Re: [tsvwg] <tsvwg> Using NQB in mobile network

[Thomas Fossati <[e-mail]>]

Hi Xuesong,

On 05/12/2019, 07:13, Geng Xuesong wrote:
> I notice that in section 7.2, you mentioned that "To support the NQB
> PHB, the mobile network MUST be configured to give UEs a dedicated,
> low-latency, non-GBR, EPS bearer ... or Data Radio Bearer..."

First, whatever we say in 7.2 should be at the RECOMMEND level.  Any
MUST in that section is wrong in principle -- my bad.  This will be
fixed in -01.

>  I'm a little confused about why NQB is limited to provide service for
>  non-GBR service. I think considering the low latency and congestion
>  avoidance feature of NQB, it is more suitable for delay-critical GBR
>  defined in 3GPP TR23.501, or do you have any other considerations in
>  this point?

Now to your main point, per the PHB definition (Section 5, third para):

   NQB traffic SHOULD NOT be rate limited or rate policed separately
   from queue-building traffic of equivalent importance.

Which looks incompatible with an implementation of the PHB that routes
NQB through a GBR bearer and QB via non-GBR.  (And this looks to me like
the only option here since we don't want QB on GBR.)

It is still possible to get what you have in mind, but that needs a
second dedicated low-latency GBR bearer.  So you could do the first
split between QB and NQB based on the DSCP marking and then have a
further bisection inside the NQB class and say that, e.g., UDP:12345
warrants delay-critical treatment and therefore gets mapped to the
GBR bearer whereas the rest receives the "normal" NQB handling.

cheers, thanks
t



IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.