NT and Linux PPP dialup bps rate questions

NT and Linux PPP dialup bps rate questions

Post by Some_.. » Sun, 06 Aug 2000 04:00:00



(OK, I'm crossposting,  but I think this is benign enough to not start
any OS flamewars)

I have a dual boot box running NT4 (sp3) and RedHat 6.2 w. Gnome.
I'm curious about the differences in the dial-up PPP interface.

On NT,  I use the DialUp Networking tool, it runs the script, then
pops up a little box for a few seconds that says:

Connected to: Netaxs
Line Speed:  46,660 bps

(Sometimes I instead get other numbers such as 31,000 bps or  43,000
bps. or something similar)

On Linux, I use the RH dialup tool, which after running the script
pops up a little window showing a red & green LED-ish thingy which
changes according to the incoming bits.  (the rate is shown at the
bottom in numbers)

My questions:

- What exactly is NT doing that it can determine the bps?   Is it
sending out some kind of intial ping and then translating it into a
rate for the little popup?    

- The deeper question: is this bps rate in the little popup my true
connection speed, or was it just the momentary rate at the time of
connection?   Or are different modems on the other end at my ISP
really sending out at various rates?   (The times when the intial bps
are slow, they stay slow)

- On the Linux side, how can I tell the equivalent of what NT gives me
as the initial bps rate?   What terminal command is most applicable?
Or is the intial bps rate (shown in the NT popup) irrelevant for the
life of the PPP connection?

Thanks in advance.

 
 
 

NT and Linux PPP dialup bps rate questions

Post by Eugene Strulyo » Sun, 06 Aug 2000 04:00:00


You really need to ask a modem guru about this. Basically, my
understanding is that the number you see on NT is the actual line speed
that the two modems have negotiated during the handshake. However, modems
can re-negotiate the line speed after the connection has been
established, if the line noise becomes better/worse, so the number you
see doesn't mean much. This has absolutely nothing to do with ping, btw.
And I've no idea how to determine the line speed. You could just try
downloading something and see what speed you get.

Eugene


> (OK, I'm crossposting,  but I think this is benign enough to not start
> any OS flamewars)

> I have a dual boot box running NT4 (sp3) and RedHat 6.2 w. Gnome.
> I'm curious about the differences in the dial-up PPP interface.

> On NT,  I use the DialUp Networking tool, it runs the script, then
> pops up a little box for a few seconds that says:

> Connected to: Netaxs
> Line Speed:  46,660 bps

> (Sometimes I instead get other numbers such as 31,000 bps or  43,000
> bps. or something similar)

> On Linux, I use the RH dialup tool, which after running the script
> pops up a little window showing a red & green LED-ish thingy which
> changes according to the incoming bits.  (the rate is shown at the
> bottom in numbers)

> My questions:

> - What exactly is NT doing that it can determine the bps?   Is it
> sending out some kind of intial ping and then translating it into a
> rate for the little popup?

> - The deeper question: is this bps rate in the little popup my true
> connection speed, or was it just the momentary rate at the time of
> connection?   Or are different modems on the other end at my ISP
> really sending out at various rates?   (The times when the intial bps
> are slow, they stay slow)

> - On the Linux side, how can I tell the equivalent of what NT gives me
> as the initial bps rate?   What terminal command is most applicable?
> Or is the intial bps rate (shown in the NT popup) irrelevant for the
> life of the PPP connection?

> Thanks in advance.


 
 
 

NT and Linux PPP dialup bps rate questions

Post by Bartek Kostrzew » Sun, 06 Aug 2000 04:00:00



> (OK, I'm crossposting,  but I think this is benign enough to not start
> any OS flamewars)

> I have a dual boot box running NT4 (sp3) and RedHat 6.2 w. Gnome.
> I'm curious about the differences in the dial-up PPP interface.

> On NT,  I use the DialUp Networking tool, it runs the script, then
> pops up a little box for a few seconds that says:

> Connected to: Netaxs
> Line Speed:  46,660 bps

> (Sometimes I instead get other numbers such as 31,000 bps or  43,000
> bps. or something similar)

> On Linux, I use the RH dialup tool, which after running the script
> pops up a little window showing a red & green LED-ish thingy which
> changes according to the incoming bits.  (the rate is shown at the
> bottom in numbers)

> My questions:

> - What exactly is NT doing that it can determine the bps?   Is it
> sending out some kind of intial ping and then translating it into a
> rate for the little popup?

It asks the modem for AT_CONNECT_SPEED

Quote:> - The deeper question: is this bps rate in the little popup my true
> connection speed, or was it just the momentary rate at the time of
> connection?   Or are different modems on the other end at my ISP
> really sending out at various rates?   (The times when the intial bps
> are slow, they stay slow)

It is the momentary speed at the current line quality, so it changes all
the time.

Quote:> - On the Linux side, how can I tell the equivalent of what NT gives me
> as the initial bps rate?   What terminal command is most applicable?
> Or is the intial bps rate (shown in the NT popup) irrelevant for the
> life of the PPP connection?

kpppd does that for example.

Quote:

> Thanks in advance.

--

<<< http://technoage.web.lu >>>
 
 
 

NT and Linux PPP dialup bps rate questions

Post by David Efflan » Mon, 07 Aug 2000 04:00:00




>> (OK, I'm crossposting,  but I think this is benign enough to not start
>> any OS flamewars)

>> I have a dual boot box running NT4 (sp3) and RedHat 6.2 w. Gnome.
>> I'm curious about the differences in the dial-up PPP interface.

>> On NT,  I use the DialUp Networking tool, it runs the script, then
>> pops up a little box for a few seconds that says:

>> Connected to: Netaxs
>> Line Speed:  46,660 bps

>> (Sometimes I instead get other numbers such as 31,000 bps or  43,000
>> bps. or something similar)

>> On Linux, I use the RH dialup tool, which after running the script
>> pops up a little window showing a red & green LED-ish thingy which
>> changes according to the incoming bits.  (the rate is shown at the
>> bottom in numbers)

>> My questions:

>> - What exactly is NT doing that it can determine the bps?   Is it
>> sending out some kind of intial ping and then translating it into a
>> rate for the little popup?

>It asks the modem for AT_CONNECT_SPEED

Not quite, the modem is configured (with an AT init string if needed) to
show modem2modem speed in the CONNECT string (and/or CARRIER string)
instead of cpu2modem speed.  See REPORT STRINGS in 'man chat'

- Show quoted text -

Quote:>> - The deeper question: is this bps rate in the little popup my true
>> connection speed, or was it just the momentary rate at the time of
>> connection?   Or are different modems on the other end at my ISP
>> really sending out at various rates?   (The times when the intial bps
>> are slow, they stay slow)

>It is the momentary speed at the current line quality, so it changes all
>the time.

>> - On the Linux side, how can I tell the equivalent of what NT gives me
>> as the initial bps rate?   What terminal command is most applicable?
>> Or is the intial bps rate (shown in the NT popup) irrelevant for the
>> life of the PPP connection?

>kpppd does that for example.

You can find the speed range of the connection by setting up minicom to
not reset you modem when it starts (or -o switch).  You may be able to see
initial connect rate, last connect rate and how many times it retrained
with at&vi with Rockwell chip or ati11 with Lucent chip (not sure about
USR/3Com/whatever it is now).

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