Subject: [Isis-wg] Question on TLV type 135

From: Prashant Kumar <[email-masked]>
Date: Tue, 07 Dec 1999 17:17:38 -0500

I have a question on TLV type 135 in "IS-IS extension for Traffic
Engineering".

under the description it is told that this TLV corrects some 
problems in existing "IP reachability TLV".

But the thing which confuses me is: Is this TLV(type 135) is aimed at
replacing the existing IP Internal reachability TLV(type 128) and IP
External reachability TLV(type 129). If so section 3.10.2 of RFC1195 
"Order of Preference of Routes in the Level 2 routing" does not apply
directly anymore because in TLV type 135 there is no bit to indicate
"internal" and "external" routes. Also, how are we going to distinguish
internal and external reachability.

I assume, extended IP reachability TLV deserves more explanation.

Regards,
-- 
Prashant Kumar
Nortel Networks

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From: Henk Smit <[email-masked]>
Date: Wed, 8 Dec 1999 03:36:05 +0100 (MET)

> External reachability TLV(type 129).

  Yes.

> If so section 3.10.2 of RFC1195 
> "internal" and "external" routes.

  Correct.

> Also, how are we going to distinguish

  There is no definition of internal or external routes in the draft.
 An IP prefix is an IP prefix. If you see the same IP prefix as an
 internal and an external prefix in your IGP, you already have
 a big problem (redistribution feedback). Only doing making a
 distinction between internal/external prefixes during route
 installation is not going prevent you from problems.

  If you really want to prevent redistribution feedback, you
 need to tag the origin of your prefix. If there is a real
 interest to be able to do that, we have the sub-TLVs in TLV 135
 to do things like route coloring/tagging.

     Henk.

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From: "Rajesh Saluja" <[email-masked]>
Date: Wed, 08 Dec 1999 09:03:50 -0500

>  to do things like route coloring/tagging.

Henk,
Will you please give pointer to the draft explaining the sub-TLVs for
route coloring?

Thanks,
Rajesh

--

-------------------------------------------------------------
Rajesh Saluja
Nortel Networks Inc 600 Technology Park Billerica, MA  01821
Ph: (978) 288-7791      Fax: (978) 670-8760
--------------------------------------------------------------

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From: Henk Smit <[email-masked]>
Date: Wed, 8 Dec 1999 16:26:32 +0100 (MET)

> Will you please give pointer to the draft explaining the sub-TLVs for

  draft-ietf-isis-traffic-02.txt only defines the format of the sub-TLVs,
 in case we want the. There are no sub-TLVs defined for TLV 135 yet.

  The sub-TLVs for TLV 135 work the same way as the sub-TLVs for TLV 22.
 If you want to define some sub-TLVs for TLV 135, feel free to build
 something yourself, write a new draft, and propose it to the WG.

    Cheers,

        henk.

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From: [email-masked] (Christian E. Hopps)
Date: 13 Dec 1999 21:09:09 -0500

>  to do things like route coloring/tagging.

But this means I have to implement sub-tlv's even though I'm not going
to do TE with the TLV.

:)

Chris.