Re: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap

[Xuxiaohu <[e-mail]>]

Hi Les,

In your example, how could the receiver know what type of tunnel technology is supported by the originator? In other words, how could the receiver know what tunnel type a given tag indicates? Are you planning to configure mappings between tags and tunnel types on each routers? If so, it seems error-prone and an unnecessary burden on network operators.

Best regards,
Xiaohu

From: Les Ginsberg (ginsberg) [mailto:[e-mail]]
Sent: Monday, May 09, 2016 4:36 PM
To: Uma Chunduri; Xuxiaohu; Marc Binderberger; Hannes Gredler
Cc: Christian Hopps; [e-mail] list
Subject: RE: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap

Uma -

First of all, I answered the question that was asked. :)

As regards additional tunnel parameters, you are correct that for some tunnel types there are additional parameters required - and both Marc and I have acknowledged this earlier in the thread. However, many of the use cases cited in the draft Introduction do not require additional parameters to be advertised i.e. use of admin tags as I have described would be sufficient - so this lessens the strength of your argument.

My position is that:

a)The additional advertisements themselves require local configuration to control what is advertised - so at least some of the potential config savings you hope for is reduced by the need to configure what is advertised (IS-IS itself knows nothing about tunnel encaps)
b)You are using the IGP as a transport for configuration information - not the direction I would like to see us go in general
c)From a real world deployment standpoint it would be helpful to have validation that this proposal solves a real problem - not just a theoretical one. In doing so you need to consider that admin tags suffice for many use cases.

Hope this clarifies things - even if we still do not agree.

   Les



From: Uma Chunduri [mailto:[e-mail]]
Sent: Friday, May 06, 2016 1:02 PM
To: Les Ginsberg (ginsberg); Xuxiaohu; Marc Binderberger; Hannes Gredler
Cc: Christian Hopps; [e-mail]<mailto:[e-mail]> list
Subject: RE: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap

Les,

        >"rlfa tag 100"
        > This indicates that any endpoint address advertised with tag 100 can be used for the specified technology ("rlfa" in this example).
        >The receiver of such an advertisement then knows two things about the advertising node:
        >1)It supports the tunnel type
        >2)It wants the specified address to be used as the tunnel endpoint

[Uma]: But this will not give any information if that particular tunnel type needs some parameters  of the sender at the receiver.
              Say for L2TPv3 Over IP, Session ID and optional Cookie and for GRE, you need GRE Key in some cases, for IPSec tunnel mode options etc.
             Some more tunnel specific information need to be exchanged is specified in Section 5 of the current version of the draft.
            I don't see a way tags help here and I alluded this on this thread and earlier.

--
Uma C.