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RE: WG last call: draft-ietf-tewg-diff-te-proto-03.txt
Dimitry,
Please check the draft text I proposed in message titled "Reflecting
new-MAM/SAM definition in diff-te drafts" (assuming the enhancement to
MAM definition). This should address your comments on section 5.1.
BTW: any thoughts on the "SAM" name?
Regarding your other comment, I actually think that "Max Link Bw" is
correct in the CAC formulas.
draft-ietf-isis-traffic-xx says:
"This sub-TLV contains the maximum bandwidth that can be used on this
link in this direction (from the system originating the LSP to its
neighbors). This is useful for traffic engineering."
I believe the intent is that one given TE-tunnel can not exceed the max
link Bw. I believe this check is commonly implemented by multiple
implementations. Perhaps the text of draft-ietf-isis-traffic could be
made a little clearer on that. I will mention this to the authors (and
same for OSPF draft).
Also, it wouldn't make much sense to me to check separately that B is
below Max Reservable Bw, since Unreserved Bw will always be smaller than
Max Reservable bw.
Thanks for your review.
Francois
>> -----Original Message-----
>> From: Dimitry Haskin [mailto:dhaskin@axiowave.com]
>> Sent: 11 April 2003 21:05
>> To: 'Jim Boyle'; te-wg@ops.ietf.org
>> Subject: RE: WG last call: draft-ietf-tewg-diff-te-proto-03.txt
>>
>>
>>
>> Section 5.1, page 10:
>>
>> "With DS-TE, the existing "Maximum Reservable Bw" sub-TLV
>> is retained
>> with a generalized semantic so that it MUST now be interpreted as
>> Bandwidth Constraint 0 (BC0)."
>>
>> also Section 5.1, page 10:
>>
>> "A DS-TE LSR which does advertise Bandwidth Constraints, MAY also
>> include the existing "Maximum Reservable Bw" sub-TLV. This may be
>> useful in migration situations where some LSRs in the
>> network are not
>> DS-TE capable (see Appendix C) and thus do not understand the new
>> "Bandwidth Constraints" sub-TLV. In that case, the DS-TE
>> LSR MUST set
>> the value of the "Maximum Reservable Bw" sub-TLV to the
>> same value as
>> the one for BC0 encoded in the "Bandwidth Constraints" sub-TLV.
>>
>> A DS-TE LSR receiving both the old "Maximum Reservable Bw" sub-TLV
>> and the new "Bandwidth Constraints" sub-TLV for a given link MAY
>> ignore the "Maximum Reservable Bw" sub-TLV."
>>
>> The above statements are implying that the "Maximum
>> Reservable Bw" sub-TLV
>> is redundant in the presence of Bandwidth Constraints.
>> Furthermore, they
>> indicate that BC0 has semantics of the maximum reservable
>> bandwidth. This
>> could be true for the RD model. However it is clearly not
>> true for other
>> models. Therefore these statements should be removed from
>> the specification
>> or, even better, replaced with something along the following lines:
>>
>> The "Maximum Reservable Bw" sub-TLV represents the
>> aggregate bandwidth
>> constraint of the link and as such complements the
>> advertised Bandwidth
>> Constraints.
>>
>>
>> Section 10.2, page 20:
>>
>> "A DS-TE LSR MUST support the following admission control rule:
>>
>> Regardless of how the admission control algorithm actually
>> computes
>> the unreserved bandwidth for TE-Class[i] for one of its
>> local link,
>> an LSP of bandwidth B, of set-up preemption priority p and
>> of Class-
>> Type CTc is admissible on that link iff:
>>
>> B <= unreserved bandwidth for TE-Class[i], AND
>> B <= Max Link Bandwidth
>>
>> Where
>>
>> - TE-Class [i] maps to < CTc , p > in the LSR's
>> configured TE-
>> Class mapping
>> - Max Link Bandwidth is the maximum link bandwidth
>> configured
>> on the link and advertised in IGP."
>>
>>
>> "Max Link Bandwidth" should be replaced with "Maximum
>> Reservable Bandwidth".
>>
>>
>> Section 10.3.4, page 22
>>
>> "Regardless of how the admission control algorithm
>> actually computes
>> the unreserved bandwidth for TE-Class[i] for one of its
>> local link,
>> an LSP of bandwidth B, of set-up preemption priority p and
>> of Class-
>> Type CTc is admissible on that link iff:
>>
>> (i) B <= unreserved bandwidth for TE-Class[i], AND
>> (ii) B <= Max Link Bandwidth
>>
>> Where
>>
>> - TE-Class [i] maps to < CTc , p > in the LSR's
>> configured TE-
>> Class mapping
>> - Max Link Bandwidth is the maximum link bandwidth
>> configured
>> on the link and advertised in IGP."
>>
>> "Max Link Bandwidth" should be replaced with "Maximum
>> Reservable Bandwidth".
>>
>>
>> Dimitry
>>
>>
>>
>> > -----Original Message-----
>> > From: Jim Boyle [mailto:jboyle@pdnets.com]
>> > Sent: Monday, April 07, 2003 11:56 PM
>> > To: te-wg@ops.ietf.org
>> > Subject: WG last call: draft-ietf-tewg-diff-te-proto-03.txt
>> >
>> >
>> >
>> > http://www.ietf.org/internet-drafts/draft-ietf-tewg-diff-te-pr
>> > oto-03.txt
>> >
>> > This is WG last call for this draft to be advanced standards track.
>> > Since notice was sent to other WGs for review, we will
>> take 3 weeks.
>> >
>> > Last call for this draft closes 4/28.
>> >
>> > thanks,
>> >
>> > Jim Boyle
>> >
>> >
>> >
>>
>>