Wi-Fi Structures

1. Wi-Fi Structures

2. Types of Wi-Fi Network Products • Access Point • Radio transceiver (transmitter/receiver) unit that plugs into a router, switch, or hub on a home network to let wireless clients– your computers – access your wired network (and Internet connection).

3. Types of Wi-Fi Network Products • router (gateway) • Shares broadband Internet connection among all the client PCs on the network. • Only difference between wired and wireless router is the latter has the access pointbuilt in.

4. Types of Wi-Fi Network Products • router (gateway), continued... • Built in Ethernet switch allows for communication between clients, as well. Expect enough Ethernet ports to connect from 2 to 8 computers using Cat 5 cable.

5. 1 2 3 4 Types of Wi-Fi Network Products • Wireless Network Interface Cards (NICs) • The adapter that allows a PC to connect to the access point, and thus talk to the wireless network. • All shapes and sizes: • Internal – PC Card (Sometimes called CardBus) for laptops • Internal --PCI Card for desktops • External – USB or Ethernet-to-Wireless Adapter • Embedded (non-removable) – miniPCI, comes with laptop.

6. Other Equipment • Repeaters – used to extend the signal range of a WLAN component. • Bridge – connects two separate wired or wireless LANs

7. Basic Home Wi-Fi Network Cable/DSL Modem The Internet AKA the WAN Router Home PC connected by Ethernet Access Point Second Home PC connected by Wi-Fi Second Laptop First Laptop

8. Home PCs connected by Ethernet Basic Home Wi-Fi Network (alternate) Cable/DSL Modem Hub or Switch The Internet Wireless Router Home PC via Wi-Fi PDA Laptop Game Console

9. Get the LAN Talking • DHCP • A Dynamic Host Configuration Protocol (DHCP) server will provide IP addresses to all the computers on the network. • Most routers include a DHCP server to serve a range of addresses.

10. Get the LAN Talking • DHCP • Each computer should be set to be a DHCP client. • In Windows, set the network card’s settings to “Obtain IP address automatically.”

11. Get the LAN Talking • DHCP • The router will typically be your “default gateway” to the Internet and will provide the IP address indicating that to all clients. • If your router’s IP address is 192.168.0.1, all computers using 192.168.0.2 to 192.168.0.254 will use that router to access the Internet.

12. Home Network- IP Addresses Cable/DSL Modem – gets IP from your ISP, 64.185.133.92 The Internet Router Gateway for LAN: 192.168.0.1; To Internet appears as 64.185.133.91 192.168.0.100 Access Point: 192.168.0.102 192.168.0.103 192.168.0.105 192.168.0.104

13. Home Networking Tip • “ipconfig” • If you need to quickly find out the IP address of your computer and the router/gateway, go to a command window and type ipconfig. (winipcfg in Windows 9x)

14. Get the WLAN Talking • Set up the SSID: • To connect to an access point, each client must know the Service Set Identifier (SSID) – the name of the wireless network -- of the access point and set that in its configuration utility. • CHANGE the SSID -- Vendors typically set the SSID of products to a simple, generic name, like the company name or “default” • Good Security: Pick a hard-to-guess SSID, such as a mix of letters and numbers with no obvious identifying logic.

15. Get the WLAN Talking • Set the channel • Most access points run on a single channel • Set the access point channel and all the clients that associate to it will use the same channel: • NOTE: 802.11b has 14 channels worldwide and 11 in the United States, but no more than three – 1, 6, and 11 -- that don’t overlap and thus don’t cause interference. This is only a problem if you’re near other WLANs.

16. Home Networking Tip • “ping” • Want to find out if your computer is talking to other computers, or the Internet? Send a ping. At a DOS window, type “ping” and the IP address for a computer or a Web site.

17. Home LAN Issues

18. WAN settings • The Wide Area Network (WAN), at least when it concerns your home network, is the network connection from your Internet Service Provider or broadband Cable/DSL company. • Some ISPs require you to enter information in your router such as: • Static IP address • Domain Name Server (DNS) • Point to Point Protocol over Ethernet (PPPoE) for DSL providers, with username and password

19. Network Address Translation (NAT) • NAT lets you share the one “real” IP address provided by the ISP among multiple computers on the home LAN. • The router/gateway gets that IP address from the ISP and translates it for the other computers, working hand-in-hand with DHCP.

20. Firewall • Uses rules to filter traffic from the outside Internet to your LAN, and sometimes vice versa. • Built into many routers; also available via software installed on each computer.

21. IP Ports • Not the physical jacks on the back of the PC... • Each port number Identifies the type of data being sent to/from a computer. • Port 80: HTTP (Hypertext Transfer Protocol, web browser traffic) • Port 25 & 110: SMTP & POP (Simple Mail Transfer Protocol & Point Of Presence, e-mail) • Port 21: FTP (File Transfer Protocol) • Port 53: DNS (Domain Name Resolution)

22. Port Forwarding • Port Forwarding associates traffic meant for a specific port on the computer and allows it through. • Setting a computer as a Web server means you forward traffic to port 80 (reserved for Web traffic) on one specific computer, based on its IP address. • Also called port mapping, pass-through, punch-through • Could require use of a “Dynamic DNS” service

23. DMZ • The Demilitarized Zone (DMZ) is the term used for a single computer on the network that is given completely unfettered access to the Internet. • Traffic can be incoming or outgoing. • Reserve for PCs that are • Web servers • Gaming systems • Use video conferencing • That computer is wide open to the Internet and hackers– keep isolated from others.

24. Universal Plug and Play (UPnP) • UPnP (www.upnp.org) developed by Microsoft, is meant to automate connection, installation, and configuration of network products • Performs “NAT Traversal” to automatically open the ports on a PC needed to work with a routers firewall • Both router and PC must support UPnP to get the benefit • Mainly works under Windows XP for now

25. VPN Pass-Through • Virtual Private Networks (VPNs) allow people to create a direct “tunnel” connection to their corporate network. Many routers will allow you to have the tunnel “pass-through” to the Internet and on to the corporate network. • Watch for how many simultaneous tunnels are supported

26. Firmware Upgrades • Firmware is the built-in software inside of a device that defines functions and features • Updating most access points/routers requires a firmware upgrade. • Download a software file and generally install via a utility or through the Web browser interface.