I'm configuring MQC between a 6500 and a 7304 on a Gi interface. I'm using the bandwidth command to mirror a bottleneck further on in the network and then bandwidth percent for each traffic class. Reading the documentation for bandwidth, I expected to get a complaint from the IOS when I configured > 75% of the bandwidth for the classes and applied the service-policy, but I'm not (I haven't used the max-reserved-bandwidth command either).
Does this mean I need to include my own form of bandwidth reservation for the stuff that normal gets that 25% left over, and if so would class-default catch this traffic? Or is that the configurable 100% I see is actually onyl 75% of the interface bandwidth to start with (despite the fact that the output of sh policy-map int gix/y tells me the total kbps assigned equals the bandwidth of sh int gix/y).
Thoughts greatly appreciated, many thanks, regards.
First, you should use nested policy-maps to"mirror a bottleneck". As far as I understand, you want to apply a Qos policy, which ensures to not overload a bottleneck further down the line!? If so, an example config could look like this:
class-map match-all important
match protocol http
class-map match-all MoreImportant
match protocol telnet
shape average 50000000
service-policy output QoS4Apps
bandwidth percent 60
bandwidth percent 30
As you see, the sum in the example is more than 75%, in fact in could be 100% of the SHAPED bandwidth.
The 75% rule for INTERFACE bandwidth come from the fact that you always need some bandwidth for L2 keepalives, etc. which are not counted in the policy-map.
Thus giving 100% to user traffic is not reasonable.
IF you use the nested policy-map example given above, there will be much less traffic in outgoing direction than the interface can handle. Thus reserving bandwidth for L2 keepalives, etc. is not a requirement and accordingly IOS allows to give 100% of the SHAPED bandwidth to user applications.
OK, honestly I am not quite sure about your config in place. Can you post the relevant parts please? Especially highlight, whether you are refering to the "bandwidth" interface command, the "bandwith" command in policy-maps (CBWFQ) or in nested policy-maps.
In case my example above did not address your problem to solve, could you please help a non-native speaker to get the essential parts? ;-)
In case my example above did solve your issue: please, live happily ever after!
Hope this helps!