Re: [OSPF] draft-ietf-ospf-segment-routing-extensions-03

[Peter Psenak <[e-mail]>]

Shraddha,

On 12/17/14 09:51 , Shraddha Hegde wrote:
> <Shraddha> Lets say set  S1 has some characteristic  "X" and set S2 has characteristic "Y".
>  Lets say we want to build explicit routed label stack which says " give me load balancing path using links with characteristic X".
>
> Lets say there is another set of nodes R3 and R4 and similar S1 and S2 bundles on them and R3 advertising label 30 and 40 for S1 and S2
> Respectively. Labels are local to the nodes and we cannot use labels to identify what characteristic or set they stand for.
>
> To satisfy the constraint whether to use label 10
> Or 20 on R1 and whether to use 30 or 40 is a problem. The application which is trying to build the label stack cannot identify which label to use from R1 and R3 because there are              sets and labels but which label  Represents which set is missing.
> If there is an identifier for the set and this identifier comes with label it can be done easily.

If I understand you correctly, what you want to color links based on the 
link characteristics - e.g. you want to associate link with a group 
(color) and group (color) to have global significance.

Sure, you can do that, but I do not see a direct relationship to SR, 
e.g. I would not add the group-id to the Adj-SID sub-TLV. You can define 
a new sub-TLV for the group-id distribution and advertise it in the 
Extended link TLV.

thanks,
Peter