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2901 ISR - Cellular 0/0/0 interface flapping continually

                   I am configuring a 2901 ISR with an EHWIC 4G LTE Verizon module for the first time.  I've followed the configuration instructions but I'm having trouble with the interface changing state to down every 30 seconds or so.  The dialer idle-timout is set to defaults. I'm also using a Verizon private IP address allocated in an IP pool for our enterprise environment. Any help would be greatly appreciated.

See attached configuration output below:

  

*Dec 10 21:42:03.586: %LINK-3-UPDOWN: Interface Cellular0/0/0, changed state to up

*Dec 10 21:42:04.586: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/0/0, changed state to up

*Dec 10 21:42:48.106: %LINK-5-CHANGED: Interface Cellular0/0/0, changed state to reset

*Dec 10 21:42:49.106: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/0/0, changed state to down

*Dec 10 21:42:53.106: %LINK-3-UPDOWN: Interface Cellular0/0/0, changed state to down

*Dec 10 21:43:07.426: %LINK-3-UPDOWN: Interface Cellular0/0/0, changed state to up

*Dec 10 21:43:08.426: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/0/0, changed state to up

*Dec 10 21:43:18.986: %LINK-5-CHANGED: Interface Cellular0/0/0, changed state to reset

*Dec 10 21:43:19.986: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/0/0, changed state to down

*Dec 10 21:43:23.986: %LINK-3-UPDOWN: Interface Cellular0/0/0, changed state to down

*Dec 10 21:43:39.338: %LINK-3-UPDOWN: Interface Cellular0/0/0, changed state to up

*Dec 10 21:43:40.338: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/0/0, changed state to up

chat-script lte "" "AT!CALL" TIMEOUT 60 "OK" 

!

controller Cellular 0/0

!

interface Cellular0/0/0

ip address negotiated

encapsulation slip

dialer in-band

dialer string lte

dialer-group 1

!

!

ip route 0.0.0.0 0.0.0.0 Cellular0/0/0

!

line 0/0/0

script dialer lte

no exec

rxspeed 100000000

txspeed 50000000

dialer-list 1 protocol ip permit
!

line 0/0/0
script dialer lte
no exec
rxspeed 100000000
txspeed 50000000

*****

Thanks in advance for any assistance

1 REPLY
Hall of Fame Super Silver

2901 ISR - Cellular 0/0/0 interface flapping continually

I have experienced symptoms similar to what you describe when configuring a router to use a cellular interface. The issue was caused when the provider sees traffic with a source address that is different from the subnet of the address that they assigned for the cellular. Since you show us only the parts of the config very specifically related to the cellular interface I can not be sure if this is your problem or not. But my first guess is that Verizon is seeing traffic with a source address that they do not expect and are resetting the cellular. I would check the address translation (or configure address translation) as a first step in troubleshooting.

HTH

Rick

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