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Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 15 Oversubscribing Physical and Virtual Links
Configuring Oversubscription
Configuration Example for Oversubscribing Frame Relay PVCs Using a Map Class
Example 15-4
shows how to oversubscribe a T1 network with a capacity of 1536 kbps. In the example,
the policy map named Business shapes traffic to 1024 kbps. This QoS policy is applied to both PVCs
(100 and 101) configured on serial interface 1/0/0/1:0. Each PVC has 1024 kbps of bandwidth or a total
of 2048 kbps, which exceeds the capacity of the T1 network. Therefore, the PVCs are oversubscribed.
Alternatively, if each PVC had a bandwidth of 768 kbps or less, they would not be oversubscribed.
Example 15-4 Oversubscription of Frame Relay PVCs
Router(config)#
policy-map Business
Router(config-pmap)#
class class-default
Router(config-pmap-c)#
shape 1024
Router(config-pmap-c)#
exit
Router(config-pmap)#
exit
Router(config)#
frame-relay map-class Bronze
Router(config-map-c)#
service-policy output Business
Router(config-map-c)#
exit
Router(config)#
interface serial 1/0/0/1:0
Router(config-if)#
encapsulation frame-relay
Router(config-if)#
frame-relay interface-dlci 100
Router(config-if-dlci)#
frame-relay class Bronze
Router(config-if-dlci)#
frame-relay interface-dlci 101
Router(config-if-dlci)#
frame-relay class Bronze
Oversubscribing 802.1Q VLANs
To enable oversubscription of 802.1Q VLANs, enter the following commands beginning in global
configuration mode:
Command
Purpose
Step 1
Router(config)#
policy-map
policy-map-name
Creates or modifies a child policy map. Enters policy-map
configuration mode.
policy-map-name
is the name of the policy map. The name
can be a maximum of 40 alphanumeric characters.
Step 2
Router(config-pmap)#
class
class-map-name
Assigns the traffic class you specify to the policy map.
Enters policy-map class configuration mode.
class-map-name
is the name of a previously configured
class map and is the traffic class for which you want to
define QoS actions.
Step 3
Router(config-pmap-c)#
priority
(Optional) Assigns strict priority to the traffic class.
Note
In Cisco IOS Release 12.0(25)S and
Release 12.3(7)XI, and later releases, the
priority
command has no arguments. To specify a bandwidth
rate, use the
police
command. For more
information, see
Chapter 6, “Policing Traffic.”
