Re: [OSPF] 答复: WG adoption poll for draft-ppsenak-ospf-te-link-attr-reuse

Peter Psenak <> Mon, 17 July 2017 07:04 UTC

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Date: Mon, 17 Jul 2017 09:04:10 +0200
From: Peter Psenak <>
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To: Shraddha Hegde <>, Xuxiaohu <>, Abhay Roy <>, "" <>
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Subject: Re: [OSPF] 答复: WG adoption poll for draft-ppsenak-ospf-te-link-attr-reuse
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Hi Shraddha,

thanks for your comments. I believe all of them can be addressed by
editorial changes and I'll be more then happy to work with you on those.

More importantly, it looks to me you are not objecting the problem
statement and the direction that the draft is taking to address it. Is
my understanding correct?


On 17/07/17 06:31 , Shraddha Hegde wrote:
> There has been a long debate on this draft, probably the most discussed in
> OSPF WG.  The major contention point with this draft has been around
> 1. Definition of TE and Non-TE applications.
>       The draft still uses the terminology of TE and non-TE applications without defining
> 	 the meaning of what is considered TE and what is non-TE.
> 2. There are implementations that make use of TE LSAs for the purpose of implementing
>      [I-D.ietf-rtgwg-lfa-manageability] and
>     [I-D.psarkar-rtgwg-rlfa-node-protection]. Normative language is required to make sure
>     application such as RSVP and LFA do not suddenly become invalid because one vendor chooses to
>     implement this draft and stops advertising link attributes in TE LSAs.
>     The backward compatibility section specifies
>     "When an OSPF routing domain includes routers using link attributes
>     from TE Opaque LSAs for Non-RSVP TE applications such as LFA, OSPF
>     routers in that domain should continue to advertise such TE Opaque
>     LSAs."
>     In order to make sure operators do not end up seeing inter-op issues due to
>     different vendors implementing the draft at different times a normative
>     language such as below MUST be used.
>     "Routers in the OSPF Domain MUST continue to advertise TE Opaque LSAs, when there are
>     applications that make use of TE Opaque LSAs.In the interest of backward compatibility,
>     implementations MUST implement appropriate knobs to facilitate advertisement of link attributes in
>     TE LSAs. Implementations MUST also support processing link attributes advertised in TE-LSAs. A separate IETF draft
>     MAY be wriiten in future when the deployments are mature enough to move completely to the advertisements
>     defined in this draft"
> 3.  The encodings for the recent addition "Application Specific Values" has scope for improvement. Having seperate
>      Masks for standard and user defined applications does not seem necessary.
> 4. Acee's reference to different OSPF LSAs and comparing them to Chicken, egg and the
>     Rooster describes the problem aptly in one sentence.
>     Chicken and egg problem is age old in OSPF and all implementations have handled it very well.
>     Handling rooster wouldn't have been as difficult but with this draft, chicken, egg and the rooster have moved from
>     vendor's backyard to operator's front yard.
>     Operator's have to co-ordinate which vendor advertises what attributes in which LSA and which node/link
>     in the network should have which knobs turned on.
>     Deployment consideration section needs to consider various cases of upgrade process.
>     There is definitely need for text describing how the advertisements would look like if RSVP, LFA-manageability
>     and SR-TE are deployed together.
>     These comments on the draft are an effort to make sure existing IETF standardized applications
>     would not break when new enhancements are introduced.
> Rgds
> Shraddha
> -----Original Message-----
> From: OSPF [] On Behalf Of Xuxiaohu
> Sent: Monday, July 10, 2017 3:20 PM
> To: Abhay Roy <>;
> Subject: [OSPF] 答复: WG adoption poll for draft-ppsenak-ospf-te-link-attr-reuse
> I have read this draft and support the WG adoption.
> Xiaohu
>> -----邮件原件-----
>> 发件人: OSPF [] 代表 Abhay Roy
>> 发送时间: 2017年7月4日 2:37
>> 收件人:
>> 主题: [OSPF] WG adoption poll for draft-ppsenak-ospf-te-link-attr-reuse
>> We would like to kick-off a poll for WG adoption of the following
>> document (per Authors request):
>> Please let us know if you support or have concerns with OSPF WG
>> adopting this work.
>> Regards,
>> -Abhay
>> _______________________________________________
>> OSPF mailing list
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