Cisco 881 3G connectivity

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Jan 26th, 2010
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I've configured my Cisco 881G with a Vodafone 3G access, following the guide.

It seems not to work , all the profiles are Inactive, especially the 2nd , which I configure.

Here is my configuration and the show cellular output.

An idea of what missing or is NOk?

Thanks in advance for helping me

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Giuseppe Larosa Tue, 02/02/2010 - 06:04
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Hello Rose,

unfortunately there is no file in attachment

if you haven't solved you may want to attach your config file.

Remove all sensitive information like usernames passwords and mask public ip addresses for your safety

Hope to help


arcacisco Tue, 02/02/2010 - 13:32
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The upload doesn't work

I try one more time

Hello Giuseppe,

Thank you for your answer!!

It will be eaisier withe the config file :-)

I haven't solved the issue yet.

I don't get any IP from the telco.

I'm wondering if there is something to do to activate the connectivity?

I've launched some telnets and ping but it gets nowhere

thank you in advance


Ce message a été modifié par: Rose Arca

Giuseppe Larosa Tue, 02/02/2010 - 22:10
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Hello Rose,

3G cellular has to be used as an ISDN interface with DDR.

If you use a dialer logical interface the physical interface has to use no ip address

do the following:

config t

interface Cellular0

no ip address


remove  the default route pointing to cellular:

config t

no ip  route Cell0

or remove interface dialer 0 and any reference to it.

Another important point is that the 3G interface is a sort of a modem that has to dial in band.

A so called chat script is needed in order to make it dial.

see this basic example taken from HWIC 3G configuration guide:

chat-script gsm "" "ATDT*98*2#" TIMEOUT 60 "CONNECT“

interface Cellular0/0/0

ip address negotiated
encapsulation ppp
dialer in-band
dialer string gsm
dialer-group 1
async mode interactive
ppp chap hostname [email protected]
ppp chap password 0 cisco
ppp ipcp dns request
ip route Cellular0/0/0
access-list 1 permit any
dialer-list 1 protocol ip list 1
line 0/0/0
exec-timeout 0 0
script dialer gsm
modem InOut

as you see no dialer interface is used, a chat script gsm is defined and referenced in two different contexts. cellular interface and corresponding async line 0/0/0

you could try to adapt this to your case, use sh line to find out what line number is associated to cellular0 in your router.

for more info see:

I know you have a different router but the configuration steps should be similar.


consider also the following if you would like to use the cell interface as a backup interface, 881G specific

Hope to help


arcacisco Wed, 02/03/2010 - 09:46
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Thank you Giuseppe

One thing the chat-script gsm would be     "" "ATDT*99*2#" TIMEOUT 60 "CONNECT“

It 's the number given by the telco.

The line number is associated to cellular0 is line 3.

I'll try using your indications and let you know.

Thanks a lot


Robert Juric Wed, 02/03/2010 - 16:00
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I'm not sure if this is against the rules, but check out my short blog post on how I setup my router for AT&T 3G, it might help.

Also make sure you are attempting to ping something as a test. The cellular interface will not come up and pull an IP address until there is interesting traffic.

Giuseppe Larosa Thu, 02/04/2010 - 12:44
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Hello Rose,

this is good news !!!

Hope to help


juancarlosorellana Wed, 03/03/2010 - 11:01
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I have a Card HWIC-3G-HSPA router 881 and now in my country in HSDPA coverage is (not in HSPA and HSUPA), my question is whether even so using the Card HWIC-3G-HSPA I connect to HSDPA network without any problem?

juancarlosorellana Wed, 03/03/2010 - 11:44
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There is not a problem if the card HWIC-3G-HSPA network sticks to HSDPA, there will be no compatibility problem? Could you explain a little more

paolo bevilacqua Wed, 03/03/2010 - 14:48
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There is no problem as explained in the document above.

Please remember to rate useful posts clicking on the stars below.


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