Jorge,
Lots of thanks for a prompt response.

AFAIK it is perfectly valid to advertise Implicit Null label for a FEC 
representing a local address in RSVP-TE.
And I am not sure what you mean by "single-hop LSPs in general".

>From my POV, LSP are, generally speaking, unidirectional while PWs and 
>Ethernet Segments are inherently bi-directional.
In the case of Ethernet Segments:

  *   Their egress direction affects the results of DF election
  *   Their ingress direction affects inclusion - or non-inclusion of ESI label 
in certain copies of flooded BUM traffic.
So I still think that if you want to treat an LSP as a virtual Ethernet 
Segment, you need a bi-directional LSP (Be it MPLS-TP or not).

The draft, in its current form, simply ignores these differences.
What, if anything, do I miss?

Regards,
Sasha

From: Jorge Rabadan (Nokia) <jorge.raba...@nokia.com>
Sent: Monday, April 17, 2023 9:08 AM
To: Alexander Vainshtein <alexander.vainsht...@rbbn.com>; last-ca...@ietf.org; 
draft-ietf-bess-evpn-virtual-eth-segm...@ietf.org
Cc: bess@ietf.org
Subject: [EXTERNAL] Re: Last Call: 
<draft-ietf-bess-evpn-virtual-eth-segment-08.txt> (EVPN Virtual Ethernet 
Segment) to Proposed Standard

Hi Sasha,

There would be more cases where you can identify traffic coming from a given 
LSP.
For instance RSVP-TE, or single-hop LSPs in general, etc - there is no need for 
bidirectional MPLS-TP.

The text itself implicitly refers to the cases where PWs can be aggregated into 
a common LSP, so not sure if anything else is needed.

Thanks.
Jorge



From: Alexander Vainshtein 
<alexander.vainsht...@rbbn.com<mailto:alexander.vainsht...@rbbn.com>>
Date: Sunday, April 16, 2023 at 5:44 PM
To: last-ca...@ietf.org<mailto:last-ca...@ietf.org> 
<last-ca...@ietf.org<mailto:last-ca...@ietf.org>>, 
draft-ietf-bess-evpn-virtual-eth-segm...@ietf.org<mailto:draft-ietf-bess-evpn-virtual-eth-segm...@ietf.org>
 
<draft-ietf-bess-evpn-virtual-eth-segm...@ietf.org<mailto:draft-ietf-bess-evpn-virtual-eth-segm...@ietf.org>>
Cc: GTD-SYS-Packet Solutions 
<gtd-sys-packet-soluti...@rbbn.com<mailto:gtd-sys-packet-soluti...@rbbn.com>>, 
bess@ietf.org<mailto:bess@ietf.org> <bess@ietf.org<mailto:bess@ietf.org>>
Subject: Re: Last Call: <draft-ietf-bess-evpn-virtual-eth-segment-08.txt> (EVPN 
Virtual Ethernet Segment) to Proposed Standard

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.


Hi all,
I have doubts regarding the text in Section 1.2 of the draft that refers to 
LSPs (as opposed to PWs) as virtual Ethernet Segments.

The problematic (from my POV) text refers to Figure 2 and says (the problematic 
part is highlighted):


   In such scenarios, a virtual ES (vES) is defined as a set of
   individual PWs if they cannot be aggregated into a common LSP.  If
   the aggregation of PWs is possible, the vES can be associated to an
   LSP in a given PE.  In the example of Figure 2, EVC3 is connected to
   a VPWS instance in AG2 that is connected to PE1 and PE2 via PW3 and
   PW5 respectively.  EVC4 is connected to a separate VPWS instance on
   AG2 that gets connected to an EVI on PE1 and PE2 via PW4 and PW6,
   respectively.  Since the PWs for the two VPWS instances can be
   aggregated into the same LSPs going to the MPLS network, a common
   virtual ES can be defined for LSP1 and LSP2.  This vES will be shared
   by two separate EVIs in the EVPN network.


The problem with the highlighted text is that PE1 and PE2 always can identify 
the PW from which they receive this or that packet, but, in most cases, cannot 
identify the LSP in which this PW has been running.
(The only exception of which I am aware, is the case of static PWEs in 
bi-directional MPLS-TP LSPs).
If LSP1 and LSP2 were components of a common virtual MH ES,  PE1, upon 
reception of a BUM packet from PW4, would not be able to identify this MH ES 
and to insert a suitable ESI label into the EVPN encapsulation of the copy it 
would be sending to PE2.

IMHO and FWIW some clarification (e.g., restricting ability to use LSPs as 
virtual Ethernet Segments to just bi-directional MPLS-TP LSPs?) would be very 
much in place.

Hopefully these notes will be useful.

Regards,
Sasha

________________________________
The IESG has received a request from the BGP Enabled ServiceS WG (bess) to 
consider the following document: - 'EVPN Virtual Ethernet Segment'
  <draft-ietf-bess-evpn-virtual-eth-segment-08.txt> as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final 
comments on this action. Please send substantive comments to the 
last-c...@ietf.org<mailto:last-c...@ietf.org> mailing lists by 2023-04-27. 
Exceptionally, comments may be sent to i...@ietf.org<mailto:i...@ietf.org> 
instead. In either case, please retain the beginning of the Subject line to 
allow automated sorting.

Abstract


   EVPN and PBB-EVPN introduce a family of solutions for multipoint
   Ethernet services over MPLS/IP network with many advanced features
   among which their multi-homing capabilities.  These solutions
   introduce Single-Active and All-Active for an Ethernet Segment (ES),
   itself defined as a set of physical links between the multi-homed
   device/network and a set of PE devices that they are connected to.
   This document extends the Ethernet Segment concept so that an ES can
   be associated to a set of EVCs (e.g., VLANs) or other objects such as
   MPLS Label Switch Paths (LSPs) or Pseudowires (PWs), referred to as
   Virtual Ethernet Segments (vES).  This draft describes the
   requirements and the extensions needed to support vES in EVPN and
   PBB-EVPN.





The file can be obtained via
https://clicktime.symantec.com/15sLvSMFe6yJaL7it9kEb?h=WX7sPrWtPYj6YArP1_IG-VUvi72ntJf3jPZD8aotZlk=&u=https://clicktime.symantec.com/15siFA9u7fT6Pcy1rRzYE?h=oH6e_3PB3X1eWGKah_83SV7rAO13MiTubvXyMPWLSs4=&u=https://datatracker.ietf.org/doc/draft-ietf-bess-evpn-virtual-eth-segment/


The following IPR Declarations may be related to this I-D:

   
https://clicktime.symantec.com/15sM1GYY6ietzGweRi9PD?h=LatO2AZiVAH39lrwHIwya5amzj8HrV_kDAIVEAeg85M=&u=https://clicktime.symantec.com/15siKzMBaH8goZnwPzPgr?h=2sUb0zrdQ5wcPvhgS2fD7IYQBGY3koDFG7wzpwkjYlU=&u=https://datatracker.ietf.org/ipr/3169/
   
https://clicktime.symantec.com/15sMAvw71x25pAbVWpwgT?h=GdR-katv1Fmx1tCzKJUyhSBiuWnAI85UP95ltcuRR_U=&u=https://clicktime.symantec.com/15siVejkVWVsdTSnV7Bz6?h=sT7aE2ZEJl5mDkO4HW9iizdbIbzENVSMXvgn_zrG5lg=&u=https://datatracker.ietf.org/ipr/3354/
   
https://clicktime.symantec.com/15sM66jpZLLVQDmZyGYXq?h=Hr8E955Kl0orr2_O8JUL1JHDwJMJS1wH8Q2F_JhQIrM=&u=https://clicktime.symantec.com/15siQpYU2tpHDWcrwYnqU?h=vhhGcaEYULDbhQhTesln7lZn7Qj-ZfAKgO-VH6KAeCU=&u=https://datatracker.ietf.org/ipr/3353/





Regards,
Sasha


Notice: This e-mail together with any attachments may contain information of 
Ribbon Communications Inc. and its Affiliates that is confidential and/or 
proprietary for the sole use of the intended recipient. Any review, disclosure, 
reliance or distribution by others or forwarding without express permission is 
strictly prohibited. If you are not the intended recipient, please notify the 
sender immediately and then delete all copies, including any attachments.

Notice: This e-mail together with any attachments may contain information of 
Ribbon Communications Inc. and its Affiliates that is confidential and/or 
proprietary for the sole use of the intended recipient. Any review, disclosure, 
reliance or distribution by others or forwarding without express permission is 
strictly prohibited. If you are not the intended recipient, please notify the 
sender immediately and then delete all copies, including any attachments.
_______________________________________________
BESS mailing list
BESS@ietf.org
https://www.ietf.org/mailman/listinfo/bess

Reply via email to