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Poor wifi performance?
If I ping my router from N810, I see fairly substantial delays:
/home/user # ping 192.168.0.1 PING 192.168.0.1 (192.168.0.1): 56 data bytes 64 bytes from 192.168.0.1: seq=0 ttl=64 time=8.6 ms 64 bytes from 192.168.0.1: seq=1 ttl=64 time=17.7 ms 64 bytes from 192.168.0.1: seq=2 ttl=64 time=17.7 ms 64 bytes from 192.168.0.1: seq=3 ttl=64 time=17.7 ms 64 bytes from 192.168.0.1: seq=4 ttl=64 time=67.9 ms 64 bytes from 192.168.0.1: seq=5 ttl=64 time=59.3 ms 64 bytes from 192.168.0.1: seq=6 ttl=64 time=41.8 ms 64 bytes from 192.168.0.1: seq=7 ttl=64 time=42.0 ms 64 bytes from 192.168.0.1: seq=8 ttl=64 time=44.9 ms 64 bytes from 192.168.0.1: seq=9 ttl=64 time=43.6 ms 64 bytes from 192.168.0.1: seq=10 ttl=64 time=103.1 ms 64 bytes from 192.168.0.1: seq=11 ttl=64 time=44.0 ms 64 bytes from 192.168.0.1: seq=12 ttl=64 time=44.9 ms 64 bytes from 192.168.0.1: seq=13 ttl=64 time=60.6 ms I am literally 10 feet away from the router. Occasionally, there is also packet loss. ifconfig reports some TX errors: wlan0 Link encap:Ethernet HWaddr xx:xx:xx:xx inet addr:192.168.0.80 Bcast:192.168.0.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2525 errors:0 dropped:0 overruns:0 frame:0 TX packets:1379 errors:14 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1209590 (1.1 MiB) TX bytes:329245 (321.5 KiB) For comparison, my Ubuntu laptop has a consistent ping time of 1.2 ms. Things are even worse when pinging N810 from another device on the local network. ping 192.168.0.80 PING 192.168.0.80 (192.168.0.80) 56(84) bytes of data. 64 bytes from 192.168.0.80: icmp_seq=1 ttl=64 time=168 ms 64 bytes from 192.168.0.80: icmp_seq=2 ttl=64 time=81.7 ms 64 bytes from 192.168.0.80: icmp_seq=3 ttl=64 time=107 ms 64 bytes from 192.168.0.80: icmp_seq=4 ttl=64 time=130 ms 64 bytes from 192.168.0.80: icmp_seq=5 ttl=64 time=153 ms 64 bytes from 192.168.0.80: icmp_seq=6 ttl=64 time=74.7 ms 64 bytes from 192.168.0.80: icmp_seq=7 ttl=64 time=98.1 ms 64 bytes from 192.168.0.80: icmp_seq=8 ttl=64 time=123 ms 64 bytes from 192.168.0.80: icmp_seq=9 ttl=64 time=147 ms 64 bytes from 192.168.0.80: icmp_seq=10 ttl=64 time=67.6 ms This is pretty bad. I wonder if the problem is specific to my device, or if all N810's are affected. If anyone has root access, can you please ping your router a few times and post the results in this thread? Thanks! |
Re: Poor wifi performance?
Similar here: PC ping time 2ms, N810 ping 18ms or longer.
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Re: Poor wifi performance?
The tablet's a much slower machine than your PC is, so it's normal that a ping is longer. Also, if you have QoS, it's possible that your ping packets are receiving lower priority than it really takes to go back and forth to the server, throwing the numbers off completely.
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Re: Poor wifi performance?
FWIW, I see 10-25ms ping times to my wifi router. I wouldn't worry about slightly elevated times, but packet loss is another story. You might want to try another wifi channel or see if any form of "turbo" mode can be disabled.
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Re: Poor wifi performance?
N800 here, running OS2008 beta.
When pinging tablet to PC, I get times between 2.5 to 68ms, but mostly around 15ms. However, when pinging PC to tablet, I'm seeing a pattern of increasing ping times up to 100ms or so, then the patterns starts over again. Nothing else running on the N800. Good Wi-Fi signal. And the pattern is unique to pinging the tablet, nothing else. Weird. Quote:
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Re: Poor wifi performance?
Ubuntu Gutsy Gibbon w/Intel 10/100 PRO NIC pinging N800:
Code:
neil@nm-tyan:~$ ping n8devN800 pinging Ubuntu Gutsy Gibbon PC: Code:
/home/user # ping 192.168.0.12Ubuntu Gutsy Gibbon pinging a TiVo Series 1 over a bridged wireless connection: Code:
neil@nm-tyan:~$ ping tivoThe TiVo Series 1 is using a 50mhz PowerPC processor, connected by wired ethernet to a Linksys WRT54GS (200mhz Broadcom CPU) which is bridged (11g, WPA PSK/TKIP) to another WRT54GS Access Point, to which the Ubuntu PC is connected via a Gig ethernet switch. The TiVo connection is a far more convoluted route than that taken by the N800, yet the TiVo - a far less poweful device than the N800 - responds in a fraction of the time taken by the N800. The N800 has a more powerful CPU than either of the Linksys wireless routers and the TiVo, so I can't believe the poor ping time is due to CPU issues on the N800. Pinging *FROM* the N800 to the Ubuntu PC results in a better ping time - less than a third of that when going the other way - which suggests something odd is going on (power saving?) I've suspected for some time that the WiFi speed on N800s (also 770s) is poor, but doubt we'll see any improvement due to the open/closed nature of the WiFi stack and the lack of apparent care/importance Nokia give to the wireless side of things. I don't think the problem is with the CPU, more likely a poor or duff implementation. |
Re: Poor wifi performance?
I think the latency is due to the power saving mode, I seem to remember ping times going down when I started a SIP call, or some other task that needed low latency.
Or maybe I had switched it into power sucking mode manually :) |
Re: Poor wifi performance?
This is most probably caused by the power saving feature. If you are bothered by this try to increase PSM timeout to something longer than your ping interval.
EDIT: oops, dblank was faster |
Re: Poor wifi performance?
Ping results for different power saving settings (from Ubuntu Gutsy Gibbon w/Intel 10/100 PRO NIC to N800).
Power Saving OFF Code:
neil@nm-tyan:~$ ping n8devPower Saving On (INTERMEDIATE) Code:
neil@nm-tyan:~$ ping n8devPower Saving On (MAXIMUM) Code:
neil@nm-tyan:~$ ping n8devSo it's definitely due to the power saving feature - with the default maximum power save setting (200ms?) latency increases dramatically. It's hard to say how much battery life is gained by using the maximum setting, but I guess increased latency is the price to be paid for a slight increase in battery life. If low latency is required, reduce or disable the power saving setting. Turning the power saving feature off entirely probably isn't a good idea but it's interesting to note that with power saving disabled entirely the latency of the N800 is still twice that of a TiVo. |
Re: Poor wifi performance?
Same results here. Thanks!
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