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Dialbackup on cisco 877

I've been trying unsuccessfully to configure dial backup on a cisco

877. I'm missing something fundamental somewhere that doesn't seem to be covered in the documentation.

Basically every time I enable the modem the router crashes. It'll either lockup or hard reboot. There are many ways to create this crash so I'm thinking there must be an option I've missed somewhere (tried every IOS available for this router and they all do the same so it's not simply a bug, since I find it hard to believe nobody has tried dial backup in the life of entire 12.4 series).

Basically forgetting about dial backup.. try to get the router to detect the modem (based on

formatting link
Start with minimal configuration (pasted below), then follow the cisco recommended configuration: interface line con 0 exec-timeout 0 0 enable modem

-- Router locks hard requiring a power cycle.

OK try an undocmented route interface line aux 0 (as far as I can tell aux 0 == con 0 but they have different options) modem inout (appears to work, but tracing shows it's not seeing the modem at all 'unable to set default speed' all the time) flowcontrol hardware

-- Router reboots

Any ideas at all? I'd really like this to work as I'm reduced to dialup for much of next week due to a change of ISP.. and configuring Windows 'internet connection sharing' is something I'm trying to avoid..

Tony

version 12.4 no service pad service timestamps debug datetime msec service timestamps log datetime msec service password-encryption ! hostname Router ! boot-start-marker boot-end-marker ! enable password 7 xxxxx ! aaa new-model ! ! aaa authentication login default local aaa authentication enable default enable ! aaa session-id common ! resource policy ! ip cef ! ! ! ! ! ! ! username root privilege 15 password 7 xxxx ! ! ! ! ! ! interface ATM0 no ip address shutdown no atm ilmi-keepalive dsl operating-mode auto ! interface FastEthernet0 ! interface FastEthernet1 ! interface FastEthernet2 ! interface FastEthernet3 ! interface Vlan1 ip address 192.168.44.1 255.255.255.0 ! ! ! username root privilege 15 password 7 070D2D594B1D0B001C1559 ! ! ! ! ! ! interface ATM0 no ip address shutdown no atm ilmi-keepalive dsl operating-mode auto ! interface FastEthernet0 ! interface FastEthernet1 ! interface FastEthernet2 ! interface FastEthernet3 ! interface Vlan1 ip address 192.168.44.1 255.255.255.0 ! ! ! ip http server no ip http secure-server ! no cdp run ! ! ! ! control-plane ! ! line con 0 no modem enable speed 57600 line aux 0 line vty 0 4 ! scheduler max-task-time 5000 ! webvpn context Default_context ssl authenticate verify all ! no inservice ! end

Reply to
Tony Hoyle
Loading thread data ...

That should be just line con 0

And that should be modem enable...

Anyway I managed to recover it after a lockup (not sure how.. )

*Sep 30 15:16:57.219: %SYS-3-NOELEMENT: data_enqueue:Ran out of buffer elements for enqueue -Process= "", ipl= 6, pid= 40

-Traceback= 0x80814CEC 0x8031478C 0x800E7094 0x8036A504 0x800D76A8

0x800D76A8 0x8036A5C4 0x80133A2C *Sep 30 15:16:57.619: %SYS-2-CHUNKBOUNDS: Could not find the sibling to allocate memory from. Chunk Packet Element, total free 2 inuse 55402.

-Process= "", ipl= 6, pid= 40 -Traceback= 0x80814CEC

0x8004C828 0x80049DA8 0x8031470C 0x800E7094 0x8036A504 0x800D76A8 0x800D76A8 0x8036A5C4 0x8008FFD8

So it shows what's wrong.. a buffer is too small.. but I can't for the life of me work out what buffer, why, and how I rectify that.

Tony

Reply to
Tony Hoyle

Hello,

I tested Modem DialIn with my 876 succesfully:

line aux 0 exec-timeout 0 0 login authentication local_authen modem InOut modem autoconfigure discovery transport input all transport output telnet stopbits 1 speed 115200 flowcontrol hardware

May be that helps !

Tony Hoyle schrieb:

...

Reply to
Georg Dingler

I can't realy help much with the modem and Aux port however maybe more some more general observations may assist.

The log mesages that you are seeing /are/ indicative of a bug. If you have support open a TAC case.

It /may/ be posible to relieve whatever buffer issues are causing the hang-up.

First however, the Aux port is traditionally sepearte from the Console with a different connection. On the low end kit this facility has been eliminated. I have seen references to a virtual Aux port which is basically re-configuring the console to act as an Aux port instead. The console for example does not have a full set of modem control lines as understand it.

I would imagine that when you configure the port to be an Aux port for dial backup then you would lose console access. You should therefore configure the port from a telnet session or some other network method.

How about :- Use network access for configuration of AUX port. Turn off console logging - no logg cons. If you get another crash and can recover the box. do a sh tech from enabled mode and capture the output.

Post the sh buff and the first few lines of sh mem.

Check that you have enough memory

sh mem ! First few lines

Have a look at the buffers sh buff and consider manually allocating sufficient buffers to certainly avoid failures and I like to avoid most misses too.

If you are really lucky and the crash is as a result of running out of buffers and pre-allocating buffers alleviates the problem you may get a workaround.

Reply to
Bod43

Hello,

I forget some lines:

line con 0 login authentication local_authen modem enable transport output telnet

"Switching" the Con port to Aux on the 876.

Reply to
Georg Dingler

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