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New Member

3G interface going idle

Hi All

I have configured 3G interface on my router, the link is up and running but the link is goes down/idle after 2 minites even when there is traffic over the link.

Is there a command to stop this from happening,

-------Show interface----------

Cellular0 is up, line protocol is up

  Hardware is 3G Modem-HSPA/UMTS/EDGE/GPRS-850/900/1800/1900/2100MHz / Global

  Internet address is x.x.x.x

  MTU 1500 bytes, BW 2000 Kbit/sec, DLY 100000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation PPP, LCP Open

  Open: IPCP, loopback not set

  Keepalive not supported

  Time to interface disconnect: idle 00:01:21  -------------------------------- this counter just counts down .

  Last input 00:00:00, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: weighted fair

  Output queue: 0/1000/64/0 (size/max total/threshold/drops)

     Conversations  0/1/16 (active/max active/max total)

     Reserved Conversations 0/0 (allocated/max allocated)

     Available Bandwidth 1500 kilobits/sec

  5 minute input rate 14000 bits/sec, 4 packets/sec

  5 minute output rate 4000 bits/sec, 4 packets/sec

     19791 packets input, 12414889 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     16157 packets output, 2976781 bytes, 0 underruns


Running configuration of the 3G interface.

interface Cellular0
ip address negotiated
ip access-group cell-in in
ip virtual-reassembly
encapsulation ppp
dialer in-band
dialer string gsm
dialer-group 1
async mode interactive
ppp chap hostname x.x.x.x.x
ppp chap password 0 x.x.x.x.x
crypto map VPN-MAP

Regards MJ

Hall of Fame Super Silver

Re: 3G interface going idle

Hello MJ,

3G interface is used in a dial on demand routing context DDR.

An idle counter is present.

You define what is interesting traffic with

>> dialer-group 1

have you defined a dialer-list 1 object ?

if this is your primary link you can use simply

dialer-list 1 permit ip

otherwise a more precise definition is needed using also an IP ACL


be aware that unless it is a flat contract the risk is to pay very high bills as reported in previous threads

Hope to help


New Member

Re: 3G interface going idle

Hi Giuseppe

Many thanks for your response on this. I have just set a idle timeout longer than 2 mins on the interface.

Regards MJ

Hall of Fame Super Silver

Re: 3G interface going idle

Hello MJ,

I was meaning that the idle timeout expires if no interesting traffic is seen on the link.

increasing the idle timeout can help but it may not be enough if the definition of interesting traffic is not correct

Hope to help


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