What protocol do routers use to share data and determine optimal traffic paths?

Routers use the Border Gateway Protocol (BGP) to share data among themselves and determine the most efficient paths for traffic across the internet. BGP is a standardized exterior gateway protocol that facilitates the exchange of routing information between different autonomous systems (AS) on the internet. It enables routers to make informed decisions about the best routes for data packets based on various factors such as path attributes, policies, and network conditions. This capability is essential for maintaining the overall efficiency and performance of internet traffic.

The other protocols listed serve different purposes. For instance, Hypertext Transfer Protocol (HTTP) is primarily used for transmitting web pages and data on the internet but does not manage routing information. File Transfer Protocol (FTP) is designed for transferring files between client and server but does not play a role in the routing process. Transmission Control Protocol (TCP) is a core protocol that ensures reliable delivery of data across networks but works at a different layer than routing protocols like BGP. Thus, BGP is the appropriate protocol for routers to manage and optimize traffic paths.