RE: WG last call: draft-ietf-tewg-diff-te-proto-03.txt

[Dimitry Haskin <dhaskin@axiowave.com>]

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
> 
> 
>