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br
New Member

dial-in: data is lost when doing a tcp-forward aka "TCP clear"

Dear all,

we are using a 3640 for analog dialin. In the router a 2-channel PRI card and two 30-channel digital modems are installed.

When dialling in a TCP connection shall be established to a host (depending on DNIS) and the data be exchanged.

Sounds simple but I have a heavy problem where I don't know what to do:

1st case - Device dials in and sends data first:

==================================================

- Debug output of router shows the call

- Session is opened, TCP connection is established

- On the TCP host the correctly established tcp connection is visible

*** Obligatory wait of 7 seconds of the device prior of sending data ***

- Data is displayed as hexdump on the host

If I omit the 7 seconds waiting the data send by the calling device is lost anywhere in the router.

2nd case - Device dials in and tcp host sends data first:

===========================================================

- Debug output of router shows the call

- Session is opened, TCP connection is established

- On the TCP host the correctly established tcp connection is visible

- Data is sent to the calling device correctly

- Data exchange works correctly

In this case everything works as it should.

The only difference is that the tcp host is the first one sending data.

FYI: The connect speed is maximum 9600bits/sec.

I read already every doc and newsgroup message but unfortunately no solution for my problem. Please help - any hints or example configs appreciated.

Don't hesitate to ask me more questions or more debug output.

Best regards,

Bernhard Roth

Cisco Internetwork Operating System Software

IOS (tm) 3600 Software (C3640-IS-M), Version 12.3(16a), RELEASE SOFTWARE (fc2)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by cisco Systems, Inc.

Compiled Wed 09-Nov-05 21:49 by evmiller

Image text-base: 0x60008B00, data-base: 0x61BFA000

ROM: System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

ROM: 3600 Software (C3640-IS-M), Version 12.3(16a), RELEASE SOFTWARE (fc2)

router uptime is 15 minutes

System returned to ROM by power-on

System restarted at 19:32:41 MEZ Mon Jan 23 2006

System image file is "flash:c3640-is-mz.123-16a.bin"

cisco 3640 (R4700) processor (revision 0x00) with 120832K/10240K bytes of memory.

Processor board ID 26877946

R4700 CPU at 100MHz, Implementation 33, Rev 1.0

MICA-6DM Firmware: CP ver 2950 - 9/9/2003, SP ver 2950 - 9/9/2003.

Channelized E1, Version 1.0.

Bridging software.

X.25 software, Version 3.0.0.

SuperLAT software (copyright 1990 by Meridian Technology Corp).

Primary Rate ISDN software, Version 1.1.

1 FastEthernet/IEEE 802.3 interface(s)

60 Serial network interface(s)

60 terminal line(s)

2 Channelized E1/PRI port(s)

DRAM configuration is 64 bits wide with parity disabled.

125K bytes of non-volatile configuration memory.

24576K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

Relevant config-part:

username xxxx nopassword xxxx

username xxxx autocommand telnet 10.xx.xx.xx /quiet /stream

line 1 30

session-timeout 1

no motd-banner

no exec-banner

no vacant-message

modem Dialin

no activation-character

exec-character-bits 8

special-character-bits 8

escape-character NONE

autohangup

dispatch-timeout 250

  • Remote Access
3 REPLIES
VIP Purple

Re: dial-in: data is lost when doing a tcp-forward aka "TCP clea

Hello Bernhard,

there are numerous bugs in your IOS release...

Can you post the output of ´debug modem´ ? That might render a clue of what is going on...

Regards,

GP

br
New Member

Re: dial-in: data is lost when doing a tcp-forward aka "TCP clea

Dear GP,

what IOS-Version is recommended for my application? Below 12.3-12 is not usable because the IOS sorts the config in a wrong way that "username dnis" is not accepted ("aaa new-model" is sorted after user definitions).

As attachment the debug output ("debug modem" and "debug ip tcp transaction") of case 1 (device sends first -> error) and case 2 (server sends first -> works).

Best regards,

Bernhard Roth

br
New Member

Re: dial-in: data is lost when doing a tcp-forward aka "TCP clea

Hello!

I found the reason why it does not work:

When a modem connects with

CONNECT at 2400/2400 (Tx/Rx), V22bis, Async, None

the router does have problems forwarding the data (data loss)

When a modem connects with

CONNECT at 2400/2400 (Tx/Rx), V22bis, MNP, MNP5

everything works fine.

We are using currently IOS 12.3-16a

I guess this is related to a bug in the IOS.

Please check

Best regards,

Bernhard Roth

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