Re: [PWE3] [mpls] WG Last Call for draft-ietf-pwe3-endpoint-fast-protection-01

Hi Mingui,

Thanks for the comments. Please see inline...

Thanks,

/Yimin

-----Original Message-----
From: mpls [mailto:mpls-bounces@ietf.org] On Behalf Of Mingui Zhang
Sent: Thursday, August 07, 2014 10:47 PM
To: Stewart Bryant (stbryant)
Cc: mpls@ietf.org; pwe3; pwe3-chairs@tools.ietf.org
Subject: Re: [mpls] [PWE3] WG Last Call for draft-ietf-pwe3-endpoint-fast-protection-01 - RFC4447

Hi Stewart,

I think authors would say the S-PE stitching method involves the control plane processing during the repair procedure. They emphasized their method uses data plane & local repair, which can be faster.
Here, I want to raise one issue: 

If the primary PE fails and the PLR redirects the traffic during the flying of the packets, hoping the backup PE delivers the packets immediately. This means the AC at the backup PE side is also ACTIVE. So the CE has active-active connections to both egress PEs. This is obviously different from the PW-RED's active-standby mechanism [RFC6718]. Will this difference bring us the frame duplication issue? I think we need to address this in the updated version. 

[yshen] Don't confuse the backup PW in this document with the standby PW in RFC 6718. Each active or standby PW in RFC 6718 could be protected by a backup PW specified in this draft, if that's intended. There shouldn't be any packet duplication during local repair, because PLR only sends packets to protector.

Thanks,
Mingui

>-----Original Message-----
>From: Stewart Bryant (stbryant) [mailto:stbryant@cisco.com]
>Sent: Thursday, August 07, 2014 3:27 PM
>To: Mingui Zhang
>Cc: Eric Rosen (erosen); Alexander Vainshtein; mpls@ietf.org; pwe3; 
>pwe3-chairs@tools.ietf.org
>Subject: Re: [PWE3] [mpls] WG Last Call for
>draft-ietf-pwe3-endpoint-fast-protection-01 - RFC4447
>
>
>
>Sent from my iPad
>
>> On 7 Aug 2014, at 04:57, "Mingui Zhang" <zhangmingui@huawei.com> wrote:
>>
>> Hi Eric,
>>
>> The explanation of the story is very clear. Let me complement a bit.
>>
>>> - A "primary egress PE" partitions its set of PWs into n sets, where 
>>> each set is associated with a given "protector".  The "protector" is 
>>> the backup egress PE for those PWs.
>>
>> When the backup PE acts as the protector, it is the 'co-located' model.
>
>This case does not however need context labels. It is a form of S-PE 
>and can stitch the PWs just like every existing S-PE already does.
>
>Stewart
>

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Re: [PWE3] [mpls] WG Last Call for draft-ietf-pwe3-endpoint-fast-protection-01 - RFC4447