Hi,
I'm fine with the below.
Do folks have any concerns with the below, or can I update the draft?
Please speak up if you disagree.
thanks,
Peter
On 12/05/2021 17:33, Les Ginsberg (ginsberg) wrote:
Alvaro (and everyone) -
I think we can do better than this.
Prefix-attributes sub-TLV is necessary when a prefix is leaked between levels -
and more specifically when leaked upwards in the hierarchy.
(We have the "D" bit in the TLV itself when leaked downwards.)
While I would prefer that we simplify things and simply require the sub-TLV all
the time, I think we can be more generous and still be functional.
1)Prefix-attributes SHOULD be included in Locator TLV
2)Prefix-attributes MUST be included when TLV is leaked upwards in the hierarchy
3)Prefix-attributes sub-TLV MUST be included when the advertisement is
"redistributed" from another protocol
Note that because the sub-TLV is not mandatory, if #2 and #3 are NOT followed, receivers
will be unable to determine the correct source of the advertisement and may do the
"wrong thing". And the receivers will be unable to detect the violation.
Finally, RFC 7794 was published over 5 years ago.
Vendors make their own choices as to what protocol extensions they choose to
support. But given the usefulness of the information in prefix-attributes
sub-TLV I would encourage implementations which do not yet support the sub-TLV
to add it.
Les
-----Original Message-----
From: Alvaro Retana <aretana.i...@gmail.com>
Sent: Wednesday, May 12, 2021 7:17 AM
To: Gengxuesong (Geng Xuesong) <gengxues...@huawei.com>; Peter
Psenak (ppsenak) <ppse...@cisco.com>; bruno.decra...@orange.com
Cc: Van De Velde, Gunter (Nokia - BE/Antwerp)
<gunter.van_de_ve...@nokia.com>; draft-ietf-lsr-isis-srv6-
extensi...@ietf.org; Les Ginsberg (ginsberg) <ginsb...@cisco.com>;
Shraddha Hegde <shraddha=40juniper....@dmarc.ietf.org>; lsr@ietf.org;
cho...@chopps.org
Subject: Re: [Lsr] Last Call: <draft-ietf-lsr-isis-srv6-extensions-14.txt>
(IS-IS
Extension to Support Segment Routing over IPv6 Dataplane) to Proposed
Standard
Peter:
Hi!
As Xuesong suggested earlier, could you/we live with “SHOULD send”?
The mitigating circumstance (recommend vs require) is precisely the
lack of support. I think your original reply to Gunter about how it
could be hard to mandate the Flags TLV at this point is spot on.
Thanks!
Alvaro.
On May 12, 2021 at 4:49:58 AM, Peter Psenak wrote:
as I said, if we want to mandate the presence of the Prefix Attribute
sub-TLV, we MUST ignore Locators without it. If we don't, then the MUST
on the originator does not mean anything.
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