Subject: [Apn] FW: [Int-area] Comments on "per-app networking considerations" draft

From: Linda Dunbar <[email-masked]>
Date: Tue, 6 Jul 2021 17:35:42 +0000

Frode,

That is a good summary.

3GPP use the notion of “Application Controller” that controls the services for applications. It is less likely to be users or application themselves exchanging App characteristics with network operators, more like that the users and applications register with their specific controllers for the types of services they need. Then the Controller exchange with the network.

Linda Dunbar

From: Int-area <[email-masked]<mailto:[email-masked]>> On Behalf Of Sørensen, Frode
Sent: Sunday, July 4, 2021 12:54 AM
To: [email-masked]<mailto:[email-masked]>
Subject: Re: [Int-area] Comments on "per-app networking considerations" draft

Many thanks for an interesting draft and follow-up discussion on the list. A couple of supplementary thoughts from my side:

1) Application-based vs. user-based (or user-controlled)

I think the draft could benefit from distinguishing between these two terms. The intro section mentions that “use cases where network operators, or applications, might desire for application traffic to be treated differently by the network”. Applications don’t have desires per se, while such desires come from some person, which could be the end-user, the application developer or network operator (if the latter has influence on the implementation of the user host, as the draft explains).

The discussion thread on the list is touching the distinction. The user-based approach, signalled from the application to the network, mentioned by Yiannis, is interesting. In my understanding, the user could either request specific QoS treatment per session, or the user could configure this in the application via some user-interface. In both cases, this selection would be user-controlled, as opposed to operator-controlled.

2) Application categories vs. traffic categories

The draft uses the terms “categories” and “classes” several times, which is an essential part of the discussion. I think the text could benefit from distinguishing more clearly between whether the categories/classes are “application categories” or “traffic categories”. The distinction may be subtle, and an example might illustrate the point:

It is essential whether the network operator is classifying the traffic (e.g. by using DPI) based on application characteristics – or the end-user is selecting any application for special treatment (whereby the corresponding traffic is marked). The former case could be understood as an application category (and would be application-specific), and the latter could be understood as a traffic category (and would be application-agnostic, since any application may belong to the traffic category).

3) Regarding application categories

Application categories are easy to relate to when discussing principles, but are not that easy when it comes to practical implementation. This is already covered to some extent by the discussion thread below, regarding zero-rating in particular. A major challenge is how to define the categories and how to decide which category specific applications belong to.

One might of course establish procedures regarding such questions (as elaborated in the email thread), but it is likely that there will anyway be borderline cases, and conflicts may occur. To that end, traffic categories which are user-controlled and application-agnostic will be significantly different from application categories. Therefore, I think it would be valuable to further clarify the description regarding categorization in the draft.

In my view, the draft describes an important topic, providing an implementation-independent overview of per-application networking, and discussing principal implications of such networking, which could be useful when considering different concrete implementations. I support continued development of the draft.

Best,
Frode