The Routing Over Large Clouds Mailing List Archive by date

[Grenville Armitage <gja@bellcore.com>]

Andy,

>>However, I (as an equipment purchaser) would think twice before
>>purchasing any router, cell switching or otherwise, that doesn't meet
>>at least the most important requirements in RFC 1812 (Requirements for
>>IP Version 4 Routers).  High on the list is the requirement to
>>decrement TTL and not forward packets with a TTL of zero.

Not focussing on the 'router' per se, but the end to end impact...

The implicit comparison with NHRP has me confused. So confused I
went back and spent 35 minutes scanning the spec (and then realized
in was version 07 just towards the end - but I digress...)

What's the problem with nodes not decrementing TTLs, given that
(as far as I can tell) the same end to end effect will be the
result of using NHRP ?  (i.e. packets will arrive closer to, or
at, the destination with TTL that doesn't reflect the actual
number of IP hops according to IP topology.)

The only reason I could think of is that CSRs might be vulnerable
to non-damped routing loops, while NHRP can detect them during the
query/response phase. Is that what you're getting at? (And if
so, would anyone like to hazard a guess at exactly how vulnerable
they are?)

cheers,
gja