Subject: Questions about the Controlled Load Service.

From: Muneyoshi Suzuki <[email-masked]>
Date: Wed, 22 May 1996 14:18:12 +0900

Dear,

I have questions about the Controlled Load Service.

1. Definition of the minimum policed unit.

>5. Invocation Information
>  .....
>   in bytes.  Network elements MUST reject a service request if the
>   requested maximum packet size is larger than the MTU of the link.
>   Both m and M must be positive, and m must be less then or equal to M.
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I think, it is not an error if [M] is less than to [m] logically. In this
case, there are no problem if token bucket regards all packet size as [m].
And there are possibility, if [M] is used MTU size discovery negotiation, 
[M] may be decreased less than [m]. Are there reasons that require this 
restriction? 

2. Policing description.

>7. Policing
>   Controlled-load service modules provide QoS control for traffic
>   conforming to the TSpec given at setup time.  The TSpec's token
>   bucket parameters require that traffic must obey the rule that over
>   all time periods, the amount of data sent does not exceed rT+b, where
                                              ^^^^^^^^^^^^^^^^^^^^
>   r and b are the token bucket parameters and T is the length of the
>   time period.  For the purposes of this accounting, links must count

Above formulation assumes token bucket is empty at initial time period of T.
But I think this assumption is not always true. I think worst case is "rT".
What am I missing?

3. Token Bucket Definition.

>5. Invocation Information
>.....
>   The bucket depth, b, is measured in bytes. Values of this parameter
>   may range from 1 byte to 250 gigabytes. Network elements MUST return

Does bucket rate include data rate generated by IPv4, v5, v6 header?
Does bucket depth include IPv4, v5, v6 header length? Does int-serv flow
spec support IP flow that across IPv4 and IPv6 networks?

And another question is necessity of b parameter. Why b is needed for
controlled load service specification? Is it not enough to specify
r, m and M? Which part of controlled load service characteristic 
does b parameter affect to?

4. RSVP FlowSpec.

>Appendix 1: RSVP Messages used with Controlled-Load Service
>....
>       |  Minimum Policed Unit [m] (32-bit integer)                    |
>       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>       |  Maximum Packet Size [M]  (32-bit integer)                    |
>       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>     (a) - Version number (0)

I have two questions in this section. What does Version number means?
Is this means Int-Serv FlowSpec version or Controlled Load Service version?
And another question is field length about [m] and [M]. Is it not enough
16bit integer fields? 

Best Regards,

Muneyoshi Suzuki
NTT Telecom. Net. Labs.