Randy is correct. In most cases, the two protocols are running co-incident for a while so you can do your table validation and topology mapping and then you turn off OSPF. For vendors that aren't capable of supporting ISIS, this is a feature and not a bug.
On Sun, May 12, 2013 at 1:57 AM, Randy Bush <[email protected]> wrote: > > One scenario that i can think of when somebody might run the 2 protocols > > ISIS and OSPF together for a brief period is when the admin is migrating > > from one IGP to the other. This, i understand never happens in steady > > state. The only time this can happen is if an AS gets merged into another > > AS (due to mergers and acquisitions) and the two ASes happen to run ISIS > > and OSPF respectively. In such instances, there is a brief period when > two > > protocols might run together before one gets turned off and there is only > > one left. > > no. some ops come to see the light and move their network from ospf to > is-is. see vijay gill's nanog preso > http://nanog.org/meetings/nanog29/presentations/aol-backbone.ram > >
