[mpls] Re: 答复: Working Group Last Call on draft-ietf-mpls-mna-hdr (2nd WG call)

[Tony Li <[e-mail]>]

[WG chair hat: off]

Hi Loa,

> I agree that it is important to take the input we can get from implementations. I'm quite surprised by the perceived resistance for the WG chair that has spoken up on this. Taking the lessons we can from existing implementations has been there for MPLS Standard Track RFCs, since the start.

I think it’s a poor idea because I’ve sat through many hardware design meetings where someone raises the question of whether something is ready to consider for implementation. The hardware folks inevitably feel that something has not reached RFC status, then it is still in flux and not ready for hardware implementation.

Thus, an implementation mandate would create an unsolvable chicken-and-egg problem whereby we could not go to RFC without hardware and we could not get hardware without an RFC.

Thus, my concern is that requiring implementation experience is effectively ensuring that no progress can be made.

> There is one more thing, I've said several times. The P-flag and the PSD Present Op Code and the indicating the offset are by definition ISD, and should go in the ISD draft.
> 
> On the people supporting progressing the draft-ietf-mpls-mna-hdr, say that already today we know how the presence of PSD should be specified, so based on their arguments I see no  reason to wait.

Again, we have no justification for implementing PSD.  Until that’s presented, adding PSD indications to the ISD header is premature.

If there is truly justification for PSD, then members of the WG should simply put it on the table. The fact that they have not done so strongly suggests that it simply does not exist.

Regards,
Tony