Hi Shraddha, please see inline:
On 13/10/17 15:49 , Shraddha Hegde wrote:
Stephane, In certain cases MPLS forwarding may not be supported on some legacy linecards.
The problem you are describing is not SR specific, it would apply to LDP as well. So the indication should not be about SR, but about MPLS forwarding support on interface.
With MPLS being deployed for more then 20 years, I wonder why there was no need to solve this issue earlier and why we need to address it now with SR.
Since these links should be used for IP forwarding IGPs will advertise these links. It is better to have explicit indication of this rather than use absence of adjacency-sid on the link. With the new SR flag, while the SPF and the SR-Path does not change, there is an indication To the controller and head-end nodes that the links cannot do SR-MPLS forwarding. The controller or head-end implementations may have mechanisms to prevent pulling Traffic on SR paths. When Head-end node detects a prefix-sid path going through such incapable links It may skip installing SR paths for such prefix-SID and implementations may decide to use other mechanisms (such as RSVP or IP) at the head-end which would prevent Traffic loss. This is also a useful tool during transition to SR when certain links should avoid carrying SR traffic due to operational reasons.
there are standardized mechanisms like affinities that can be used to address above mentioned operational issue.
thanks, Peter
Rgds Shraddha -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Thursday, October 12, 2017 4:03 PM To: [email protected]; [email protected] Subject: RE: [Isis-wg] WG Adoption poll for draft-hegde-isis-advertising-te-protocols Hi Authors, One question, why do you think it is really needed to introduce the SR flag ? Couldn't it be deduced from the presence of an Adj-SID and the SR router cap ? The SR flag unset while the router supports SR looks strange to me. Why do you want to prevent "SR forwarding" on a link if the node supports SR ? " With this information, a centralized application can decide to use a different path for that traffic by using a different label stack." In such a case, the usage of a Node-SID may be complex, as the Node-SID may cross a link with the SR flag unset. This will force the controller to use Adj-SIDs only. If the controller uses only Adj-SIDs, then an implementation can allow the user to prevent the advertisement of Adj-SIDs on a particular link. Could you clarify the use case here ? Thanks, -----Original Message----- From: Isis-wg [mailto:[email protected]] On Behalf Of Christian Hopps Sent: Saturday, October 07, 2017 04:43 To: [email protected] Cc: [email protected]; [email protected]; [email protected] Subject: [Isis-wg] WG Adoption poll for draft-hegde-isis-advertising-te-protocols Hi Folks, The authors have requested the IS-IS WG adopt https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_doc_draft-2Dhegde-2Disis-2Dadvertising-2Dte-2Dprotocols_&d=DwIFAg&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=NyjLsr7JA7mvpCJa0YmPdVKcmMXJ31bpbBaNqzCNrng&m=C2KWg-TNJXOgV_qiX8ZDhjjJW6rn3GhpPaBzHTDjqZ0&s=lHsxN1TAflKdy5QZ1sKRfmprtswYQGOljhQpvPNoJkE&e= as a working group document. Please indicate your support or no-support for taking on this work. Authors: Please indicate your knowledge of any IPR related to this work to the list as well. Thanks, Chris & Hannes. _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. Thank you. _______________________________________________ Isis-wg mailing list [email protected] https://www.ietf.org/mailman/listinfo/isis-wg .
_______________________________________________ Isis-wg mailing list [email protected] https://www.ietf.org/mailman/listinfo/isis-wg
