rja@corp.home.net (Ran Atkinson) writes:

Letting LSR in two hops lets outsiders trying to debug (e.g. some routing problem) at least perform first-level fault-isolation so they know whose NOC to call for further debugging assistance. So I view the 2-hop notion as an attempt at "reasonable compromise".

Cool, and I now view the 2-hop notion as the first reasonable argument for encouraging people to totally flatten their network into a full mesh. Security policy should not under any circumstances prevent the Internet as a whole from functioning reasonably well, scaling decently, or make discovering and diagnosing problems any harder than it already is. Your opinion may vary with mine, but I am solidly in line with Randy's suggestion that enabling LSRR on backbone routers should be a requirement for peering. (This is not surprising as I used to require it of a couple of peers in a previous life, because in practice it is unfortunately an irreplaceable diagnostic tool). Sean.