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

[[e-mail]]

Hi Jeffrey,






Maybe I was confused by the last mail.


Let's discuss it on the basis of the text of the [EVPN Virtual Hub] draft.





In section 7.1, it says that:





   In case of IR with MPLS          


   unicast tunnels, VH1 must advertise different labels to different


   PEs, so that it can identify the sending PE based on the label in the


   traffic from a V-spoke.





I don't understand that sentence in the following questions:





1) How does VH1 advertise many labels to a single RR with the same NLRI?


2) How does the RR recognise that each (instead of only the recent one) of these labels should be reflected?


3) Will the RR reflect all these labels to all V-Spokes?


4) Will each of the V-Spokes receive only the exact one (which is allocated for that V-spoke by the VH1) of these labels from the same RR?





Thanks,


Bob














原始邮件



发件人：Jeffrey(Zhaohui)Zhang <[e-mail]>
收件人：王玉保10045807;[e-mail] <[e-mail]>;
抄送人：张征00007940;陈然00080434;
日 期 ：2020年08月21日 23:33
主 题 ：RE: Re:Hub-and-spoke support in EVPN: RFC 8317vs.draft-wang-bess-evpn-context-label-04




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


 


 


Juniper Business Use Only



From: [e-mail] <[e-mail]>
Sent: Thursday, August 20, 2020 9:52 PM
To: [e-mail]; Jeffrey (Zhaohui) Zhang <[e-mail]>; [e-mail]
Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail] <[e-mail]>; [e-mail]
Subject: Re:Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04




 


[External Email. Be cautious of content]


 

 

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]>



收件人：Alexander Vainshtein <[e-mail]>;[e-mail]
 <[e-mail]>;



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




 


[External Email. Be cautious of content]


 


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 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) in any way.


 


Regards, and lots of thanks in advance,


Sasha


 


Office: [phone]


Cell:      [phone]


Email:  [e-mail]


 


 



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