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Cisco AVVID Network Infrastructure Enterprise Quality of Service Design
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Chapter 3 QoS in an AVVID-Enabled Campus Network
Selecting a Distribution-Layer Switch
In this scenario, the policing code tags the traffic flows with DSCP values of AF31 for VoIP control
traffic, EF for VoIP bearer traffic, and 0 for all other packets.
Step 1
Create classes that use ACLs as admission criteria.
Cat6k-distrib (config)#class-map match-all VOICE-CONTROL
Cat6k-distrib (config-cmap)#match access-group 100
Cat6k-distrib (config)#class-map match-all VOICE
Cat6k-distrib (config-cmap)#match access-group 101
Cat6k-distrib (config)#class-map match-all BEST-EFFORT-DATA
Cat6k-distrib (config-cmap)#match access-group 102
Step 2
Create policies to tag the traffic flows with the appropriate DSCP values.
Note
The policer value (4000000000) below should be sized appropriately in your network.
Cat6k-distrib (config)#policy-map DISTRIBUTION-C6000-UPLINK-IN
Cat6k-distrib (config-pmap)#class VOICE-CONTROL
Cat6k-distrib (config-pmap-c)#police 4000000000 125000000 125000000 conform-action
set-dscp-transmit 26 exceed-action transmit
Cat6k-distrib (config-pmap)#class VOICE
Cat6k-distrib (config-pmap-c)#police 4000000000 125000000 125000000 conform-action
set-dscp-transmit 46 exceed-action transmit
Cat6k-distrib (config-pmap)#class BEST-EFFORT-DATA
Cat6k-distrib (config-pmap-c)#police 4000000000 125000000 125000000 conform-action
set-dscp-transmit 0 exceed-action transmit
Step 3
Create an access list for VoIP control traffic.
Cat6k-distrib (config)#access-list 100 permit tcp any any range 2000 2002
Cat6k-distrib (config)#access-list 100 permit tcp any any eq 1720
Cat6k-distrib (config)#access-list 100 permit tcp any any range 11000 11999
Cat6k-distrib (config)#access-list 100 permit udp any any eq 2427
Step 4
Create an access list for VoIP bearer traffic.
Cat6k-distrib (config)#access-list 101 permit udp any any range 16384 32767
Step 5
Create an access list for best effort traffic.
Cat6k-distrib (config)#access-list 102 permit ip any any
Step 6
Enable trust for DSCP values from adjacent Layer 3 access switches. Use VLAN-based QoS on the
trunking port.
Cat6k-distrib (config)#interface GigabitEthernet2/2
Cat6k-distrib (config-if)#no ip address
Cat6k-distrib (config-if)#wrr-queue cos-map 2 1 3 4
Cat6k-distrib (config-if)#mls qos vlan-based
Cat6k-distrib (config-if)#switchport
Cat6k-distrib (config-if)#switchport trunk encapsulation dot1q
Cat6k-distrib (config-if)#switchport mode trunk
Cat6k-distrib (config)#interface GigabitEthernet3/1
Cat6k-distrib (config-if)#no ip address
Cat6k-distrib (config-if)#wrr-queue cos-map 2 1 3 4
Cat6k-distrib (config-if)#mls qos vlan-based
Cat6k-distrib (config-if)#switchport
Cat6k-distrib (config-if)#switchport trunk encapsulation dot1q
Cat6k-distrib (config-if)#switchport mode trunk