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I'm trying to debug a wireless lan issue. I have 2 devices connected to the same wifi router.

Ping results to router from Device #1: ~3ms

mbp:~ rmb$ ping 192.168.8.1
PING 192.168.8.1 (192.168.8.1): 56 data bytes
64 bytes from 192.168.8.1: icmp_seq=0 ttl=64 time=3.639 ms
64 bytes from 192.168.8.1: icmp_seq=1 ttl=64 time=3.751 ms
64 bytes from 192.168.8.1: icmp_seq=2 ttl=64 time=3.706 ms
64 bytes from 192.168.8.1: icmp_seq=3 ttl=64 time=3.649 ms
...
--- 192.168.8.1 ping statistics ---
29 packets transmitted, 29 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.945/2.645/4.260/1.249 ms

Ping results to router from Device #2: ~3ms

rmp:~ rmp$ ping 192.168.8.1
PING 192.168.8.1 (192.168.8.1): 56 data bytes
64 bytes from 192.168.8.1: icmp_seq=0 ttl=64 time=1.192 ms
64 bytes from 192.168.8.1: icmp_seq=1 ttl=64 time=0.932 ms
64 bytes from 192.168.8.1: icmp_seq=2 ttl=64 time=3.420 ms
64 bytes from 192.168.8.1: icmp_seq=3 ttl=64 time=3.361 ms
....
--- 192.168.8.1 ping statistics ---
22 packets transmitted, 22 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.821/2.965/4.134/1.006 ms

I would expect then that pinging between each of the devices would be in the same ball park, but it's way off.

Ping results between Device #1 and #2: 3 - 114ms

mbp:~ rmb$ ping 192.168.8.2
PING 192.168.8.2 (192.168.8.2): 56 data bytes
64 bytes from 192.168.8.2: icmp_seq=0 ttl=64 time=3.766 ms
64 bytes from 192.168.8.2: icmp_seq=1 ttl=64 time=67.722 ms
64 bytes from 192.168.8.2: icmp_seq=2 ttl=64 time=91.376 ms
64 bytes from 192.168.8.2: icmp_seq=3 ttl=64 time=114.361 ms
64 bytes from 192.168.8.2: icmp_seq=4 ttl=64 time=35.975 ms

I find it hard to fathom how it could be possible to get a 90 - 114ms ping when both devices are right next to the router.

So I'm wondering - what could be the bottleneck when both devices can ping at acceptable rates to the router. What are pings like from the router?

Ping results from Router to #Device 1

PING 192.168.8.2 (192.168.8.2): 64 data bytes
72 bytes from 192.168.8.2: seq=0 ttl=64 time=66.163 ms
72 bytes from 192.168.8.2: seq=1 ttl=64 time=93.665 ms
72 bytes from 192.168.8.2: seq=2 ttl=64 time=112.366 ms

--- 192.168.8.2 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 66.163/90.731/112.366 ms

Ping results from Router to Device #2:

PING 192.168.8.3 (192.168.8.3): 64 data bytes
72 bytes from 192.168.8.3: seq=0 ttl=64 time=2.577 ms
72 bytes from 192.168.8.3: seq=1 ttl=64 time=60.316 ms
72 bytes from 192.168.8.3: seq=2 ttl=64 time=101.978 ms

--- 192.168.8.3 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 2.577/54.957/101.978 ms

The router is a Huawei 4G E5186s-22a. I'm guessing there's either something wrong with the config or it is just more well marketed rubbish.

Other symptoms to note have been some occasional dropouts of the wlan while I've been sharing between devices. Any other devices that are on the wifi network at the same time will also be dropped out and it appears like the wifi router is resetting itself.

Any ideas what might cause this kind of behaviour so I could search more into ways to debug it?

Additional notes

I do have another wireless router which I have plugged into the 4G router via ethernet and used it instead to manage the wireless. When I have done this, the wireless pings are under 5ms and stable. While it's an option to solve the problem, it seems less than idea to have 2 routers running to perform the job of 1.

  • 1
    I have the same issue. Can ping under 5ms to router but ping to others on same network gets 20-120ms :( – cosmicbdog Mar 13 '16 at 5:46
2

Because ping packets need to do this.

host1 > router | router > host1.

host1 > router | router > host2 | host2 > router | router > host1.

If you test it will cable you will get nearly 1ms, but in wireless networking you have got a lot of variables: signal mode, strenght, latency, free bandwith, etc. And yes, how router manage Wi-Fi does the trick. Is not the same a 50$ router that a 300$ one.

If the routers are the same model, I'm sure you can get same results with the first one, disconnecting it from WAN and closing all computer programs, to be sure the network is only managing the ping packets.

Ping - How does it work?

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