From: Robert Shearman <rshea...@brocade.com> Date: Fri, 10 Mar 2017 20:43:23 +0000
> It is sometimes desirable to present an MPLS transport network as a > single hop to traffic transiting it because it prevents confusion when > diagnosing failures. An example of where confusion can be generated is > when addresses used in the provider network overlap with addresses in > the overlay network and the addresses get exposed through ICMP errors > generated as packets transit the provider network. > > In addition, RFC 3443 defines two methods of deriving TTL for an > outgoing packet: Uniform Model where the TTL is propagated to/from the > MPLS header and both Pipe Models and Short Pipe Models (with and > without PHP) where the TTL is not propagated to/from the MPLS header. > > Changes in v3: > - decrement ttl on popping last label when not doing ttl propagation, > as suggested by David Ahern. > - add comment to describe what the somewhat complex conditionals are > doing to work out what ttl to use in mpls_iptunnel.c. > - rearrange fields fields in struct netns_mpls to keep the platform > label fields together, as suggested by David Ahern. > > Changes in v2: > - add references to RFC 3443 as suggested by David Ahern > - fix setting of skb->protocol as noticed by David Ahern > - implement per-route/per-LWT configurability as suggested by Eric > Biederman > - split into two patches for ease of review Series applied, thanks.
