PPP LCP Termination by peer

[johneynesanp]

Hai all,
I’m using Linux 2.6.20 and pppd 2.4.4 version for my embedded application.
And I have the GPRS activated SIM card.

The below options file and chat script file I’m using for Dialup connection

=~=~=~=~=~=~=~=~=~=~=~=~= Options file =~=~=~=~=~=~=~=~=~=~=~=~=

/dev/ttyS1
115200
maxfail 0
user myuser
password
modem
nodefaultroute
nodetach
noauth
persist
connect "/usr/sbin/chat -e -E -v -r /var/log/connect.log -f /etc/config/chat.ppp0"
ipcp-accept-local
ipcp-accept-remote
lcp-echo-interval 5
lcp-echo-failure 2
unit 0

=~=~=~=~=~=~=~=~=~=~=~=~= Chat Script file =~=~=~=~=~=~=~=~=~=~=~=~=

'' ATQ0
OK ATV1&C1
OK ATE1
OK AT&F
OK AT+CMEE=1
OK AT+CGDCONT=1
OK AT+CGDCONT=1,"IP","airtelgprs.com",,0,0
OK AT+CGQREQ=1,0,0,0,0,0
OK AT+CGQMIN=1,0,0,0,0,0
OK ATD*99***1#
~ ''

And this is the output of dialup sequence.

=~=~=~=~=~=~=~=~=~=~=~=~= Script output =~=~=~=~=~=~=~=~=~=~=~=~=

ATQ0
OK
ATV1&C1
OK
ATE1
OK
AT&F
OK
AT+CMEE=1
OK
AT+CGDCONT=1
OK
AT+CGDCONT=1,"IP","airtelgprs.com",,0,0
OK
AT+CGQREQ=1,0,0,0,0,0
OK
AT+CGQMIN=1,0,0,0,0,0
OK
ATD*99***1#
CONNECT 115200
~
Serial connection established.
using channel 17
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS1
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6a69530e> <pcomp> <accomp>]
rcvd [LCP ConfRej id=0x1 <magic 0x6a69530e>]
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="myuser" password=<hidden>]
rcvd [LCP EchoRep id=0x0 magic=0x0]
rcvd [PAP AuthAck id=0x1 "Welcome!"]
Remote message: Welcome!
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <compress VJ 0f 01>]
sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
rcvd [IPCP ConfReq id=0x1 <addr 192.168.111.111>]
sent [IPCP ConfAck id=0x1 <addr 192.168.111.111>]
rcvd [IPCP ConfRej id=0x1 <compress VJ 0f 01>]
sent [IPCP ConfReq id=0x2 <addr 0.0.0.0>]
rcvd [LCP ProtRej id=0x16 80 fd 01 01 00 0f 1a 04 78 00 18 04 78 00 15 03 2f]
rcvd [IPCP ConfNak id=0x2 <addr 192.168.111.112>]
sent [IPCP ConfReq id=0x3 <addr 192.168.111.112>]
rcvd [IPCP ConfAck id=0x3 <addr 192.168.111.112>]
local IP address 192.168.111.112
remote IP address 192.168.111.111
Script /etc/ppp/ip-up started (pid 5680)
Script /etc/ppp/ip-up finished (pid 5680), status = 0x0
rcvd [LCP TermReq id=0x2]
LCP terminated by peer
Script /etc/ppp/ip-down started (pid 5689)
sent [LCP TermAck id=0x2]
Script /etc/ppp/ip-down finished (pid 5689), status = 0x0
Connection terminated.
Connect time 0.1 minutes.
Sent 61 bytes, received 40 bytes.


The connection gets automatically terminated by LCP Termination request received by the Modem. I don’t know why this termination sent to the Modem by peer. I thought this might happens due to loopbacks in Modem. Because when I tried Dialup with KPP in Linux PC I got the message as
“Connection terminated. Loopback detected”
But I don’t know how to rectify the Loopback or real issue. I tried lot of alternate options and AT commands to get the dialup connection. But all didn’t work.
When I tried the same options, Chat scripts and SIM card with another modem for dialup connection, I got the connection without any problem and I can surf the net.

Kindly revert back to me if anybody needs clarification or having any suggestions.


Thanks and Regards
Johney Nesan

[wildpossum]

The printout you provided is correct (protocol wise and one I would expect if there is a problem down the line). The LCP (Local Control Protocol) request came from the modem you called, so either the modem you used has a feature that is required to work e.g.: different type of compression or likewise is what is missing I suspect.

Lines:
rcvd [IPCP ConfRej id=0x1 <compress VJ 0f 01>] - Says Configure Rejected is the pointer I would strongly suggest.

sent [IPCP ConfReq id=0x2 <addr 0.0.0.0>]

rcvd [LCP ProtRej id=0x16 80 fd 01 01 00 0f 1a 04 78 00 18 04 78 00 15 03 2f] This stream is possibly telling you why the config was rejected by the receiving connection. Unfortunately I don't recall the decode stream data of hand.

Do a feature by feature comparsion between the two modems to see what may be the issue. It could be anything obscure.

Hope this helps you.

[johneynesanp]

I compared the two logs but I couldn't find any odd things
Here is the complete log of the Modem gets connection on Dial up

ATQ0
OK
ATV1&C0
OK
ATE1
OK
AT&F
OK
AT+CMEE=1
OK
AT+CGDCONT=1
OK
AT+CGDCONT=1,"IP","airtelgprs.com",,0,0
OK
AT+CGQREQ=1,0,0,0,0,0
OK
AT+CGQMIN=1,0,0,0,0,0
OK
ATD*99***1#
CONNECT 115200
~
Serial connection established.
using channel 19
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS7
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6119c58c> <pcomp> <accomp>]
rcvd [LCP ConfRej id=0x1 <magic 0x6119c58c>]
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="myname" password=<hidden>]
rcvd [LCP EchoRep id=0x0 magic=0x0]
rcvd [PAP AuthAck id=0x1 "Welcome!"]
Remote message: Welcome!
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <compress VJ 0f 01> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
rcvd [IPCP ConfReq id=0x1 <addr 192.168.111.111>]
sent [IPCP ConfAck id=0x1 <addr 192.168.111.111>]
rcvd [IPCP ConfRej id=0x1 <compress VJ 0f 01>]
sent [IPCP ConfReq id=0x2 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
rcvd [LCP ProtRej id=0x1 80 fd 01 01 00 0f 1a 04 78 00 18 04 78 00 15 03 2f]
rcvd [IPCP ConfNak id=0x2 <addr 117.97.136.245>
sent [IPCP ConfReq id=0x3 <addr 117.97.136.245>
rcvd [IPCP ConfAck id=0x3 <addr 117.97.136.245>
local IP address 117.97.136.245
remote IP address 192.168.111.111
Script /etc/ppp/ip-up started (pid 296
Script /etc/ppp/ip-up finished (pid 296, status = 0x0
sent [LCP EchoReq id=0x1 magic=0x0]
rcvd [LCP EchoRep id=0x1 magic=0x0]
sent [LCP EchoReq id=0x2 magic=0x0]
rcvd [LCP EchoRep id=0x2 magic=0x0]

[JacquesD]

Hi,

According to my comms knowledge, &C should only be active after receiving the CONNECT message from the modem. This means you should have &C0 before the connection, and &C1 after the connexion is established. If you have &C1 right at the start, you are effectively saying: "I already have a Carrier Detect" ... which you don't have.

Now, does this directly affect LCP termination ? I don't know, but my initialisation scripts and modem profiles all have an &C0 before attempting to establish connections which work OK.

Hope this helps,

JacquesD

[johneynesanp]

Dear Jacques,
I've tried that option also, but the result was same. Please see the very first post.