Re: [mpls] MPLS label and LSE data models

[Jeffrey Haas <[e-mail]>]

Xufeng,

On Tue, Jun 06, 2017 at 07:33:05PM +0000, Xufeng Liu wrote:
> From: Greg Mirsky [mailto:[e-mail]]
>   *   yes, grouping mpls-label-stack covers LSE though I cannot see why it needs id, sequence identifier. I'd expect the label stack already be properly ordered;
> [Xufeng] There are two ways to achieve the ordering: 1) Explicit sequence id, 2) Implicit order of the list items. Personally I feel that the explicit way is more clear and easier to use, but have no strong objection to the implicit way.

While I found the semantics of mpls-label-stack[id] to be clear, it does
have the peculiar property that the ids present in the list may have
gaps.  E.g. 10,20,30 instead of 1,2,3.  And also the ambiguity of whether
people's implementations starting counting at 0 or 1.

I'm not conversant with common Yang tool suites, but it seems if the
ordered-by user rather than the default of system, then the tooling might
present the bottom of stack entry as the first or last node of the list
rather than requiring the consumer to have to run a sort of the nodes based
on the id number and then select the first node.

-- Jeff