Re: [bess] Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04

["Jeffrey (Zhaohui) Zhang" <[e-mail]>]

Hi Bob,

  *   *If* the AR REPLICATOR behaviors are removed from that draft,I think the hub/spoke scenario can't be well supported because that the RRs are widely used.
What do you mean by *if* in the above statement? It is the designed behavior with hub and spoke scenario – with that do you still think there is a problem?

RR is only used for route distribution and should not make any difference.

Thanks.
Jeffrey



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Subject: Re:Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04

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Hi Jeffrey and Sasha,



The flows of E-tree services typically are P2MP conections,

But the flows of hub/spoke services typically are MP2MP connections,

the spoke PEs can connect to each other under the assistance of the hub PE.

The hub/spoke services is actually a special pattern of VPLS, whose MP2MP nature will be persisted.



So they are very different as what Jeffrey has pointed out.



But the hub/spoke secenario is very similar to the AR REPLICATOR/LEAF, IMHO.

And draft-ietf-bess-evpn-virtual-hub already applied a certain extent of AR REPLICATOR behaviors to the hub PEs.

The only issues remained in draft-ietf-bess-evpn-virtual-hub is that when RRs exists between hub-PE and spoke-PEs.

If the AR REPLICATOR behaviors are removed from that draft,

I think the hub/spoke scenario can't be well supported because that the RRs are widely used.

and the AR REPLICATOR behaviors will still be required even if there are no RRs.



And I think the approaches discribed in draft-wang-bess-evpn-context-label-04  can solve the problems caused by RR existence.



Best Regards,

Bob


原始邮件
发件人：Jeffrey(Zhaohui)Zhang <[e-mail]<mailto:[e-mail]>>
收件人：Alexander Vainshtein <[e-mail]<mailto:[e-mail]>>;[e-mail] <[e-mail]<mailto:[e-mail]>>;
抄送人：Michael Gorokhovsky <[e-mail]<mailto:[e-mail]>>;[e-mail] <[e-mail]<mailto:[e-mail]>>;
日 期 ：2020年08月20日 22:46
主 题 ：RE: Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04
Hub and spoke EVPN and E-tree are different.

However, draft-ietf-bess-evpn-virtual-hub should address the following two at least:

   *  MPLS EVPN can't support hub/spoke usecase, where the spoke PEs can
      only connect to each other through the hub PE.  Especially when at
      least two of the spoke PEs are connected to a common route
      reflector.

   *  MPLS EVPN can't work as an AR-REPLICATOR.  Because the AR-
      REPLICATOR will apply replication for the ingress AR-LEAF too.
      But a packet shoud not be sent back to the AR-LEAF where it is
      received from.

Jeffrey



Juniper Business Use Only
From: BESS <[e-mail]<mailto:[e-mail]>> On Behalf Of Alexander Vainshtein
Sent: Thursday, August 20, 2020 9:36 AM
To: [e-mail]<mailto:[e-mail]>
Cc: Michael Gorokhovsky <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Subject: [bess] Hub-and-spoke support in EVPN: RFC 8317 vs. draft-wang-bess-evpn-context-label-04

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Dear authors of draft-wang-bess-evpn-context-label-04,

Section 2 “Problem Statement” of draft-wang-bess-evpn-context-label-04 states that “MPLS EVPN can't support hub/spoke use case, where the spoke PEs can only connect to each other through the hub PE.  Especially when at least two of the spoke PEs are connected to a common route reflector”.

I have to admit that I do not understand why support of the generic E-Tree functionality in EVPN defined inRFC 8317<https://urldefense.com/v3/__https:/tools.ietf.org/html/rfc8317__;!!NEt6yMaO-gk!QRZOPg7Or-dqLm0vGwqM2vyyPBISCyDo4uu4Jq2MEDW8fuSMZV6tLNIvZnaam81J$> is not sufficient for handling this use case.

In particular I do not see why connection of Spoke PEs to a common RR affects the EVPN behavior (or L3vPN Hub-and-Spoke VPN behavior as defined inSection 4.3.5 of RFC 4364<https://urldefense.com/v3/__https:/tools.ietf.org/html/rfc4364*section-4.3.5__;Iw!!NEt6yMaO-gk!QRZOPg7Or-dqLm0vGwqM2vyyPBISCyDo4uu4Jq2MEDW8fuSMZV6tLNIvZunniYWF$>) in any way.

Regards, and lots of thanks in advance,
Sasha

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