Cisco Catalyst 4500 Series, Software Configuration Manual

Page: 1185 / 2086

44-89
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 44 Configuring Quality of Service
Configuring Auto-QoS on a Standalone Supervisor Engine 6-E/6L-E or Supervisor Engine 7-E/7L-E/8-E
We need QoS in both directions, both on inbound and outbound. Inbound, the switch port needs to trust
the DSCP in the packet (done by default). Outbound, the switch port needs to give voice packets "front
of line" priority. If voice is delayed too long by waiting behind other packets in the outbound queue, the
end host drops the packet because it arrives outside of the receive window for that packet.
Note
QoS is a two way street. So, it might work in one direction and not in the other.
Auto-QoS Policy and Class Maps
• There are 7 policy maps that must be defined (5 Input, 2 output)
•
AutoQos-4.0-Input-Policy
• AutoQos-VoIP-Input-Cos-Policy
•
AutoQos-VoIP-Input-Dscp-Policy
•
AutoQos-4.0-Cisco-Phone-Input-Policy
•
AutoQos-4.0-Output-Policy
• AutoQos-4.0-Cisco-Softphone-Input-Policy
•
AutoQos-VoIP-Output-Policy
On all ports. The problem with COS is that packets on the native VLAN is marked as zero.
The class maps used for input matching are as follows:
! for control traffic between the phone and the callmanager
! and phone to phone [Bearer] DSCP matching
! Note: Control traffic can be either AF31 or CS3. So, we match to both values and assign
them to different qos-groups when matching DSCP and only a single group when matching COS.
class-map match-all AutoQos-VoIP-Control-Dscp26
match dscp af31
class-map match-all AutoQos-VoIP-Control-Dscp24
match dscp cs3
class-map match-all AutoQos-VoIP-Bearer-Dscp
match dscp ef
! for control traffic and phone to phone [Bearer] COS matching
! Note: Both CS3 and AF31 control traffic maps to COS 3
class-map match-all AutoQos-VoIP-Control-Cos
match cos 3
class-map match-all AutoQos-VoIP-Bearer-Cos
match cos 5
! for control traffic between the softphonephone and the callmanager
! and softphone to softphonephone [Bearer] DSCP matching
Class Map match-all AutoQos-4.0-Multimedia-Conf-Classify (id 36)
Match access-group name AutoQos-4.0-ACL-Multimedia-Conf
Class Map match-all AutoQos-4.0-Signaling-Classify (id 2)
Match access-group name AutoQos-4.0-ACL-Signaling
Class Map match-all AutoQos-4.0-Transaction-Classify (id 18)
Match access-group name AutoQos-4.0-ACL-Transactional-Data
Class Map match-all AutoQos-4.0-Bulk-Data-Classify (id 29)
Match access-group name AutoQos-4.0-ACL-Bulk-Data
Class Map match-all AutoQos-4.0-Scavenger-Classify (id 1)
Match access-group name AutoQos-4.0-ACL-Scavenger