The WCCP-configured router identifies if the Cisco WSA is functional by exchanging periodic messages with the WSA. The WSA sends a Here-I-Am message every 10 seconds to the router, which contains information such as the WSA’s IP address, service group, and hash assignment. The router responds with an I-See-You message, which acknowledges the receipt of the Here-I-Am message and provides information such as the router’s IP address, service group, and view of the WCCP topology. These messages allow the router and the WSA to maintain a bidirectional communication and to detect any changes or failures in the WCCP network12.

Option C is the correct answer, as it describes the correct message exchange between the WCCP-configured router and the Cisco WSA. Option A is incorrect, as the router does not use ICMP ping to check the WSA’s functionality, and the traffic is not transmitted to the router, but redirected by the router. Option B is incorrect, as the router does not use ICMP ping to check the WSA’s functionality, and the traffic is not transmitted to the WSA, but redirected by the WSA. Option D is incorrect, as the router does not send a Here-I-Am message, but an I-See-You message, and the WSA does not acknowledge with an I-See-You message, but a Here-I-Am message. References: WCCP Router Configuration Example - Cisco. Cisco ASA WCCP Traffic Redirection Guide - Cisco.