When multiple WAN ports are available, such as multiple internet connections, it helps evenly distribute requests and information through them. Example: You have a cable internet connection that gives you 3Mbits speed, and a dsl connection giving you 1.5Mbits speed, it would pull requested packets, or downloads from both connections, effectively giving you seamless 4.5Mbit connection speeds.
Common Internet Speed Services:1. Dial-up. 56kbits/s2. DSL. 512kbits/s - 3mbits/s3. Cable. 3mbits/s - 10mbits/s4. Fiber Optic. 5mbits/s - 30mbits/s*Speeds and services provided depend completely on specific ISP. Above are common ranges of speeds that many ISP's may offer today.