Hi Jeffrey,
On 11/5/15, 7:19 AM, "Jeffrey (Zhaohui) Zhang" <[email protected]> wrote: >Hi, > >I have a few questions: > > On the S-PEs, the pseudowires from the Access PEs are terminated onto > VRFs, such that all pseudowires within a given redundancy set > terminate on a single IP endpoint on the S-PEs. To achieve this, the > S-PEs in a given Redundancy Group are configured with the same > Anycast IP and MAC addresses on the virtual (sub)interface > corresponding to the VRF termination point. > >Is the virtual interface (like) an IRB interface? No IRB interface in this case. This is the virtual interface/sub-interface address. > > Since the S-PEs are running in EVPN single-active redundancy mode, > the S-PEs would advertise an Ethernet AD route per vES with the > single-active flag set per [RFC7432]. Since only the DF S-PE has its > access pseudowire in Active state, only that device would establish > an eBGP session with the CE and receive control and data traffic. > >Will the IRB/virtual interface on a non-DF PE be up? I assume it is - >even though the PW is not active. Would the non-DF PE keeps trying to >establish the eBGP session with the CE? Would that cause issue to the >session between CE and the DF PE? The backup PW will be in stand-by mode (not up) and thus there won¹t be a eBGP session established between non-DF and the CE. Only when the non-DF becomes DF, then eBGP session gets established. > > The > DF S-PE advertises host prefixes that it receives, from the CE over > the eBGP session, to other PEs in the EVI using EVPN route type-5, > with the proper ESI set. Remote PEs learn the host prefixes and > associate them with the ESI, using the advertising PE as the next-hop > for forwarding. > >Would he DF S-PE advertise other prefixes received on the eBGP session? I >assume so but the text only says host prefixes. That¹s Correct. There will be other prefixes. We¹ll take care of it in the next rev. > > Other S-PEs in the same Redundancy Group as the advertising PE will > receive the same EVPN route type-5 advertisement, and will recognize > the associated ESI as a locally attached vES. > >What is the RT that limits the routes to be imported only the PEs in the >same redundancy group? Is it that all PEs in the same EVPN instance will >import the routes? Or is it that different redundancy groups will have >different EVPN instances? I assume it's latter (since we need one IRB >interface for each redundancy group?). The RT will be the RT associated with the vES/ES. > > The withdrawal of the Ethernet > Segment route serves as an indication to the backup S-PE to go active > (i.e. act as a backup DF), and activate its pseudowires to the Access > PE. The withdrawal of the Ethernet A-D route triggers a "mass > withdraw" on the remote PEs: these PEs adjust their next-hop > associated with the prefixes that were originally advertised by the > failed PE to point to the "backup path" per [RFC7432]. > >Can you elaborate the procedure for the PEs to adjust their next-hop? Please refer to sections 8.4 and 14.1.1. > >I don't see reference to draft-ietf-bess-evpn-vpws. Is that used at all? Evpn-vpws is not used but it can be used to reduce the PW provisioning to only single-side. Cheers, Ali > >Thanks. >Jeffrey _______________________________________________ BESS mailing list [email protected] https://www.ietf.org/mailman/listinfo/bess
