2 Aug
2026
2 Aug
'26
11:21 a.m.
On Sun, 2 Aug 2026 at 12:31, Mark Tinka <mark@tinka.africa> wrote:
An obvious case against multi-level IS-IS is that to create end-to-end MPLS LSP's, you need each node to have every other node in its LFIB.
I think 'end-to-end' here can be defined in many ways. But I would consider seamless MPLS as end-to-end, and of course in this case you have no global IGP, you have metros having their own level2, and core having its own level2, none of them communicate. I've done that as well, and that's generally the approach if you cannot justify global L2, there is no real case for L1, L1L2, L2 design. -- ++ytti