The MPLS WG Archive

[mgoel@hss.hns.com]

Hi Sumit !

But how mpls will handle the IP's Record route option which requires that each
intermediate router should insert its IP address in the datagram. MPLS cannot
drop that packet simply because record route option is enabled in it. Moreover
if explicit routing is there then ingress router can insert the complete IP
addresses of the intermediate LSRs in the datagram, but what will happen in the
case of hop by hop LSP.

Thanks
Mohit Goel





suchauhan@hss.hns.com on 04/26/2001 04:23:23 PM

To:   Mohit Goel/HSS@HSS
cc:   mpls@UU.NET

Subject:  Re: IP Source Route Option






hi mohit!
     Ideally this thing should be handled at the Ingress LER and he should
translate the IP Source Route to MPLS sourse Route by defining a complete path
for the packet (means asking the downstream routers for this). The question
still hold weight as to what should be done if such a path does not exist at the
time of the packet coming in or the path cannot be setup even when requested. My
guess is that its best in both cases to discard the packet and send a normal
ICMP packet back to source as is normally done.  Going a bit deeper we generally
use IP Source Routing for testing purposes and not as a means of data path
reservation. Hence it might make sense to try and set up the LSP requested
starting at the Ingress LER to the Egress LER if possible while holding on to
the packet. This does complicate things but I guess if we have to do source
routing we have to do this. ;o(
regards
sumit




mgoel@hss.hns.com on 04/26/2001 04:20:06 PM

To:   mpls@UU.NET
cc:    (bcc: Sumit Chauhan/HSS)

Subject:  IP Source Route Option






Hi All,

I have a small doubt. Let an unlabelled IP packet with IP source route option
enabled comes in MPLS domain. Let the packet is assigned to a LSP (say numbered
1). While traversing the MPLS domain, packet will not go to the Network layer,
thus the LSR in between the ingress LSR and egress LSR cannot insert their IP
addresses in the datagram. So does MPLS supports IP source route option or it
does not support it?

Thanks
Mohit Goel