PPP is for computer to modem or for computer to operator?

[narke]

Hi,

I am trying to connect from my computer, via a GPRS modem, to our local
network operator. But I don't understand here for what the PPP is come
to use. The PPP data communication is only between the computer and the
modem or between the computer and the network operator? In the +CGDCONT
settings, should I specify 'PPP' or 'IP' for the 'Type of PDF Context'
field?

Thanks in advance.

[John Henderson]

Post by narke
I am trying to connect from my computer, via a GPRS modem, to our local
network operator. But I don't understand here for what the PPP is come
to use. The PPP data communication is only between the computer and the
modem or between the computer and the network operator? In the +CGDCONT
settings, should I specify 'PPP' or 'IP' for the 'Type of PDF Context'
field?

"IP".

Let's assume the APN you require is "wombat". And then let's
assume you want to use context one (where your dialling string
can be either "*99#" or "*99***1#"). The command you then need
is:

AT+CGDCONT=1,"IP","wombat"

The only other thing to get right is the authentication (PAP,
CHAP, NONE, etc). This doesn't usually cause a problem, and the
command to set it up is device-dependant.

John

[narke]

Post by John Henderson

Post by narke
I am trying to connect from my computer, via a GPRS modem, to our local
network operator. But I don't understand here for what the PPP is come
to use. The PPP data communication is only between the computer and the
modem or between the computer and the network operator? In the +CGDCONT
settings, should I specify 'PPP' or 'IP' for the 'Type of PDF Context'
field?

"IP".
Let's assume the APN you require is "wombat". And then let's
assume you want to use context one (where your dialling string
can be either "*99#" or "*99***1#"). The command you then need
AT+CGDCONT=1,"IP","wombat"
The only other thing to get right is the authentication (PAP,
CHAP, NONE, etc). This doesn't usually cause a problem, and the
command to set it up is device-dependant.
John

Thanks. I can understand that in the +CGDCONT, I should set the protocol
type as "IP". What I cannot understand is, if it's the IP between the
modem and the network providor, how the PPP encapsulated authentication
info (username,password) can be passed to the providor side? Befor the
authentication get passed and IP address get assigned from the operator
side, there should be no "IP" protocol at all -- hence it's impossible
to exchange IP packets between modem and the providor.

Best Regards,
narke

[John Henderson]

Post by narke
Thanks. I can understand that in the +CGDCONT, I should set the protocol
type as "IP". What I cannot understand is, if it's the IP between the
modem and the network providor, how the PPP encapsulated authentication
info (username,password) can be passed to the providor side? Befor the
authentication get passed and IP address get assigned from the operator
side, there should be no "IP" protocol at all -- hence it's impossible
to exchange IP packets between modem and the providor.

Very good observations and questions. Without doing more
research myself, anything I add would be only speculation.

John

[narke]

Post by John Henderson

Post by narke
Thanks. I can understand that in the +CGDCONT, I should set the protocol
type as "IP". What I cannot understand is, if it's the IP between the
modem and the network providor, how the PPP encapsulated authentication
info (username,password) can be passed to the providor side? Befor the
authentication get passed and IP address get assigned from the operator
side, there should be no "IP" protocol at all -- hence it's impossible
to exchange IP packets between modem and the providor.

Very good observations and questions. Without doing more
research myself, anything I add would be only speculation.
John

Still thanks~