Jai, The new DF becomes DF because it re-runs DF election. Thx Jorge
From: Jaikumar Somasundaram <jaikumar.somasunda...@ericsson.com> Date: Thursday, October 4, 2018 at 12:23 PM To: "Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.raba...@nokia.com>, "bess@ietf.org" <bess@ietf.org> Cc: Jiang He <jiang...@ericsson.com>, P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com> Subject: RE: [bess] EVPN MH: Backup node behavior in Primary Path Failure In-line. From: Rabadan, Jorge (Nokia - US/Mountain View) <jorge.raba...@nokia.com> Sent: Thursday, October 4, 2018 3:33 PM To: Jaikumar Somasundaram <jaikumar.somasunda...@ericsson.com>; bess@ietf.org Cc: Jiang He <jiang...@ericsson.com>; P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com> Subject: Re: [bess] EVPN MH: Backup node behavior in Primary Path Failure In-line. Thx Jorge From: Jaikumar Somasundaram <jaikumar.somasunda...@ericsson.com<mailto:jaikumar.somasunda...@ericsson.com>> Date: Thursday, October 4, 2018 at 11:28 AM To: "Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.raba...@nokia.com<mailto:jorge.raba...@nokia.com>>, "bess@ietf.org<mailto:bess@ietf.org>" <bess@ietf.org<mailto:bess@ietf.org>> Cc: Jiang He <jiang...@ericsson.com<mailto:jiang...@ericsson.com>>, P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com<mailto:p.muthu.arul.mo...@ericsson.com>> Subject: RE: [bess] EVPN MH: Backup node behavior in Primary Path Failure Thanks Jorge for the quick reply. Please find further question below. From: Rabadan, Jorge (Nokia - US/Mountain View) <jorge.raba...@nokia.com<mailto:jorge.raba...@nokia.com>> Sent: Thursday, October 4, 2018 1:52 PM To: Jaikumar Somasundaram <jaikumar.somasunda...@ericsson.com<mailto:jaikumar.somasunda...@ericsson.com>>; bess@ietf.org<mailto:bess@ietf.org> Cc: Jiang He <jiang...@ericsson.com<mailto:jiang...@ericsson.com>>; P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com<mailto:p.muthu.arul.mo...@ericsson.com>> Subject: Re: [bess] EVPN MH: Backup node behavior in Primary Path Failure Hi, Questions: 1. Will the node in backup mode forward the packet to CE? [JORGE] as soon as it becomes DF it can forward packets to the CE. The backup node will have to run DF election upon the ES route withdrawal from the primary. If AC-DF is enabled, it can also react to the withdrawal of AD routes from the primary PE. [Jai] Does that mean if any packet comes to a node that is still in the backup mode will get dropped, before the new DF election is complete? Why cant this be used as FRR? Or what is the use case of having backup node(s)? [JORGE2] when the primary node fails, ES and AD routes are withdrawn. The AD route withdrawal is an indication for remote nodes that they have to send traffic to the backup (for a given MAC) or to flush the MACs if there are more than 2 PEs in the ES. Around the same time or maybe earlier, the ES route withdrawal will make the backup PE take over as DF [Jai] will it become DF without DF election? What if there is more than one PE in backup mode? . So the overall convergence time will depend on how/when those two things happen in time. Only the DF PE can forward traffic. A non-DF can never forward traffic or there will be risk of duplicate packets. 2. Will all the nodes in backup mode forward the packet before DF election? [JORGE] Only the new DF can forward. 3. If they forward, how is duplicate packets handled, in this case? [JORGE] see above. My two cents.. Thanks. Jorge From: BESS <bess-boun...@ietf.org<mailto:bess-boun...@ietf.org>> on behalf of Jaikumar Somasundaram <jaikumar.somasunda...@ericsson.com<mailto:jaikumar.somasunda...@ericsson.com>> Date: Thursday, October 4, 2018 at 10:03 AM To: "bess@ietf.org<mailto:bess@ietf.org>" <bess@ietf.org<mailto:bess@ietf.org>> Cc: Jiang He <jiang...@ericsson.com<mailto:jiang...@ericsson.com>>, P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com<mailto:p.muthu.arul.mo...@ericsson.com>> Subject: [bess] EVPN MH: Backup node behavior in Primary Path Failure Hello Everyone, Sorry if it is a duplicate. I repost this query as I did not receive any response yet. (I was wondering if this mail already reached the group or not) I have a question on Primary PE encountering a failure in EVPN multihoming in single active mode. RFC7432, section 14.1.1: <snip> If there is more than one backup PE for a given ES, the remote PE MUST use the primary PE's withdrawal of its set of Ethernet A-D per ES routes as a trigger to start flooding traffic for the associated MAC addresses (as long as flooding of unknown unicast packets is administratively allowed), as it is not possible to select a single backup PE. </snip> Questions: 1. Will the node in backup mode forward the packet to CE? 2. Will all the nodes in backup mode forward the packet before DF election? 3. If they forward, how is duplicate packets handled, in this case? Please help me anwere these questions. Thanks & Regards Jaikumar S
_______________________________________________ BESS mailing list BESS@ietf.org https://www.ietf.org/mailman/listinfo/bess
