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RE: TE/CT Configuration scalability
>>
>> As far as I can see there is a considerable difference
>> bteween the inter-AS
>> Diffserv case and the inter-AS DS-TE case.
>>
>> In Diffserv, the DIFFSERV TLV uses a standard PSC coding.
Let's forget MPLS for a second. In non-MPLS IP Diffserv, there is no
signaling whatsoever across AS, with respect to Diffserv. Operators who
wish to offer inter-AS Diffserv just agree on a common set of classes,
markings, traffic contracts, QoS commitments, compensation, ...
Currently there is no "recommended/standard" set of Diffserv classes. It
is up to each operator to decide what set of classes is optimum for
their environment, and this choice, along with corresponding QoS
commitments, is a strong differentiation factor.
If, in the future, operators feel that it is desirable to convergence on
a "recommended/standard" set of Diffserv classes and specify those, then
we could look at how to support that set of classes when TE/DS-TE
mechanisms are used. For now, I am not aware of the existence of such a
"recommended/standard" set. I am not even sure that there is convergence
among operators that it makes sense to specify that.
Francois
>> This promotes
>> the possibility of agreement between the AS. They have to
>> agree on the
>> PSC/Classes implemented and perhaps on policing, etc. There
>> are no coding
>> issues.
>>
>> In the DS-TE, there is no standard CLASSTYPE coding. As
>> Tony Li writes, a
>> "standard" mapping may be useful. But given that the idea of
>> TE/CT is to
>> define a limited number of combinations from a set
>> prevalent alternatives,
>> this may be difficult. In the absence of a standard mapping, it is
>> presumably necessary to have a mechanism to explicitly map
>> between the
>> TE/CT codes of every AS pair.
>>
>> Do you agree that this is required? if so, is it feasible?
>>
>> Lionel Silman, System, Optical Networks Division, ECI Telecom
>>
>>
>>
>>
>>
>> "Francois Le
>>
>> Faucheur To: "Ina
>> Minei" <ina@juniper.net>,
>> \(flefauch\)"
>> <Lionel.Silman@ecitele.com>
>> <flefauch@cisco. cc:
>> <te-wg@ops.ietf.org>, "FLF"
>> com>
>> <flefauch@cisco.com>
>> Subject: RE:
>> TE/CT Configuration scalability
>> 02/07/2004 11:42
>>
>>
>>
>>
>>
>>
>>
>>
>> Hello,
>>
>> Expanding on Ina's response.
>>
>> The TE-Class Mapping need NOT be the same in different Autonomous
>> Systems which are span by a given inter-AS DS-TE LSP. It may
>> be that AS1
>> supports 4 preemption priorities within its AS for CT1,
>> while AS2 only
>> supports 2 preemption priorities within its AS for CT1.
>>
>> Now, the two AS administrators certainly have to carefully agree on a
>> number of things before they can support inter-AS LSPs; like
>> which CTs
>> they are allowed to use across ASes, which preemption, how
>> much maximum
>> bandwidth etc. But but this is how Diffserv works anyway
>> independently
>> of DS-TE: for inter-AS Diffserv, operators have to agree on which
>> classes they want to share, which marking, what maximum rate
>> for each,
>> and then configure mechansisms such as Traffic Conditioning
>> accordingly.
>> DS-TE just fits in this existing Diffserv mode of operations.
>>
>> Cheers
>>
>> Francois
>>
>> >> -----Original Message-----
>> >> From: owner-te-wg@ops.ietf.org
>> >> [mailto:owner-te-wg@ops.ietf.org] On Behalf Of Ina Minei
>> >> Sent: jeudi 1 juillet 2004 19:26
>> >> To: Lionel.Silman@ecitele.com
>> >> Cc: te-wg@ops.ietf.org
>> >> Subject: Re: TE/CT Configuration scalability
>> >>
>> >>
>> >> Lionel,
>> >>
>> >> I assume your question is "can I establish an inter-as
>> >> diffserv-te
>> >> lsp given the requirement for uniform TE-class
>> >> configuration" ? The answer
>> >> is yes.
>> >>
>> >> The reason for having a requirement for uniform TE-Class
>> >> configuration is because of the way IGP siganling is
>> defined in the
>> >> te-proto draft. If instead of only advertising 8 values
>> out of the 64
>> >> possible (ct, prio) combinations we would have advertised
>> >> all 64, there
>> >> wouldn't have been the concept of TE-classes or the
>> >> requirement to keep
>> >> them uniform.
>> >>
>> >> The only thing we get from the requirement is
>> to be able to
>> >> consistently set up an LSP conforming to some SLAs within
>> >> one domain. So
>> >> what happens when you cross to a different domain? All you
>> >> need to do is
>> >> translate the LSP's SLAs to the necessary parameters in the
>> >> new domain.
>> >>
>> >> There is no requirement to signal the TE-class
>> matrix across
>> >> domains.
>> >>
>> >> Ina
>> >>
>> >> On Thu, 1 Jul 2004 Lionel.Silman@ecitele.com wrote:
>> >>
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > draft-ietf-tewg-diff-te-proto-07, "Protocol extensions for
>> >> support of
>> >> > Differentiated-Service-aware MPLS Traffic Engineering" states:-
>> >> >
>> >> > "To ensure coherent DS-TE operation, the network
>> administrator MUST
>> >> > configure exactly the same TE-Class Mapping on all LSRs of
>> >> the DS-TE
>> >> > domain"
>> >> >
>> >> > How does this idea of identical TE/CT configuration work
>> >> over multiple
>> >> > domains? Is there any possibility of interoperability?
>> >> >
>> >> >
>> >> -------------------------------------------------------------
>> >> ---------------------------------------
>> >> >
>> >> > Lionel Silman, System, Optical Networks Division, ECI Telecom
>> >> > Tel Work: +972 (3) 9266007; Home: +972 (3) 6417464
>> >> >
>> >> >
>> >>
>> >>
>>
>>
>>
>>