Ping to gateway very high when connected through AP

[Udupikrishna091]

Hello Guys,

I have connected few clients to Cisco AP which is under a WLC, when I get a DHCP ip to the clients, I started ping to the gateway and below was the reponse

Reply from 172.19.12.1: bytes=32 time=18ms TTL=255

Reply from 172.19.12.1: bytes=32 time=2990ms TTL=255

Reply from 172.19.12.1: bytes=32 time=520ms TTL=255

Reply from 172.19.12.1: bytes=32 time=428ms TTL=255

Reply from 172.19.12.1: bytes=32 time=1ms TTL=255

Reply from 172.19.12.1: bytes=32 time=1ms TTL=255

Reply from 172.19.12.1: bytes=32 time=45ms TTL=255

Reply from 172.19.12.1: bytes=32 time=493ms TTL=255

Reply from 172.19.12.1: bytes=32 time=646ms TTL=255

Reply from 172.19.12.1: bytes=32 time=351ms TTL=255

Reply from 172.19.12.1: bytes=32 time=365ms TTL=255

Reply from 172.19.12.1: bytes=32 time=414ms TTL=255

Reply from 172.19.12.1: bytes=32 time=133ms TTL=255

Reply from 172.19.12.1: bytes=32 time=2ms TTL=255

Reply from 172.19.12.1: bytes=32 time=2ms TTL=255

Reply from 172.19.12.1: bytes=32 time=3ms TTL=255

Reply from 172.19.12.1: bytes=32 time=18ms TTL=255

Reply from 172.19.12.1: bytes=32 time=589ms TTL=255

Reply from 172.19.12.1: bytes=32 time=304ms TTL=255

Reply from 172.19.12.1: bytes=32 time=3ms TTL=255

Reply from 172.19.12.1: bytes=32 time=98ms TTL=255

Reply from 172.19.12.1: bytes=32 time=350ms TTL=255                  

Reply from 172.19.12.1: bytes=32 time=18ms TTL=255
Reply from 172.19.12.1: bytes=32 time=170ms TTL=255
Reply from 172.19.12.1: bytes=32 time=1ms TTL=255
Reply from 172.19.12.1: bytes=32 time=1ms TTL=255
Reply from 172.19.12.1: bytes=32 time=2ms TTL=255
Reply from 172.19.12.1: bytes=32 time=1ms TTL=255
Reply from 172.19.12.1: bytes=32 time=24ms TTL=255
Reply from 172.19.12.1: bytes=32 time=2990ms TTL=255
Reply from 172.19.12.1: bytes=32 time=520ms TTL=255
Reply from 172.19.12.1: bytes=32 time=428ms TTL=255
Reply from 172.19.12.1: bytes=32 time=1ms TTL=255
Reply from 172.19.12.1: bytes=32 time=1ms TTL=255
Reply from 172.19.12.1: bytes=32 time=45ms TTL=255
Reply from 172.19.12.1: bytes=32 time=493ms TTL=255
Reply from 172.19.12.1: bytes=32 time=646ms TTL=255

Reply from 172.19.12.1: bytes=32 time=133ms TTL=255

Reply from 172.19.12.1: bytes=32 time=18ms TTL=255
Reply from 172.19.12.1: bytes=32 time=589ms TTL=255
Reply from 172.19.12.1: bytes=32 time=304ms TTL=255
Reply from 172.19.12.1: bytes=32 time=3ms TTL=255
Reply from 172.19.12.1: bytes=32 time=98ms TTL=255
Reply from 172.19.12.1: bytes=32 time=350ms TTL=255

I know that this is not normal, please need help so that I can start troubleshooting step by step

Regards

Krishna

[Amjad Abdullah]

Krishna:

You need to check wireless RF. Check the noise and interference. Have you made a site survey?

The number of clients available also may have effect. Your distance from the AP plays a role.

Does the AP support 802.11n? (what AP model you use?). If yes, make sure the wired connection speed is 1 Gbps, not 100 Mbps.

Where does your gateway reside? please provide brief about the topology.

I suggest you eliminate or the issues mentioned above and test with only one client connected to the AP and test.

HTH

Amjad

[George Stefanick]

I might also check with other devices. If your device is set to high roaming, your client will be off channel and can cause higher pings.

[Scott Fella]

You might also want to ping from the wired side just to make sure it related only to the wireless. Duplicate address on the gateway might be causing the issue, so if your ping from a wired pc to that gateway is fine, then look at your wireless side.

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[Andrew Vlasek]

I am experiencing the same behavior and trying to determine if its normal or an issue. My indicator on my local laptop seems to jump around a lot from saying i am geting 54 Mbps all the way to 150 Mbps but here are my symptoms:

Ping from wired to host:

CS2NW#ping 10.19.12.207 r 100

Type escape sequence to abort.

Sending 100, 100-byte ICMP Echos to 10.19.12.207, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (100/100), round-trip min/avg/max = 1/2/8 ms

From host to wired:

Reply from 10.31.110.1: bytes=32 time=3ms TTL=252

Request timed out.

Reply from 10.31.110.1: bytes=32 time=6ms TTL=252

Reply from 10.31.110.1: bytes=32 time=1ms TTL=252

Reply from 10.31.110.1: bytes=32 time=2ms TTL=252

Request timed out.

Reply from 10.31.110.1: bytes=32 time=2ms TTL=252

Reply from 10.31.110.1: bytes=32 time=2ms TTL=252

Reply from 10.31.110.1: bytes=32 time=3ms TTL=252

Reply from 10.31.1: bytes=32 time=8ms TTL=252

Reply from 10.31.110.1: bytes=32 time=2ms TTL=252

Reply from 10.31.110.1: bytes=32 time=1ms TTL=252

Request timed out.

Request timed out.

Ping statistics for 10.31.110.1:

    Packets: Sent = 5407, Received = 3519, Lost = 1888 (34% loss),

Approximate round trip times in milli-seconds:

    Minimum = 0ms, Maximum = 3512ms, Average = 15ms

But then I can stream an HD video on youtube from the client with no lag.... I am running latest greatest 3602 APs latest controller code and 5508 controllers. Wireless is just know going production and I am trying to confirm that there is no issues.

[Scott Fella]

I had a client that experienced the same issues with a bunch of contractors. The issue was to update the drivers on their adapters and review the adapter properties. Some devices was set to 20mhz channels not auto or 802.11an/802.11bgn. Also some had Thinkvantage or IntelProSet and once we set the laptop to use windows zero config, they started working good.

The clients would get an ip address and be in the run state, but the pings to their gateway was in the hundred to 1000ms. We also had one client using Cisco AnyConnect that had the same issue but others using AnyConnect didn't. The adapter driver was the issue.

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[Andrew Vlasek]

I can play around with the client settings to see if there is a difference but that seems like quite a hassle to have tune on the client side. I still need to confirm whether this is or is not an issue or whether it is effecting only ping because like I said I did play and HD 1080p video without any issue. This is a new rollout replacing the old IOS AP model, so it has not been stress tested yet.

[timur.bessembe]

I've got the similar problem. When i'm pinging, for example, gateway from client on wireless, ping is very bad, some are packets lost. And when i'm connecting via apple device, i'm pinging it worse that from pc. Sometime wireless connections are lost.

Can't find some information.

For example, ping mobile from wired pc:

eply from 10.10.44.57: bytes=32 time=94ms TTL=63

eply from 10.10.44.57: bytes=32 time=52ms TTL=63

equest timed out.

eply from 10.10.44.57: bytes=32 time=572ms TTL=63

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

eply from 10.10.44.57: bytes=32 time=195ms TTL=63

eply from 10.10.44.57: bytes=32 time=283ms TTL=63

eply from 10.10.44.57: bytes=32 time=181ms TTL=63

eply from 10.10.44.57: bytes=32 time=403ms TTL=63

eply from 10.10.44.57: bytes=32 time=41ms TTL=63

equest timed out.

equest timed out.

equest timed out.

equest timed out.

equest timed out.

[Scott Fella]

Well since that is from a wired PC, it might be an issue with a duplicate address on the network. You need to look at your dhcp scopes if you have multiple dhcp servers and make sure the scopes are not overlapping. You might also need to look at the logs on the switch to see maybe if its a connectivity issues.

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[Udupikrishna091]

Hi Scott

I sorted out the issue it was due to some kind of Vlan mismatch we did have multiple dhcp scopes and few users were getting IP address from the right dhcp scope and they had no issues well this might not be specifically the case with other people here

[Scott Fella]

That's would do it too:). Thanks for the follow up!

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[Yahya Jaber]

Hi,

Well, generally speaking, Ping-over-Wireless connection is not a RELIABLE test for the wireless client connectivity!  To understand this, let us get back to the basic ICMP protocol knowledge:

- Now, in a Nutshell, assume an ICMP Echo-Request (i.e. ping) is lost on the wired network for some reason, if we ask ourselves:
Would there be an error-reporting message for the lost ICMP echo?  The answer would be NO; because ICMP itself is an Error-Reporting protocol for connectivity loss, and it does not have any means to report about itself if an abnormality happens.

Now, such scenarios is very very rare on Wired.  But on wireless, it is very frequent; because the ICMP echo request (i.e. ping) may be lost over wireless due to RF interference … etc. and that is why it is expected to see PING drop over wireless whilst the connection itself is stable somehow, but with some Packet Drops and Retries; hence, we will have an RF issue.

To identify if there is some retries, collect the ‘show client detail XX:XX:XX:XX:XX:XX’ from the WLC and check if we have data retries.  For example:
       …
       Client Statistics:
      Number of Bytes Received................... 5213388
      Number of Bytes Sent....................... 16391664
      Number of Packets Received................. 13982
      Number of Packets Sent..................... 15247
      Number of EAP Id Request Msg Timeouts...... 0
      Number of EAP Request Msg Timeouts......... 0
      Number of EAP Key Msg Timeouts............. 1
      Number of Data Retries..................... 3756
      Number of RTS Retries...................... 0
      Number of Duplicate Received Packets....... 69
      Number of Decrypt Failed Packets........... 18
      Number of Mic Failured Packets............. 0
      Number of Mic Missing Packets.............. 0
      Number of Policy Errors.................... 0
      Radio Signal Strength Indicator............ -71 dBm
       …

Hope that helps