The MPLS WG Archive

[Apratim Mukherjee <ApratimM@netbrahma.com>]

Hi,

The Label Request Object carries the L3PID expected to be supported at the 
'reciever' .
draft-ietf-mpls-rsvp-lsp-tunnel-08.txt:
"If the receiver cannot support the protocol L3PID, it SHOULD send a PathErr
with the error code "Routing problem" and the error value"Unsupported
L3PID."  This causes the RSVP session to fail."
But it is not clear to me as to where the check for this support is to be
carried out . Existing documents ( especially the Juniper implementation
white paper ) seem to suggest that this check should be carried out at every
LSR . 
But , lets look at a situation :
Ingress-->LSR1-->LSR2--->Egress
IPv6        IPv4       IPv4      IPv6 

So , in this case the LSP will be aborted at  LSR1 itself. However , if the
check were to be made only at the egress , the Lsp would have been set up
and data packets also would have gone through , since they do not need any
IPv6 support at either LSR 1 or LSR 2, they need it only at the Ingress and
Egress .

Please tell me if I am missing out on something here,
Thanks,
Apratim