Tag Archive

IS-IS Multitopology: IPv4 and IPv6

Published on March 13, 2012 By Jose Miguel Huertas

When working with IPv6 prefixes in IS-IS, you can configure IS-IS to be in a single topology for both IPv4 and IPv6 or to run different topologies for IPv4 and IPv6. Reading all the official documentation about IS-IS Multitopology I didn’t get a clear conclusion, so I decided to check it out on the lab. […]

IS-IS :: Identifying the DIS

Published on May 18, 2011 By Jose Miguel Huertas

This is a topic that has been running around forums for a long time. IS-IS is a very powerful and interesting IGP, but since OSPF and EIGRP are more popular on enterprise networks, sometimes people have a hard time working with it. When we run IS-IS on broadcast multi-access networks, it operates in a somewhat […]

TRILL: The end of Spanning-Tree?

Published on March 9, 2011 By Jose Miguel Huertas

For all of those who fear spanning-tree, I’m sure the tittle got your attention, at least for a while. For those who support SPT, I must say don’t panic,  the end of SPT is not so close. All of us know we need spanning-tree in a Layer 2 network, even more when there are built-in […]

SPF calculation in OSPF and IS-IS

Published on February 16, 2011 By Jose Miguel Huertas

Today I would like to talk about Shortest Path First (SPF) calculation in OSPF and IS-IS. We already know that both OSPF and IS-IS are link state routing protocols and that they use the Dijkstra SPF algorithm to build a shortest path tree from a specific node acting as root to all other nodes in […]