Subject: I-D Action: draft-ietf-l2vpn-evpn-04.txt

From: [email-masked]
Date: Sun, 14 Jul 2013 19:40:42 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.
 This draft is a work item of the Layer 2 Virtual Private Networks Working Group of the IETF.

	Title           : BGP MPLS Based Ethernet VPN
	Author(s)       : Ali Sajassi
                          Rahul Aggarwal
                          Wim Henderickx
                          Florin Balus
                          Aldrin Isaac
                          James Uttaro
	Filename        : draft-ietf-l2vpn-evpn-04.txt
	Pages           : 47
	Date            : 2013-07-14

Abstract:
   This document describes procedures for BGP MPLS based Ethernet VPNs
   (EVPN).

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-l2vpn-evpn

There's also a htmlized version available at:
http://tools.ietf.org/html/draft-ietf-l2vpn-evpn-04

A diff from the previous version is available at:
http://www.ietf.org/rfcdiff?url2=draft-ietf-l2vpn-evpn-04

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

---

From: Satya Mohanty <[email-masked]>
Date: Thu, 25 Jul 2013 00:21:59 +0000

Hi,

With respect to sec 6.3 Ethernet Segment 

3. The ESI may be configured.

The bytes that comprise the Route-Target value i.e. bytes 2 till 8 of the configured esi, can they all be zeros?
AFAIK regular Route-Targets in 2-byte AS (as-num >= 1) or ip-address format (community-value >= 1), the bytes that comprise the value fields can't all be 0.

Minor Nit: In sec 8.6, the reference to section 9.1 "Redundancy Group Discovery" is in error.
I guess the reference name needs to be changed.

Best regards,
--Satya

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of [email-masked]
Sent: Sunday, July 14, 2013 7:41 PM
To: [email-masked]
Cc: [email-masked]
Subject: I-D Action: draft-ietf-l2vpn-evpn-04.txt

Abstract:

---

From: "Ali Sajassi (sajassi)" <[email-masked]>
Date: Thu, 25 Jul 2013 17:04:33 +0000

Hi Satya,

Section 6 doesn't talk about RT. How did you arrive at RT of zero?

Regarding the nit. Agreed - the referenced section number is correct but
not the referenced title.

Cheers,
Ali  

On 7/25/13 2:21 AM, "Satya Mohanty" <[email-masked]> wrote:

>AFAIK regular Route-Targets in 2-byte AS (as-num >= 1) or ip-address
>format (community-value >= 1), the bytes that comprise the value fields
>can't all be 0.
>

---

From: Satya Mohanty <[email-masked]>
Date: Thu, 25 Jul 2013 17:37:33 +0000

Hi Ali,

Let me clarify further.

In Section 6 Ethernet segment, three ways to generate the esi are described using (1)LACP (2)Root Bridge Mac address and priority and (3)Configured value.

>From Section 8.6 ES-Import Route Target

"This is a new transitive Route Target extended community carried with the Ethernet Segment route. When used, it enables all the PEs connected to the same multi-homed site to import the Ethernet Segment routes. The value is derived automatically from the ESI by encoding the 6-byte MAC address portion of the ESI in the ES-Import Route"

Interpreted above (in absence of explicit mention) I would think that regardless of how the ESI is configured, for purposes of deriving the value of the ES-Import Route Target, one always extracts the six bytes starting from the third byte (system mac placeholder).

For instance, let's say somebody configures the esi using the third option as 1.2.0.0.0.0.0.0.0.1, the system mac placeholder is 0.0.0.0.0.0 (bytes 3 till 8). This is the value which will be embedded in the route-target field. Basically a value of 0.

Wanted to clarify if this will be allowed? Normal Route Target formats don't support value of 0, I think.

Best,
Satya

-----Original Message-----
From: Ali Sajassi (sajassi) [mailto:[email-masked]] 
Sent: Thursday, July 25, 2013 10:05 AM
To: Satya Mohanty; [email-masked]; [email-masked]
Cc: [email-masked]
Subject: Re: I-D Action: draft-ietf-l2vpn-evpn-04.txt

Hi Satya,

Regarding the nit. Agreed - the referenced section number is correct but not the referenced title.

Cheers,
Ali  

On 7/25/13 2:21 AM, "Satya Mohanty" <[email-masked]> wrote:

>The bytes that comprise the Route-Target value i.e. bytes 2 till 8 of 
>the configured esi, can they all be zeros?

---

From: "Ali Sajassi (sajassi)" <[email-masked]>
Date: Sat, 27 Jul 2013 14:26:51 +0000

Hi Satya,

On 7/25/13 7:37 PM, "Satya Mohanty" <[email-masked]> wrote:

>Hi Ali,
>
>Let me clarify further.
>
>In Section 6 Ethernet segment, three ways to generate the esi are
>described using (1)LACP (2)Root Bridge Mac address and priority and
>(3)Configured value.
>
>"This is a new transitive Route Target extended community carried with
>the Ethernet Segment route. When used, it enables all the PEs connected
>to the same multi-homed site to import the Ethernet Segment routes. The
>value is derived automatically from the ESI by encoding the 6-byte MAC
>address portion of the ESI in the ES-Import Route"
>
>Interpreted above (in absence of explicit mention) I would think that
>regardless of how the ESI is configured, for purposes of deriving the
>value of the ES-Import Route Target, one always extracts the six bytes
>starting from the third byte (system mac placeholder).
>
>For instance, let's say somebody configures the esi using the third
>option as 1.2.0.0.0.0.0.0.0.1, the system mac placeholder is 0.0.0.0.0.0
>(bytes 3 till 8). This is the value which will be embedded in the
>route-target field. Basically a value of 0.
>

This would still work since this is a new RT derived based on MAC. And if
someone configures MAC as 0, then the lower six bytes of this new RT will
be zero. If you have multiple ESIs, with zero MAC, then the RTs for all
these ESIs, will be zero which means the ES route messages will not be
properly filtered by their RTs. However, they will eventually be properly
filtered because the ESI values for these sites are different.

Cheers,
Ali