Subject: Re: IP Source Route Option

From: [email-masked]
Date: Thu, 26 Apr 2001 16:51:16 +0530

hi mohit!
     yes that is a definite problem and our point regarding the record route
being filled in my the ingress is also not done bacause ingress can not know the
IP address of all intermediate LSR's IP addresses. So even that cannot be done.
Sorry I dont  have the answer to this. My best guess is that these troublesome
options cannot be supported for MPLS. Easy after all , eh?! ;o)))

ciao
sumit

[email-masked] on 04/26/2001 04:54:42 PM

To:   Sumit Chauhan/HSS@HSS
cc:   [email-masked]

Subject:  Re: IP Source Route Option

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

[email-masked] on 04/26/2001 04:23:23 PM

To:   Mohit Goel/HSS@HSS
cc:   [email-masked]

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

[email-masked] on 04/26/2001 04:20:06 PM

To:   [email-masked]
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

---

From: "Loa Andersson" <[email-masked]>
Date: Fri, 27 Apr 2001 07:36:02 +0200

All,

why not forward on L3?

/Loa

-- 
Loa Andersson
Chief Architect,
Utfors Research, Architecture and Future Lab (URAX)
Utfors AB
Råsundavägen 12
Box 525, 169 29 Solna
Office          +46 8 5270 2000
Office direct   +46 8 5270 5038
Mobile          +46 70 848 5038
Email           [email-masked]
WWW             www.utfors.se

---

From: "Vincent Hamrick" <[email-masked]>
Date: Fri, 27 Apr 2001 09:58:04 -0400

Could this be a use for the Router Alert label?

-V

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
[email-masked]
Sent: Thursday, April 26, 2001 7:21 AM
To: [email-masked]
Cc: [email-masked]
Subject: Re: IP Source Route Option

hi mohit!
     yes that is a definite problem and our point regarding the record route
being filled in my the ingress is also not done bacause ingress can not know
the
IP address of all intermediate LSR's IP addresses. So even that cannot be
done.
Sorry I dont  have the answer to this. My best guess is that these
troublesome
options cannot be supported for MPLS. Easy after all , eh?! ;o)))

ciao
sumit

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

To:   Mohit Goel/HSS@HSS
cc:   [email-masked]

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

To:   [email-masked]

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