On 27/07/2026 19:08, Tom via NANOG wrote:
Hello,
I'm wondering what some practical/real experiences have been with building out a large flat IS-IS network. I've read a lot of threads on conjecture and older docs on what the vendors recommend but haven't found anything yet or real world examples. Two questions,
1) Is anyone running a flat IS-IS L2 network with approx 300 routers? If not, what is the higher end you've seen? 2) On aggregation routers, what is the upper end of IS-IS adj to downstream routers? Would agg routers with approx 100 connections be an issue moving to IS-IS with the addition of keeping track of that many adj?
With today's control planes, 300 nodes is not even a corn flake :-). We did that number back in 2009, on Cisco CRS-1's, ME3600X's and Juniper M320's, T320's and MX480's. The state-of-the-art has moved on a great deal, since then. Mark.