just a single DIS that may be pre-empted.
OSPF assigns area 0, which is a backbone area, for advertisements within an area; while IS-IS systematizes the domain into two layers.