Re: [tsvwg] I-D Action: draft-henry-tsvwg-diffserv-to-qci-00.txt

[<[e-mail]>]

Hi Brian,

thanks for the pointer to the draft. Before discussing details of the draft, I'm having some questions to the authors.

Within 3GPP TS 23.207 V15.0.0 (2018-06), "3rd Generation Partnership Project;
Technical Specification Group Services and System Aspects;
End-to-end Quality of Service (QoS) concept and architecture
(Release 15)"

I found the following statement:
 	 
The end-to-end QoS is provided by a local mechanism in the UE, the PDP context over the UMTS access network, DiffServ through the backbone IP network, and DiffServ in the remote access network in the scenario shown in the figure below. The GGSN provides the interworking between the PDP context and the DiffServ function.

My take is, that the GGSN decides about the Diffserv markings to be set and it does so using a PDP context. DSCPs set by a UE don't matter then. From what I have read I think to understand, that DSCPs play a role within an LTE network only, if the schedulers there honor them. I've stopped being active in this area some years ago. I've not yet heard of an LTE network supporting any kind of DSCP based resource scheduling. Did this change? If it did not and DSCP settings depend on GGSN PDP context (at a wholesale or carrier internal interface, I assume), what's the point of this draft?

Further, I searched TS 23.207 for "DSCP". The result is limited to a section where provider internal DSCPs are required only, but no standard ones:

Annex S (normative):
Fixed Broadband Access
S.1	General
This annex specifies the enhancement to PCC framework for supporting policy and charging control in the fixed broadband access network in the convergent scenario where a single operator is deploying both the fixed broadband access network and the Evolved Packet Core (EPC).....

I'd like to understand which problem the draft addresses.

Regards,

Ruediger


-----Ursprüngliche Nachricht-----
Von: tsvwg <[e-mail]> Im Auftrag von Brian E Carpenter
Gesendet: Montag, 29. Oktober 2018 02:20
An: [e-mail]; [e-mail]
Betreff: Re: [tsvwg] I-D Action: draft-henry-tsvwg-diffserv-to-qci-00.txt

Hi,

In https://tools.ietf.org/html/draft-henry-tsvwg-diffserv-to-qci-00#section-4.2.10
we find:

>    ...recommend Low-Priority Data be marked CS1 DSCP.
> 
>    Note: This marking recommendation may change in the future, as [LE-
>    PHB] defines a Lower Effort (LE) PHB for Low-Priority Data traffic
>    and recommends an additional DSCP for this traffic.

It seems to me that [LE-PHB] has advanced to the point where this recommendation should be the other way round: recommend the new LE codepoint, with a note that historically the CS1 codepoint has been (mis)used for this purpose.

Regards
   Brian Carpenter