03-07-2008 08:19 AM - edited 03-03-2019 09:01 PM
Hi,
We are not able to browse the Internet using the Cisco 1721 router. The router is connected using straight-through cable to the T1/smartjack. A firewall sits behind the router. A host behind the ASA5505 firewall can telnet to the router, however cannot browse the internet. The T1 circuit/smartjack has two green light, the lower two lights are amber. Sh ip int br is 'up' and 'down'. AT&T tests the circuit to the smartjack to be good. AT&T's router shows 'down' and 'down'.
I would appreciate any suggestions. the attachment has the config.
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03-10-2008 01:04 PM
With your Smartjack showing amber lights it typically means that their is a carrier issue. I would open a ticket with the provider that the T-1 is down and have it tested. I would work with them to provide a hard loop at the cable end right before your router to make sure the smartjack card is good.
With having an up/down you are seeing the smartjack but not the line.
When you say AT&T Router down down, what is that in the topology?
03-07-2008 08:54 AM
Said:
The "up, down" indication on your router means that your router is receiving a T1 signal from the network, but is not synchronizing on the layer 2 level. I imagine you're running either HDLC or PPP layer 2 encapsulation on this T1 link.
1.) Check the framing and coding on the CSU to see if it is set correctly - I imagine its an ESF/B8ZS circuit.
2.) Check your clocking. You should probably be set for "line" or "network" timing and AT&T should be set for "internal." One side has to be internal and the other line.
3.) If its a FRAC-T1, make sure you have the correct number of DS0s enabled. A full T1 is 24 DS0s, where each DS0 is 64kbps.
4.) Ask AT&T to loop up your CSU/DSU. If they cannot, then you should try replacing the cable between the router and the Smart Jack with a KNOWN good cable.
5.) If it still doesnt work, you have 2 choices: either you demand that AT*T go out and run a head-to-head test with the distant end or you just take the hit and try replacing the serial interface.
HTH
Feel free to come back with more questions.
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Victor
03-10-2008 01:04 PM
With your Smartjack showing amber lights it typically means that their is a carrier issue. I would open a ticket with the provider that the T-1 is down and have it tested. I would work with them to provide a hard loop at the cable end right before your router to make sure the smartjack card is good.
With having an up/down you are seeing the smartjack but not the line.
When you say AT&T Router down down, what is that in the topology?
03-10-2008 05:06 PM
The AT&T router's serial int was down. Shut and then no shut command brought it up.
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