Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
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Chapter 3 WAN Aggregator <strong>QoS</strong> <strong>Design</strong><br />
Version 3.3<br />
WAN Edge Link-Specific <strong>QoS</strong> <strong>Design</strong><br />
Also, if policy maps that require bandwidth statements on class-default are being attached to the<br />
multilink interface, the max-reserved-bandwidth 100 command is required on the interface before the<br />
service-policy output statement can be applied, as shown in Example 3-14.<br />
Example 3-14 High-Speed (‡ Multiple T1/E1) Leased Line <strong>QoS</strong> <strong>Design</strong> Example<br />
!<br />
interface Multilink1<br />
description Dual-T1 to RBR-3745-Left<br />
ip address 10.1.112.1 255.255.255.252<br />
max-reserved-bandwidth 100 ! Overrides the default 75% BW limit<br />
service-policy output WAN-EDGE ! Attaches the MQC policy to Mu1<br />
ppp multilink<br />
ppp multilink group 1 ! Identifies Mu1 as logical int for Mu1 group<br />
!<br />
…<br />
!<br />
interface Serial1/0<br />
bandwidth 1536 ! defined on physical interface only<br />
no ip address<br />
encapsulation ppp<br />
ppp multilink<br />
ppp multilink group 1 ! includes interface Ser1/0 into Mu1 group<br />
!<br />
interface Serial1/1<br />
bandwidth 1536 ! defined on physical interface only<br />
no ip address<br />
encapsulation ppp<br />
ppp multilink<br />
ppp multilink group 1 ! includes interface Ser1/1 into Mu1 group<br />
!<br />
Note Interface bandwidth commands (not to be confused with policy map CBWFQ bandwidth commands)<br />
should be defined only on the physical interfaces, not on multilink interfaces. This way, if any physical<br />
interfaces go down, the Cisco IOS Software will reflect the change in the multilink interface’s bandwidth<br />
for routing and <strong>QoS</strong> purposes. This change can be verified by the show interface command. However,<br />
if a bandwidth statement is configured under the multilink interface, the bandwidth value for the<br />
interface will be static even if an underlying physical interface is lost.<br />
Verification commands:<br />
show policy<br />
show interface<br />
show policy interface<br />
show ppp multilink<br />
Verification Command: show policy interface (<strong>QoS</strong> Baseline Policy)<br />
A more complex example of the show policy interface command is given in Example 3-15, where a <strong>QoS</strong><br />
Baseline WAN edge policy is being applied to a dual-T1 (high-speed) leased line.<br />
Example 3-15 show policy interface Verification of a <strong>QoS</strong> Baseline Policy on a High-Speed Leased<br />
Line<br />
WAG-7206-Left#show policy interface multilink 1<br />
<strong>Enterprise</strong> <strong>QoS</strong> <strong>Solution</strong> <strong>Reference</strong> <strong>Network</strong> <strong>Design</strong> <strong>Guide</strong><br />
3-21
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