> 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
