Re: Command Preference?

Brian McGahan @ 29/03/2011 20:23 -0300 dixit:
> Test it out and see for yourself. It's always been a known design problem for OSPF,
> that's the the MTU check is there to begin with.

AFAIK, it's a design *feature*.
At least, that's Moy point of view, citing from "Anatomy of an internet
protocol":
  ...
  Over these data links, it is possible that two neighboring routers will
  disagree on the largest packet that can be sent over the link, which
  causes problems in forwarding. As one router sends a packet that is too
  big for the other to receive, it becomes impossible to deliver large
  packets over certain paths. (One might think that IP fragmentation
  would deal with this situation, but although fragmentation nicely
  handles links with differing MTUs, it assumes that all routers attached
  to a given link agree on that link's MTU.) As a result, OSPF was
  modified to detect and avoid links having MTU mismatches.

i.e. it's done on purpouse.

Given that PMTU discovery can be hard to get done because of security
wizards, having the routing protocol choose routes over a consistent MTU
path sounds right. We should not resort to tcp mss tinkering if it was
always that way.

-Carlos

-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
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