PDA

View Full Version : Serious SB3 problems.



fmayhar
2006-01-14, 15:46
I received my spanking new SB3 shortly after Thanksgiving and have enjoyed it a lot. I got it configured properly and even have my old series 1 Tivo connected through it so as to do away with an annoying network cable that my wife regularly tripped over.

Today, unfortunately, that changed. While it can talk to the wireless access point just fine, it's having a lot of trouble keeping a continuous link going, to the point that it drops the connection to the Slimserver. Running a continuous ping, I see serious packet loss:

--- squeeze.exit.com ping statistics ---
3488 packets transmitted, 1169 packets received, 66% packet loss
round-trip min/avg/max/stddev = 1.009/19.680/14871.431/435.113 ms

Only about a third of the packets are getting through. Interestingly, if I do a hard reset it picks up and starts to work fine, but shortly starts dropping packets again. It looks like communication to the Tivo behind it also drops packets, so it must be something in the little protocol stack on the SB3 itself, but I have no idea as to what it might be. I've been watching it as I write this, as it keeps losing and regaining the connection.

I do have a 2.4GHz phone about, but as I said it doesn't seem to have anything to do with the wireless connectivity as far as I can see. According to the AP, the signal stays near 100% pretty much constantly, which makes sense as the SB3 is only about eight feet from the AP (albeit through a wall and a thin piece of particle board).

Any hints would be appreciated; if I can provide any more information I would be happy to do so.

snarlydwarf
2006-01-14, 16:24
I do have a 2.4GHz phone about, but as I said it doesn't seem to have anything to do with the wireless connectivity as far as I can see. According to the AP, the signal stays near 100% pretty much constantly, which makes sense as the SB3 is only about eight feet from the AP (albeit through a wall and a thin piece of particle board).


Just a general FYI, with 802.11 devices, 'Strength' is sort of a meaningless number. It's slightly useful in if it's "very low" that is a problem, but the real number that matters (which most devices won't really record) is 'signal quality'.

Microwaves, cordless phones, wireless alarm systems, neighbors on close channels, all contribute to noise, lowering the quality of the signal, but not the strength.

I guess the audio equivalent is having your amp set to max volume, but someone drives by with a CB and nicely broadcasts his "10-4, Good buddy" into the middle of your concerto. Yes, your music is at full volume, but that doesn't mean it's listenable like that.

Unfortunately, most hardware doesn't monitor signal quality at all so you're left to guess what the problem is. (Cisco/Aironet devices did, but then they cost a bundle compared to the $50 routers we all use... my Belkin doesn't even tell me the strength, let alone quality or packet retransmits or radio retrains...)

In other words: even with 100% signal strength, something may be spitting on your wireless signal. Have you tried changing which channel you're on? That may move it away from whatever it is that is causing problems.

fmayhar
2006-01-14, 18:37
Just a general FYI, with 802.11 devices, 'Strength' is sort of a meaningless number. It's slightly useful in if it's "very low" that is a problem, but the real number that matters (which most devices won't really record) is 'signal quality'.

In other words: even with 100% signal strength, something may be spitting on your wireless signal. Have you tried changing which channel you're on? That may move it away from whatever it is that is causing problems.

Yes, that's true, but no, it's not the case. I have a laptop on the same AP, across the room from the SB3. The laptop is working fine. I'm watching the SB3 do its intermittent-connectivity thing while I continue to use the network no problem. Here's an example (better than last time but still showing problems):

Between the laptop and the SB3:
--- squeeze.exit.com ping statistics ---
189 packets transmitted, 182 packets received, 3% packet loss
round-trip min/avg/max/stddev = 0.940/5.837/42.690/6.617 ms

Between the laptop and the Slimserver:
--- jill.exit.com ping statistics ---
188 packets transmitted, 188 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.914/2.473/64.434/6.584 ms

So it's definitely not wireless interference. I don't know what it is, but it's not that.

kdf
2006-01-14, 18:48
fmayhar wrote:
>
> So it's definitely not wireless interference. I don't know what it is,
> but it's not that.
>
and many other users will tell you that they have no problems, so it's
not a "fundamental flaw" in the squeezebox. It is most certainly
something in your setup or your squeezebox, because we are not talking
about something that happens to everyone. The best course of action
would be to contact support (at) slimdevices.com to get the experts to
help you walk through all the basics to check. You may have a loose
card, and you may STILL have interference. Different models will react
differently. I have an old router that could not operate with the
microwave running, but my current router doesn't even blink. Of course,
you could keep your mind closed to options; it is up to you.

-kdf

fmayhar
2006-01-14, 19:16
Listen, I don't need to "walk through all the basics" since I've already done that. Unlike many who may post to boards like this, I'm a software engineer with literally years of experience dealing with networks, including wireless networks. I know what I'm doing and I didn't post until I was positive that it wasn't the wireless network itself, having exhausted all potential problems (and their solutions) there. It has to be either in the SB3 itself, a distinct possiblity, or in something to do with the interaction of the server and the SB3.

Note, by the way, that I do not use the phrase "fundamental flaw," nor did I in either of my other posts. Defensive much?

Considering that I've seen the SB3 freeze with alarming regularity, I'm putting my money on it as having the problem. But I am by no means "keeping my mind closed to options" and I don't appreciate being accused of doing so. If you have any suggestions or ideas, say so, but otherwise keep your insults to yourself.

Oh, and I have in fact opened a bug on this problem. I just thought I would see if the community could help me out first (particularly considering that it's a weekend). Guess not. My bad.

seanadams
2006-01-14, 19:25
You may want to contact support@slimdevices.com - it's possible the internal wireless card is defective or an antenna connection is loose.

fmayhar
2006-01-14, 19:44
Okay, thanks, Sean. Will do.

kdf
2006-01-14, 19:46
fmayhar wrote:
> Considering that I've seen the SB3 freeze with alarming regularity, I'm
> putting my money on it as having the problem. But I am by no means
> "keeping my mind closed to options" and I don't appreciate being
> accused of doing so. If you have any suggestions or ideas, say so, but
> otherwise keep your insults to yourself.
>
I did.
> Oh, and I have in fact opened a bug on this problem. I just thought I
> would see if the community could help me out first (particularly
> considering that it's a weekend). Guess not. My bad.
>
>
In case you missed it, there was help. You just didn't show any
interest in following the path given by that help. Contacting
support (AT) slimevices (DOT) com is still our best plan at this point, given the
problems you have stated. Filing a bug, wil not have it solved any time
sooner as bugzilla is a developer tool. What your issue needs is
support. In most cases, they can solve the issue without having to wait
for a developer to get around to stepping through all of the same 'first
steps'. I'm sorry you don't like how you are being told, but the
process is still the same. Take it how you will.

-k

snarlydwarf
2006-01-14, 19:55
But it very well could be interference...

If you have something like this (pardon bad ascii art):

AP-| |-SB |-Laptop

That doesn't mean that an interference pattern 'between' the AP and the SB will interfere with the laptop. The pattern may be from a phone sitting near the SB, making everything the SB receives look like junk.. but 5' away in either direction (at the laptop and AP), the problem may be undetectable.

Add in that certain chipset combinations are going to behave differently when they see junk (assuming they see it: the discrimination on a given chipset may be higher or lower... and the noise on a low-discrimination chipset may actually be -less- than on a high depending on how centered the noise is). RF gets very messy very quickly.

What you describe sounds -exactly- like RF interference, including packet retransmits and perhaps radio retrains on the longer outages.

Have you tried switching channels on your router?

I have a hard time believing it's a problem in the TCP/IP stack: a lot more people would be seeing it if that were the case. There's lots of people with exactly the same firmware on their SB and exactly the same OS as you... so the question is, "what is different about your setup?" ie, why are -you- seeing this problem and I'm not?

Perhaps it's a flaky reciever in your SB. Perhaps it's a loose antenna connection in it. Or it's some outside RF problem from a cordless phone or neighbor. Or even the a heating duct in the wall between the AP and the SB is deflecting signals around.

But the probability says it's going to be something "wrong" with the RF, not the software in the TCP/IP stack or a LOT more people would be seeing the problem.

Because things like fixing a bad receiver or loose antenna connection are complex, it's best to try the easiest thing first. If it works, problem solved. If not, you spent a minute to get a slightly better diagnosis.

I believe there's software that will record signal quality and things like retransmits. (Remember, even UDP packets on a wireless link get some protection -- the receiving radio has to send a "yes I got that" packet or the sender must assume that there was a collision and retransmit it.... a lot of retransmits means you are losing data somewhere.) You may want to see if you can get that on your laptop and see if there's something odd going on with your network. Is the SB not seeing the packets and not acknowledging them? Is the AP not seeing them?

That's all complex stuff, though.. I would certainly try to change the channel on the router first.

machinehead
2006-01-15, 00:22
"snarlydwarf"
<snarlydwarf.21nebz (AT) no-mx (DOT) forums.slimdevices.com>
wrote in message news:snarlydwarf.21nebz (AT) no-mx (DOT) forums.slimdevices.com...
>
> Just a general FYI, with 802.11 devices, 'Strength' is sort of a
> meaningless number. It's slightly useful in if it's "very low" that is
> a problem, but the real number that matters (which most devices won't
> really record) is 'signal quality'.
>
> Microwaves, cordless phones, wireless alarm systems, neighbors on close
> channels, all contribute to noise, lowering the quality of the signal,
> but not the strength.

I not only concur, but I will add that there's a bunch of other things that
can cause problems. For example, metal surfaces nearby causing reflection
or refraction, or the ever popular "multipath". I pretty much did
everything for a certificate in wireless networking (CWNA) except take the
test, and notwithstanding that, I gave up and wired my Squeezebox because of
dropouts. Didn't have them bad at first, but got worse over time, to the
point where I just couldn't take it anymore. And like the OP, I had good
signal strength, and my wireless bridge that the SB was connected to was a
foot or two from the ceiling of the 1st floor, and almost directly above it,
3-4 feet off the carpet on the 2nd floor sits my wireless router/AP.

I would definitely suggest changing channels, as it may be a strong signal
from one of your neighbors. In the U.S., much equipment defaults to channel
6. Try Channel 1 or Channel 11, as those have the least overlap with 6
(they are the "farthest away", so to speak). Try moving antennas around,
and bear in mind that the signal radiates outward from the long side; i.e.,
in theory, antennae that are "parallel" to each other should talk better
than ones whose ends are "pointed" at each other. Avoid large flat pieces
of metal (amp cabinets, maybe?) nearby if at all possible.

Of course, it may indeed be a problem with the Squeezebox itself. I have a
SB1 not a 3 at the moment, but IIRC the 3's have the dual antenna? Perhaps
check that both are enabled...

Ed
89CamaroZ28 (AT) nowherenow (DOT) com

machinehead
2006-01-15, 00:44
"fmayhar"
<fmayhar.21nm7b (AT) no-mx (DOT) forums.slimdevices.com>
wrote in message news:fmayhar.21nm7b (AT) no-mx (DOT) forums.slimdevices.com...
>
> Listen, I don't need to "walk through all the basics" since I've already
> done that. Unlike many who may post to boards like this, I'm a software
> engineer with literally years of experience dealing with networks,
> including wireless networks. I know what I'm doing and I didn't post
> until I was positive that it wasn't the wireless network itself, having
> exhausted all potential problems (and their solutions) there. It has to
> be either in the SB3 itself, a distinct possiblity, or in something to
> do with the interaction of the server and the SB3.

Not necessarily. Your laptop is in a different spot, doing differnet things
with different hardware than the Squeezebox. Again, your experience mirrors
my own; I had no problems with my laptop 12 feet away from the bridge. But
the laptop was using a different wireless card, was 12 feet away from
potential sources of interference and reflection/refraction/multipath
(again, metal enclosures?) and "ping" is not the same thing as streaming
audio.

It may well be the SB3; as suggested elsewhere, a loose card or antenna
connection or a downright flaky card; but it also may be interference. It
is almost certainly not the protocol stack. And as a software engineer
myself with years of experience with networks, wireless networks, and
networking protocols, including implementing, troubleshooting, and downright
beating on protocol stacks, I humbly suggest that "software engineer" and
"RF engineer" are two different animals. You are getting good advice in
this thread.

Ed
89CamaroZ28 (AT) nowherenow (DOT) com

phatteus
2006-01-15, 15:14
I have an SB3 in bridge mode with a Tivo connected to it and don't have the problems you describe. I transfer large tivo shows quite often and it is just as fast as the Linksys bridge I had in place before the SB3. My pings also show no packet loss.