Luc,
Lots of thanks for a prompt and highly informative response.

I am adding the PALS WG to the CC list since, from my POV, your proposal goes 
beyond the PW network reference model as shown in Figure 2 of RFC 
3985<https://tools.ietf.org/html/rfc3985>.
While this model has been extended to cover multi-segment PWs (RFC 
6073<https://tools.ietf.org/html/rfc6073>), PW redundancy (RFC 
6718<https://tools.ietf.org/html/rfc6718>) and ICCP (RFC 
7275<https://tools.ietf.org/html/rfc7275>)  none of these extensions seem to be 
directly applicable to the proposed scheme.

My 2c,
Sasha

Office: +972-39266302
Cell:      +972-549266302
Email:   alexander.vainsht...@ecitele.com

From: Luc Andre Burdet (lburdet) [mailto:lbur...@cisco.com]
Sent: Tuesday, September 25, 2018 5:46 PM
To: Alexander Vainshtein <alexander.vainsht...@ecitele.com>; 
draft-sajassi-bess-evpn-virtual-eth-segment.auth...@ietf.org
Cc: Michael Gorokhovsky <michael.gorokhov...@ecitele.com>; Alexander Ferdman 
<alexander.ferd...@ecitele.com>; Shell Nakash <shell.nak...@ecitele.com>; 
bess@ietf.org
Subject: Re: [bess] All-Active Multi-homing and Virtual Ethernet Segments: A 
Question

Hi Sasha,

I agree the vES draft does not go in great detail about A/A PWs.

For A/A PWs terminating at peering PEs, the concept is similar to LAG, using 
static label at peering PEs:
-          The CE sets up a single PW to remote endpoint to anycast IP1, Label1.
-          PE1, PE2 set up a PW each to CE, using local static label Label1.
-          PE1,PE2 adv IP1 as anycast IP towards CE-side
There will not be excessive MAC-moves since the CE sees only one pseudowire to 
a single remote—very similar to what is done for LAG on “real” links.

We can update the draft to be more descriptive—that draft needs a re-read 
anyways, the header on each page still reads “PBB-EVPN” ☺

HTH,
Luc André

[http://www.cisco.com/c/dam/m/en_us/signaturetool/images/banners/standard/09_standard_graphic.png]




Luc André Burdet
lbur...@cisco.com<mailto:lbur...@cisco.com>
Tel: +1 613 254 4814






Cisco Systems Canada Co. / Les Systemes Cisco Canada CIE
Cisco.com<http://www.cisco.com/web/CA/>







From: BESS <bess-boun...@ietf.org<mailto:bess-boun...@ietf.org>> on behalf of 
Alexander Vainshtein 
<alexander.vainsht...@ecitele.com<mailto:alexander.vainsht...@ecitele.com>>
Date: Tuesday, September 25, 2018 at 06:25
To: 
"draft-sajassi-bess-evpn-virtual-eth-segment.auth...@ietf.org<mailto:draft-sajassi-bess-evpn-virtual-eth-segment.auth...@ietf.org>"
 
<draft-sajassi-bess-evpn-virtual-eth-segment.auth...@ietf.org<mailto:draft-sajassi-bess-evpn-virtual-eth-segment.auth...@ietf.org>>
Cc: Michael Gorokhovsky 
<michael.gorokhov...@ecitele.com<mailto:michael.gorokhov...@ecitele.com>>, 
Alexander Ferdman 
<alexander.ferd...@ecitele.com<mailto:alexander.ferd...@ecitele.com>>, Shell 
Nakash <shell.nak...@ecitele.com<mailto:shell.nak...@ecitele.com>>, 
"bess@ietf.org<mailto:bess@ietf.org>" <bess@ietf.org<mailto:bess@ietf.org>>
Subject: [bess] All-Active Multi-homing and Virtual Ethernet Segments: A 
Question

Dear authors of the EVPN Virtual Ethernet 
Segment<https://tools.ietf.org/html/draft-sajassi-bess-evpn-virtual-eth-segment-03>
 draft,
My colleagues and I have a question pertaining to support of All-Active 
redundancy mode in EVPN that uses virtual Ethernet Segments.

Section 8.5 of RFC 7432<https://tools.ietf.org/html/rfc7432#section-8.5> says:

   If a bridged network is multihomed to more than one PE in an EVPN
   network via switches, then the support of All-Active redundancy mode
   requires the bridged network to be connected to two or more PEs using
   a LAG.

   If a bridged network does not connect to the PEs using a LAG, then
   only one of the links between the bridged network and the PEs must be
   the active link for a given <ES, VLAN> or <ES, VLAN bundle>.  In this
   case, the set of Ethernet A-D per ES routes advertised by each PE
   MUST have the "Single-Active" bit in the flags of the ESI Label
   extended community set to 1.

This restriction is easy to understand, since, with the All-Active multi-homing 
mode of an Ethernet Segment, a CE attached to such a segment potentially would 
receive traffic from all the PEs attached to this  segment. Since A CE that is 
part of a bridged network must learn MAC addresses of the received traffic, it 
would potentially experience continuous MAC Move events – with undesirable 
consequences.

The EVPN Virtual Ethernet Segment draft replaces Ethernet links (forming a 
“real” ES) with Ethernet PWs, and claims support of both Single-homed and 
multi-homed multi-homing modes. When I compare these claims with the quoted 
above statement from RFC 7432, I see two possibilities:

  *   Either a CE that is connected to an All-Active vES cannot be part of a 
bridged network (and thus would not do any MAC learning)
  *   Or  an extension of LAG that deals with Ethernet PWs instead of Ethernet 
links is required.

Could you please clarify which of these two options is correct?

Note: The draft includes Informative references to the two drafts that have 
been published as RFC 7432 and RFC 7623.

Regards,
Sasha

Office: +972-39266302
Cell:      +972-549266302
Email:   
alexander.vainsht...@ecitele.com<mailto:alexander.vainsht...@ecitele.com>


___________________________________________________________________________

This e-mail message is intended for the recipient only and contains information 
which is
CONFIDENTIAL and which may be proprietary to ECI Telecom. If you have received 
this
transmission in error, please inform us by e-mail, phone or fax, and then 
delete the original
and all copies thereof.
___________________________________________________________________________

___________________________________________________________________________

This e-mail message is intended for the recipient only and contains information 
which is 
CONFIDENTIAL and which may be proprietary to ECI Telecom. If you have received 
this 
transmission in error, please inform us by e-mail, phone or fax, and then 
delete the original 
and all copies thereof.
___________________________________________________________________________
_______________________________________________
BESS mailing list
BESS@ietf.org
https://www.ietf.org/mailman/listinfo/bess

Reply via email to