Some feedback :
> (D) Potentially big number of targeted LDP sessions [SLI] Based on our simulation, only 4 T-LDP sessions at max is needed (for our case), 2 or 1 only in most cases. (now routers are able to handle hundreds of LDP sessions without issue, so adding few is not a big deal) > (E) Inability to provide 100% coverage with arbitrary cost structure [SLI] What do you mean exactly ? Do you mean that with some topology, you are unable to have 100% coverage ? Yes, few topologies can't work with rLFA as for LFA ... But is it really an issue ? I'm always trying to see simplicity vs gain ... As you mention rLFA is still an easy mechanism (as LFA is ...), it would provide you strong coverage extension. Note that as already mentionned in the draft (and I'm currently writing some more detail stuff on this), it is still possible to achieve 100% coverage but you should add explicit TE tunnel (implementation may be able to propose to establish it dynamically if it becomes a need). (F) Presented coverage values are not fully convincing due to several reasons (if I was just missing results, then sorry!): (F1) Only relatively dense core-like topologies have been investigated, where LFA is mostly good enough anyway. However, IP/MPLS is getting pushed to the aggregation/access, where the topology is far from being that sparse, there ARE rings and there are (sparse) tree-like topologies which are extended with a few links here and there to boost redundancy. How does it work in such relatively sparse topos? [SLI] It is already planned as far as I know to add new use cases within the doc. I can already say that rLFA works very well with rings. We have plenty variety of rings with different metric patterns, different size of ring, and LFA provides 100% coverage in all of these cases (bidirectional). (F3) Even if an operator tunes its topo to have high RLFA coverage, a topo change might ruin it (e.g. failures, etc.). So, what would be very useful is to see numbers on various topologies how a high coverage value changes with a small modification of the topology (e.g. one or two failures...) [SLI] This is clearly a good point, I think most people are already aware of (I hope :) ), as it concerns already LFA ... If you have a good coverage with your nominal topo, a backup topology may not have a good coverage ... (G) Have not yet seen papers/guidelines how to tune the network to be more RLFA friendly (which is possible, see e.g. (B)) [SLI] this point could be addressed easily ... I do understand that accepting it as a WG item still leaves the opportunity to answer some of these concerns. If we adopt it, I think we should give guidelines on the RLFA friendly topologies and cost structures. [SLI] Doable easily and necessary ;) (I already talked about this with Clarence F.) > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf > Of Alia Atlas > Sent: 2012. május 30. 18:59 > To: [email protected] > Subject: opinions on adoption of draft-shand-remote-lfa as a WG draft > > draft-shand-remote-lfa was presented favorably this last IETF. There > is known IPR associated with it on file ( > https://datatracker.ietf.org/ipr/1770/ ) This draft presents a > solution for IP/LDP fast-reroute that does not guarantee 100% coverage > but can substantially improve coverage over LFAs. > > We would like to initiate a WG poll to determine whether to adopt > draft- shand-remote-lfa. > We are, of course, interested in opinions and reasoning rather than > simple yes/no. > > Thanks, > Alia > _______________________________________________ > rtgwg mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/rtgwg _______________________________________________ rtgwg mailing list [email protected] https://www.ietf.org/mailman/listinfo/rtgwg _________________________________________________________________________________________________________________________ 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, France Telecom - 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, France Telecom - Orange is not liable for messages that have been modified, changed or falsified. Thank you. _______________________________________________ rtgwg mailing list [email protected] https://www.ietf.org/mailman/listinfo/rtgwg
