Frozen Router Problem

[alvan.cottrell]

Hi All,

I recently encountered a problem with a 3600 series router whereby a while trying to bring up a BRI onterface with the command "no shutdown" my telnet session froze and I could not re-establish a telnet connection, On further investigation I found that the router had stopped passing traffic through all its interfaces. The solution was to reboot the router.

Does any one know why a simle command as "no shutdown" would cause this

Further info: we had two newly installed ISDN 2's connected to the BRI ports.and prior to to them being installed test calls wrer made from the ISDNs

[Erick Bergquist]

It's possible that when you brought the BRI interface up a call was placed and the routing table was changed effecting your telnet session.

The freezing isn't normal and might have be an IOS issue or could have a one-time event. If thats really what happened. Might be hard to find out after the event.

Having the config of the router would give us a idea of what could have happened.

[alvan.cottrell]

Thanks for your quick response,

The freezing has occurred on two seperate occasions and actually only happened when I tried to bring up the BRI1/1 interface the config for the router is quite big so I have attached the additons which were made to add the two new dialers BRI''s etc.

I was unaware the BRI would place call when it is brought up, I thought a ping would initiate traffic and cause the dialer to dial out.

version 12.1

interface BRI1/0

no ip address

ip inspect ************ out

encapsulation ppp

dialer rotary-group 3

dialer priority 255

isdn switch-type basic-net3

no cdp enable

!

interface BRI1/1

no ip address

ip inspect ************ out

encapsulation ppp

dialer rotary-group 3

dialer priority 255

isdn switch-type basic-net3

no cdp enable

!

interface Dialer4

description Connection to ************

ip address ************ 255.255.255.252

ip access-group 102 in

ip access-group 101 out

ip directed-broadcast

ip inspect ************ out

encapsulation ppp

no keepalive

dialer in-band

dialer idle-timeout 1800

dialer string ************

dialer load-threshold 60 either

dialer-group 5

no cdp enable

ppp authentication chap

ppp multilink

!

interface Dialer5

description Connection to ************

ip address ************ 255.255.255.252

ip access-group 102 in

ip access-group 101 out

ip directed-broadcast

ip inspect ************ out

encapsulation ppp

no keepalive

dialer in-band

dialer idle-timeout 1800

dialer string ************

dialer load-threshold 60 either

dialer-group 5

no cdp enable

ppp authentication chap

ppp multilink

!

ip route ************** 255.255.255.0 Dialer4

[andyirving]

Do you have other dialer interfaces or is this it , just wondering why the dialer interfaces don't tie into the physical BRI interfaces (dialer rotary-group number should match the virtual dialer interface number).

Have you configured the dialer-list 5 for call triggering.

Have you tried shutting the dialer interfaces first and then opening the BRI ports.

Are you running any debugs as the router freezes?

[alvan.cottrell]

Yes we do Dialer interfaces 1,2,3, 4+5 will be the new ones

Sorry had fat fingers on the privious config:

interface BRI1/0

no ip address

ip inspect ********** out

encapsulation ppp

dialer rotary-group 4

dialer priority 255

isdn switch-type basic-net3

no cdp enable

!

interface BRI1/1

no ip address

ip inspect ********* out

encapsulation ppp

dialer rotary-group 5

dialer priority 255

isdn switch-type basic-1tr6

no cdp enable

Dialer list 5 is as follows:

dialer-list 5 protocol ip permit

Debug is switched off.

I will try shutting down the dialer interfaces down first and bringing up the BRI's

Although I will have to wait and do this out of hours.

Thanks