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Re: 14.4kbps PPP link?



On Tue, Nov 16, 1999 at 10:20:17PM -0800, aphro wrote:
> so, it seems its more of a modem connection problem then a network
> protocol/performance problem..Do you have a shell or ftp access to a

Nothing seems to make much sense (too me). *If* it was a modem
problem, then I would expect ping to return high RTT values.

Perhaps the problem is because of transmission errors:

ifconfig reports

          RX packets:5931 errors:295 dropped:0 overruns:0 frame:295

This is rather large number of errors, assuming the count reset
when I reset the PPP connection several hours ago.

Perhaps a new set of modems would help ;-)

Still, I thought PPP was meant to be able to handle errors internally?
I think the statistics above mention the number of packet errors
that need to be fixed by TCP retransmitting it, but please correct
me if I am wrong.

Does tcpdump show currupted packets?

> machine on your isp's network?  its a good test to try to d/l something
> off the isp's network..i bet the admins there would be willing to throw
> something up on anonymous ftp for you to get for testing.

Thats what I was doing (apana.org.au isn't a ISP in the usual sense, is
based on work provided by volunteers, and has mirrors of Debian).

> bam >AT&V
> bam >ACTIVE PROFILE:
> bam >B0 E1 L2 M1 N1 Q0 T V1 W2 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5 &R1 &S1 &T4 &X0 &Y0
> bam >S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:004 S07:030 S08:004 S09:006
> bam >S10:018 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:000 S44:000
> bam >S46:138 S48:007 S95:000
> bam >
> bam >Anything look wrong here? Anything dumb, like XON/XOFF flow control
> bam >enabled when it shouldn't be? I can't find a manually right now to tell
> bam >my what these codes mean :-(
> 
> to be honest i dont know :/ its been SOOOO LONG since i used a 14.4k
> (~1994) this is the init string i use for my k56flex/v90 modem(i know it
> wont help you int his case but others may want, i found it makes for a
> VERY stable and fast connection)
> 
> AT +MS=12,1,40000,56000 E0 V1 &D2 &C1 W1 S0=0 S95=47 S202=32

Main differences to my setup seem to be
+MS=...                 - SELECT MODULATION
E0			- disable command echo
W1			- CONNECT MESSAGE CONTROL
S95=47			- EXTENDED RESULT CODES

> as for the AT commands, i got a PDF file here you can download and
> read.. http://www.firetrail.com/~aphro/atmodem.pdf  it explains everything
> rpretty much.  the admin at my local isp here helped me out a lot in
> getting a good string goin, im lucky to have such a good admin down here
> :)  i forgot most of my modem stuff when i quot BBS'n back in '95.

Thanks for the URL - will try that latter. Have found some documentation
on a supplied disk for now, seems OK, but were some errors on the disk
:-(.
-- 
Brian May <bam@debian.org>


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