03-14-2011 03:10 AM - edited 07-03-2021 07:56 PM
I have a wireless setup of WLC 4402 and four 1250 APs.
There are about 10 users. Some times they have freezes and lags in network connection.
The end users notice ping latency above 5ms, below is a ping test for 30 seconds.
Reply from 10.1.10.160: bytes=32 time=25ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=18ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=1ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=4ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=1ms TTL=127
Reply from 10.1.10.160: bytes=32 time=19ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=2ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=23ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=37ms TTL=127
Reply from 10.1.10.160: bytes=32 time=83ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=89ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=10ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=11ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=14ms TTL=127
Reply from 10.1.10.160: bytes=32 time=29ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=10ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=11ms TTL=127
Reply from 10.1.10.160: bytes=32 time=73ms TTL=127
Reply from 10.1.10.160: bytes=32 time=1ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=10ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=256ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=179ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=13ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=18ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=6ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=272ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=14ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=4ms TTL=127
Reply from 10.1.10.160: bytes=32 time=2ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=5ms TTL=127
Reply from 10.1.10.160: bytes=32 time=13ms TTL=127
Reply from 10.1.10.160: bytes=32 time=19ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=4ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=2ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=16ms TTL=127
Reply from 10.1.10.160: bytes=32 time=455ms TTL=127
Reply from 10.1.10.160: bytes=32 time=16ms TTL=127
Reply from 10.1.10.160: bytes=32 time=4ms TTL=127
Reply from 10.1.10.160: bytes=32 time=12ms TTL=127
Reply from 10.1.10.160: bytes=32 time=3ms TTL=127
Reply from 10.1.10.160: bytes=32 time=2ms TTL=127
Reply from 10.1.10.160: bytes=32 time=1ms TTL=127
Reply from 10.1.10.160: bytes=32 time=6ms TTL=127
Reply from 10.1.10.160: bytes=32 time=15ms TTL=127
Reply from 10.1.10.160: bytes=32 time=21ms TTL=127
Reply from 10.1.10.160: bytes=32 time=4ms TTL=127
Ping statistics for 10.1.10.160:
Packets: Sent = 142, Received = 142, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 455ms, Average = 16ms
Is this normal?
Any help will be appreciated.
03-14-2011 06:56 AM
Ping is not a reliable test for wireless. Wireless clients use "sleep mode" to save on battery and don't necessarily reply to pings with a high priority.
You could see a wireless client having high latency and then perfect latency if starting a huge file transfer.
Your problem is the lag noticed by the user. the ping itself is not a problem.
Nicolas.
03-14-2011 07:32 AM
Thankyou Nicolas for replying.
The lag is the exact issue users are complaining about. They connect to a Citrix Presentation Server 4.5 and lag is noticeable and sometimes they have a 5 second freeze!!!
Has anyone else seen this?
03-14-2011 10:01 AM
Strangely enough it happens a lot with Citrix more than any other application :-)
The only way to get to the bottom is to dive deep in the problem. Checking if the lag happens on all laptops of an area at the same time (too much load). Checking interference level. Maybe some coverage hole areas ? Maybe laptops are roaming a lot and the roaming is not happening smoothly ... Could be a lot of things.
03-16-2011 12:45 AM
I would say yes, higher than 5ms is not unusual. Your output is quite normal.
Here is my output on FPING on a moving train. FPING sends a ping every 10ms.
03:26:59 : Reply[2126] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2127] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2128] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2129] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2130] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2131] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2132] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2133] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2134] from 10.0.0.13: bytes=185 time=3.2 ms TTL=127
03:27:00 : Reply[2135] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:00 : Reply[2136] from 10.0.0.13: bytes=185 time=3.5 ms TTL=127
03:27:01 : Reply[2137] from 10.0.0.13: bytes=185 time=3.3 ms TTL=127
03:27:01 : Reply[2138] from 10.0.0.13: bytes=185 time=3.0 ms TTL=127
03:27:01 : Reply[2139] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
03:27:01 : Reply[2140] from 10.0.0.13: bytes=185 time=3.0 ms TTL=127
03:27:01 : Reply[2141] from 10.0.0.13: bytes=185 time=2.9 ms TTL=127
03:27:01 : Reply[2142] from 10.0.0.13: bytes=185 time=10.9 ms TTL=127
03:27:01 : Reply[2143] from 10.0.0.13: bytes=185 time=3.0 ms TTL=127
03:27:01 : Reply[2144] from 10.0.0.13: bytes=185 time=3.1 ms TTL=127
Summary was:
Ping statistics for 10.0.0.13:
Packets: Sent = 4548, Received = 4534, Lost = 14 (0% loss)
Approximate round trip times in milli-seconds:
Minimum = 2.7 ms, Maximum = 31.4 ms, Average = 3.2 ms
As long as your average is quite good and your packet loss is very low, you should be fine.
Not sure about the Citrix application. Haven't gotten around to using that on trains at the moment!
I typically find that the higher latency and the packet loss correlates nicely with when I roam.
Good luck!
James
03-16-2011 02:23 AM
Thankyou all for replying.
I have found document 'Optimizing Citrix technology for operation over wireless wide area networks'. It states sensitivity to latency will cause lags but suggests solutions, I will be going over this and will post update.
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