Qos Configuration For The Intelligent Wiring Closet - Cisco Catalyst 3550 series Software Configuration Manual

Chapter 29 Configuring QoS
For the Catalyst 3500 XL and 2900 XL switches, CoS configures each 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 802.1P CoS values of 0 to 3 are placed in the normal-priority transmit queue
whereas frames with CoS values of 4 to 7 are placed in the expedite (high-priority) queue.

QoS Configuration for the Intelligent Wiring Closet

The intelligent wiring closet in
the 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 56
is assigned to the video traffic. This traffic is stored in the expedite queue (queue 4), which is serviced
until empty before the other queues are serviced. The appropriate CoS value selects queue 4 in the
CoS-to-egress-queue map.
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 56
Step 9
police 5000000 2000000 exceed-action drop
Step 10 exit
Step 11 exit
Step 12
interface gigabitethernet0/1
Step 13
service-policy input videopolicy
Step 14 exit
Step 15 interface gigabitethernet0/2
Step 16
priority-queue out
78-11194-09
Figure 29-11 is composed of Catalyst 3550 multilayer switches. One of
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
access list 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
56.
Define a policer for the classified video traffic to drop traffic that
exceeds 5-Mbps average traffic rate with a 2-MB burst size.
Return to policy-map configuration mode.
Return to global configuration mode.
Enter interface configuration mode, and specify the ingress
interface.
Apply the policy to the ingress interface.
Return to global configuration mode.
Enter interface configuration mode, and specify the egress
interface (to configure the queues).
Enable the expedite queue.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Standard QoS Configuration Examples
29-71