Configuration Example For Oversubscribing 802.1Q Vlans; How The Router Determines Vc Weights - Cisco 10000 Series Configuration Manual

How the Router Determines VC Weights

Configuration Example for Oversubscribing 802.1Q VLANs

Example 15-5
receives 30 percent of the configured shape rate and Gold priority receives 60 percent. The Business
child policy map is applied to the Business-shape parent policy map, which shapes the aggregate traffic
to 512,000 kbps. The Business-shape policy map attached to VLAN 4 and VLAN 2 shapes the aggregate
traffic of each VLAN to 512,000 kbps or a combined total of 1024 Mbps, which exceeds the transmission
capacity of the Gigabit Ethernet interface. Therefore, the VLANs are oversubscribed.
Example 15-5 Oversubscribing 802.1Q VLANs
Router(config)# policy-map Business [child policy]
Router(config-pmap)# class Bronze
Router(config-pmap)# bandwidth percent 30
Router(config-pmap-c)# set ip precedence 1 2
Router(config-pmap-c)# class Gold
Router(config-pmap-c)# priority
Router(config-pmap-c)# police percent 60
Router(config-pmap-c)# set dscp 50
Router(config-pmap-c)# exit
Router(config-pmap)# exit
Router(config)# policy-map Business-shape [parent policy]
Router(config-pmap)# class class-default
Router(config-pmap-c)# shape 512000000
Router(config-pmap-c)# service-policy Business [child policy]
Router(config-pmap-c)# exit
Router(config-pmap)# exit
Router(config)# interface GigabitEthernet 5/0/0.10 point-to-point
Router(config-subif)# ip address 172.16.0.2 255.255.255.252
Router(config-subif)# encapsulation dot1q 4
Router(config-subif)# service-policy output Business-shape [attaches parent policy]
Router(config-subif)# interface GigabitEthernet 5/0/0.2 point-to-point
Router(config-subif)# ip address 10.0.0.10 255.32.0.0
Router(config-subif)# encapsulation dot1q 2
Router(config-subif)3 service-policy output Business-shape [attaches parent policy]
How the Router Determines VC Weights
On the PRE1 or PRE2, weight is applicable to VCs in VP tunnels and affects the behavior of the VCs.
On the PRE3, weight is applicable to VCs in VP tunnels and VCs not in a VP tunnel. In both cases, the
weight affects the behavior of the VCs.
The way in which the router determines the weight of a VC depends upon the Cisco IOS release running
on the router.
Table 15-2
Cisco IOS Release
Release 12.0(17)SL to Release 12.3(7)XI
Release 12.3(7)XI1 and later releases
Cisco 10000 Series Router Quality of Service Configuration Guide
15-20
shows how to oversubscribe an 802.1Q VLAN. In the example, the Bronze business traffic
Table 15-2 summarizes VC weighting on the Cisco 10000 series router.
VC Weighting on the Cisco 10000 Series Router
Chapter 15 Oversubscribing Physical and Virtual Links
User Configurable VC Weight
No Proportional to the VC speed.
Yes Configured using the weight
command.
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