Subject: RE: [Diffserv] diffserv-pib-02; qosIfClassificationCaps

From: "Iliff, Tina" <[email-masked]>
Date: Thu, 21 Dec 2000 23:34:35 +0000

Maybe I should have stated it as a question or request:
Please clarify the use of the qosIfClassificationCaps PRC as well as Specs
attribute value.

I agree.  I do not see a requirement for classification on egress.  I also
understand the requirement to perform classification on egress in order to
have a mechanism to separate traffic in order to provide different levels of
service.  This is exactly why I pose the question regarding the intent of
the qosIfClassificationCapsSpec.

-----Original Message-----
From: Brian E Carpenter [mailto:[email-masked]]
Sent: Thursday, December 21, 2000 3:46 PM
To: Iliff, Tina
Cc: [email-masked]'
Subject: Re: [Diffserv] diffserv-pib-02; qosIfClassificationCaps

Not quite sure why you see a problem. Classification on egress would be 
somewhat unusual, but if there is no classifier on input a node
cannot possibly be a diffserv node.  I would assume that all classifiers
will have a wild card match (a.k.a. an "else" clause) to catch packets
that aren't caught by any explicit filter. Presumably, these packets would
get default behavior.

   Brian

> "Iliff, Tina" wrote:
> 
> All,
> 
> Comment regarding qosIfClassificationCapsSpec:
> The inputIpClassification value is stated to indicate whether or not the
PEP supports classification on the ingress.  My
> concern is that the PIB draft specifically states the following:  On a
given interface, there must be a complete  classifier
> in  place  at  all  times in   the ingress direction. This means that
there will always
> 
> be one or more filters that match every possible pattern  that  could be
presented in an incoming packet.
>        There is no such requirement in the egress direction."
> 
> Maybe the capability indication which the PEP can provide for the ingress
direction is whether or not it supports DiffServ QoS
> on ingress.
> What are your thoughts?
> Tina Iliff

_______________________________________________
diffserv mailing list
[email-masked]
http://www1.ietf.org/mailman/listinfo/diffserv
Archive:
http://www2.ietf.org/mail-archive/working-groups/diffserv/current/maillist.h
tml

_______________________________________________
diffserv mailing list
[email-masked]
http://www1.ietf.org/mailman/listinfo/diffserv
Archive: http://www2.ietf.org/mail-archive/working-groups/diffserv/current/maillist.html

---

From: Jay Wang <[email-masked]>
Date: Thu, 21 Dec 2000 17:06:12 -0800

> I agree.  I do not see a requirement for classification on 
> egress.  

> I also understand the requirement to perform classification on 
> egress in order to have a mechanism to separate traffic in order to
provide 
> different levels of service.  

You meant ingress here, right. Obviously, It is not "required" to do
classification
on Egress to support diffserv. Also, regarding your question regarding 
the use of qosIfClassificationCaps, you stated: 

	"Maybe the capability indication which the PEP can provide for the
ingress 
	direction is whether or not it supports DiffServ QoS on ingress."

Trying to guess what you mean from this, I think the answer is no because
classification is a necessary, but NOT a sufficient, condition for
QoS/Diffserv.
So classification capability alone can not imply the if/node necessarily
supports
Diffserv/QoS.

- Jay