RE: -proto-05: Final Format of "Bandwidth Constraints" sub-TLV

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

Hi Rahul,

>> > So at initial DS-TE deployment, O may want to use CT3 for 
>> Voice and CT0 for Best Effort Premium
>> to save CT1 and CT2 for future use.
>> >
>> 
>> To save CT1 and CT2 for future use the operator can announce 
>> the BCs such
>> that the bandwidth associated with CT1 and CT2 is 0. 
>>When the operator
>> starts using CT1 and CT2 the bandwidth can be announced 
>> appropriately. The
>> bitmap is not needed to do this.

It is clear you can set aside CT1 and CT2 without the bitmap by
advertising dummy BC values. The argument for the bitmap was not that
you cannot do this without it, the argument was that it lets you do it
slightly more efficiently by avoiding increasing the IGP advertising
with dummy values (optimising IGP advertisement was an ongoing DS-TE
objective).

Having said this, the suggested bitmap optimisation would just be a
minor optimisation and is not quite generating a massive wave of
enthusiasm on the list. So I'll stick to the format WITHOUT bitmap.

>> Merci !

Merci a toi.

Francois

>> 
>> rahul
>> 
>> > I'd expect setting aside CTs when deploying DSTE with RDM 
>> (or any BC Model with ordered CTs) to
>> be fairly common practise. The bit map would be useful in 
>> these cases.
>> >
>> > No?
>> >
>> > Cheers
>> >
>> > Francois
>> >
>> > >> The new format without the bitmap seems
>> > >> preferable, as the
>> > >> bitmap may not be useful in practice.
>> > >>
>> > >> Thanks,
>> > >> rahul
>> > >>
>> > >>
>> > >>
>> > >> > Old format (as per -proto-05):
>> > >> > ==============================
>> > >> > "
>> > >> > "Bandwidth Constraints" sub-TLV:
>> > >> > - Bandwidth Constraint Model Id (1 octet)
>> > >> > - Bandwidth Constraints (Nx4 octets)
>> > >> > "
>> > >> >
>> > >> > New Format Without Bitmap:
>> > >> > ==========================
>> > >> > "
>> > >> > "Bandwidth Constraints" sub-TLV:
>> > >> > - Bandwidth Constraints Model Id (1 octet)
>> > >> > - Reserved (3 octets)
>> > >> > - Bandwidth Constraints (Nx4 octets)
>> > >> > + some text explaining that "Reserved" is to be set to
>> > >> zero on transmit,
>> > >> > ignored on receipt.
>> > >> > "
>> > >> >
>> > >> > New Format With Bitmap:
>> > >> > =======================
>> > >> > "
>> > >> > "Bandwidth Constraints" sub-TLV:
>> > >> > - Bandwidth Constraints Model Id (1 octet)
>> > >> > - Bandwidth Constraints Bitmap (1 octet)
>> > >> > - Reserved (2 octets)
>> > >> > - Bandwidth Constraints (Nx4 octets)
>> > >> > + some text explaining that :
>> > >> > 	* "Reserved" is to be set to zero on transmit, 
>> ignored on
>> > >> > receipt.
>> > >> > 	* "Bitmap" is a set of 8 flags each indicating if the
>> > >> > corresponding BC is included in sub-TLV (eg. 10100001
>> > >> means that BC0,
>> > >> > BC2 and BC7 will be included).
>> > >> > "
>> > >> >
>> > >> > Cheers
>> > >> > Francois
>> > >> >
>> > >> >
>> > >>
>> >
>>