Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

"Ali Sajassi (sajassi)" <> Tue, 15 January 2019 18:36 UTC

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From: "Ali Sajassi (sajassi)" <>
To: Yu Tianpeng <>, "" <>
CC: "" <>, "" <>
Thread-Topic: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment
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Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment
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Hi Yu,

From: Yu Tianpeng <>
Date: Friday, January 11, 2019 at 1:44 PM
To: Cisco Employee <>, "" <>
Cc: "" <>, "" <>
Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

Hi Ali and Stephane,
Sorry again for comment too many times at this stage. I understand LC officially ended (but failed), thanks for Ali’s patient.
If we check the document we still have many changes in recent days and part of them are real mistakes not just optimization right?

There is no “pass” or “fail” for WGLC. After WGLC ends, the editor addresses the comments (if any) gathered during the WGLC. So, the WG participants are obligated to send their comments during the two-week WGLC period.

Ali, please read comment 5 again.  TBH for the others I don’t worry too much as they are wording optimization to avoid confusion.
Comments below inline.

Section 5.3 clearly describes the procedure for EVCs in context of physical ENNI. Now if one wants to use logical ENNI (PW, or MPLS LSP), then the same procedure can be used for logical ENNI – i.e., using ESI type-3 for the logical ENNI and coloring vES by using MAC address of ENNI’s ESI as describe in section 5.3


Thanks for understanding.

发件人: Ali Sajassi (sajassi) []
发送时间: 2019年1月12日 3:50
收件人: Yu Tianpeng;
主题: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

Hi Stephane,

The WGLC for this draft was ended on Dec/17. Yu sent his 1st batch of editorial comments about 3 weeks after WGLC ended on 1/7 and I addressed them. He then generated a new set which I addressed them as well. He has now generated the third set which are mostly invalid and indicative of lack of understanding of RFC 7623 which is prerequisite to this draft. I am rejected this third set not because he keeps generating new set but because of invalidity of them which I explain in the text below. I want to encourage participation of new incomers like Yu but they should also take time to understand both IETF procedures on WG calls and also on RFCs related to a draft before keep generating comments.

From: Yu Tianpeng <<>>
Date: Thursday, January 10, 2019 at 10:29 AM
To: Cisco Employee <<>>, "<>" <<>>
Cc: "<>" <<>>, "<>" <<>>
Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

Thanks a lot Ali for the 03 version. This version fixs all comments raised before and also some others e.g. df election criteria.

But unfortuatelly I have more comments, sorry abount that...
Comment 5 is a major one, others are mainly wording and typo...

1. Related with 5.1 to 5.4, I suggest rename title as below:
5.1 Single vES Failure Handling in multi-homed EVPN
5.2 Single vES Failure Handling in multi-homed PBB-EVPN
5.3 Multiple vES Failure Handling in multi-homed EVPN
5.4 Multiple vES Failure Handling in multi-homed PBB-EVPN
1) procedure described should applies to multi-homed active-active, we should not say single-active, suggest use multi-homed instead
2) multiple vES failure can be caused by ENNI port/link failure, and EVC/PW failure (even failure of one EVC fails can lead to failure of multiple vES), but for EVPN, actually failure procedure are same.
Correspondingly some words in the content might need to be changed if we decide to change the title.

REJECTED: The current titles are correct. Please read RFC 7623. If you read it, you will see that All-Active multi-homing does NOT require MAC flushing !! The sections are about Single-Active vES and NOT single failure in vES.

[Tim]: PBB all active does not require, But EVPN 7432 requires a withdraw of ES or vES in this document. vES actually should follow 7432 process if only one fails.

2. 5.1 need changes from "CMAC" to "MAC". Probablly "Ethernet Segment" to "vES" also will be better.

REJECTED: The current text is correct. The first paragraph is about Ethernet Segment and not vES. The second paragraph is about vES and EVC !!

[Tim]: Title of 5.1 is EVPN 7432 related not PBB-EVPN, why we mention CMAC? I would say the description inside is confusing. Is it describing PBB-EVPN processing??

3. Some wording changes are needed in 5.1
To be precise, there is no
MAC flush per-se if there is only one backup PE for a given ES -
i.e., only an update of the forwarding entries per backup-path
procedure in [RFC 7432].
To be precise, there is no per MAC basis flush, only an update of the forwarding entries and delete the failure vES in MAC nexthop table based on
procedure in the section 8.2 of [RFC 7432].

Or at least we need to fix "per-se", anyhow it seems to be a typo..

“per se” is and adverb.

4. Section 5.3
Router's MAC Extended Community is newly added in version-03. Before my understanding was I should always use type 3 ESI (Port MAC address + Discriminator) in EAD.
So the correct understanding should be: I can use any type of ESI in AD stage, and I need to include Router's MAC Extended Community with port MAC along with EAD, but type 3 has to be used in MASS-withdraw based on -03 version
Is my understanding correct?

REJECTED: We are talking about two different things. There is a vESI for vES and there is ESI for ES associated with ENNI. Bullet 1 in section 5.3 talks about when advertising vES you need to color them and the way to color them is to use Router’s MAC EC. vESI can be of any format. Bullet 2 talks about when withdrawing ES associated with the ENNI, then you advertise the withdraw message with this special ESI.

[Tim]: This is not a comment, just a question. My fault for description not being clear.  I am not asking to change anything,

Till 03 version, EVPN Router's MAC Extended Community is added here. Before MAC extended community is only mentioned in PBB-EVPN related procedure, but in EVPN 7432 related (5.1, 5.3) this community is not mentioned.

So my understanding based  on 02 version is not correct and updated by 03 version.

5. Still section 5.3
For this part I have a concern on the mechanism to be used in PW or when ENNI is a LAG.
When system terminate PWs and start EVPN, the ENNI will be a logical "virtual" interface in the system and not physical interface.
This logical interface will use system mac (some people call it bridge mac), and it will be shared by all ENNIs in the same device.
If I fill in the mass-withdraw ESI with this MAC+0xFFFFFF it will withdraw all ENNIs on this PE even those not failed.
Same logic, when ENNI is LAG, also system MAC used.
So based on my understanding, this mechanism only works if: EVC is terminated directly on physical ENNI.
The mechanism will not work if: EVC is terminated on LAG or PW terminated and ENNI is logical interface.
Or we plan mac address of all logical ENNIs manually:)...

REJECTED: For logical interface such as RSVP-TE tunnel where it can aggregate many PWs, then the tunnel can be considered as ENNI and each PW can be considered as an EVC associated with a vES.

[Tim]: Please read the comment, the answer is not answering the concern.

The question is if ENNI is not a physical interface, the MAC address is system MAC and shared by multiple ENNIs. System MAC cannot be used in the procedure described in section 5.3 (bullet 2).

6. Small Nits in section 3.4
vc-type VLAN could lead to misunderstanding as meaning of this word differs between vendors. Appreciate if we can use language in RFC4448 (e.g. Raw mode)




Thanks & Regards,

On Thu, 10 Jan 2019, 06:17 Ali Sajassi (sajassi) <<> wrote:

From: Yu Tianpeng <<>>
Date: Wednesday, January 9, 2019 at 4:03 AM
To: Cisco Employee <<>>
Cc: "<>" <<>>, "<>" <<>>
Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

Thanks a lot Ali for the updating.
Looks fine for me apart from one point.
Correct me if I am wrong for what mentioned below.
This document aims to enable capability of evpn to be used on ENNI. But ENNI also have EVPL, ELAN and ETREE services.  This document have a brilliant solution, but overall current document only mentions usage in ELAN, so the question is how about ETREE and VPWS? As the solution in this document is vES based, I believe it should work for ETREE and VPWS without much extra considerations.  So if authors agree, I prefer to cover this in the current document. It is also fine for me if authors' choice is out of scope and prefer to cover other scenarios in a separate document.

I have already added VPWS. However, there is no point to list every EVPN solution in this document or else we have to list not just evpn-etree but evpn-overlay, evpn-irb, evpn-mcast, evpn-fxc, etc.

By the way another nits..
Sub type in figure 6 is not consistent with description above. I got lost on this as previous version was still 0x04.. so if 0x07 is the correct one please fix the value in the figure

That has already been corrected.


Thanks a lot.


On Wed, 9 Jan 2019, 00:31 Mankamana Mishra (mankamis) <<> wrote:
Thanks ali. I took look at the diff, it looks ok to me to move forward.


From: BESS <<>> on behalf of "Ali Sajassi (sajassi)" <<>>
Date: Tuesday, January 8, 2019 at 3:17 PM
To: Tim <<>>, "<>" <<>>, "<>" <<>>
Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment

Tim, Mankamana,

The rev02 of the draft has the updates to address your latest comments.


From: BESS <<>> on behalf of Tim <<>>
Date: Monday, January 7, 2019 at 2:53 PM
To: "<>" <<>>, "<>" <<>>
Subject: Re: [bess] WGLC, IPR and implementation poll for draft-ietf-bess-evpn-virtual-eth-segment


Support this work as an individual. This document is a great and elegant step for EVPN towards SP network.

Some small comments by the way:

1. Figure 2 shows the scope of EVPN network but the other figures in the document not. Please kindly update, then it is more readable.

2. There are 2 Figure 2

3. Document is lack of mention on E-Tree, it should work without any extra consideration right?

4. Please fix format issue in section 8 and update TBD in section 9.



On 2018/12/3 18:43,<> wrote:

Hello Working Group,

This email starts a two-week Working Group Last Call on draft-ietf-bess-evpn-virtual-eth-segment [1]

This poll runs until *the 17th of December*.

We are also polling for knowledge of any undisclosed IPR that applies to this Document, to ensure that IPR has been disclosed in compliance with IETF IPR rules (see RFCs 3979, 4879, 3669 and 5378 for more details).

If you are listed as an Author or a Contributor of this Document please respond to this email and indicate whether or not you are aware of any relevant undisclosed IPR. The Document won't progress without answers from all the Authors and Contributors.

There is currently no IPR disclosed.

If you are not listed as an Author or a Contributor, then please explicitly respond only if you are aware of any IPR that has not yet been disclosed in conformance with IETF rules.

We are also polling for any existing implementation as per [2].

    Thank you,

    Stephane & Matthew




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