Wired and wireless networks1

Wired and wireless networks1

1. Wide Area Networks (WAN)

   • Internet
     • 相互連接的網絡的集合
       • A collection of inter-connected networks
   • WAN使用電纜，電話線，衛星和無線電波
     • 連接，通常分佈在廣泛的地理區域
     • A WAN uses cables, telephone lines, satellites and radio waves to connect, usually spread over a wide geographical area
   • The Internet is a Wide Area Network (WAN)

2. IPv4 Addressing

   • every network in the world has a separate, unique address
     • 世界上的每個網絡有一個
       • 單獨的，獨特的地址
   • too many computer now IPv4 addresses is running out
     • 可用的IPv4地址的數量正在用完
   • A new IPv6 system of addressing is replacing IPv4
     • 新的IPv6尋址系統正在取代IPv4

3. Domain Name System (DNS) 域名系統

   • DNS technology allows you to type a name such as google.co.uk into your web browser
     • DNS技術允許您在Web瀏覽器中鍵入一個名稱
       • 它將網址轉換為IP地址
     • It translates the web address google.co.uk into an IP address
       • e.g. www.google.co.uk = 74.125.131.94