Wireless Access

Hi ,

I was troubleshooting a deployment of  4 nos of IAP-93 in network. Below are the details;

1. IAPs running with latest available  firmware( support site).

2. working on 2.4 GHz Band.

3. 5 SSIds are broadcasted ( a mess) wpa,wpa 2 and TKIP and AES encryptions and a ssid with Radius auth. 2 SSIds are mapped with 2 different Vlans and other 3 are mapped with default vlan.

4. 2 SSIDs are sharing Vlan with wired network

5.Spectrum analysis running on test IAP 105 is gave following results;

6. User distribution is somewhat like 19 users on 1 IAP -93 and 7,3,5 on other 3 IAPs.

7. Applications are browsing , some (3-4)are using gmaps, 1 or 2 voice calls( once in a hour) on skype or go to meeting ( skype voice and screen sharing  might be killing the IAP 93 )

Now the Issues are :

1. client gets good coverage like 4 Bars on win 7 b/g/n machine ( Inssider RSSI 58) but when tried to download a file Frame retry increses to 36 as seen in IAP dashboard for youtube video streaming very less frame retry was observed. Also the connection  dropped once and I had to reconnect.

2. The SNR values for clients as seen on IAP dashboard are changing randomly , .

3. Large no of frame retries and frequent disconnction is the major issue.

4. Also a Skype/Go to meeting call drops randomly like after 5-10 mins.

Will dropping broadcast or optimisation hamper any application or network usage ?

SSIDs are to be made 2 or 3 .

Separating wired and wireless Vlans How will it help ?

Any other recommendations ?

thanks,

IAP -93 :smileywink:

5 SSIDs is entirely too much.  Find a way to remove two of them and you will improve performance.

Dropping broadcasts will not harm network traffic, no.  You should enable that.

Hi Colin,

Thanks for reply one more thing can we know the exact reason for frame retries ? what may be the normal count ?

From spectrum analysis it seems the spectrum is clear. 

And Skype/Go to meeting screen sharing + voice call is it too much for IAP 93  though  these calls are very few.

Anytime a client cannot send a frame on the first try, it is considered a retry.  If there was only a single client sending traffic, there would be few retries, because there would be little contention.  More traffic=more retries because you have more contention.  If 50% or more of your traffic are retries, that cuts your usable throughput in half.

How many retries  are norman is different for each location.

Here are things that increase contention and increase retries:

- Broadcasts

- More SSIDs

- Wired and wireless traffic sharing the same network (due to the wired broadcasts)

- More access points than 3 in an area

- Foreign access points on the same channel as you own access points

- non-802.11 interference like Microwaves, etc.

You need to remove as many of those as possible to keep retries down.