Re: [tsvwg] draft-ietf-tsvwg-nqb-15.txt - 5.1 Primary Requirements, Forwarding

[Greg White <[e-mail]>]

In order to provide low loss, low latency and low jitter, it is necessary that the queue remain small. The EF definition is one way to achieve that, the NQB definition is another. I am not interested in redefining NQB PHB to just be another EF.   So, I don't agree that adding the EF requirements language to the NQB PHB is needed (or desired).

-Greg



On 2/3/23, 1:00 AM, "[e-mail] <mailto:[e-mail]>" <[e-mail] <mailto:[e-mail]>> wrote:


Hi Greg,


the goal of draft-ietf-tsvwg-nqb is a PHB providing statistically better loss, latency (very low queueing delay, respectively), and jitter performance as compared to the default PHB. 


https://www.rfc-editor.org/rfc/rfc2598.html <https://www.rfc-editor.org/rfc/rfc2598.html> (which has been obsoleted) specifies a PHB which can be used to build a low loss, low latency, low jitter ...end-to-end service through DS domains.


Apart from offering similar goals (and recommending similar DSCPs), both share a set of common features, in particular the treatment of aggregates, at least at the bottleneck. RFC2598 determines these common basic requirements as follows:


The EF PHB is defined as a forwarding treatment for a particular
diffserv aggregate where the departure rate of the aggregate's
packets from any diffserv node must equal or exceed a configurable
rate. The EF traffic SHOULD receive this rate independent of the
intensity of any other traffic attempting to transit the node. It
SHOULD average at least the configured rate when measured over any
time interval equal to or longer than the time it takes to send an
output link MTU sized packet at the configured rate. (Behavior at
time scales shorter than a packet time at the configured rate is
deliberately not specified.) The configured minimum rate MUST be
settable by a network administrator (using whatever mechanism the
node supports for non-volatile configuration).


Low loss, low latency and low jitter REQUIRE the above to hold. Please add that text in section 5.1. "Primary Requirements" of draft NQB and a please add a reference to RFC2598.




Regards,


Ruediger










-----Ursprüngliche Nachricht-----
Von: tsvwg <[e-mail] <mailto:[e-mail]>> Im Auftrag von [e-mail] <mailto:[e-mail]>
Gesendet: Donnerstag, 12. Januar 2023 01:34
An: [e-mail] <mailto:[e-mail]>
Cc: [e-mail] <mailto:[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/ <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 <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 <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