RE: Reflecting new-MAM/SAM definition in diff-te drafts

["Francois Le Faucheur (flefauch)" <flefauch@cisco.com>]

Hello Dimitry, Jerry, Waisum,

>> -----Original Message-----
>> From: Dimitry Haskin [mailto:dhaskin@axiowave.com] 
>> Sent: 20 May 2003 16:58
>> To: 'Ash, Gerald R (Jerry), ALABS'; Francois Le Faucheur (flefauch)
>> Cc: te-wg@ops.ietf.org; Lai, Wai S (Waisum), ALABS; Dimitry Haskin
>> Subject: RE: Reflecting new-MAM/SAM definition in diff-te drafts
>> 
>> 
>> > 
>> > Use of "Max Reservable Bandwidth" appears to be OK without 
>> > per-CT Local Overbooking Multipliers (LOMs).  That is, when 
>> > there is only *one* LOM for the entire link, then the formula 
>> > you give appears to be correct:
>> > 
>> >     o SUM (Reserved (CTc)) <= Max Reservable Bandwidth, 
>> >         for all "c" in the range 0 <= c <= (MaxCT-1)
>> > 
>> > However, this formula is incorrect for DS-TE when per-CT 
>> > LOM's are used, since the above formula only reflects the Max 
>> > Reservable Bandwidth for the entire link, and does not 
>> > reflect the per-CT local overbooking factors.  So what 
>> > formula do you suggest when per-CT LOM's are used?
>> >
>> 
>> Wouldn't 'Reserved (CTc)' it the above formula already 
>> accounts for the
>> overbooking multiplier at CTc?  I don't see how this formula 
>> precludes
>> per-CT LOM's to be used. Please explain.
>>

I've been using "Reserved" and "Normalised" as per their definitions in
the proto draft, the RDM draft and the MAM draft.

Quoting from these drafts:

==================================
- "Reserved (CTc)": For a given Class-Type CTc ( 0 <= c <= MaxCT ) ,let
us define "Reserved(CTc)" as the sum of the bandwidth reserved by all
established LSPs which belong to CTc. 
- Normalised(CTc) : let us define "Normalised(CTc)" as
"Reserved(CTc)/LOM(c)", where LOM (c) is the Local Overbooking
Multiplier for CTc defined in [DSTE-PROTO].
=====================================

What that means is that "Reserved(CTc)" does factor in the overbooking
method which is refered to as "LSP/link size overbooking" method and is
the overbooking method commonly used in TE networks. However, it does
NOT factor in the optional "Local Overbooking Multiplier" method.

"Normalised (CTc)"  factors-in both the "LSP/link size overbooking" and
the optional "Local Overbooking Multiplier" method.

Definitions of the "LSP/link size overbooking" method and "Local
overbooking Multiplier" method can be found in section "4.1.2. per-CT
Local Overbooking Multipliers (LOMs) of the dste-proto draft.

Based on this, my proposal is to include the following condition to
reflect the aggregate constraint when both overbooking methods are used
(ie "LSP/link size overbooking" method and "Local overbooking
Multiplier" method):

    o SUM (Normalised (CTc)) <= Max Reservable Bandwidth, 
        for all "c" in the range 0 <= c <= (MaxCT-1)

where "Normalised (CTc) is equal to "Reserved(CTc)/LOM(c)" as currently
defined in RDM and MAM drafts.

Thanks

Francois

>> Regards,
>>   Dimitry 
>>