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:[email protected]] 
>> Sent: 11 April 2003 21:05
>> To: 'Jim Boyle'; [email protected]
>> 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:[email protected]]
>> > Sent: Monday, April 07, 2003 11:56 PM
>> > To: [email protected]
>> > 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
>> > 
>> > 
>> > 
>> 
>>