[Green] Re: [Lsr] Re: Next steps for draft-many-lsr-power-group-02

[Vishnu Pavan Beeram <[e-mail]>]

*>>> What if North/Central/South links are designed to protect each other
under a single failure scenario ? And while perhaps saving some money by
shutting Central and South, are we not making our SLAs thin when it comes
to potential failure of North when C/S are off and there is no other
protection path available (especially quite topology dependent in MPLS-TE
networks) ? *

Sufficient guardrails are in place to ensure no compromise in resiliency.
The expectation is that the intelligence that determines whether a TE link
needs to be put to sleep is aware of any backup paths (in-use or not) that
traverse this link and makes an informed decision based on that. If RSVP-TE
is in use, there is sufficient state on the node itself to make an informed
decision.

Regards,
-Pavan

On Fri, May 22, 2026 at 2:42 AM Robert Raszuk <[e-mail]> wrote:

> Hi Tony,
>
> Ok so *all* headends need to be smart and apply rule of traffic
> aggregation (180 degrees to one of traditional uses of TE which is traffic
> spreading over available topology). Then again *all* headends need to be
> super smart  to say Oh those 100 headends from opposite side is aggregating
> traffic over North ... I will try to do the same. To me the
> correlation between traffic removed from South and Central to take North
> link from A to B is missing such that B to A knows that increase of
> reservations on North actually were caused by traffic shift from
> South/Central.
>
> Yes this is mapping traffic to LSPs which to the best of my recollection
> we do not flood.
>
> Of course as we all agree that all works with 100% RSVP-TE forwarding in
> the network.
>
>
> But let's put that aside for a moment - I have a different question which
> popped up yesterday.
>
> All wise operators today build networks and use various FRR techniques to
> minimize packet loss upon link or node failure. Waiting for any protocol
> convergence IMHO is a thing of the past when it comes to connectivity
> restoration time.
>
> I am not seeing where in this entire story we are taking this aspect into
> consideration. What if North/Central/South links are designed to protect
> each other under a single failure scenario ? And while perhaps saving some
> money by shutting Central and South, are we not making our SLAs thin when
> it comes to potential failure of North when C/S are off and there is no
> other protection path available (especially quite topology dependent in
> MPLS-TE networks) ?
>
> And while in theory headends do have all information to possibly make
> what-if analysis for any network failure I strongly doubt that they will be
> able to predict FRR options on possible potential shutdown of surrounding
> links in the topology when making the traffic aggregation decisions.
>
> Regards,
> Robert
>
>
>
> On Thu, May 21, 2026 at 12:06 PM Tony Li <[e-mail]> wrote:
>
>>
>> Hi Robert,
>>
>> > But I see no connection nor hint for also consolidating traffic from B
>> to A to the North path. Traffic B to A may have completely different
>> characteristics then traffic from A to B. And unless we are talking UDLR
>> freeing links must be done bidirectionally - wouldn't you agree ?
>>
>>
>> RFC 5305 tells us the unreserved bandwidth on the link.  If you look at
>> both ends of the link, you get both directions. That’s the hint.
>>
>> Tony
>>
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