[bess] Re: Rtgdir early review of draft-ietf-bess-evpn-redundant-mcast-source-10

[[e-mail]]

Hi Jorge, 
sorry for the late response. 
The mail was put in wrong folder and I just found it. 
The update of 11 version looks good to me. 
Thanks for the update!
Best regards,
Sandy











Original


From: JorgeRabadan(Nokia) <[e-mail]>
To: 张征00007940;[e-mail] <[e-mail]>;
Cc: [e-mail] <[e-mail]>;[e-mail] <[e-mail]>;
Date: 2024年11月13日 22:03
Subject: Re: Rtgdir early review of draft-ietf-bess-evpn-redundant-mcast-source-10




Hi Zheng,
 
Thank you very much for the review. We addressed all your (very good) points in rev 11.
Please see my comments below with [jorge].
 
Thanks.
Jorge
 
 


From: Zheng Zhang via Datatracker <[e-mail]>
 Date: Wednesday, October 23, 2024 at 9:38 PM
 To: [e-mail] <[e-mail]>
 Cc: [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
 Subject: Rtgdir early review of draft-ietf-bess-evpn-redundant-mcast-source-10




 CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information.
 
 
 
 Reviewer: Zheng Zhang
 Review result: Ready
 
 Hello
 
 I have been selected to do a routing directorate “early” review of this draft.
 https://datatracker.ietf.org/doc/draft-ietf-bess-evpn-redundant-mcast-source/
 
 The routing directorate will, on request from the working group chair, perform
 an “early” review of a draft before it is submitted for publication to the
 IESG. The early review can be performed at any time during the draft’s lifetime
 as a working group document. The purpose of the early review depends on the
 stage that the document has reached.
 
 Document: draft-ietf-bess-evpn-redundant-mcast-source-10.txt
 Reviewer: Zheng Zhang
 Review Date: Oct 24th, 2024
 Intended Status: Standards Track
 
 Summary:
 No issues found. This documents is ready to proceed to next step.
 
 Comments:
 Generally, the draft written clearly.
 Please consider the comments listed to improve the draft.
 Overall, please replace the [I-D.ietf-bess-evpn-irb-mcast] with [RFC9625].
[jorge] done, thanks.

 Please find the comments below with ZZ>.
 
               Multicast Source Redundancy in EVPN Networks
              draft-ietf-bess-evpn-redundant-mcast-source-10
 Abstract
 ......
 1.  Introduction
 ......
    The solution provides support for Warm Standby and Hot Standby
    redundancy.  Warm Standby is defined as the redundancy scenario in
    which the upstream PEs, attached to the redundant sources of the same
    tenant, make sure that only one source of the same flow can send
    multicast to the interested downstream PEs at the same time.  In Hot
    Standby mode, the upstream PEs forward the redundant multicast flows
    to the downstream PEs, and the downstream PEs make sure only one flow
    is forwarded to the interested attached receivers.
 ZZ> It's better to move the Warm Standby and Hot Standby explaination to
 Terminology section.
[jorge] done, thanks.

 
 ......
 4.  Warm Standby (WS) Solution for Redundant G-Sources
 
    The general procedure is described as follows:
 ZZ> It's better to add a 'specification' sub-section for the solution procedure
 description.
[jorge] done, thanks.

 
    1.  Configuration of the upstream PEs
 ......
    2.  Signaling the location of a G-source for a given Single Flow
        Group
 ......
        *  The S-PMSI A-D route is imported by all the PEs attached to
           the tenant domain.  In order to do that, the route will use
           the SBD-RT (Supplementary Broadcast Domain Route Target) in
           addition to the BD-RT (Broadcast Domain Route Target) of the
           Broadcast Domain over which the G-traffic is received.  The
           route SHOULD also carry a Designated Forwarder Election
           Extended Community and a flag indicating that it conveys an
           SFG.  The Designated Forwarder Election extended community and
           its use is specified in [RFC8584].
 ZZ> Since the SBD-RT may not existed if there is no multiple BDs, please add
 "if the SBD exists" to the SBD-RT description.
[jorge] done, thanks.

 
 ......
 4.1.  Warm Standby Example in an OISM Network
 ......
    The Warm Standby solution works as follows:
 ......
    2.  Signaling the location of S1 and S2 for (*,G1)
        Upon receiving (S1,G1) traffic on a local Attachment Circuit, PE1
        and PE2 originate S-PMSI A-D (*,G1) routes with the SBD-RT
        (Supplementary Broadcast Domain Route Target), Designated
        Forwarder Election Extended Community and a flag indicating that
        it conveys a Single Flow Group.
 ZZ> The "a flag" indicates the "Single Flow Group (SFG) flag" defined in
 Multicast Flags Extended Community Flag, right? Please replace the 'a flag'
 with the "SFG flag".
[jorge] yes, it is. I added “and the SFG flag in the Multicast Flags Extended Community, indicating that it conveys a Single Flow Group”

 
 ......
    The end result is that, upon receiving reports for (*,G1) or (S,G1),
    the downstream PEs (PE3 and PE5) will issue SMET routes and will pull
    the multicast Single Flow Group from PE1, and PE1 only.  Upon a
    failure on S1, the Attachment Circuit connected to source S1 or PE1
    itself will trigger the S-PMSI A-D (*,G1) withdrawal from PE1 and PE2
    will be promoted to Single Forwarder.
 ZZ> Please add "IGMP/MLD" in front of "reports for (*,G1) or (S,G1)" in the
 first sentence.
[jorge] done, thanks.

 
 ......
 5.  Hot Standby Solution for Redundant G-Sources
 ZZ> It's better to add a 'specification' sub-section for the solution procedure
 description.
[jorge] done, thanks.

 
    1.  Configuration of the PEs
 ......
        Contrary to what is specified in the Warm Standby method (that is
        ......  The downstream PEs will locally select an Ethernet
        Segment Identifier for a given Single Flow Group, and will
        program a Reverse Path Forwarding check to the (*,G)/(S,G) state
        for the Single Flow Group that will discard (*,G)/(S,G) packets
        from the rest of the Ethernet Segment Identifiers.  The selection
        of the Ethernet Segment Identifier for the Single Flow Group is
        based on local policy.
 ZZ> So different downstream PEs may select different upstream PE, this may be
 described explicitly in the paragraph.
[jorge] Added: “The selection of the Ethernet Segment Identifier for the Single Flow Group is based on local policy, and therefore, different downstream PEs may select different Ethernet Segment Identifiers.”

 
 ......
    3.  Distribution of DCB (Domain-wide Common Block) ESI-labels and
        G-source ES routes
 ......
        b.  The EVPN A-D per EVI and A-D per ES routes MUST include the
            route target SBD-RT since they have to be imported by all the
            PEs in the tenant domain.
 ZZ> Since the SBD may not existed, please add "if the SBD exists" to indicate.
[jorge] done, thanks.

 
 ......
 5.3.  Hot Standby Example in an OISM Network
 ......
    2.  PE1 and PE2 advertise S-PMSI A-D (*,G1) and EVPN ES, A-D per ES
        and A-D per EVI routes
 
        Based on the configuration of step 1, PE1 and PE2 advertise an
        S-PMSI A-D (*,G1) route each.  The route from each of the two PEs
        will include TWO ESI Label Extended Communities with ESI-1 and
        ESI-2 respectively, as well as route target BD1-RT plus SBD-RT
        and a flag that indicates that (*,G1) is a Single Flow Group.
 ZZ> Same with previous comments, please replace "a flag" with "SFB flag".
 And in the sentence
       'The route from each of the two PEs
        will include TWO ESI Label Extended Communities with ESI-1 and
        ESI-2 respectively,'
 please use lower case for the "TWO", if it has no special meaning.
[jorge] done both things, thanks.
 

 
 [End of Review]