Re: [bess] A doubt about draft-sajassi-bess-evpn-ip-aliasing-05

["Jorge Rabadan (Nokia)" <[e-mail]>]

Hi Sasha,

The document explicitly mentions single-active and all-active. Maybe we can add a sentence saying that those are the two multi-homing modes addressed by the spec. I don’t think we should mention anything else?

Thanks.
Jorge

From: Alexander Vainshtein <[e-mail]>
Date: Wednesday, November 23, 2022 at 11:36 PM
To: Ali Sajassi (sajassi) <[e-mail]>
Cc: Luc André Burdet <[e-mail]>, [e-mail] <[e-mail]>, Nitsan Dolev <[e-mail]>, Alexander Ferdman <[e-mail]>, Ron Sdayoor <[e-mail]>, Dmitry Valdman <[e-mail]>, [e-mail] <[e-mail]>
Subject: RE: A doubt about draft-sajassi-bess-evpn-ip-aliasing-05
Hi Ali,
Lots of thanks for a prompt response and my sincere apologies for a much-delayed response.
Your response matches my understanding.

May I suggest that, since draft-sajassi-bess-evpn-ip-aliasing-05<https://clicktime.symantec.com/15siKyXAKWkixmcG2nv1Y?h=ewnEsUd2iE4xin3_mbyooIY1ENSU7btYKRsi0Xr6wM8=&u=https://datatracker.ietf.org/doc/html/draft-sajassi-bess-evpn-ip-aliasing-05> is not intended for use with single flow-active multi-homing, this would be explicitly stated in the next revision of the draft?

Regards, and lots of thanks in advance,
Sasha

From: Ali Sajassi (sajassi) <[e-mail]>
Sent: Thursday, November 17, 2022 5:49 PM
To: Alexander Vainshtein <[e-mail]>; [e-mail]
Cc: Luc André Burdet <[e-mail]>; [e-mail]; Nitsan Dolev <[e-mail]>; Alexander Ferdman <[e-mail]>; Ron Sdayoor <[e-mail]>; Dmitry Valdman <[e-mail]>
Subject: [EXTERNAL] Re: A doubt about draft-sajassi-bess-evpn-ip-aliasing-05

Hi Sasha,

EVPN based RFCs (7432 and 8365) define two types of multi-homing: All-Active and Single-Active. Both of these multi-homing mechanism relies on multi-homing PEs to control loop detection and prevention using DF election and split-horizon filtering.  draft-ietf-bess-evpn-l2gw-proto-02<https://clicktime.symantec.com/15siF9Ksru58YpnLVEWrv?h=gJyaiM0MQ9etseWoNrSRgEXyb9bM6DrwLUAnALqYv_g=&u=https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-l2gw-proto-02> introduces a 3rd multi-homing mechanism called Single-Flow-Active for scenarios where loop detection and prevention are performed by CE devices (running L2GW protocols) and not PEs.

draft-sajassi-bess-evpn-ip-aliasing-05<https://clicktime.symantec.com/15siKyXAKWkixmcG2nv1Y?h=ewnEsUd2iE4xin3_mbyooIY1ENSU7btYKRsi0Xr6wM8=&u=https://datatracker.ietf.org/doc/html/draft-sajassi-bess-evpn-ip-aliasing-05> basically extends the baseline multi-homing mechanism of All-Active to L3 use cases mentioned in the draft (e.g., symmetric IRB). This draft is NOT intended for Single-Flow-Active multi-homing use case.  If single-flow-active multi-homing need to get extended to L3 use cases, then it can be covered in a follow-up single-flow-active draft.

Cheers,
Ali

From: Alexander Vainshtein <[e-mail]<mailto:[e-mail]>>
Date: Thursday, November 17, 2022 at 2:25 AM
To: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Cc: Luc André Burdet <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, Nitsan Dolev <[e-mail]<mailto:[e-mail]>>, Alexander Ferdman <[e-mail]<mailto:[e-mail]>>, Ron Sdayoor <[e-mail]<mailto:[e-mail]>>, Dmitry Valdman <[e-mail]<mailto:[e-mail]>>
Subject: A doubt about draft-sajassi-bess-evpn-ip-aliasing-05
Hi,
I have doubts regarding applicability of the solution for L3 fast convergence defined in draft-sajassi-bess-evpn-ip-aliasing-05<https://clicktime.symantec.com/15siKyXAKWkixmcG2nv1Y?h=ewnEsUd2iE4xin3_mbyooIY1ENSU7btYKRsi0Xr6wM8=&u=https://datatracker.ietf.org/doc/html/draft-sajassi-bess-evpn-ip-aliasing-05> for the scenarios in which the MH ES in question operates in Single Flow-Active load-balancing mode as described in draft-ietf-bess-evpn-l2gw-proto-02<https://clicktime.symantec.com/15siF9Ksru58YpnLVEWrv?h=gJyaiM0MQ9etseWoNrSRgEXyb9bM6DrwLUAnALqYv_g=&u=https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-l2gw-proto-02>.

These doubts are based on the fact that, in Single Flow-Active load-balancing mode, the Primary PE is defined by the Layer 2 Control Protocol (or its equivalent) for each specific host, while the EVPN IP Aliasing draft advertises Primary/Backup paths via P/B bits in the EVPN Layer 2 Extended Community attached to the IP A-D EVPN routes.

What, if anything, did I miss?

Your feedback would be highly appreciated.

Regards, and lots of thanks in advance,
Sasha


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