QoS Basics: Simple VoWLAN Priorisierung ohne MQC
Ausgangslage:
- SSID QOS1 / VLAN12 soll für Phones und Laptop benutz werden
- Stelle sicher, dass 792xG Phones auf dieser SSID die Radio Utilisation mitgeteilt bekommen
- Stelle sicher, dass RTP Pakete die richtige Queue benutzen. (Ohne Accessliste)
- Stelle sicher, dass Voice Pakete von Wired to Wireless mit dem richtigen QoS Wert übersetzt werden.
SSID und VLAN Definieren:
AAP1(config)#dot11 ssid QOS1 AAP1(config-ssid)#authentication open AAP1(config-ssid)#vlan 12 AAP1(config-ssid)#interface dot11Radio 1 AAP1(config-if)#ssid QOS1 AAP1(config-if)#interface dot11Radio 1.12 AAP1(config-subif)#encapsulation dot1Q 12 AAP1(config-subif)#bridge-group 12 AAP1(config-if)#interface FastEthernet 1.12 AAP1(config-subif)#encapsulation dot1Q 12 AAP1(config-subif)#bridge-group 12
Radio Utilization dem Client mitteilen:
Dies wird über CDP mitgeteilt. Standardmässig aktiviert. Sollte es deaktiviert sein
AAP1(config)#interface dot11Radio 1 AAP1(config-if)#cdp enable
Sicherstellen, dass RTP Pakete die richtige Queue benutzen:
AAP1(config)#interface dot11Radio 1 AAP1(config-if)#dot11 qos mode wmm
Erklärung:
When you enable QoS, the access point uses Wi-Fi Multimedia (WMM) mode by default. WMM provides these enhancements over basic QoS mode:
The access point adds each packet’s class of service to the packet’s 802.11 header to be passed to the receiving station.
Each access class has its own 802.11 sequence number. The sequence number allows a high-priority packet to interrupt the retries of a lower-priority packet without overflowing the duplicate checking buffer on the receiving side.
For access classes that are configured to allow it, transmitters that are qualified to transmit through the normal backoff procedure are allowed to send a set of pending packets during the configured transmit opportunity (a specific number of microseconds). Sending a set of pending packets improves throughput because each packet does not have to wait for a backoff to gain access; instead, the packets can be transmitted immediately one after the other.
The access point uses WMM enhancements in packets sent to client devices that support WMM. The access point applies basic QoS policies to packets sent to clients that do not support WMM.
AAP1(config)#Dot11 phone
When you enable QoS Elements for wireless phones, the AP give top priority to voice packets even if you do not enable QoS. This settings operate independently from the QoS policies that you configure.
Stelle sicher, dass Voice Pakete von Wired to Wireless mit dem richtigen QoS Wert übersetzt werden.
AAP1(config)#dot11 priority-map avvid
Erklärung:
Dieses Feature ist per Default ausgeschaltet. Es sorgt dafür, dass COS5 Ethernet Pakete zu COS6 getagged werden.
This maps ethernet packets tagged as CoS 5 to CoS6. This feature enables the AP to apply correct priority to voice packets for compatibility with Cisco AVVID networks.