7920 and 7921G mixed environment

MICHAEL SCHROEDER · ‎10-10-2007

Hi Team, have you any experiences with both 7920 and 7921G in the same WLAN? My Customer is using WLC440x w AP1242. How to Configuree the SSID Parameters regarding QOS and CAC, have you any hints? Thx, Regards, Michael

migilles · ‎10-24-2007

The big issue here is with CAC/TSPEC.

The 7921 gives precedence to TSPEC over QBSS for CAC as TSPEC can be utilized for inbound and outbound CAC, where QBSS is just for outbound dialing.

4.1 release for the Cisco WLAN controller has the load based CAC feature. This means it will account for all traffic and energy on the channel, not just the # of TSPEC clients on a given AP.

So if wanting to enable CAC/TSPEC in mixed environment of 7920 and 7921, would want to ensure you use 4.1 release and enable load based CAC.

If 7921 will be in G mode, it will send out the CTS to self for G protection, which the 7920 will adhere to.

The other is capacity. If you have calls at 11mbps or other 802.11b rates, then capacity will get reduced.

Typically can get up to 10 RTP streams per AP @ 11 mbps and up to 20 calls @ 24 mbps or higher.