The MPLS WG Archive

[Ben Mack-Crane <Ben.Mack-Crane@tellabs.com>]

Eric,

I don't know if one could describe the OAM proposal we're working on as
a "connection-oriented ITU-like scheme," but I have often found functional
modeling of layered networks (defined by ITU) useful in understanding how 
networks work (or fail to work) in various configurations.  I have even 
found it useful in understanding connectionless networks.

It seems to me that during its evolution MPLS has developed two personas.
It has a connectionless persona, exemplified by features like independent
unsolicited label distribution and PHP.  It also has developed a connection-
oriented persona with features like LSP tunnels and VPN applications.

For cases in which an LSP must have well-defined endpoints and there is
a need to be able to effectively detect MPLS layer defects (e.g. mis-merging)
some additional OAM features are needed.  These OAM features apply to the
MPLS (shim header) packet layer, not to sub-ip layers (for which similar
OAM features are already defined).

Regards,
Ben Mack-Crane


Eric Rosen wrote:
> 
> Neil> I  guess  the discussion  above  gave enough  pointers  as  to why  an
> Neil> unambiguous location of the trail termination function is important
> 
> Well, I can say that it  didn't give me a clue.  Repeated unsupported claims
> that it is "vital" to follow ITU architectures just aren't very persuasive.
> 
> Are  you expecting  to achieve  WG  consensus on  an OAM  proposal?  If  the
> proposal is  an attempt to warp  an IP-based architecture into  some kind of
> connection-oriented ITU-like scheme,  my guess is that there  is very little
> chance of achieving consensus.
> 
> Actually, I  wonder if the  OAM stuff falls  under the charter of  the CCAMP
> group rather than the MPLS group.