Tuesday, May 10, 2011

Autonomous AP voice QoS

There are a number of settings one must configure via CLI to get voice QoS working on an AAP.  This is my attempt at putting all of them in a single post...  I can already see the edits coming:

dot11 ssid
 admit traffic
//Enables call admission control on the SSID.
dot11 arp-cache optional
//Best practices.  Reduces WLAN overhead by allowing AP to respond to ARP for known clients
dot11 priority-map avvid
//Forces the AP to translate from 802.11e to 802.1p
dot11 phone [dot11e]
//Configures the QBSS IE for 7920 or 802.11e (i.e. 7921, etc)
interface Dot11Radio0
 speed basic-12.0 18.0 24.0
//Best practice datarates for 802.11a/g/n; for 802.11b use basic-11.0
 dot11 qos class voice local
    admit-traffic narrowband max-channel 70 roam-channel 6
//sets AP CAC to allow 64% of bandwidth to voice + 6% roaming = 70%
 dot11 qos class voice cell
//Allows the AP to factor in client QBSS readings for CAC

class-map voice
 match ip dscp ef
class-map video
 match ip dscp cs4
class-map voicecontrol
 match ip dscp cs3
//Create class maps to identify traffic
policy-map QoS
 class voice
  set cos 6
 class video
  set cos 5
 class voicecontrol
  set cos 4
//Create a policy map to tag traffic
int d0.20
 service-policy input QoS
 servicy-policy output QoS
//Tag the traffic as it traverses your wireless interface
int f0.20
 service-policy input QoS
 service-policy output QoS
//Tag the traffic as it traverses your wired interface

It is important to ensure that your traffic is tagged on both the wired and wireless interfaces because the traffic could be coming off another SSID on the AP (int d0.10 for example).
I guess that's about it.  Not nearly as daunting when you get them all down in one place ;)

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