[altq 465] Re: CBQ Question!

[Kenjiro Cho <kjc@csl.sony.co.jp>]

Takashi Ikebe wrote:
> Sorry for inconvenience mail,
> I want to know, how current Queuing move.
> In the case if there are communications which want to come this side
> 
>       (50Mb/s)                (50Mb/s)             (50Mb/s)
>          LinkA       CBQ1     LinkB      CBQ2  LinkC
>         ------------[R1]----------------[R2]--------------
>                          -------->            <--------?????
> ?????communication1             communication2
> R1,R2:Router
> 
> Communication1 comes from LinkA,communication2 comes form LinkC.
> And communication1&2 request bandwidth, so on the router, both
> communications are assigned to adequate Queue(gurantee XMb/s).
> Now, CBQ1(R1 to R2) configured as total bandwidth 50Mb/s, and guarantee
> 15Mb/s TCP & 15Mb/s UDP, and CBQ2(R2 to R1) is also set to guarantee 15Mb/s
> TCP & 15Mb/s UDP.
> Is this possible to guarantee bandwidth?? total bandwidth is 50Mb/s, but
> guaranteed bandwidth is amount to 60Mb/s!(in half-duplex link)
> In this case, how Queueing move??

You cannot guarantee the assigned rate because LinkB is
over-subscribed.   
Capacity provisioning is in the different layer from packet scheduling
(queueing).  When they are misconfigured, it is generally
not predictable how they interact with each other.

-Kenjiro