> Right, which is probably why routers today can count badly > checksum'ed Ethernet frames, but don't have the equivalent > for MPLS. If Ethernet frames keep failing the check, you know you have a local problem that needs fixing. That's why it's instrumented. Do any routers count TCP/UDP checksum failures, much less expose the count via SNMP? Lloyd Wood http://about.me/lloydwood ________________________________________ From: Mark Tinka [mark.tinka@xxxxxxxxx] Sent: 12 January 2014 12:26 To: mpls@xxxxxxxx Cc: Wood L Dr (Electronic Eng); adrian@xxxxxxxxxxxx; randy@xxxxxxx; gorry@xxxxxxxxxxxxxx; lisp@xxxxxxxx; ietf@xxxxxxxx; david.black@xxxxxxx; jnc@xxxxxxx; tsvwg@xxxxxxxx Subject: Re: [mpls] draft-ietf-mpls-in-udp was RE: gre-in-udp draft (was: RE: [tsvwg] Milestones changed for tsvwg WG) On Sunday, January 12, 2014 04:59:41 AM l.wood@xxxxxxxxxxxx wrote: > The MPLS assumption is that it's protected and checked by > a strong link CRC like Ethernet, and checked/regenerated > by stack processing between hops; here, in a path > context, with zero UDP checksums MPLS has no checking at > all. Right, which is probably why routers today can count badly checksum'ed Ethernet frames, but don't have the equivalent for MPLS. > I'm sorry, when was MPLS cheap? Current-generation ASIC's have no problem forwarding MPLS frames at wire rate. One could go so far as to say that MPLS has allowed vendors to make cheaper line cards also because IP FIB's and traffic queues can be scaled down dramatically (not that I'd every buy such line cards, but...). Mark.