ietf
[Top] [All Lists]

RE: [mpls] Last Call: <draft-ietf-mpls-in-udp-04.txt> (Encapsulating MPLS in UDP) to Proposed Standard

2014-01-27 16:18:34
Hi Curtis, 

-----Original Message-----
[my post chopped]


Reality check time.

To get the PW over MPLS drafts past the TSV AD there is a SHOULD regarding
congestion control.

AFAIK: No service providers ask for it.  No one implements it.  If they did
implement it no one would deploy it.

PW over MPLS is generally carrying relatively low volumes of high priority
traffic.  The TC bits (MPLS flavor of Diffserv DSCP) are used to enforce the
higher priority.  If congestion occurs other traffic on that infrastructure
(typically plain old Internet) sees loss.  That is intended.  This is the 
reality of
how PW over MPLS is deployed.

Anyone who knows of implementation or deployment of congestion control for
PW over MPLS can correct me.

I don't know about the "over GRE" or "over L2TP" tunneling.

Essentially, my point is that with traditional carriage environments there is 
an underlying medium which it may be possible to traffic engineer.
The value of a SHOULD is that it isn't necessary to there is a valid reason not 
to follow it (i.e. you control the medium and/or the ingress traffic flows and 
the traffic remains private).  The onus remains on the implementer and deployer 
not to mess up the Internet.

I think that similar guidance may be applicable in this case (as in GRE and 
L2TP encapsulations), where the next label switch could be across paths shared 
with other Internet traffic that has congestion avoidance, mitigation or 
control.

Sincerely, 

Greg Daley

<Prev in Thread] Current Thread [Next in Thread>