[c-nsp] QoS Cisco Serie 800 and 1800

[Alejandro Selios]

Hi,

I want to configure QoS on a Cisco's 800 and 1800 series router and I
couldn't make it work the way I want. I've configured three classes of
service called GOLD, SILVER and BRONZE, designed for low latency, low loss
and data respectively.

* I want the GOLD class to have a maximum bandwidth of 25%, even if there is
traffic in the other classes.

* The SILVER class has a minimum bandwidth of 50% and, if there's no traffic
in the GOLD queue, I want this class to take the available bandwidth which
is not used by the GOLD class. Thats means that the SILVER class has a 50%
of assured bandwidth and can increase to a maximum of 75% of the total
bandwidth.

* The BRONZE class has no assured bandwidth and can only take the bandwidth
which is not used for the other classes.

The problem is that with Cisco's QoS tools I have not reached the desired
goal. I have tried with different configurations and IOS and I couldn't get
any successful result . Below I attach the policy configuration that I have
tried (just to give you an example).

Is there any way in which I can achieve the behavior that was described
above?.

Thanks in advance.


Standard Configuration
-------------------------------------

policy-map QoS_POLICY
 class GOLD
   priority percent 25
   police cir percent 25 pir percent 25
   set dscp ef
 class SILVER
   set dscp af41
    bandwidth percent 50
    shape average percent 75
 class class-default
    fair-queue
    set dscp af12
    bandwidth percent 25




Hierarchical Configuration
---------------------------------------------
policy-map GOLD+SILVER
 class GOLD
    priority percent 33
    police rate percent 33
 class class-default
    fair-queue

policy-map QOS
 class GOLD+SILVER
    shape average percent 75
    bandwidth percent 75
    service-policy GOLD+SILVER
 class class-default
    fair-queue


Note: This configuration was applied in a subinterface (xDSL, 802.1q
ethernet) and for the outgoing traffic.