In conducting Agent$-$to$-$Server network measurements within the Cisco ThousandEyes platform, how do ICMP and TCP protocols differ in their approach to collecting network data, and what are the specific considerations and implications of using each protocol for network performance metrics?

ICMP measurements involve sending a stream of data packets to assess server load and CPU utilization, while TCP measurements focus on user interface responsiveness and application load times.

ICMP$-$based measurements send ICMP Echo Request packets and expect Echo Reply packets, ideal for devices without open TCP ports, while TCP$-$based measurements utilize SYN or SACK packets, providing a more accurate reflection of traffic and are preferred due to lower resource utilization on the target.

ICMP protocols are used for measuring internal network traffic and firewall performance, while TCP protocols focus on external network routing efficiency and bandwidth allocation.

ICMP and TCP measurements both focus on analyzing the stability of external internet connections, with ICMP assessing the efficiency of routing protocols and TCP analyzing the bandwidth allocation and connection stability.