The MPLS WG Archive

[Curtis Villamizar <curtis@workhorse.fictitious.org>]

In message <4B6D09F3B826D411A67300D0B706EFDE84A483@nt-exch-yow.pmc-sierra.bc.ca
>, Shahram Davari writes:
> Curtis,
>  
> > The rate should be configurable.  If you want to fix it at one second
> > in your network you can still do so.  
> 
> Being configurable is different than being variable ! You were arguing
> that the ingress should vary its rate.

Target rate should be configurable.  Actual rate should be fixed
unless stability is threatenned.  Stability is alway more important
than accurate measurement.

> It is fairly obvious that the BW usage in LSP-ping method is double of the
> Harrison's proposal. And as Dave McDyson mentioned BW usage is an important 
> factor. It seems redundant to me, to feedback the information to the source, 
> when there is no problem.

Dave was referring to the forward path BW on a strictly provisioned
LSP, not the return path which is of a traffic class (IP control
traffic) that should have plenty of excess bandwidth.

> > Current hardware does not remember the prior label after it is popped,
> > so there may be a problem identifying the LSP after inspecting what is
> > underneath it.  For that we made need to limit TTL, recognize the the
> > bottom label is special (whether MPLS-OAM or IPv4 Explicit Null) and
> > process according to the banished TTL expired rules.
> 
> This problem is solved easily in Harrison's draft by using a TTSI identifier.
> 
> -Shahram 

Both the TTSI and any identifier in a regularly sent UDP will require
processing and therefore are undesirable except in checks run at a
frequency lower than the basic connectivity check.

Curtis