Re: [tsvwg] Some comments on NQB (part 2) - DSCP policy

[Greg White <[e-mail]>]

See [GW].

On 5/4/22, 1:42 AM, "[e-mail]" <[e-mail]> wrote:

    Greg, Gorry

    I favour an approach on the recommended marking respecting that DiffServ is operational in some networks for more than a decade.

    I think, an approach to maintain DSCP 45 on an end-to-end basis is likely to fail without SLAs at interconnection. That's why I oppose to that. And as I said, the motivation to have this DSCP to support NQB on outdated WiFi boxes to me is not what standards should be written for. 

[GW] But, we've heard the opposite from other network operators, who feel that 45 end-to-end is simplest.  And, we've heard the view that IP precedence is deprecated and is not what standards should be written for.  Also, similar to what I indicated in my response to David, I don't know what you mean by "outdated WiFi boxes".  We're talking about nearly every WiFi device on the planet and nearly all of the ones that are available for purchase today.  That's a deployed base that is probably two orders of magnitude larger than the DT network (and growing).  If we had to pick one or the other, I would go with interoperation with Wi-Fi rather than interoperation with DT.   

[GW] I think we all need to agree that there is a lot of history with different established practices in place for DSCP usage, and we need to be willing to be flexible. No one is arguing from a position of architectural purity here (well, perhaps Gorry is to some degree), so I think it is a matter of coming up with recommendations that give us the best chance of having the widest support with the least effort and confusion.   







    Which scenarios do apply?
    a) Access provider supports NQB at Access Gateway: 
        a1) fixed & mobile networks: the Access Gateway is likely a QoS policy point, (Multi-Field) classification and re-marking are operational.
        a2) I'm not sure about broadband network Access Gateway policy functions.. could these support NQB 
               without being QoS policy point? If yes, is that prevalent?     -I try to be careful, no blaming intended-
    b) Access provider supports QoS at Access Gateway, but doesn't want to support NQB: then the Gateway is likely a policy point and re-marking is to be expected (in a negative sense could well be DSCP 000 000).
    c) Access provider doesn't support QoS at Access Gateway, but wants at least outdated WiFi gear to benefit from NQB. Then DSCP 45 may make sense.
    d) Access provider really doesn't care about QoS at any location. Then DSCP 45 may make sense.

    In cases b), c) and d), the Access Gateway is forwarding NQB like default (and NQB inherits default performance). Than all the effort is at best only about the WiFi AP. To me that's not justifying an end-to-end marking scheme likely conflicting with providers operating a1). As Greg has mentioned, the home network gateway may deal with the issue (and that should become part of the draft).

    Regards, Ruediger

    <snip>