Zee,
You might find this useful - it explains WAN, what hardware is required, and has some links to examples.
WAN
As for the main hardware elements, here are some, off the top of my head-
• Hub
• LAN
• ISP providing connection to outside world (using ISDN, MPLS, ATM, SDSL, etc)
• Cat 5/6 cables
• Routers
• Switches
• Cables (Fibre and Cat5/6)
• Mounting Hardware & Cabinets
I don't know if you have to include environments for the WAN kit, but you usually have a comms room with AirCon, Fire Suppression, Uninterruptible Power Supply (UPS), Environment Monitoring; and for resilience, you usually have diverse routing into the building/room, from different Exchanges.
Here's a good link from
BTinternet