On 22/Oct/15 21:35, Dave Bell wrote:
I'm unsure if this is a serious argument, but its such a poor point today. Everything has to be connected to a level 2 in IS-IS. If you want a flat area 0 network in OSPF, go nuts. As long as you are sensible about what you put in your IGP, both IS-IS and OSPF scale very well.
The differences between the two protocols are so small, that people really grasp at straws when 'proving' that one is better over the other. 'IS-IS doesn't work over IP, so its more secure'. 'IS-IS uses TLVs so new features are quicker to implement'. While these may be vaguely valid arguments, they don't hold much water. If you don't secure your routers to bad actors forming OSPF adjacencies with you, you're doing something wrong.Who is running code that is so bleeding edge that feature X might be available for IS-IS, but not OSPF?
Chose whichever you and your operational team are most comfortable with, and run with it.
OSPFv3 scaled better than OSPFv2 in 2008. But multi-AF support for OSPFv3 was only developing then, so that was not a viable replacement for OSPFv2. OSPFv2 should scale better in 2015 (I say "should" because more routers now have x86-based control planes, but I don't run OSPF so I'm hand-waving). You're right, a single Level-2 domain in IS-IS is akin to a single Area 0 in OSPF. But those "so small" differences between the protocols in 2008 meant I was less eager to try the single area with OSPF than I was the single level with IS-IS. Mark.