Subject: [bess] Opsdir last call review of draft-ietf-bess-evpn-inter-subnet-forwarding-09

From: Joel Jaeggli via Datatracker <[email-masked]>
Date: Mon, 06 Jul 2020 20:06:44 -0700

Reviewer: Joel Jaeggli
Review result: Ready

greetings,

I have reviewed draft-ietf-bess-evpn-inter-subnet-forwarding on behalf of the
ops directorate.

as a datacenter operator something of a conflict appears for me in this work in
that  I struggle with the state explosion that IRBs each host / subnet
represent on the PE switches. As the document says:

   In other words, each PE participating in
   asymmetric IRB MUST maintain ARP entries for remote hosts (hosts
   connected to other PEs) as well as maintain MAC-VRFs/BTs and IRB
   interfaces for ALL subnets in an IP VRF including subnets that may
   not be locally attached.

We designed ourselves into  a corner where we need this document.

it would be helpful if section 4 would be more explicit for non-implementors on
when symetric or asymetric modules would be chosen, as it stands the variation
basically reads like the enumeration of the features of various implementations.

I think this document is ready to proceed and it clearly addresses needs in
these implementations.

joel

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From: "Ali Sajassi (sajassi)" <[email-masked]>
Date: Tue, 7 Jul 2020 21:20:31 +0000

Hi Joel,

Thanks for your review and comments, please see inline for my reply marked with AS>:

On 7/6/20, 8:06 PM, "Joel Jaeggli via Datatracker" <[email-masked]> wrote:

    Reviewer: Joel Jaeggli
    Review result: Ready

    greetings,

AS> There are tradeoffs between symmetric and asymmetric IRB among which the scale in terms of # of bridge tables, # of ARP entries, and # of MAC addresses that a PE need to keep. I will add a note to section 4 that for asymmetric IRB application, careful consideration needs to be given for these scale aspects.

Regards,
Ali

    joel