ppp multilink doesn't combine ppp0 and ppp1
 

I am trying to set up multilink ppp on my home Debian Sarge PC to increase the very poor bandwidth from my gprs (GSM cell telephone) Internet connection. I have ppp 2.4.3 with a custom-compiled 2.6.8 kernel with multilink enabled.

To enable multilink I added the option "multilink" to the ppp connection options for both serial interfaces (/dev/ttyUSB0 and /dev/ ttyUSB1). That's all I did. It does not appear to be necessary to set the "endpoint" option.

With the "multilink" option specified, during the "chat" negotiations ppp sends a request to my ISP to set the "endpoint". I can see that my ISP acknowledges and accepts this "endpoint", which makes me believe that my ISP supports multilink. (It is impossible to communicate with the state-owned ISP here in Costa Rica.)

The problem is, however, that when I dial up with my second modem (/dev/ttyUSB1), instead of adding it to ppp0, it initiates a *second* ppp interface (ppp1). Shouldn't the "bundled" interface be ppp0, the
first multilink-enabled ppp connection?

I have pasted the ppp chat dialog for device /dev/ttyUSB0 below. The
dialog when connecting /dev/ttyUSB1 looks similar, except it becomes interface ppp1.

I hope someone can help me. Thanks in advance.



Starting negotiation on /dev/ttyUSB0
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x4e168c34> <pcomp> <accomp> <mrr u 1500> <endpoint [MAC:00:10:b5:92:c8:12]>]
rcvd [LCP ConfRej id=0x1 <magic 0x4e168c34> <mrru 1500> <endpoint [MAC:00:10:b5:92:c8:12]>]
sent [LCP ConfReq id=0x2 <asyncmap 0x0> <pcomp> <accomp>]
rcvd [LCP ConfAck id=0x2 <asyncmap 0x0> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x1 <mru 1500> <asyncmap 0x0> <pcomp> <accomp> <auth pap>]
sent [LCP ConfAck id=0x1 <mru 1500> <asyncmap 0x0> <pcomp> <accomp> <auth pap>]
sent [LCP EchoReq id=0x0 magic=0x0]
sent [PAP AuthReq id=0x1 user="lloyd" password=<hidden>]
rcvd [LCP EchoRep id=0x0 magic=0x0]
sent [PAP AuthReq id=0x2 user="lloyd" password=<hidden>]
rcvd [PAP AuthAck id=0x1 "Welcome!"]
Remote message: Welcome!
PAP authentication succeeded
Using interface ppp0

<snip>

local IP address 10.40.88.85
remote IP address 192.168.111.111
primary DNS address 208.133.206.44
Script /etc/ppp/ip-up started (pid 11142)
Script /etc/ppp/ip-up finished (pid 11142), status = 0x0