[mdlug] Help with Spotty Internet/Network Problems

[Joseph C. Bender]

Elisa Gomez wrote:
[SNIP]
> 
> I can also
> generate a technician readout and a whole bunch of
> other advanced features, but I'm not sure what most of
> it means or how to interpret it. This does show up in
> the technician readout, under PPP Last Connection
> Error:	Your local connection is still busy, please
> wait a few seconds before attempting to connect.
> 
	If the technician readout includes upstream and downstream power levels 
and signal to noise ratio (SNR) information, it would at least show if 
there's a signal problem of some kind.  If the signals are just on the 
right side of "good", I have seen heavy data transfer cause the modem to 
lose sync with the DSLAM.


> PC-side, I'm using the standard gnome network manager
> programs. I haven't touched anything,
> configuration-wise. The wired connection is set to
> "Roaming Mode" rather than a specific set of
> connection settings. I imagine setting those may help,
> but I don't know what to ask for when I call tech
> support, so I can spend minimal time running through
> irritating cache clearing exercises.
> 
	Just wondering, is the machine getting a AT&T IP or a private 
(192.168.x.x, 10.x.x.x 172.16.x.x) IP address?  IIRC the 4100 can do 
NAT, which is why I ask.

> Also, in the interests of full disclosure, this seems
> to always happen to me when I'm downloading torrents.
> This makes me exceptionally paranoid, because they're
> torrents and it's AT&T. Sometimes I will go through a
> period of spotty service and then if I shut down my
> torrent client, my service won't go down anymore
> 
	Throwing "Speedstream 4100" and "BitTorrent" into Google came up with 
some interesting results.  People do seem to have the same issues with 
that modem, it appears.

	The issue might be the PPP encapsulation and and decapsulation on the 
DSL uplink.  The 4100 might be getting overloaded with too many 
concurrent connection attempts and streams.  BitTorrent's capable of 
generating hundreds or thousands of connections and maintaining them all 
at once, and the DSL modem might be crashing trying to encap and decap 
all that traffic into PPP streams.  More so if the modem's providing 
NAT, as it's got to maintain translation tables too, which is why I 
asked the address question further up the email.

> ....
> 
> I think I'm just being really paranoid, but it could
> be an effect of transferring a lot of megs of data. I
> don't really know. But know you all know everything I
> know, so any help or advice would be greatly
> appreciated!
> 
	It very well could be, but not for the reasons you might think.  AT&T 
isn't doing active traffic shaping (yet) as far as I know (none of my 
AT&T DSL using clients have had issues so far).  The fact that 
Bittorrent isn't a terribly well behaved application when it comes to 
network resource utilization probably isn't helping here.



-- 
Joseph Bender
Bendorius Consulting
P: 248-434-5580
F: 248-434-5581
jcbender at bendorius com