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 >>> > _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf