Hello Pierre, Please use "ip address negotiated" under interface dialer instead of using "ip address dhcp client-id FastEthernet4". Please use " ip mtu 1492" instead of 1452. Are you getting a valid IP address in the dialer after making those changes? Regards. ... View more

Hello, If you have a WIC-1DSU-T1, WIC-1DSU-T1-V2 or HWIC-1DSU-T1, you need to go under interface configuration and type service-module t1 clock source: 3845_2(config)#int serial 0/1/0 3845_2(config-if)#service-module t1 clock source ?   internal  Use adapter internal clock   line      Recover clock from line You have 2 options here as you can see. Internal provides clocking and line receives clocking. In a back-to-back circuit, it is recommended to configure one end as "internal" while the other remains "line". If your provider is in the middle providing clocking for both ends, the "line" configuration is recommended but this depends on the circuit specifications. You can use the "show service-module" (do not forget clearing the counters to see the fresh statistics) command to know if there are clocking issues. Basically, you need to focus on the " Slip Secs" value. If it is increasing, it is recommended to check if clocking is properly configured. Sometimes you will need to get the provider involved to confirm the proper clocking configuration you should have. On the other hand, if you have a VWICX-XMFT-T1/E1 you need to enter controller configuration and choose the proper clocking configuration. It basically works the same as in a WIC-1DSU-T1 and similar hardware. 3845_1(config)#controller t1 0/0/0 3845_1(config-controller)#clock source ?   free-running  Free Running Clock   internal      Internal Clock   line          Recovered Clock "The free-running keyword  specifies a free-running clock derived from the oscillator on the  motherboard, which is used only for testing and back-to-back  connections". http://www.cisco.com/en/US/docs/ios/12_2/12_2z/12_2zj/feature/guide/gthwecan.html To look for statistics use the "show controllers t1 X/X/X" command and avoid using any "loopback" command for it would affect the connection since it is used just for testing purposes. I hope this information helps and do not forget rating the useful posts. Regards. ... View more