PDA

View Full Version : Network(?) woes



Hugh Greene
2004-06-05, 16:05
[BTW, someone on this list may have a virus. After subscribing today I got a
mail to this address -- not used for anything else -- with a virus attached.
The "Received:" header says "81-86-176-91.dsl.pipex.com", in case that
helps.]


Hi again,

this time I'm looking for clues on the probably-network-related hassles I've
been having recently.

In brief ... My SliMP3 had been running fine for at least a year, with my
usual pattern of just playing everything on shuffle and hitting "next" when I
get something I don't like. After some changes of flatmates a couple of
months ago (and hence PCs on the network, which may or may not be part of the
problem), I now find it "skips" quite often, where "skip" really means "skip
back a second or two". With the 3.0b4 server this happened every few seconds
so it was unusable; with both 3.0 final and 5.1.5 it seems to happen only a
few times per song (on average) but it's still quite irritating.

Now for some more gory details ...


The flat network is laid out as follows:

Blueyonder cable modem
|
|
|
gateway PC (P100, Debian, providing firewall, DHCP and DNS)
|
|
|
BENQ 10/100 8-port switch (hallway) --- PPro200, Debian, SliMP3 server 3.0b4
| \
| --- [4 other PCs, all running Windows]
|
BENQ 10/100 8-port switch (my room) --- SliMP3 === amp === speakers
| \
| --- [Windows PC, turned off]
|
Athlon XP 2400+, Debian, running SliMP3 server 3.0 or SlimServer 5.1.5

On each of the Slim-server machines the music is being read from a local
drive. Neither machine is heavily loaded, nor is there any obvious change in
load, IO activity or network traffic when the skipping happens. (Might well
be non-obvious changes, though.)

If I disconnect the switch in my room from the rest of the network, the
skipping still happens.

If I connect the SliMP3 to the network somewhere closer to the P100 (assuming
that's running the server), the skipping seems to happen less often. If I
connect the SliMP3's audio output to my PC's "aux in", instead of to my
hi-fi, the skipping seems to happen less often! This seems a bit
implausible, but I've been re-testing this as I write, and it still seems to
be true, whether or not I use the same Ethernet cable. It *is* an old,
second-hand amp, and I've had problems with the power supply in this room(*),
so maybe it's some interference problem?!?

(* One set of light fittings is connected to a spur off the ring main, rather
than to the overhead light circuit. When we got a new set of circuit
breakers and an RCD fitted in the flat, those fittings kept blowing bulbs and
tripping breakers, until I change to low-power flourescent bulbs.)

Any network-diagnostic or other clues most welcome. I'm not feeling *too*
music-starved at the moment, as I just bought an iRiver iHP-120 MP3
player :-) but it'd be good to get the SliMP3 usable again.

Thanks in advance,
Hugh

Hugh Greene
2004-06-06, 06:14
On Sunday 06 Jun 2004 00:05, Hugh Greene <Hugh Greene <slim (AT) tameter (DOT) org>>
wrote:
> Hi again,
>
> this time I'm looking for clues on the probably-network-related hassles
> I've been having recently.
>
> In brief ... My SliMP3 had been running fine for at least a year, with my
> usual pattern of just playing everything on shuffle and hitting "next" when
> I get something I don't like. After some changes of flatmates a couple of
> months ago (and hence PCs on the network, which may or may not be part of
> the problem), I now find it "skips" quite often, where "skip" really means
> "skip back a second or two". With the 3.0b4 server this happened every few
> seconds so it was unusable; with both 3.0 final and 5.1.5 it seems to
> happen only a few times per song (on average) but it's still quite
> irritating.
>
> [...] If I connect the SliMP3's audio output to my PC's "aux in", instead
> of to my hi-fi, the skipping seems to happen less often! This seems a bit
> implausible, but I've been re-testing this as I write, and it still seems
> to be true, whether or not I use the same Ethernet cable. It *is* an old,
> second-hand amp, and I've had problems with the power supply in this
> room(*), so maybe it's some interference problem?!?

Well, the problem is now diagnosed, as far as I can go. I stumbled onto the
very handy server option to turn the progress bar into a "buffer fullness"
bar, and used that to find out which connection was causing the problem. It
turned out to be ...

.... my TV aerial ... which is connected to the VCR, which is connected to same
amp as the SliMP3. I've tried several different coax cables between the wall
socket and the VCR, and plugging the aerial straight into the, TV (also
connected to the VCR) with the same effect.

Why some kind of electrical flaw in the aerial should cause the SliMP3 to fail
to fill its buffer (and often fail to get time updates from the server for
several seconds), I dunno, but there it is. Time to call TV Repair Man, I
spoze ...

Cheers,
Hugh