Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

How many 7920 phones can be supported on one Cisco 1131AG access point?

hi all,

who knows that how many 7920 phones can be supported on one 1131ag AP? Thanks a lot...

7 REPLIES
Hall of Fame Super Red

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Hi Alomar,

Hopefully this info will help;

Number of 802.11b Phones per AP

Before any discussion about network planning can take place, it helps to understand the basics of the overall network capacity.

The following network capacity guidelines apply to sizing the Wireless IP Telephony network:

No more than 7 concurrent G.711 calls per AP.

No more than 8 concurrent G.729 calls per AP.

--------------------------------------------------------------------------------

Note These design recommendations assume that Voice Activity Detection (VAD) has been disabled on the Cisco 7920 Wireless IP Phones. Use of VAD on the Cisco 7920 phones can conserve bandwidth, but Cisco recommends that you disable VAD on all Cisco CallManager servers to provide better overall voice quality.

--------------------------------------------------------------------------------

In addition to determining how much bandwidth is needed for an 802.11b VoIP call, you must also consider overall radio contention for a particular RF channel. The general rule is that you should not deploy any more than 20 to 25 802.11b endpoints per AP. The more endpoints you add to an AP, the more you reduce the amount of overall bandwidth and potentially increase transmission delays.

The maximum number of phones per AP depends on the calling patterns of individual users (based on Erlang ratios). Cisco recommends no more than 7 concurrent calls using G.711 or 8 concurrent calls using G.729. Beyond that number of calls, when excessive background data is present, the voice quality of all calls becomes unacceptable.

From this doc;

http://www.cisco.com/en/US/products/hw/phones/ps379/products_implementation_design_guide_chapter09186a00802a0a05.html

Hope this helps!

Rob

Please remember to rate helpful posts.....

Cisco Employee

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Usually about 15-20 idle clients. Only 7 of the 7920s can be on call @ 11mbps.

New Member

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Thanks Rob and Migilles,your answers help me a lot.The one AP only can provide 7 or 8 phone with associate.Can I deny the phones associate with the 8 or 9 phones?Now I have the WLC 4404 controller and Cisco LWP1131AG.Thanks a lot.

Cisco Employee

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

You can limit # of associations per SSID on the autonomous (IOS) solution, but don't think it's possible on the Airespace side. Can only set the roaming threshold.

New Member

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Several options to limit calls on the Lightweight side.

802.11b > Voice Parameters

Call Admission Control (CAC)

Admission Control (ACM) Enabled

Max RF Bandwidth (%) 80

Reserved Roaming Bandwidth (%) 6

Another method is aggressive load balancing to help limit clients on the AP - no help limiting calls - just associations.

Hall of Fame Super Red

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Hi Alomar,

Have a good read of this doc, it explains a number of methods to mitigate the type of problems due to the number of 7920 phones per AP;

Is Your WLAN Ready for Voice?

http://www.cisco.com/en/US/netsol/ns340/ns394/ns348/networking_solutions_white_paper0900aecd80472e80.shtml

Hope this helps!

Rob

Please remember to rate helpful posts.....

New Member

Re: How many 7920 phones can be supported on one Cisco 1131AG ac

Hi Migilles and Rob,

Thanks your answers again.These information helps me a lot.Thanks ~

373
Views
0
Helpful
7
Replies