Unformatted text preview:

LectureWhat is a Network?1: Physical ConnectionProtocol - Definition2. Networking Protocols/Software2. Networking Protocols (cont.)Protocols you use everyday3. Networking Devices3. Networking Devices (cont.)Networking MatrixSpeed Chart – Pros/ConsTypes of Networks:Peer to Peer NetworkPeer-to-Peer Networks – Cont.Client / Server Network LAN Local Area NetworkClient Server NetworksThe Internet – WAN Wide Area NetworkInternet History -- WANFirst Internet: 1969Slide 20Internet History (cont)Internet EvolutionA Look at PacificNetUnderstanding PortsPort Scanning & Malicious ProbesLectureNetworkingWhat is a Network?•Two or More Devices Exchanging Information•Networks Require:1. A physical connection (medium)2. A language – software (protocol)3. Devices to facilitate1: Physical Connection•Telephone / Network Lines–Cat-3, Cat-5, Cat-5e, Cat-6–T1•Cables–Fiber Optic–Coaxial•Wireless (air)(a physical connection is also called a “medium”)Protocol - Definition•When computers communicate with each other, there needs to be a common set of rules and instructions that each computer follows.•An agreed-upon format for transmitting data between two devices.•A specific set of communication rules is called a protocol.2. Networking Protocols/Software•PPP (Point-to-Point Protocol)–dial-up connections•Ethernet –used for local area networks (LANs)•802.11 b/g/n/ac–short/long range wireless – 30 ft•Bluetooth–personal-range wireless•Wi-Max – “Xohm” (Sprint/Nextel, Intel, Comcast, Time Warner) 802.16–Enables usage across greater distances – up to 31 mi –30 – 40 Mbps–Distance vs. Speed2. Networking Protocols (cont.)•TCP/IP (Part of O/S)–Layered or suite of protocols for all commercial and private networks–“TCP/IP is the glue thatholds the Internet andweb together”…(TCP/IP for Dummies)Protocols you use everyday•Protocols within TCP/IP:–DNS – Resolves www address to IP address (Domain Name system)–FTP – Homework 4 – File Transfers (File Transfer Protocol)–HTTP – Rules for all web-pages (Hypertext Transfer Protocol)–IMAP – Rules for E-Mail (Internet mail access protocol)–IRC –Internet Relay Chat – AIM, MySpace–POP3 – Incoming Email (Post Office Protocol)–SMTP – Outgoing email (Simple Mail Transfer Protocol)–Telnet –Contacting computers remotely–BitTorrent P2P sharing, Limewire, KaazaList of Protocols3. Networking Devices•Hubs and Switches•Routers•Modems•Radios (Wireless)•NICs (Network Interface Card)•NIU (Network Interface Unit)3. Networking Devices (cont.)•Hub: This is the cheapest way to connect computers on a network. It's basically a box with several ports on it, one for each computer on the network. The hub helps transfer information from one computer to the other over the networking cables. •Switch: A switch is basically a better, faster version of a hub. •Router: The best way to connect your computers, especially if you plan to add a high-speed modem to the network, is with a router. The router not only connects the computers but also helps wisely manage them. It also helps put up a firewall between your computer network and the Internet.Networking MatrixNetwork Medium Protocol DeviceDial-UpTelephone LineV.90Analog ModemDSLSplit Signal Telephone LinePPPoE DSL ModemLANCat-5 Cable Ethernet NICWirelessAir 802.11/x RadioCableCoaxial Cable Ethernet Cable ModemCellularAir CDMA RadioSpeed Chart – Pros/ConsDial Up2400 bps – 56KbpsCheap – SlowCable512 KBps – 100 MbpsMust have existing cableShared bandwidthDSL129 Kbps – 8 MbpsDedicated bandwidth, not sharedWireless54 Mbps +Can be used for high speed data such as broadcast TVSatellite6 Mbps + High setup feesFiber15 Mbps – 500 MbpsGood for high bandwidth demands - MultitaskingT-3 ( 28/T-1’s $3k/monthly)44.736 MbpsLarge businesses and ISP (static IP)Types of Networks:•PAN – Personal Area Network•Peer to Peer*•LAN – Local Area Network*•CAN – Campus Area Network•MAN – Metropolitan Area Network•WAN – Wide Area Network*Peer to Peer Network•All members have equal rights•Each member authenticates users•Typical of home or small offices•Inexpensive and easy to set up•Also called a “Workgroup”Peer-to-Peer Networks – Cont.In a peer-to-peer system there are no fixed clients and servers.Client / Server Network LANLocal Area Network•Server(s) for special applications–Printing–File Sharing•Single login authentication•Typical of campus or enterprise networks•Expensive servers and software best for large number of users•Also called a “Domain”•Managed servicesClient Server NetworksA network with two or more clients and one server.FTP client enables “client” to contact “server”The Internet – WANWide Area Network•An interconnected network of smaller networks–Schools and Government –Commercial Entities–Residential Users–Access Providers•Common set of mostly-open protocolsInternet History -- WAN•1957: Sputnik launched•1958: ARPA formed under DOD–“Come up with a bomb proof network”•1961: Packet Switching –Network Protocol, precursor of TCP(cont)First Internet: 1969Stanford 12KB of RAMFirst Internet: 1969Stanford #1: 12KB of RAMInternet History (cont)•1975 First Email sent•1978 First Virus•1986 NSFnet•1988 First Chat•1989 First “commercial email”•1990 ARPANET ceases to exist•1991 Gopher = Search tool•1991 WWW is developed by Tim Berners-Lee•1993 Mozilla, Mosaic; NetscapeInternet Evolution•Search Tools•Internet 2.0•Content – Web 2.0A Look at PacificNetUnderstanding Ports•A port is a doorway to a connection in the Internet world.•Part of TCP/IP layer –65,535 possible ports•Different layers of TCP/IP use different ports, eg:•Port 80 for web traffic•Port 21 for FTP•Port 25 for emailPort TablePort Scanning & Malicious Probes•It is similar to a thief going through your neighborhood and checking every door and window on each house to see which ones are open and which ones are locked.•Port scanning software sends out a request to each port sequentially and makes a note of which ports responded or seem open to more in-depth


View Full Document

PACIFIC COMP 025 - Networking

Download Networking
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Networking and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Networking 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?