Enterprise QoS Solution Reference Network Design Guide

Chapter 2 Campus QoS Design
Version 3.3
Catalyst 2950—QoS Considerations and Design
CAT2950(config-if)# mls qos trust cos ! Trust CoS from IP Phone
CAT2950(config-if)# service-policy input IPPHONE+PC ! Policing policy
CAT2950(config-if)#exit
CAT2950(config)#
CAT2950(config)#ip access list standard VVLAN-ANY
CAT2950(config-std-nacl)# permit 10.1.110.0 0.0.0.255 ! VVLAN subnet
CAT2950(config-std-nacl)#
CAT2950(config-std-nacl)#ip access list standard DVLAN-ANY
CAT2950(config-std-nacl)# permit 10.1.10.0 0.0.0.255 ! DVLAN subnet
CAT2950(config-std-nacl)#end
CAT2950#
Other Catalyst MLS QoS verification commands include the following:
show mls qos interface
show mls qos interface policers
show mls qos map
show class-map
show policy-map
show mls masks qos
Catalyst 2950—Conditionally-Trusted IP Phone + PC with Scavenger-Class QoS
(Advanced) Model
Catalyst 2950—Queuing
Configuration
The advanced model of the Conditionally-Trusted IP Phone + PC with Scavenger-class QoS, as shown
in Figure 2-9 and Figure 2-10, cannot be supported on the Catalyst 2950 because of the previously
discussed caveats and limitations of the Catalyst 2950, including the maximum number of policers
supported per FE interface, the overly coarse policer granularity, the inability to mix user-defined masks
with system-defined masks and other constraints.
This section includes the following topics:
Configuration
Catalyst MLS QoS Verification Commands
The Catalyst 2950 can be configured to operate in a 4Q1T mode or in a 1P3Q1T mode (with Queue 4
being configured as a strict-priority queue); the 1P3Q1T mode is recommended for converged networks.
The strict priority queue is enabled by configuring the fourth queue’s weight parameter, as defined in the
wrr-queue bandwidth command, to be 0 (as shown in the example below).
The remaining bandwidth is allocated the other queues according to their defined weights. To allocate
remaining bandwidths of 5%, 25% and 70% to Queues 1, 2 and 3, weights of 5, 25, 70 can be assigned
these queues, respectively. The logic of these bandwidth allocations recommendations will be discussed
in more detail momentarily.
Enterprise QoS Solution Reference Network Design Guide
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