With respect, Brian, I don't think this is simply the failure of
journalists to discern the distinction between Informational RFCs and
Standards Track RFCs. Nobody has made the claim that the IETF produced a
standard for accounting and billing for QoS or anything else.
Informational RFCs are a perfectly fine record of what certain people in
the IETF community may be "envisioning" at a given time, as long as
people understand that "envisioning" is not the same as "requiring,"
which is basic English literacy.
This debate was also not started by AT&T throwing the name of IETF in to
the regulatory stew as Russ was quoted as saying to CNET's Declan
McCullagh. ("We didn't foresee AT&T throwing our name into this
discussion," the IETF's Housley said. He added: "This characterization
of the IETF standard and the use of the term 'paid prioritization' by
AT&T is misleading.")
The immediate debate was started by a letter filed with the FCC by a
group called National Organizations on Aug. 2nd addressing DiffServ and
IntServ. This letter drew a reply from Free Press invoking the name of
IETF and interpreting DiffServ. AT&T's letter offering their view of
DiffServ was a reply to the Free Press letter, which said:
"Second, it is nonsensical to portray DiffServ as something that a
third-party content provider could pay an ISP to use for
paid-prioritization. Either an ISP respects DiffServ flags as outlined
by IETF and chosen by the application or they do not -- and if they do
not, then it isn’t DiffServ. By way of analogy, an individual customer
cannot pay a restaurant to obey the health code -- they either do or
they don’t. If an ISP is using DiffServ, but not respecting application
flags, then that is not the standard as outlined by the IETF. Similar to
how Comcast was improperly using RST packets to block BitTorrent, such a
nonstandard use of DiffServ would be entirely new, improper, and not at
all in line with that outlined by the IETF."
So there was a chain of "throwings of the name of IETF into this
discussion" before AT&T jumped into to it. It would have been pretty
damn hard for them to address the arguments that had already been made
by Free Press without referring to IETF, so Russ' remark is, well, not
very well informed. Perhaps he's not a professional FCC-watcher.
So what we have at the FCC at the moment is a number of people arguing
about the meaning of RFCs because they think the RFCs (even the
Informational ones) hold the key to understanding the spirit of the
Internet. I think this is wonderful, because it's much more productive
-- potentially -- than a bunch of law professors invoking end-to-end
arguments as the First Commandment, a binding law that bans anything
beyond best efforts as far as the eye can see.
I can see how technical people would find this whole process
distasteful. Journalists don't understand what they're told, they don't
ask the right questions, and they don't repeat the right comments.
Regulators are even worse. It's no wonder that Dave Clark used his time
addressing the FCC after me at the Harvard hearing on Comcast in 2008 to
talk about economics. These are hard questions for the network
engineering community to resolve, and even harder for regulators. No
doubt about it.
But you can't blame people for trying, and you can't say "go regulate
the Internet however you want but keep the IETF's name out of it." That
would lead to a result you really don't want to see.
RB
On 9/3/2010 3:53 PM, Brian E Carpenter wrote:
Richard,
This will be my last message on these points, which were beaten to death
in the diffserv WG some years ago.
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.)
I can't speak for those who have implemented EF and AF queuing algorithms;
they will have to speak for themselves.
Am I missing something when I find a gap in the dialog?
I don't see the gap. There are a few references to possible differential
payments in some of the informational documents concerning diffserv, and nobody
denies that differential pricing is possible. There are no elements in the
normative specifications of diffserv that serve in any way to support
accounting, pricing or charging. We can't control what choices the carriers
in one particular country such as the USA adopt; and it's not our business.
The fact that journalists don't read the bit at the beginning of each
RFC that defines its status is something that we've been used to for
many years.
Regards
Brian
On 2010-09-04 10:36, Richard Bennett wrote:
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.e.carpenter@xxxxxxxxx> 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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