network interface card (nic) connecting devices hubs/switches, routers network cables twisted-pair...
TRANSCRIPT
• Network Interface Card (NIC)
• Connecting DevicesHubs/switches, routers
• Network CablesTwisted-pair cable, Coaxial cable, Optical fiber
• Wireless Networks
Connecting to a Computer Network
• Each NIC has a MAC (Medium Access Control) address
– An unique hardware number to identify a computer in the network
– In Windows, to locate the MAC of a NIC:run > cmd > ipconfig /all
MAC = physical address (A hex code)
Connecting Devices Hub/Switch
– provides a central connection points for cables in a network and direct the data flow among them
– A typical client-server configuration• a cable connects the hub/switch to a server • other computers are connected to the hub/switch
Hub/ Switch
Client-server network connected with a hub/ switch
Hub/ Switch
Connecting Devices• Hub
Hubs and Switches
http://computing.concord.edu/Networking/networking.htm
Hub Only one computer can talk at a time.
SwitchComputers can talk with each other on private connections so that multiple conversations can be carried on at the same time.
1st computer sends a print job to the printer
Routers & Modems
Hub/ Switch
Client-server network connected with a hub/ switch
Router ModemHub/ Switch
Internet
Bridge
A bridge connects segments of a LAN or LANs of the same type into an aggregated network.
Wireless bridgehttp://kb.netgear.com/app/answers/detail/a_id/9587/~/bridging-and-repeating-using-wndap330
Router• A router connects a LAN to a different LAN• A router is connected to another router. A huge
network of routers connects the LAN’s together to form the Internet.
• is needed to connect a LAN and the Internet (a WAN)
• Routes (forwards/ directs) packets (of data) between networks (LANs). i.e. direct data flow.
• Most home-use routers have LAN ports and also act as hubs/switch. (router + hub/switch)
Bridge vs Router
bridge: - simple, link up to form a aggregated LAN
router: - complicated, direct traffic between two different LANs- idea: one LAN is not under control of the other LAN (ip address)
Modem (modulator demodulator)Refer to textbook
Types of modem
• Dial-up modem (telephone line)
• Cable modem (cable TV network)• ADSL modem (broadband telephone network)
– Asymmetric Digital Subscriber Line
• DSL modem (broadband telephone network)– Digital Subscriber LineActually, an ADSL/ DSL modem is not a D-A-D but a D-D device.
Network Cables Unshielded twisted-pair (UTP) cable• Use RJ45 connector• Twisted to reduce interference• Category 5 UTP
– 100Mbps (=1,000,000 bps; not 1024 x 1024bps)– Commonly used in LANs
(Shielded twisted-pair)
Network Cables Shielded twisted-pair (STP) cable
Metallic foil shielding
Straight through cable
• Cut evenly across• ½ inch left• Clip down• Insert fully in
Coaxial Cable (coax)• commonly used for VCR and cable TV
connections
• use BNC jack/ connector
• transmit more signal over longer distance than twisted-pair cable
BNC Connectors
Male Connectors 1 Male – 2 Female Connectors
Fiber optics (optical fibers) are long, thin strands of very pure glass about the diameter of a human hair. They are arranged in bundles called optical cables and used to transmit light signals over long distances.
Parts of a single optical fiberBundles of optical fibersforming optical cables
Wireless Networks
Access point (AP) (= wireless hub)
A device that transports data between a wireless LAN and a wired LAN (forming one unified LAN)
• Wireless Local Area Network (WLAN)• uses Radio Frequency (RF) technology
Hardware
Access Point
Wireless LAN adaptors
AP13 outside 5/F Staff Room
Wireless Fidelity (Wi-Fi) protocols (rules/ standard)
• 802.11b 11Mbps• 802.11g 54Mbps
Wireless Equivalent Privacy (WEP)
• security protocol
• encrypt data for wireless transmission
Wireless Broadband Router (+ hub + AP)
- connect to a modem
(then to the Internet/ other LANs)
- connecting nodes in the LAN
Google search: internet sharing routerhttp://salestores.com/linksy05.htmlLinksys WRT54G All-In-One Wireless-G Broadband Router
Access Point (= wireless hub)
- connect to a switch/hub (the LAN)
- connecting nodes in the LAN
Cable or DSL/ADSL
Modem
Internet
Revision of Concepts
Functions of devices- hub/switch/AP connecting equipment in the LAN- Router connect a LAN to another LAN’s (Internet)- Modem perform conversion to enable computer data signal to be sent over telephone/ cable TV / ADSL network.
Revision of Concepts
Home use devices > AP (wireless hub) > AP + wired-hub/ switch > router + AP + wired-hub (3 devices in a case, most popular, market name: wireless internet sharing router) > cable/ ADSL modem (for broadband connection)
At school > switch/ hub, router, broadband modem are separate devices > one router for the whole school LAN > one broadband modem
Network in our school
• Network OS: Windows, Linux
• Some functions/ services– Account management (logging on/ off) – Accessing network drives– Using network printers– File transfer– Routing to the Internet
• connecting the school LAN to the Internet
Diagram of school LAN
Visiting School’s Server Room
What to look for?
- UTP cables, Optical Fibre
- Hubs, Switches and Router
- Modem, Cable Modem
- Servers : File (FTP), Web, SAMS, …
- Backup magnetic tape system
- Patch panel
- UPS (uninterruptible power supply) systems
Other network facilities
- other servers : MMLC’s / BCR
- Switch/ Hub cabinets at Library, MMLC1/2, Staff Rooms ...