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New Member

SA520W Wireless unstable

Hi!

I am having some problems with my new SA520W. It has been upgraded to firmware 1.1.65.

While using the wireless network, it seems as the connection is slowing down pretty often. It is very unreliable.

I often listen to music over the wireless network, streaming from my laptop to a Apple Airport Express (AE), but the music skips very often. The AE is wired to the SA520W using Ethernet

I've tried to enable/disable QOS on the SA520W, but with little or no difference. I've also tried all the different channels on the AP.

I tried to ping my wireless laptop from a computer that is hardwired to the SA520W, and it gives a result like this:

--- 192.168.10.99 ping statistics ---

200 packets transmitted, 193 received, 3% packet loss, time 199030ms

rtt min/avg/max/mdev = 1.523/284.046/1909.057/401.797 ms, pipe 2

But if I enable the wireless AP in the AE (bridge mode), and connect to it, the connection is very stable, and I can listen to music for hours without skipping. The AE and The SA520W are in the same room, a few feet apart. Here is the ping statistics while connected to the AE:

--- 192.168.10.99 ping statistics ---
200 packets transmitted, 200 received, 0% packet loss, time 199009ms
rtt min/avg/max/mdev = 2.422/5.350/109.119/11.577 ms

I can't find much information in the logs of the SA520W, except this, don't know if it is related though.

Sun Oct 31 19:51:16 2010(GMT +0100)WARNKernelsize of this packet is lesser than minimum length 
Component: KERNEL
Sun Oct 31 19:51:16 2010(GMT +0100)WARNKernel*******The above log repeated 4 times ******* 
Component: KERNEL

Any help or comments are highly appreciated.

13 REPLIES
Silver

Re: SA520W Wireless unstable

From what i can gather, you have two wireless units in place: A sa520w and an AE apple wireless access point.  If that is the case, are you using the two in conjuntion with each other?  Have you tried just he sa520w's wireless to see if you see the same issue?  If not, I would test the connection to the sa520w and see if your seeing the same issue/ however if it is very different it will let you lean toward the apple or wireless interference.  Hopefully this will help you clarify where the interference is.

New Member

Re: SA520W Wireless unstable

Thanks for your reply!

Sorry for not being more clear on that, but the testing I have done in the first post, where the SA520W has 3% packet loss is done with the wireless mode disabled on the AE, using it as a hardwired music receiver only.

I have done some more testing, and it shows that the packet loss is anywhere between 1% and 11% using the SA520W.

I am currently testing different encryption types, and it seems to have an impact.

I will post results later.

New Member

Re: SA520W Wireless unstable

Just wanted to post some results from my testing.

Using different types of encryption did not have any impact, the problem is still there.

I am also seeing this problem when streaming video from a wired server on my LAN to a wireless client. The video skips often, and if I ping the wireless client from the wired server on the LAN, I am seeing the same behaviour as above.

The round trip latency is generally good, but when the skipping occurs, the latency is really high (500-1200 millisec).

This happens at random intervals.

I've also upgraded my firmware to 1.1.80 to see if the problem is solved, no luck.

I have testet all combinations of WPA/WEP/OPEN, and tried enabling each one of all of the four internal access points.

New Member

Re: SA520W Wireless unstable

Hi sigolaper,

Can you please let us know if the airport express is 802.11n enabled. Also can you confirm if you see the packet losses when switch the SA520W to "g" only mode.

Thanks,

Nitin.

New Member

Re: SA520W Wireless unstable

Hi nmanglik.

Thanks for your response.

The Airport Express is the version with 802.11n.

I tried to switch the SA520W into "g only" mode, and it seems to solve the packet loss problem.

Here are ping statistics while connected to the SA520W in g only mode:

--- 192.168.10.99 ping statistics ---
200 packets transmitted, 200 received, 0% packet loss, time 199033ms
rtt min/avg/max/mdev = 0.688/8.514/198.444/25.550 ms

2.3MB/s file copying also doesn't seem to affect the latency much:


--- 192.168.10.99 ping statistics ---
200 packets transmitted, 200 received, 0% packet loss, time 199037ms
rtt min/avg/max/mdev = 0.772/20.302/36.138/6.517 ms


Here's when I reenabled ng mode, while copying files @ 8.3MB/:

--- 192.168.10.99 ping statistics ---
200 packets transmitted, 194 received, 3% packet loss, time 199032ms
rtt min/avg/max/mdev = 1.177/123.511/1890.109/342.461 ms, pipe 2

Here's also some measurements done with inSSIDer 2.0:

New Member

Re: SA520W Wireless unstable

gents,

I have found the solution to this.

The SA520W had "channel spacing" option set to Auto. This equals 40 MHz when in ng mode.

My wireless network adapter Intel WiFi Link 5300 AGN was set to 20MHz for 2.4GHz. (default settings).

Although this should be working fine, it doesn't with this network adapter.

By changing either the SA520W to 20MHz channel spacing (not recommended if you want max performance), or setting the wireless network adapter to 40MHz channel spacing (Automatic) has both made these latency and packet loss problems go away.

Sorry for the Norwegian text, but if you are reading this post, I guess you can figure out what these settings are about:

New Member

Re: SA520W Wireless unstable

Find a wireless utility to determine what else is walking on your signal.  If you can find a copy of Netstumbler this would help.  You need to see what else is transmitting in your area; both with broadcast SSID's and without.  The AP's can coexist in close proximity but you must specify the channels to use on both devices.  Automatic channel selection will just cause you more heartache in the future.  It is hard enough to keep a neighbor from interfering with your channel selection; don't be the cause of your own interference.  Something else to keep in mind is that microwave ovens operate at the same frequency; an RF generator is called a magnetron in a microwave.  See if you can change the SA520W to a 5Ghz spectrum.  I beleive this is an option.

To recap, perform a wireless site survey with some utility either on the Airport or on the SA and determine two channels and frequencies not being used.  A this point hardcode your selections on each AP.  Maybe it is time for a MiniMac with a bluetooth keyboard and mouse.  Use the audio out on it to feed your stereo and also watch Youtube on your TV with Stereo sound!

All the best,

Robcast

New Member

SA520W Wireless unstable

Hi,

Is this issue resolved for you? Please ensure that you have WMM enabled in the wireless settings and you are using the latest firmware

Channel spacing "Auto" should take care of both 40Mhz and 20Mhz clients and backward compatabiliy and protection mode is built into it. Let me know if you have an issue with this and I can help

Regards,

Sunil

Cisco Employee

SA520W Wireless unstable

You may also try the newly release software:

https://supportforums.cisco.com/docs/DOC-16365

New Member

SA520W Wireless unstable

As stated in my previous post on Nov 18, 2010, I found the solution to this back then.

It has been running fine ever since.

Cisco Employee

SA520W Wireless unstable

Great. But just an FYI there is new firmware availalbe. Happy its working!

New Member

SA520W Wireless unstable

Hi,

  I bought the SA520W to replace an 6 year old router/VPN/Firewall that was rebooting itself. After a lot of flustration, I had given up on getting the wireless part to work.  My solution was to use an apple time capsole in combation with the SA520W, turning the wirless off on the W.

   After reading though above - Changing the channell spacing to 20MHz - it does work better but apple still wins.  Before making the change I was getting an awful  .5 (as in half or point 5)  Mbps from my Mac Book Pro to the SA520W using speedtest.net.   After the change it is getting 8Mbps - But the apple TC gets a consistent 14.7 Mbps. (My DSL is 15 Mbps, so this is full speed). 

   The SA520W - although it has been upgarded from just awful - is still not consistent.

Any other magic settings neeeded ?

Green

SA520W Wireless unstable

Hi Doug, do you have Windows computers that have the same problem?

I can tell you, I used to connect to a SA520W in the lab and had no problems from around 50 feet away with 15-30 wireless networks present so I'm a bit surprised there are any problems.

Can you change the wireless encryption to use TKIP only and not use any WMM features from the Apple? The reason asking, Apple has some issues with their AES implementation but also WMM is a terrible protocol that was developed by Apple which became standardized in Wireless-N. It may not be a bad idea to use G only with a TKIP cipher type for testing.

-Tom
Please mark answered for helpful posts

-Tom Please mark answered for helpful posts http://blogs.cisco.com/smallbusiness/
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