Large-ish scale deployment of WP820


#1

I have a client requesting approx. 30 WP820 handsets for a new office.
We have installed a few WP820 handsets but, they were not the main telephone for each user.
My concern is, how much bandwidth is needed to insure that each user has call quality and reliability.

We will be install Gb fiber based service and our LAN will also be Gb. The AP’s ( Ubiquiti) are touted as being able to provide 450Mb minimum. This client will also be streaming their video conference and in house collaboration.

I am not comfortable deploying this many WiFi enable devices on te internal network.

Has anyone deployed 20+ WP820’s in a production environment?

Any feedback is greatly appreciated.

gary


#2

How are you managing QOS for SIP/RTP ?


#3

Hi,

Assuming the worse case: Every WP820 is streaming video at highest bit rate 2048kbps (2Mbps), you’ll need about 60Mbps in bandwidth to handle all the streams. I think you have more than enough :slightly_smiling_face:.

When deploying many WiFi devices, I would take a WiFi analyzer to the deployment location to figure out the channels that are being used for each band then find the optimal channel/band based on your analysis. Most of the time 2.4ghz has a lot of overlap due to most devices using that band so you may want to try 5ghz. Hope this helps.

Thanks


#4

Just be mindful that the 5GHz range is a wide band short range frequency, 2,4 GHz is a narrow band long range frequency.

2.4GHz - better for long distance trouble spots for wifi
5GHz - better for short distance unimpeded areas for wifi

Just remember that SIP is not data which is best effort - it doesnt matter if a packet arrives late to display a web page on a desktop, SIP/RTP is real time and needs QOS support to suit. Any delays in SIP / RTP can cause chirpy sounding calls, termination of calls, major audio loss etc …


#5

Thank you.
Do I understand you correctly, Each 820 is streaming video?


#6

Re Video, he was mentioning if the telephones were using video that the bandwidth that you have would be enough to provide the video.

Every WP820 needs around 110k for a call… that equates to 3.3 Mb of bandwidth at G711a/u law

If I were you I would make sure that you allocate a minimum of 5 Mb up and 5 Mb down for calls and ensure QOS for VoIP is prioritised.


#7

Thank you GS.Rick.
We most certainly will use QOS as well as VLAN for the “phone” system.
So, in your opinion, deplyment of that many WiFi handsets is doable?


#8

Perfect. Thank you Scottsip. I completely get U/law.
This should work effectively given we VLAN and QOS.

Thank you i so much.


#9

Will there be a possibility of all handsets moving to an area where only 1 wifi AP will be available?

I would check with the manufacturer how many concurrent connections it can handle as sometimes they do some funky TDM of bandwidth and share it evenly between said devices…


#10

What access points will you be using?


#11

He said Ubiquiti as AP’s … unsure how good they perform as it is theoretical for him at this stage.


#12

Are you literally expecting every phone to be in use simultaneously? If not, you can get away with less stringent requirements, but either way, your bottleneck will be your AP’s (or APs’, if you have more than one) capacity for handling simultaneous clients and sustained throughput.


#13

Also don’t forget that there may be issues with hand-off between APs if the person is moving while talking. There are features in the GWN series of APs to deal with this and I am not sure if/how Ubiquiti handles that.


#14

Ubiquiti Inifi AP-AC-HD.

I’ve had nothing but good experience with them.


#15

Thank you all for your replies. Very much appreciated.

Gandstream support said that minimum 4Mb is required for efficient and quality calls.
I’m not sure if they meant 4Mb for each WP820. That doesn’t quite add up considering U-law is 64Kb. Sounds like a lot of overhead.

I know that this clients call volume by the architects is relatively low, very unlikely that they will have more than 3 or 4 calls concurrently.
The “heavy” users, admin, acctg, etc will be hardwired GXP2xxx handsets, conference rooms will be the grandstream conf. phones.

Ubiquiti does a really good of “seamless roaming” and many client associations.

2.4 GHz Radio Rate 800 Mbps
5 GHz Radio Rate 1733 Mbps
Wi‑Fi Client Associations 200+

I would use the Grandstream AP, also a excellent AP but I don’t have as much experience with them.

I’ll let you know how everything comes together.

Cheers
g


#16

4Mb was for streaming high def video. Something the WP820s won’t be doing, most likely. :slight_smile:

Audio bandwidth for uLaw/aLaw (G.711) encoding is ~100Kb/s, on average, rounded up. If you want to figure worst case scenario for pure SIP G.711 audio with no video, count 100Kb/s per direction per call and there’s your bandwidth.


#17

I’m not saying that the UBNT kit isn’t good stuff but I will tell you that I’ve had some issues with WiFi calling with UBNT. They don’t have any QoS support that will prioritize VoIP traffic.


#18

The Grandstream AP does have QoS that’s VoIP ready.


#19

The Grandstream AP’s work well…


#20

I agree. They do work well.