The MPLS WG Archive

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

In message <4B6D09F3B826D411A67300D0B706EFDE84A489@nt-exch-yow.pmc-sierra.bc.ca
> > 
> > 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.
> 
> BW is BW, be it LSP BW or IP BW. You are consuming BW resources.

I'm using BE not EF.

> > 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.
> 
> Actually there is no need for processing the identifier. The identifier is on
> ly
> a pointer to the corresponding state machine. And in fact the Ping's draft re
> quires
> a similar identifier:
> 
> 
>    "If there are multiple LSPs between the ingress and egress LSRs, the
>    ECHO_REQUEST messages MUST be differentiated by using unique
>    identifiers in the Identifier field of the ECHO_REQUEST message."
> 
> And I would say the Ping's proposal is more complex because not only you need
>  to check the mentioned identifier but also you need to check both the source
>  IP address in the ICMP ECHO response too.


Implementation hint.  Since this is a unique 32 bit integer sent by
the ingress and interpreted only by the ingress, a table index would
be a good choice of number to stick in there.

I hope I don't have to argue with you about whether a table index
lookup incurs excessive processing overhead.

Curtis