Hi,

I use a Scientific Atlanta Webstar cable modem and I face a peculiar
problem. I can't seem to get simultaneous connections going.

Let me explain. If I use a dial-up then lets say the first download
goes at 5Kbps. If I start another download, then both the downloads
split the available bandwidth. But this doesn't happen with my cable
connection. If I open multiple downloads to multiple sites, only one
download is active at a time. I face this problem with Windows 2000 as
well as Linux (2.4.26). With IE, Firefox, rsync and all other sorts of
data transfer applications.

As another example, I am right now uploading data from the laptop at
home to my PC in the office. The uploads are at 5-7Kbps but I can't ssh
into my laptop at home from office at all!! ssh waits for a while and
then says connection timed out.

My connection is 64kbps Up and 128kbps down. I use the USB port to
connect the modem to my laptop. I have also tweaked the TCP window size
on Windows and Linux is supposed to take care of that automatically.
The only theory I have is that somehow the USB ethernet interface isn't
able to multiplex connections. Unfortunately, I don't have a regular
ethernet interface on my laptop to verify that. I also checked with my
ISP and they said they haven't done any capping on active connections
or anything of the sort.
So any help will be appreciated.

Thanks,

Siddhartha

losttoy2000@yahoo.co.uk wrote:
Your uploads are 7Kbytes/s or 7Kbits/s. If 7kbytes/s x 8bits/byte =
56kbits/sec, the upload is saturating your 64kbits/s upstream and there
is no possibility of another upload. Note that with overhead, the
actual transfer rate is more like 10total bits/8net bits, so the
upstream could be nearly 70k total bits/sec including overhead.

Q

losttoy2000@yahoo.co.uk wrote:

I can't imagine any mechanism, that would cause that, other than limitations
imposed by the server. However, that shouldn't be an issue with multiple
sites.

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