Re: [Dime] Question on draft-ietf-dime-qos-parameters

["Hannes Tschofenig" <Hannes.Tschofenig at gmx.net>]

Hi Martin, 
 
 	Hello,

	Questions on draft-ietf-dime-qos-parameters from the Dime Virtual
meeting of Feb 19th:

1) Is the ALRP AVP appropriate for call/session level or is it bearer
related? 

	 
[hannes] The ALRP AVP is taken from the NSIS and the RSVP work. Those
documents again took it from the SIP work. 

None of these documents describe the overall architecture. Protocol
designers sometimes define building blocks and let other folks figure out
how the entire stuff has to fit together. This is the "someone else's
problem approach". 

In relationship to the RSVP/NSIS work the ALRP parameter that is received by
RSVP/NSIS is then forwarded to the AAA server for authorization. 

In relationship to the SIP work these parameters also need to come from
somewhere (or at least they need to get authorized). Hence, there is also
the possibility to provide interworking with AAA (and Diameter in this
case). 

So, to answer your question. It can be related to both depending on the
scenario. 

2) If call/session level, draft-ietf-dime-qos-parameters-09.txt makes
reference to ietf-tsvwg-emergency-rsvp, which is bearer related. Is it also
bearer related?

[hannes] draft-ietf-dime-qos-parameters-09.txt made a reference to
ietf-tsvwg-emergency-rsvp since ietf-tsvwg-emergency-rsvp converts the RFC
4412 registry into numerical values. We use numerical values in the AVPs
rather than text strings as suggested by RFC 4412. 

Hence, we have to reference ietf-tsvwg-emergency-rsvp, which then references
RFC 4412. 

3) How can a user priority level be carried in this AVP at the call/session
level?

 3a) draft-ietf-dime-qos-parameters-09.txt is for QoS and there is
difference between QoS (bearer related) and signaling priority for a
call/session (e.g, priority call/session).  Correct?

[hannes] draft-ietf-dime-qos-parameters-09.txt defines a set of AVPs.
Depending on how you use them they might be directly related to the bearer
or for a SIP signaling session. 

 3b) In draft-ietf-dime-qos-parameters-09.txt, all AVPs (except may be the
ALRP AVP) are bearer/QoS associated.

[hannes] Well. One can argue that you can also use, for example, a bandwidth
parameter with a signaling session. So, it really depends a lot on how you
want to use these AVPs. 


From the feedback of the guys in the group it seems that they preferred to
move these priority AVPs into a separate document (largely because of the
suddenly appeared dependency problem). It is probably a good idea if the new
document provides some examples to improve readability and understanding. I
think your feedback also suggests that further aspects are clarified in that
new document. 

Having said all the above, you will notice that
draft-ietf-dime-qos-parameters-10.txt does not contain the priority AVPs
anymore. Hence, when we move the priority AVPs into a new document I will
request review comments from you to determine whether things are better
described. 

Btw, you might also want to read through ietf-tsvwg-emergency-rsvp because
there ALRP is also used at the bearer level. Hence, your comments also apply
to the ietf-tsvwg-emergency-rsvp document.

Ciao
Hannes
 

	Thanks,
	Martin