Tony,

Lower traffic levels than that for which a given network is provisioned is the 
only reason we are considering this topic.  However, this proposal does not 
deterministically put to sleep all of the links that could be put be sleep.

John

Sent from my iPhone

> On Sep 4, 2026, at 10:14 AM, Tony Li <[email protected]> wrote:
> 
> 
> 
> John,
> 
> If traffic levels are high, then yes, no links may be put to sleep.  Our 
> proposal does NOT claim that links will always be put to sleep.  Traffic 
> levels must be low enough and traffic must be able to be consolidated.
> 
> Tony
> 
> 
>> On Sep 4, 2026, at 7:10 AM, John Drake <[email protected]> wrote:
>> 
>> Colby,
>> 
>> Path placement in this proposal is indeed deterministic.  However, its 
>> effects are not;  i.e.,  even though it may be possible to put some links to 
>> sleep,  this proposal will not do that deterministically.  In particular, 
>> this proposal may not put any links to sleep.
>> 
>> I don’t think that’s acceptable.
>> 
>> John
>> Sent from my iPhone
>> 
>>>> On Sep 4, 2026, at 9:47 AM, Barth, Colby 
>>>> <[email protected]> wrote:
>>>> 
>>> 
>>> Aijin,
>>> 
>>> Distributed TE path placement is deterministic.  Tony’s example is about 
>>> placing TE tunnels on paths with sufficient resources.
>>> 
>>> You are criticizing many other solutions with your example.  The PCE 
>>> architecture follows the same model.
>>> 
>>> -- Colby
>>> 
>>> From: Aijun Wang <[email protected]>
>>> Date: Thursday, September 3, 2026 at 6:23 PM
>>> To: 'Tony Li' <[email protected]>
>>> Cc: 'TEAS WG' <[email protected]>; 'lsr' <[email protected]>
>>> Subject: [Teas] Re: [Lsr] Re: [Green] 【Distributed Power-aware TE is 
>>> Impossilbe】RE: RV: Call for adoption: draft-many-teas-power-steering-01 
>>> (Ends 2026-09-10)
>>> 
>>> Hi, Tony:
>>> 
>>> Then, there will be no deterministic effect for the distributed power-aware 
>>> TE, Right?
>>> Why the operator will deploy such proposal that has the unknown probability 
>>> of success?
>>> 
>>> And, for the power group related information, since they are static, and 
>>> will almost never to be changed, even the controller based approaches need 
>>> them, it is not the IGP's role to flooding them.
>>> 
>>> Let's image the possible scenario:
>>> NMS configure the power group information on each device---->IGP flood such 
>>> information among all the nodes---->BGP-LS collect such information to the 
>>> Controller
>>> Why don’t we let the NMS synchronize such information to the Controller? In 
>>> most of the real deployment, NMS is almost the same, or collocate with SDN 
>>> controller.
>>> 
>>> So, what's the usage of the distributed power-aware TE proposal?
>>> 
>>> Best Regards
>>> 
>>> Aijun Wang
>>> China Telecom
>>> 
>>> -----Original Message-----
>>> From: [email protected] [mailto:[email protected]] On 
>>> Behalf Of Tony Li
>>> Sent: Friday, September 4, 2026 3:18 AM
>>> To: Aijun Wang <[email protected]>
>>> Cc: TEAS WG <[email protected]>; lsr <[email protected]>
>>> Subject: [Lsr] Re: [Teas] [Green] 【Distributed Power-aware TE is 
>>> Impossilbe】RE: RV: Call for adoption: draft-many-teas-power-steering-01 
>>> (Ends 2026-09-10)
>>> 
>>> 
>>> Hi Aijun,
>>> 
>>> 
>>> > Let's trim the discussions within TEAS only.
>>> 
>>> 
>>> No, let’s not.
>>> 
>>> 
>>> > "the relevant nodes can then detect that the link is idle and can put it 
>>> > into power-sleep."  via the "reserved bandwidth"?
>>> > Then the proposal depends solely on RSVP style TE.
>>> 
>>> 
>>> No.  Other proposals are free to use the information as well.  If you have 
>>> a controller-based approach and want PSP information on the network, here’s 
>>> one way.
>>> 
>>> 
>>> > Even so, how you assure all the ingress node will select to avoid the 
>>> > same link along the e2e path that is determined by its own? Only behave 
>>> > in such manner, can you move out of the traffic from one link step by 
>>> > step.
>>> 
>>> 
>>> There is no guarantee that all headends will be able to consolidate 
>>> traffic.  If the traffic levels are sufficiently low and the relevant 
>>> headends compute paths that do consolidate traffic, then links can 
>>> transition to power-sleep.  If traffic levels are not sufficiently low and 
>>> one headend cannot find a path that avoids the link, well, the the link 
>>> cannot be put into power sleep.  This is not a bug, this is a feature.
>>> 
>>> 
>>> > Changing the link metric can get the effect of " in the middle of a flock 
>>> > of birds and clap your hands, they will fly away ".
>>> > But for the distributed TE proposal, the effect will be the birds fly 
>>> > from east to west, and then from north to south, or, fly around within 
>>> > the forest, because every edge router direct them to avoid some different 
>>> > tree.
>>> 
>>> 
>>> We are not changing the link metric.  We are adding a penalty to the path 
>>> for the link in question.  There may be many links on a path that are 
>>> capable of power-sleep, so there may be many penalties.  Those penalties do 
>>> not have to be the same from LSP to LSP, nor from head-end to head-end, nor 
>>> from link to link to have an effect on path computation.  As long as each 
>>> headend finds a path with sufficient capacity, then the network is in an 
>>> acceptable state.
>>> 
>>> Tony
>>> 
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