Hi Olivier,
On 20/08/2020 13:58, olivier.dug...@orange.com wrote:
Hi Peter,
Thank for the new version.
Le 19/08/2020 à 14:00, Peter Psenak a écrit :
Olivier,
[ ... ]
So, to speed up the deployment, I would prefer a reference to a delay
value that could be advertise by means of RFC7471, RFC8570 and/or
TE-App draft. It is then up to the operator to ensure the coherency
of what it is announced in its network by the different routers.
I know you don't like the app specific link advertisement, but I'm
afraid what you ask for is absolutely wrong.
We defined the ASLA encoding to address a real problems for
advertising the link attributes. We allow the link attributes to be
advertised in both legacy and ASLA advertisement for legacy
application (RSVP-TE, SRTE) to address the backward compatibility.
Flex-algo is a new application, there is absolutely no need to use the
legacy advertisement. Doing so would just extend the problem to the
flex-algo application.
Regarding the new version you provided, new section 5.1 (for IS-IS) and
section 5.2 (for OSPF) mention respectively RFC 8570 and RFC 7471 for
the definition of Min delay and TE metric which is fine for me. But,
they also made reference to draft isis-te-app, respectively
ospf-te-link-attr-reuse to encode these value.
that's what people were asking for. And it is right because we are
mandating the usage of ALSA encoding for any flex-algo related link
attributes.
Here, it is confusing.
I don't see how much more clear we can make it.
Indeed, RFC 8570 and RFC 7471 also define the way to encode TE metric
and Min delay.
you have to distinguish between two things:
a) where Min delay and TE metric were defined - RFC 8570 and RFC 7471
b) how we encode it for flex-algo - isis-te-app,
ospf-te-link-attr-reuse
What I'm suggesting, is a clear reference to the RFC for TE metric and
Min delay definition as well as the encoding (especially for the delay)
while leaving open the door to how the router acquire these values:
legacy a.k.a. RFC 8570 & 7471 or new draft a.k.a draft-isis-te-app &
draft-ospf-link-attr-reuse.
no. This will not be done. We only allow ASLA advertisement for these
metrics and other link attributes that are used for flex-algo. It is
done for a reason and I have already explained that.
In fact, in section 17.1.2, you mention only reference to RFC 8570 &
RFC7471 for the IANA definition which is fine for me.
because in registry, we are defining a metric type, not how we are going
to advertise it for the link.
I would suggest
the same wording for section 5.1. and 5.2 leaving operator free about
how it collect the values from the neighbour routers: legacy or new method.
please stop trying to make use of legacy RSVP-TE link advertisements for
flex-algo - it will not be allowed.
thanks,
Peter
Regards
Olivier
PS. We have a pre-alpha implementation of flex algo using the legacy
metrics and I know that recent IOS-XR provided similar implementation of
flex algo based on legacy metrics.
regards,
Peter
Regards
Olivier
Le 18/08/2020 à 19:02, tony...@tony.li a écrit :
Robert,
Thank you, exactly.
We just need a clarification of the document. I don’t understand
why this is such a big deal.
Tony
On Aug 18, 2020, at 9:22 AM, Robert Raszuk <rob...@raszuk.net
<mailto:rob...@raszuk.net>> wrote:
Les,
I think this is not very obvious as Tony is pointing out.
See RFC 8570 says:
Type Description
----------------------------------------------------
33 Unidirectional Link Delay
34 Min/Max Unidirectional Link Delay
That means that is someone implementing it reads text in this draft
literally (meaning Minimum value of Unidirectional Link Delay) it
may pick minimum value from ULD type 33 :)
If you want to be precise this draft may say minimum value of
Min/Max Unidirectional Link Delay (34) and be done.
That's all.
Cheers,
R.
On Tue, Aug 18, 2020 at 6:04 PM Les Ginsberg (ginsberg)
<ginsberg=40cisco....@dmarc.ietf.org
<mailto:40cisco....@dmarc.ietf.org>> wrote:
Tony –
As an author of both RFC 8570 and I-D.ietf-isis-te-app, I am not
sure why you are confused – nor why you got misdirected to code
point 33.
RFC 8570 (and its predecessor RFC 7810) define:
34 Min/Max Unidirectional Link Delay
This sub-TLV contains two values:
“Min Delay: This 24-bit field carries the minimum measured link
delay
value (in microseconds) over a configurable interval,
encoded as
an integer value.
Max Delay: This 24-bit field carries the maximum measured
link delay
value (in microseconds) over a configurable interval,
encoded as
an integer value.”
It seems clear to me that the flex-draft is referring to Min
Unidirectional Link Delay in codepoint 34.
I agree it is important to be unambiguous in specifications, but
I think Peter has been very clear.
Please explain how you managed to end up at code point 33??
Les
*From:* Lsr <lsr-boun...@ietf.org <mailto:lsr-boun...@ietf.org>>
*On Behalf Of *tony...@tony.li <mailto:tony...@tony.li>
*Sent:* Tuesday, August 18, 2020 7:44 AM
*To:* Peter Psenak (ppsenak) <ppse...@cisco.com
<mailto:ppse...@cisco.com>>
*Cc:* lsr@ietf.org <mailto:lsr@ietf.org>; lsr-...@ietf.org
<mailto:lsr-...@ietf.org>; Christian Hopps <cho...@chopps.org
<mailto:cho...@chopps.org>>; Acee Lindem (acee) <a...@cisco.com
<mailto:a...@cisco.com>>; draft-ietf-lsr-flex-algo....@ietf.org
<mailto:draft-ietf-lsr-flex-algo....@ietf.org>
*Subject:* Re: [Lsr] WG Last Call for draft-ietf-lsr-flex-algo
Hi Peter,
section 5.1 of the draft-ietf-lsr-flex-algo says:
Min Unidirectional Link Delay as defined in
[I-D.ietf-isis-te-app].
We explicitly say "Min Unidirectional Link Delay", so this
cannot be mixed with other delay values (max, average).
The problem is that that does not exactly match “Unidirectional
Link Delay” or “Min/Max Unidirectional Link Delay”, leading to
the ambiguity. Without a clear match, you leave things open to
people guessing. Now, it’s a metriic, so of course, you always
want to take the min. So type 33 seems like a better match.
section 7.3. of ietf-isis-te-app says:
Type Description Encoding
Reference
---------------------------------------------------------
34 Min/Max Unidirectional Link Delay RFC8570
And it also says:
33 Unidirectional Link Delay RFC8570
<https://tools.ietf.org/html/rfc8570>
This does not help.
So, IMHO what we have now is correct and sufficient, but I
have no issue adding the text you proposed below.
What you have now is ambiguous. We have a responsibility, as
writers of specifications, to be precise and clear. We are not
there yet.
BTW, before I posted 09 version of flex-algo draft, I asked
if you were fine with just referencing ietf-isis-te-app in
5.1. I thought you were, as you did not indicate otherwise.
My bad, I should have pressed the issue.
Anyway, I consider this as a pure editorial issue and
hopefully not something that would cause you to object the WG
LC of the flex-algo draft.
I’m sorry, I think that this is trivially resolved, but important
clarification.
You also have an author’s email that is bouncing, so at least one
more spin is required.
Sorry,
Tony
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Orange logo <http://www.orange.com>
Olivier Dugeon
Orange Expert, Future Networks
Open Source Referent
Orange/IMT/OLN/WTC/IEE/iTeQ
fixe : +33 2 96 07 28 80
mobile : +33 6 82 90 37 85
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_________________________________________________________________________________________________________________________
Ce message et ses pieces jointes peuvent contenir des informations
confidentielles ou privilegiees et ne doivent donc
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message par erreur, veuillez le signaler
a l'expediteur et le detruire ainsi que les pieces jointes. Les messages
electroniques etant susceptibles d'alteration,
Orange decline toute responsabilite si ce message a ete altere, deforme ou
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This message and its attachments may contain confidential or privileged
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If you have received this email in error, please notify the sender and delete
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Thank you.
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