I solved my problem with this :   Specifically on page 15 of the pdf link:  https://www.cisco.com/c/en/us/td/docs/routers/access/interfaces/eesm/software/configuration/guide/4451_config.pdf   Thank you. Wale.

Hi Todd, How did you figure this out : "On our router ethernet-internal 1/0/0 maps to Gi0/18 on the etherswitch". How can I know which port on the switch module SM-X-ES3-24 maps to the Ethernet_Internal port?   Please advise.   Thank you.   Wale (jeg...