Re: multiplex mode support

[代尔欣 <daiex thunderst com>]

Thanks, Dan! I have to deal with such a modem. Except the
implementation in kernel. I am interest in the implementation on user
space. The problem I may meet:
1. How to get the data from the modem before other module get? From my
understanding, for ppp, after the link established, the data only flow
in kernel.
2. How to feed the ppp packet into ppp module after decode the
multiplexing data?

My first thought to resolve this is using a pty. PPPd seems support
pty device. Multiplexing module get the modem data from modem device
directly and decode the data and feed the decoded data(if itis  the
ppp data) into the pty device which pppd opened.

This si practicable or not? Please give me some light.


2010/9/29 Dan Williams <dcbw redhat com>:
> On Sat, 2010-09-25 at 17:50 +0800, 代尔欣 wrote:
>> Hi all,
>>      From 3gpp document, there is an at command AT+CMUX. It is a
>> multiplex protocol. Does modem manager or network manager support
>> this?
>
> Not yet, because almost all GSM/UMTS modems that I've seen provide 2 or
> more AT-capable serial ports and thus we don't require GSM MUX-ing
> support yet.  However, there may be some more embedded devices that only
> provide one serial port and do require MUX-ing.  I've never seen a
> CDMA/EVDO device that implements AT+CMUX.
>
> Alan Cox posted patches a while ago to push the MUX layer down into the
> kernel, but there are also implementations of it that we could use in
> ModemManager.  There just hasn't been a great need to do so yet.  Also,
> some modems simply lie about their CMUX support which complicates
> things.
>
> Dan
>
>