(1) How can 500 million computers attached to the Internet communicate with one another? (2) when you sign onto the Internet using a dial-up DSL, or cable modem, has your computer the IP address? (3) Why is IPv4 Internet address a 32-bit number, such as 64.49.254.91? (4) In IPv4 Internet address, why is 255 the biggest number? (5) Why does IPv4 Internet address contain up to 4 billion addresses? (6) Why is IPv6 Internet address a 128-bit number? 110