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QOS BASICS: SIMPLE Video over WLAN PRIORISIERUNG mit MQC

Ausgangslage:

• SSID QOS2 / VLAN14 soll für Video Conferencing
• Konfiguriere den AP, dass er sämtliche unmarkierten Pakete auf dieser SSID mit UP5 tagged
• Pakete mit UP5 dürfen nur die Datenraten 12,18 und 24MBits/s benutzen, andere Pakete (auf dem selben Radio Interface) dürfen sämtliche Datenraten benutzen.
• Wenn ein UP5 Paket mehr als 4 mal retried, soll es gedropped werden

SSID und VLAN

AAP2(config)#dot11 ssid QOS2
AAP2(config-ssid)#authentication open 
AAP2(config-ssid)#vlan 14

AAP2(config-ssid)#interface dot11Radio 1
AAP2(config-if)#ssid QOS2

AAP2(config-if)#interface dot11Radio 1.14
AAP2(config-subif)#encapsulation dot1Q 14
AAP2(config-subif)#bridge-group 14

AAP2(config-if)#interface FastEthernet 1.14
AAP2(config-subif)#encapsulation dot1Q 14
AAP2(config-subif)#bridge-group 14

sämtliche unmarkierten Pakete auf SSID QOS2 mit UP5 tagged

AAP2(config)#policy-map QOS-PM
AAP2(config-pmap)#class class-default
AAP2(config-pmap-c)#set cos 5

AAP2(config-if)#interface dot11Radio 1.14
AAP2(config-subif)#service-policy input QOS-PM
AAP2(config-subif)#service-policy outout QOS-PM 

Pakete mit UP5 dürfen nur mit den Datenraten 12, 18 und 24 Mbits gesendet werden:

Low latency Packet rates can also be defined at the interface level, using the following command which defines the nominal rates and the allowed rates to use: traffic-stream priority value sta-rates {[nominal rates] | [rates]}

AAP2(config)#interface dot11Radio 1
AAP2(config-if)#traffic-stream priority 5 sta-rates ?
 12.0 Allow 12.0 Mb/s rate
 18.0 Allow 18.0 Mb/s rate
 24.0 Allow 24.0 Mb/s rate
 36.0 Allow 36.0 Mb/s rate
 48.0 Allow 48.0 Mb/s rate
 54.0 Allow 54.0 Mb/s rate
 6.0 Allow 6.0 Mb/s rate
 9.0 Allow 9.0 Mb/s rate
 nom-12.0 Allow Nominal 12.0 Mb/s rate
 nom-18.0 Allow Nominal 18.0 Mb/s rate
 nom-24.0 Allow Nominal 24.0 Mb/s rate
 nom-36.0 Allow Nominal 36.0 Mb/s rate
 nom-48.0 Allow Nominal 48.0 Mb/s rate
 nom-54.0 Allow Nominal 54.0 Mb/s rate
 nom-6.0 Allow Nominal 6.0 Mb/s rate
 nom-9.0 Allow Nominal 9.0 Mb/s rate
 <cr>

AAP2(config-if)#traffic-stream priority 5 sta-rates nom-12.0 nom-18.0 nom-24

Unterschied nominal non-nominal:

• Nominal—The AP will try to use this rate to send the Low Latency Packets (using the faster rate first, and depending on the client signal level).
• Non-nominal—The AP will try not to use that rate, but will revert to it if no nominal rate is possible.
• Disabled—The AP will not try to use that rate.

Bei mehr als 4 Retry sollen UP5 Pakete gedropped werden:

AAP2(config-if)#packet max-retries 4 0 fail-threshold 100 500 priority 5 drop-packet 

AAP2(config-if)#packet max-retries 4 0?
 <0-128> # packet retries before dropping pkt if 2nd fail-threshold not
 reached

AAP2(config-if)#packet max-retries 4 0 fail-threshold 100?
 <0-1000> # consecutive dropped packets before switching max-retries
 thresholds

AAP2(config-if)#packet max-retries 4 0 fail-threshold 100 500?
 <0-1000> number of consecutive dropped packets before disassociating client

Samuel Heinrich

Senior Network Engineer at Selution AG (Switzerland)

Arbeitet in Raum Basel (Switzerland) als Senior Network Engineer mit über 15 Jahren Erfahrung im Bereich Netzwerk