[tsvwg] draft-ietf-tsvwg-nqb-15.txt - 4.2. Aggregation of the NQB DSCP with other Diffserv PHBs

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Hi Greg,

4.2. Aggregation of the NQB DSCP with other Diffserv PHBs

Last Para
Nodes that support the NQB PHB may choose to aggregate other service classes 
into the NQB queue....These could include Telephony (EF/VA), Signaling (CS5), 
Real-Time Interactive (CS4) and Broadcast Video (CS3). Or...[aggregates of] all 
traffic marked with DSCPs 40-47 (i.e., whose three MSBs are 0b101). 

https://www.rfc-editor.org/rfc/rfc9332.html#name-traffic-classification
In addition, an operator could use other identifiers to classify certain additional 
packet types into the L queue that it deems will not risk harm to the L4S service, 
for instance, addresses of specific applications or hosts; specific Diffserv 
codepoints such as EF, Voice-Admit, or the Non-Queue-Building (NQB) per-hop 
behaviour; or certain protocols (e.g., ARP and DNS) (see Section 5.4.1 of [RFC9331].

a) the last paragraph of draft NQB section 4.2 describes which service classes may be forwarded by the NQB PHB, a content which a reader wouldn't expect with the headline "Aggregation of the NQB DSCP with other Diffserv PHBs". 

b) In this last paragraph, draft NQB adds the service classes Signaling (CS5), Real-Time Interactive (CS4) and Broadcast Video (CS3) as eligible to be forwarded by an NQB PHB, as compared to EF and Voice Admit only as specified by RFC9332. Please provide text explaining, why Signaling (CS5), Real-Time Interactive (CS4) and Broadcast Video (CS3) are not queue building in draft NQB (standards track), while they seem to be queue building in RFC9332 (experimental).

I further note and take it for granted, that range based DSCP classification as a standards track DiffServ feature has been consented by the chairs.

Regards,

Ruediger



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Von: tsvwg <[e-mail]> Im Auftrag von [e-mail]
Gesendet: Donnerstag, 12. Januar 2023 01:34
An: [e-mail]
Cc: [e-mail]
Betreff: [tsvwg] I-D Action: draft-ietf-tsvwg-nqb-15.txt


A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Transport Area Working Group WG of the IETF.

        Title           : A Non-Queue-Building Per-Hop Behavior (NQB PHB) for Differentiated Services
        Authors         : Greg White
                          Thomas Fossati
  Filename        : draft-ietf-tsvwg-nqb-15.txt
  Pages           : 25
  Date            : 2023-01-11

Abstract:
   This document specifies properties and characteristics of a Non-
   Queue-Building Per-Hop Behavior (NQB PHB).  The purpose of this NQB
   PHB is to provide a separate queue that enables smooth, low-data-
   rate, application-limited traffic flows, which would ordinarily share
   a queue with bursty and capacity-seeking traffic, to avoid the
   latency, latency variation and loss caused by such traffic.  This PHB
   is implemented without prioritization and can be implemented without
   rate policing, making it suitable for environments where the use of
   these features is restricted.  The NQB PHB has been developed
   primarily for use by access network segments, where queuing delays
   and queuing loss caused by Queue-Building protocols are manifested,
   but its use is not limited to such segments.  In particular,
   applications to cable broadband links, Wi-Fi links, and mobile
   network radio and core segments are discussed.  This document
   recommends a specific Differentiated Services Code Point (DSCP) to
   identify Non-Queue-Building flows.


The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-tsvwg-nqb/

There is also an HTML version available at:
https://www.ietf.org/archive/id/draft-ietf-tsvwg-nqb-15.html

A diff from the previous version is available at:
https://author-tools.ietf.org/iddiff?url2=draft-ietf-tsvwg-nqb-15


Internet-Drafts are also available by rsync at rsync.ietf.org::internet-drafts