Re: My comments to the press about RFC 2474

 Let's go back to your original comment, the one that Russ has quoted 
elsewhere. You said: "It has been consistently hard to explain that 
diffserv is not a prioritisation scheme, even within the technical 
community, let alone to the regulators and the media." Your 
clarification is that "DiffServ deals with multiple queuing disciplines, 
which may or may not be priority based" and you get into EF and AF that 
in most implementations will end up using dedicated facilities of some 
sort, although service providers may be able to use these dedicated 
facilities for generic traffic if there's no EF or AF to send.
I can see why it's hard to explain this subtle distinction. You're 
saying here on the list that DiffServ is a higher level abstraction than 
prioritization that neither requires nor precludes prioritization to 
implement premium services. That's fine, but if you want to say that 
DiffServ is *completely removed from the realm of prioritization,* you 
have to explain away the grandfathering of IP Precedence into the 
standard. I think that you mean to say that DiffServ is *more than* a 
prioritization scheme, it's a general architecture for Internet QoS."
But even that's not correct. In fact, DiffServ is an Internet QoS 
architecture that explicitly offers priority-based services by design, 
and may also offer other types of assured or expedited services, except 
nobody really knows how that might actually work in a real scenario (or 
maybe they do, and it's just us humble developers who don't.)
Russ said to the press that he considers AT&T's belief that the RFCs 
envisioned payment for premium services implemented over DiffServ or 
MPLS to be "invalid." I find this puzzling as there are numerous 
references to payment for premium services in the RFCs AT&T cites, such 
as RFC 2638:
"At the risk of belaboring an analogy, we are motivated to provide
services tiers in somewhat the same fashion as the airlines do with
first class, business class and coach class. The latter also has
tiering built in due to the various restrictions put on the purchase.
A part of the analogy we want to stress is that best effort traffic,
like coach class seats on an airplane, is still expected to make up
the bulk of internet traffic. Business and first class carry a small
number of passengers, but are quite important to the economics of the
airline industry. The various economic forces and realities combine
to dictate the relative allocation of the seats and to try to fill
the airplane. We don't expect that differentiated services will
comprise all the traffic on the internet, but we do expect that new
services will lead to a healthy economic and service environment."


Am I missing something when I find a gap in the dialog?

RB

On 9/3/2010 3:11 PM, Brian E Carpenter wrote:
> Er, exactly what in your quotation is incompatible with what
> I wrote:
>
> > > > Diffserv deals with multiple different queuing disiplines, which may or may not 
> > > > be priority based.
> ?
>
> Regards
>     Brian Carpenter
>
> On 2010-09-04 09:34, Richard Bennett wrote:
> >    Brian's paper on DiffServ confirms the fact that prioritization is part of 
> > the
> > standard. Here are the two relevant quotes:
> >
> > "In the original design of IP [33], a byte known as the “type of service (TOS)
> > octet” was reserved in the header of every packet. This was defined to contain
> > two important fields: a three-bit “precedence” value and three TOS bits. The
> > precedence was intended as a simple priority marker, where priority 0 got the
> > worst treatment and priority 7 got the best." (p. 1480)
> >
> > "The Diffserv working group has taken the approach that a few fundamental PHBs
> > should be standardized early. These should derive from some existing experience
> > (primarily from limited deployment and experimentation with use of the IP
> > precedence field to select forwarding behaviors) and might be implemented using
> > a variety of specific mechanisms. The PHBs standardized so far are as follows...
> >
> > "• Class selector behaviors: here seven DSCP values run from 001 000 to 111 000
> > and are specified to select up to seven behaviors, each of which has a higher
> > probability of timely forwarding than its predecessor. *Experts will note that
> > the default behavior plus the class selectors exactly mirror the original eight
> > IP Precedence values.*" (p. 1487)
> >
> > This is very straightforward.
> >
> > RB
> >
> > On 9/3/2010 1:06 PM, Brian E Carpenter wrote:
> > > Richard,
> > >
> > > Diffserv deals with multiple different queuing disiplines, which may or may not 
> > > be priority based. Please read RFC 2475 and if
> > > you like, B.E. Carpenter and K. Nichols, Differentiated Services in the 
> > > Internet, Proc. IEEE, 90 (9) (2002) 1479-1494.
> > >
> > >      Brian
> > >
> > > On 2010-09-04 07:57, Richard Bennett wrote:
> > > >   DiffServ is a prioritization scheme, Brian, how can you say it's not?
> > > > IntServ is a reservation scheme, and DiffServ attempts to provide
> > > > desired PHBs in practice by sorting packets into priority queues and
> > > > invoking appropriate Link Layer  facilities, which are in most cases
> > > > priority-based, such as 802.11e traffic classes.
> > > >
> > > > What on earth could the value of DSCPs be if they didn't map to traffic
> > > > classes in the data link?
> > > >
> > > > RB
> > > >
> > > >   Brian E Carpenter<brian(_dot_)e(_dot_)carpenter(_at_)gmail(_dot_)com>   wrote:
> > > > > Russ,
> > > > > It has been consistently hard to explain that diffserv is not a
> > > > > prioritisation scheme, even within the technical community, let
> > > > > alone to the regulators and the media. I think your comments as
> > > > > quoted are as good as we can expect from journalists.
> > > > > It should be a matter of concern to all of us here that the US FCC
> > > > > isn't confused into regulating the technology. It would set a bad
> > > > > precedent for regulators in other countries. I am making no comment
> > > > > as to whether they should regulate carrier's charging practices; that's
> > > > > entirely a national matter that shouldn't concern the IETF in any way.
> > > > > Regards
> > > > > Brian Carpenter
> > > > > On 2010-09-03 05:47, Russ Housley wrote:
> > > > > > I want the whole community to be aware of the comments that I made to
> > > > > > the press yesterday. Clearly, these comments do not represent IETF
> > > > > > consensus in any way. They are my opinion, and the reporter was told to
> > > > > > express them as my opinion.
> > > > > >
> > > > > > One thing that I said was not captured quite right. The article says:
> > > > > > "With services that require certain speeds to operate smoothly, such as
> > > > > > Internet telephony, calls are given precedence over TV, Housley said."
> > > > > > I actually said that DiffServ can be used to make sure that traffic
> > > > > > associated with applications that require timely delivery, like voice
> > > > > > and video, to give preference over traffic associated with applications
> > > > > > without those demands, like email.
> > > > > >
> > > > > > The whole article is copied below, and it is online here:
> > > > > > http://www.nationaljournal.com/njonline/tc_20100902_7144.php
> > > > > >
> > > > > > Russ
> > --
> > Richard Bennett
> > Senior Research Fellow
> > Information Technology and Innovation Foundation
> > Washington, DC
--
Richard Bennett
Senior Research Fellow
Information Technology and Innovation Foundation
Washington, DC

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