Qos Configuration For The Intelligent Wiring Closet - Cisco Catalyst 2950 Software Configuration Manual

Chapter 29 Configuring QoS
For the Catalyst 2900 and 3500 XL switches, CoS configures each transmit port (the egress port) with a
normal-priority transmit queue and a high-priority transmit queue, depending on the frame tag or the port
information. Frames in the normal-priority queue are forwarded only after frames in the high-priority
queue are forwarded. Frames that have IEEE 802.1p CoS values of 0 to 3 are placed in the
normal-priority transmit queue while frames with CoS values of 4 to 7 are placed in the expedite
(high-priority) queue.

QoS Configuration for the Intelligent Wiring Closet

Figure 29-5
switches is connected to a video server, which has an IP address of 172.20.10.16.
The object of this example is to prioritize the video traffic over all other traffic. To do so, a DSCP of 46
is assigned to the video traffic. This traffic is stored in queue 4, which is serviced more frequently than
the other queues.
Beginning in privileged EXEC mode, follow these steps to configure the switch to prioritize video
packets over all other traffic:
Command
Step 1 configure terminal
Step 2
access-list 1 permit 172.20.10.16
Step 3
class-map videoclass
Step 4 match access-group 1
Step 5 exit
Step 6 policy-map videopolicy
Step 7 class videoclass
Step 8
set ip dscp 46
Step 9
police 5000000 8192 exceed-action drop
Step 10 exit
Step 11 exit
Step 12
interface interface-id
Step 13
service-policy input videopolicy
Step 14 exit
Step 15 wrr-queue bandwidth 1 2 3 4
Step 16
wrr-queue cos-map 4 6 7
Step 17
end
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shows an intelligent wiring closet with Catalyst 2950 switches, for example. One of the
Purpose
Enter global configuration mode.
Define an IP standard ACL, and permit traffic from the video
server at 172.20.10.16.
Create a class map called videoclass, and enter class-map
configuration mode.
Define the match criterion by matching the traffic specified by
ACL 1.
Return to global configuration mode.
Create a policy map called videopolicy, and enter policy-map
configuration mode.
Specify the class on which to act, and enter policy-map class
configuration mode.
For traffic matching ACL 1, set the DSCP of incoming packets to
46.
Define a policer for the classified video traffic to drop traffic that
exceeds 5-Mbps average traffic rate with an 8192-byte burst size.
Return to policy-map configuration mode.
Return to global configuration mode.
Specify the switch ingress interface that is connected to the video
server, and enter interface configuration mode.
Apply the policy to the ingress interface.
Return to global configuration mode.
Assign a higher WRR weight to queue 4.
Configure the CoS-to-egress-queue map so that CoS values 6
and 7 select queue 4.
Return to privileged EXEC mode.
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Standard QoS Configuration Examples
29-41