Re: [mpls] I-D Action: draft-ietf-mpls-mna-requirements-09.txt

[Tony Li <[e-mail]>]

Hi Matthew,

>      Requirement 53 in section 3.5 (Requirements on Ancillary Data) seems to
>      prohibit an intermediate LSR which is pushing on labels and NAI from
>      pushing on ancillary data along with them. Such a prohibition seems to
>      be a contradict the WG agreements. Please fix.
>  
>  
> Proposed resolution> Reword and split into the following:
>  
> - In-stack ancillary data MUST only be inserted in conjunction with pushing one or more labels
> onto the top of stack. 
>  
>  
> I have a concern about this.  Suppose a node wishes to add an action to an existing label stack and there are
> already NAS on the stack.  This would prevent the node from adding the action.  An example of this might be a
> transit node that wants to add an entropy action because it is the start of an ECMP path.
>  
> MB> Is this a swap of the top label (or a pop and forward in the case of SR)? Or do you mean pushing a new top label for that downstream ECMP path? If the former, then I think that is contradictory to 3031 because we are inserting something below the forwarding label. At very least it is rewriting the NAS. If the latter, I don’t think that is precluded.


As currently worded, you have precluded just rewriting the NAS.  You are insisting that additional labels be pushed. I’m not sure why, but I certainly don’t understand the rationale. This seems much more restrictive than the language in -08.

Tony