WiFi ping times fluctuating

Hi everyone, I've had a problem starting yesterday (at least that's
when I noticed it) where the wireless connection between my laptop and
(buffalo) router has not been reliable, and downloads have been very
slow.

When I try to ping the router, this is what happens:

PING 192.168.1.1 (192.168.1.1): 56 data bytes
64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=2135.790 ms
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=1141.654 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=142.660 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.921 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=3132.532 ms
64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=2132.499 ms
64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=1133.152 ms
64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=133.306 ms
64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=0.923 ms
64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=3132.179 ms
64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=2132.909 ms
64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=1132.991 ms
64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=132.959 ms
64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=0.944 ms
64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=3132.797 ms
64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=2132.787 ms
64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=0.895 ms

Most of the packets are transmitted fine, but the ping times fluctuate
from pretty reasonable (sub-one second) and pretty awful (over three
seconds).

Does anyone have any idea why this might be happening? I've tried
turning WPA off, putting the laptop right next to the router, and
changing the wifi channel, with no success.

Appreciate your thoughts!

On Aug 4, 4:48 pm, Mark <markjtur...@gmail.com> wrote:
> Hi everyone, I've had a problem starting yesterday (at least that's
> when I noticed it) where the wireless connection between my laptop and
> (buffalo) router has not been reliable, and downloads have been very
> slow.
>
> When I try to ping the router, this is what happens:
>
> PING 192.168.1.1 (192.168.1.1): 56 data bytes
> 64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=2135.790 ms
> 64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=1141.654 ms
> 64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=142.660 ms
> 64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.921 ms
> 64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=3132.532 ms
> 64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=2132.499 ms
> 64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=1133.152 ms
> 64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=133.306 ms
> 64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=0.923 ms
> 64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=3132.179 ms
> 64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=2132.909 ms
> 64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=1132.991 ms
> 64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=132.959 ms
> 64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=0.944 ms
> 64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=3132.797 ms
> 64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=2132.787 ms
> 64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=0.895 ms
>
> Most of the packets are transmitted fine, but the ping times fluctuate
> from pretty reasonable (sub-one second) and pretty awful (over three
> seconds).
>
> Does anyone have any idea why this might be happening? I've tried
> turning WPA off, putting the laptop right next to the router, and
> changing the wifi channel, with no success.
>
> Appreciate your thoughts!

I can't tell what's causing the problem, mostly because I don't
have a clue as to what you have for hardware, but the problem
is obviously packet loss. Wireless routers work on two levels
(layers). At the MAC layer, you only see the longer time delays
caused by the packet loss. Packets are retransmitted transparently.
So, at the IP layer, you get somewhat reliable delivery, but with
the observed time delays. My guess is that you have a neighbor
that just dragged home a new wireless router.

The standard fixes for interference problems are to change the
RF channel or play with directional antennas. Putting your laptop
next to the wireless router isn't going to do anything if either
is hearing the interference. Not much I can suggest until you
identify the source of the interference.

Hi Jeff, thanks for the suggestions. That's interesting that it would
report packets as delivered when actually they were dropping, I didn't
know that. What kind of hardware details would help?

There a couple of other wireless networks in the area, probably
neighbours, but they're on channel 6 and I'm on channel 11. I've tried
setting it to channel 1 as well and it's the same. What else could be
causing interference? The router is quite near my TV and stuff, could
that be causing the problem?

On Aug 4, 5:17 pm, Mark <markjtur...@gmail.com> wrote:
> Hi Jeff, thanks for the suggestions. That's interesting that it would
> report packets as delivered when actually they were dropping, I didn't
> know that.

Layer 2 diagnostics (MAC layer) are very rare in commodity
wireless. The IP layer never sees the retransmissions.
All it sees are longer delays.

>What kind of hardware details would help?

Maker and model of router. Hardware version. Firmware version
optional.
Maker and model of test client laptop.
Some clue as to the topology, neighborhood, etc.
Is the interference continuous or intermittent? Times?

Incidentally, go down this list of probable culprits and see
if any look new.
<http://wireless.wikia.com/wiki/Wi-Fi#Interference>
Municipal wireless installation seem to be becoming a
problem.

> There a couple of other wireless networks in the area, probably
> neighbours, but they're on channel 6 and I'm on channel 11. I've tried
> setting it to channel 1 as well and it's the same. What else could be
> causing interference? The router is quite near my TV and stuff, could
> that be causing the problem?

See list above. Also, you can't "see" a wireless network that
doesn't broadcast its SSID. You can use Kismet to sniff these,
or a spectrum analyzer:
<http://www.metageek.net/Products/Wi-Spy>
There are also some MIMO (802.11n) networks that don't show
up on a client utility or active scanner.

If your radios are near a window, try moving the access point
and/or client away from the window. That's the most likely
point of entry.

On Aug 5, 1:31 am, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> On Aug 4, 5:17 pm, Mark <markjtur...@gmail.com> wrote:
>
> > Hi Jeff, thanks for the suggestions. That's interesting that it would
> > report packets as delivered when actually they were dropping, I didn't
> > know that.
>
> Layer 2 diagnostics (MAC layer) are very rare in commodity
> wireless. The IP layer never sees the retransmissions.
> All it sees are longer delays.
>
> >What kind of hardware details would help?
>
> Maker and model of router. Hardware version. Firmware version
> optional.
> Maker and model of test client laptop.
> Some clue as to the topology, neighborhood, etc.
> Is the interference continuous or intermittent? Times?
>

The router is buffalo whr-g54s, according to the web interface it is:
WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)

My laptop is an apple macbook pro, just over a year old.

I live in a small city in the uk, I'm pretty sure there's no municipal
wifi here.

The problem I'm experiencing is constant, every time I've pinged the
router over the last two days I've seen the same thing.

> Incidentally, go down this list of probable culprits and see
> if any look new.
> <http://wireless.wikia.com/wiki/Wi-Fi#Interference>
> Municipal wireless installation seem to be becoming a
> problem.
>
> > There a couple of other wireless networks in the area, probably
> > neighbours, but they're on channel 6 and I'm on channel 11. I've tried
> > setting it to channel 1 as well and it's the same. What else could be
> > causing interference? The router is quite near my TV and stuff, could
> > that be causing the problem?
>
> See list above. Also, you can't "see" a wireless network that
> doesn't broadcast its SSID. You can use Kismet to sniff these,
> or a spectrum analyzer:
> <http://www.metageek.net/Products/Wi-Spy>
> There are also some MIMO (802.11n) networks that don't show
> up on a client utility or active scanner.

I've got istumbler on my mac which I believe is similar to kismet.

>
> If your radios are near a window, try moving the access point
> and/or client away from the window. That's the most likely
> point of entry.

The router is quite near a window, I've tried moving it away a bit
(it's about 10 feet away now) and that doesn't seem to have helped.

Appreciate your guidance Jeff, thanks.

On Aug 4, 5:59 pm, Mark <markjtur...@gmail.com> wrote:

> The router is buffalo whr-g54s, according to the web interface it is:
> WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)

Not exactly. The WHR-HP-G4 and WHR-G54S are two different
products. The "HP" for high power version has higher tx power
output. I like these units and use them with DD-WRT firmware.

> I live in a small city in the uk, I'm pretty sure there's no municipal
> wifi here.

Well, muni wireless was just a guess. There's a long list
of other sources of interference. The reason I asked about
the timing is that many sources are intermittent in timing.
For example, a microwave oven interferes for about 10 minutes,
with long pauses in between.


> The problem I'm experiencing is constant, every time I've pinged the
> router over the last two days I've seen the same thing.

That eliminates about half the list.
A "small city" isn't very useful, but if you see any metro wireless
security cameras, they may also be a source of interference.

> I've got istumbler on my mac which I believe is similar to kismet.

Nope. Istumbler and Netstumbler are active sniffers. They
transmit probe requests, and listen for responses. Kismet
is also a passive sniffer. It listens for traffic but does not
transmit. I stumbler will not show an access point that is
NOT broadcasting its SSID.

> The router is quite near a window, I've tried moving it away a bit
> (it's about 10 feet away now) and that doesn't seem to have helped.

Well, I think it might be useful to test this in an isolated location,
known to be interference free, such as a basement. Just the
Buffalo and the Mac laptop. If it screws up in the basement,
then there's something wrong with the hardware.

On Aug 5, 3:55 am, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> On Aug 4, 5:59 pm, Mark <markjtur...@gmail.com> wrote:
>
> > The router is buffalo whr-g54s, according to the web interface it is:
> > WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)
>
> Not exactly. The WHR-HP-G4 and WHR-G54S are two different
> products. The "HP" for high power version has higher tx power
> output. I like these units and use them with DD-WRT firmware.
>
> > I live in a small city in the uk, I'm pretty sure there's no municipal
> > wifi here.
>
> Well, muni wireless was just a guess. There's a long list
> of other sources of interference. The reason I asked about
> the timing is that many sources are intermittent in timing.
> For example, a microwave oven interferes for about 10 minutes,
> with long pauses in between.
>
> > The problem I'm experiencing is constant, every time I've pinged the
> > router over the last two days I've seen the same thing.
>
> That eliminates about half the list.
> A "small city" isn't very useful, but if you see any metro wireless
> security cameras, they may also be a source of interference.
>
> > I've got istumbler on my mac which I believe is similar to kismet.
>
> Nope. Istumbler and Netstumbler are active sniffers. They
> transmit probe requests, and listen for responses. Kismet
> is also a passive sniffer. It listens for traffic but does not
> transmit. I stumbler will not show an access point that is
> NOT broadcasting its SSID.
>
> > The router is quite near a window, I've tried moving it away a bit
> > (it's about 10 feet away now) and that doesn't seem to have helped.
>
> Well, I think it might be useful to test this in an isolated location,
> known to be interference free, such as a basement. Just the
> Buffalo and the Mac laptop. If it screws up in the basement,
> then there's something wrong with the hardware.

Hmm, well unfortunately I don't have a basement.

I have tried kismac, but it doesn't seem to work well, I've heard it
has compatibility problems with newer macbooks so maybe that's why.

Do you think trying a high-gain antenna would be a good idea? To try
and overpower the interference?

Appreciate your insight Jeff, I feel like I understand the issues a
lot better now, but I am starting to feel like I might just have to
learn to live with the problem :-(

On Aug 6, 5:51 am, Mark <markjtur...@gmail.com> wrote:

> Hmm, well unfortunately I don't have a basement.

Do you have a shovel? Never mind. My humor skills
are temporarily impaired.

> I have tried kismac, but it doesn't seem to work well, I've heard it
> has compatibility problems with newer macbooks so maybe that's why.

I previously suggested. If you can't find anything that will work
on the MacBook, then I was hoping that you would consider
dragging your wireless router and MacBook to some isolated
location know to be devoid of 2.4GHz interference or surrounded
by sufficient quantities of dirt to be effectively shielded. What
you're doing is determining if it's really interference, or if it's a
weak signal to the wireless router, or a some configuration
problem on the router or MacBook. You decide if it's worth the
exercise.

> Do you think trying a high-gain antenna would be a good idea? To try
> and overpower the interference?

Probably not. Lots of problems.
1. An omnidirectional antenna will increase the signal strength of
both the interference and the MacBook.
2. A directional antenna will help, but only if you know what
direction
the interference is coming from.
3. You still don't know if it's really interference, or something in
the
router or MacBook.
4. You don't know if the interference is entering the system at the
router end, or the MacBook end. The resultant packet loss will
be similar.

Once you've determined the source of the interference, only then can
you take remedial action. However, it might be useful to try a
directional
antenna at one or both ends. If you can see the interference as an
increase in "noise level" reported by the wireless client, you might
be
able to determine the direction of the source.

Incidentally, someone once wrote that their local source of
interference
turned out to be their new wireless doorbell receiver.

> Appreciate your insight Jeff, I feel like I understand the issues a
> lot better now, but I am starting to feel like I might just have to
> learn to live with the problem :-(

Perhaps the shovel wasn't such a bad idea.

On 6 Aug, 21:36, Jeff Liebermann <je...@comix.santa-cruz.ca.us> wrote:
> On Aug 6, 5:51 am, Mark <markjtur...@gmail.com> wrote:
>
> > Hmm, well unfortunately I don't have a basement.
>
> Do you have a shovel? Never mind. My humor skills
> are temporarily impaired.
>
> > I have tried kismac, but it doesn't seem to work well, I've heard it
> > has compatibility problems with newer macbooks so maybe that's why.
>
> I previously suggested. If you can't find anything that will work
> on the MacBook, then I was hoping that you would consider
> dragging your wireless router and MacBook to some isolated
> location know to be devoid of 2.4GHz interference or surrounded
> by sufficient quantities of dirt to be effectively shielded. What
> you're doing is determining if it's really interference, or if it's a
> weak signal to the wireless router, or a some configuration
> problem on the router or MacBook. You decide if it's worth the
> exercise.
>
> > Do you think trying a high-gain antenna would be a good idea? To try
> > and overpower the interference?
>
> Probably not. Lots of problems.
> 1. An omnidirectional antenna will increase the signal strength of
> both the interference and the MacBook.
> 2. A directional antenna will help, but only if you know what
> direction
> the interference is coming from.
> 3. You still don't know if it's really interference, or something in
> the
> router or MacBook.
> 4. You don't know if the interference is entering the system at the
> router end, or the MacBook end. The resultant packet loss will
> be similar.
>
> Once you've determined the source of the interference, only then can
> you take remedial action. However, it might be useful to try a
> directional
> antenna at one or both ends. If you can see the interference as an
> increase in "noise level" reported by the wireless client, you might
> be
> able to determine the direction of the source.
>
> Incidentally, someone once wrote that their local source of
> interference
> turned out to be their new wireless doorbell receiver.
>
> > Appreciate your insight Jeff, I feel like I understand the issues a
> > lot better now, but I am starting to feel like I might just have to
> > learn to live with the problem :-(
>
> Perhaps the shovel wasn't such a bad idea.

Ok, I think I will take my router over to my girlfriend's house and
try it out there, at least then I'll know if it's a hardware problem
or not. I can try connecting to it from her computer as well and see
if I have any success.

I've tried taking the macbook to the other end of the house, but no
difference. Would it be worth plugging the router in in a different
room?

Then if it turns out it is interference-related, do you reckon it
would be possible to use tin foil instead of dirt to achieve much the
same effect? Can I improvise a directional aerial from a wok or
something?

On Aug 6, 4:45 pm, Mark <markjtur...@gmail.com> wrote:
(trimmed...)

> Ok, I think I will take my router over to my girlfriend's house and
> try it out there, at least then I'll know if it's a hardware problem
> or not. I can try connecting to it from her computer as well and see
> if I have any success.

Well, if you're going to do that, you might want to try doing
some benchmarking over the wireless link. See IPerf at:
<http://dast.nlanr.net/Projects/Iperf/#download>
If you search this newsgroup for my postings on IPerf, you'll
find instructions and sample output.

> I've tried taking the macbook to the other end of the house, but no
> difference. Would it be worth plugging the router in in a different
> room?

Dunno. I was looking for a location that was guaranteed to have
no interference sources at either end. That means moving both
the MacBook and router. I don't think it will be worth the effort.

> Then if it turns out it is interference-related, do you reckon it
> would be possible to use tin foil instead of dirt to achieve much the
> same effect? Can I improvise a directional aerial from a wok or
> something?

Sure. See home made reflectors at:
<http://www.freeantennas.com>
However, the problem will be where to aim the antenna. If you
can't identify the source, some tinkering and trial and error will
probably suffice.