Router – How to test QoS function in router

You definitely should enable MLS QoS. It is also prerequisite for CoPP, which you should add in your TODO list to implement.

Enabling 'mls qos' without other config is extremely bad idea in low-end cats, like 3560/3750, due to unexpected default scheduling and due to heavily reduced buffers causing more microbursting.

On 7600/6500 it's comparatively safe to enable, but of course you can crash your router with 'show run'. I would feel comfortable enough to enable it during production hours.

You should monitor 'show queueing interface X' after enabling to see that you're not dropping anything. Long term, you should design QoS policy and implement it, I recommend using as few queues as possible (and assign 100% of buffer to those few queues). Example of possible QoS policy in WS-X6704-10GE:

interface TenGigabitEthernet4/1
 wrr-queue bandwidth percent 30 40 30 0 0 0 0  ## allocate 3 queues (+implied strictpriority) share buffer 30% 40% 30% on thos three queues
 wrr-queue cos-map 1 1 0 7 # map cos values to queues
 wrr-queue cos-map 2 2 3 
 wrr-queue cos-map 3 1 4 
 wrr-queue cos-map 3 2 6 

For advanced config, you may want to supplement that with 'wrr-queue random-detect' with RED curve per queue+threshold. Be sure to mark your traffic correctly when it enters your network.

To answer your questions:

• RDP traffic should get up to the 25% of the remaining bandwidth. Where the already reserved bandwidth is the 35% ( class-default gets 25% by default and EF get 10% ). So, if i'm right, you assigned ~665Kbps to RDP. Anyway you should check if you're dropping packets issuing the command below:

show policy-map <your wan interface> output class REMOTEDESKTOP

and checking for dropped packets.

• Cisco assign a queue to each user-defined class that includes the bandwidth or police commands. To make a long-story simple those commands define the amount of bandwidth assigned to every queue during congestions.

• In theory every TCP based stream should be OK with drops. In practice some of them aren't. Dropping precedence bits tell the routers what packets should be dropped, within a given class, before congestion happens. Since RDP is the only type of traffic defined in your REMOTEDESKTOP class, you should not worry about it.

• Bandwidth percentage are not in order ( as Jeremy stated ).

That said, there are a lot of things that i would change in your configuration:

• There are no matches between some of classes of the setTos and the useTos policy-map. For instance the one named AF-HIGH is processing no packets since no class in setTos sets DSCP to AF41.

• BE class in setTos is somehow self-defeating since it makes the class-default class useless. Note that class-default is the only system-defined class and get the 25% of the bandwidth by default ( 100 - max-reserved-bandwidth ) .

• bandwidth remaining percent is not the best options ( as Jeremy explained ). I would change it to bandwidth percent.

• I would prefer to mark EF packets by myself and not to rely on the phones' settings.