Re: [Idr] route-capability explained

Paul Jakma <> Mon, 04 August 2008 19:02 UTC

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Subject: Re: [Idr] route-capability explained
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Hi Samita,

On Mon, 4 Aug 2008, Samita Chakrabarti wrote:

> [SC>]  Correct.  You are right about unlikely AS4 speakers without AS4
> extended community support -- eventually that should be the case. But, since
> these two documents are separate, we can only assume and hope that an
> implementation would support both at the same time :-)


Yakhov's ext-community is probably best place to address these 
problems, no?

Also, I'd like to ask the IDR WG to adopt his draft as a working 
group document. Some kind of communication issue with the IDR chair 
seems to have prevented this from appearing on the agenda...


> [SC>] Yes. The draft-rekhter-as4octet-ext-community can use the 
> extended-asn-capability defined in RFC4893 and make the 2byte/4byte 
> mapping of ext-community decision accordingly. If it is specified 
> in the document, then the implementations will behave in a 
> consistent manner. In that case, we don't need a different 
> route-capability [as proposed in my draft] message.

Unfortunately, there are already some 4B speakers deployed which do 
not translate. So translation is perhaps not a robust answer.

> [SC>] Simpler mandate would be that no 4byte<->2byte mapping takes 
> place for as4-specific ext-community values and 4B-format can 
> operate with another 4B-format compliant system and 2B-format can 
> work with another 2B-format system. But this will again be totally 
> configuration dependent. This might not be easy for large PE 
> deployment scenarios.

Hmm: The 2B form is universally understood, so that should be used if 
the values allow - no translation needed. Surely?

Paul Jakma	Key ID: 64A2FF6A
"The great question... which I have not been able to answer... is, `What does
woman want?'"
-- Sigmund Freud
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