Re: [Bier] BIER WGLC: draft-ietf-bier-php

[Greg Mirsky <[e-mail]>]

Hi Jeffrey,
thank you for your consideration and for addressing my comments.

Regards,
Greg

On Thu, Oct 3, 2019 at 6:29 PM Jeffrey (Zhaohui) Zhang <[e-mail]>
wrote:

> Hi,
>
>
>
> I have posted -03 revision that addresses all comments from Greg,
> Nagendra, and Sandy: https://www.ietf.org/id/draft-ietf-bier-php-03.txt.
>
>
>
> Thanks!
>
> Jeffrey
>
>
>
> *From:* Jeffrey (Zhaohui) Zhang
> *Sent:* Saturday, September 28, 2019 3:55 PM
> *To:* 'Nagendra Kumar Nainar (naikumar)' <[e-mail]>; BIER WG <
> [e-mail]>; [e-mail]
> *Subject:* RE: [Bier] BIER WGLC: draft-ietf-bier-php
>
>
>
> Hi Nagendra,
>
>
>
> Please see zzh> below.
>
>
>
> *From:* Nagendra Kumar Nainar (naikumar) <[e-mail]>
> *Sent:* Friday, September 27, 2019 7:19 AM
> *To:* [e-mail]; BIER WG <[e-mail]>
> *Cc:* [e-mail]
> *Subject:* Re: [Bier] BIER WGLC: draft-ietf-bier-php
>
>
>
> Hi,
>
>
>
> Support.
>
>
>
> I have a couple of comments as below:
>
>
>
>    1. Based on the Introduction section, the upstream BFR that pops the
>    BIER header can be directly to PE (BIER incapable) or through a tunnel. In
>    case of non-directly connected BFR, Is it really “PHP” or is it BIER to LSP
>    stitching?.
>
>
>
> Zzh> From BIER point of view, it is indeed PHP, because it happens on the
> BFR upstream of the edge router (the BFER if it did support BIER).
>
>
>
>    1. In addition to the assumption/limitation mentioned in the start of
>    Section 3, I think this draft assumes the presence of LSP tunnel between
>    the upstream BFR and BIER-incapable PE. If it is non-MPLS network, does it
>    expect to encapsulate with IP/UDP?. Either way, I think it is better to
>    clarify the same in the draft.
>
>
>
> Zzh> Any tunnel is fine. Please also see below for the restriction
> mentioned in the start of Section 3 (where IP tunnels may be used in case
> of EVPN-vxlan/gre).
>
>
>
>    1. The introduction says the below:
>
> “
>
> While the above text uses MVPN/EVPN as example, BIER PHP is
>
>    applicable to any scenario where the multicast flow overlay edge
>
>    router does not support BIER.”
>
>
>
> The above appears to contradict with section 3 that says, BIER PHP is
> applicable only when BIER NH =1.
>
>
>
> Zzh> Good catch. It does apply to the following scenario as well, as
> described in the earlier version of the spec (
> https://tools.ietf.org/html/draft-zzhang-bier-php-01):
>
>
>
>    The procedures in this section can be applied only if, by means
>
>    outside the scope of this document, it is known that one of the
>
>    following conditions is met.
>
>
>
>    o  The payload after BIER header is IPv4 or IPv6 (i.e., the Proto
>
>       field in the BIER header is 4 or 6).
>
>       Notice that in this case the Destination Address in the IPv4/IPv6
>
>       header must be in the address space for the BIER layer.
>
>
>
> Zzh> It was taken out per advices given during WG adoption I think, but
> the introduction section was not changed accordingly. The reason for taking
> it out is that for the “BFER” to route IP (multicast) packets it needs to
> know the RPF interface, so it’s likely to use GTM [RFC7716] with a DCB
> label [bess-mvpn-evpn-aggregation-label], which is covered by the condition
> in section 3.
>
>
>
> Zzh> On the other hand, when BIER is used for EVPN-overlay (
> https://tools.ietf.org/html/draft-ietf-bier-evpn-01), since the
> vxlan/nvgre header uses global VNI/VSID to identify broadcast domains, it
> will also work.
>
>
>
> Zzh> In short, as long as the BFER does not rely on knowing the BFIR, it
> will work.
>
>
>
> Zzh> So I plan to add “as long as the edge router does not need to know
> the transmitting BFIR” to the text you quoted, and add the vxlan/nvgre
> scenario to section 3.
>
> Zzh> Thanks!
>
> Zzh> Jeffrey
>
>
>
> Regards,
>
> Nagendra
>
>
>
> *From: *BIER <[e-mail]> on behalf of Greg Shepherd <
> [e-mail]>
> *Reply-To: *"[e-mail]" <[e-mail]>
> *Date: *Friday, September 20, 2019 at 5:22 PM
> *To: *BIER WG <[e-mail]>
> *Subject: *Re: [Bier] BIER WGLC: draft-ietf-bier-php
>
>
>
> We're long past Aug 13th and not one response. PLEASE read and respond or
> we'll just let this expire.
>
>
>
> Thanks,
>
> Greg
>
>
>
> On Tue, Jul 30, 2019 at 11:23 AM Greg Shepherd <[e-mail]> wrote:
>
> Please read and respond to this thread:
>
>
>
> https://datatracker.ietf.org/doc/draft-ietf-bier-php/
> <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-ietf-bier-php/__;!8WoA6RjC81c!U17M0xuXqFjEd95HNxPeY_ujEfDmpbM2lywc1ZmclPy6K3fz8WnBGIfTfgpee9ht$>
>
>
>
> EOTWT: Aug 13th.
>
>
>
> Thanks,
>
> Shep
>
> (chairs)
>
>