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Review on Networking Technologies Linda Wu (CMPT 471 2003-3)
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Notes-2 CMPT 471 2003-3 2 Content Network & network categories Protocol TCP/IP internet protocol suite Ethernet technology References: chapter 1 & 2
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Notes-2 CMPT 471 2003-3 3 Network & Network Categories A network is a group of connected, communicating devices such as computers, routers and printers An internet is two or more networks that communicate with each other Most notable internet: Internet
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Notes-2 CMPT 471 2003-3 4 Network & Network Categories (cont.) Network categories Connection-oriented (circuit-switched) Dedicated connection between 2 points Guaranteed network capacity Circuit costs are independent of use e.g. telephone system Connectionless (packet-switched) Data are divided into small pieces (packet) Concurrent communication Packet is sent only when the network is idle: delay, bandwidth cannot be guaranteed
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Notes-2 CMPT 471 2003-3 5 Network & Network Categories (cont.) Packet-Switched Technology WAN (wide area network) Long distance, low speed connection A series of packet switches, connected by long-distance communication lines User computer attached to packet switches Network is expanded by adding packet switch & communication line LAN (local area network) High speed connection, short distance Computer connects to the network by Network Interface card (NIC)
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Notes-2 CMPT 471 2003-3 6 Protocol Protocol is a set of rules that governs data communication Syntax: the structure or format of data Semantics: the meaning of each section of bits Timing: when should data be sent and how fast can it be sent A protocol specifies: The details of message formats How a source sends a message How a destination responses when message arrives How a computer handles errors or other abnormal conditions
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Notes-2 CMPT 471 2003-3 7 TCP/IP Internet Protocol Suite Resulted from research funded by US ARPA TCP: Transmission Control Protocol IP: Internet Protocol 5 layers Application layer: user applications Transport layer: end-to-end delivery of data (TCP, UDP) Network layer: data transmission across multiple networks (IP) Data link layer: organize bits into frames Physical layer: transmit bits over a medium
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Notes-2 CMPT 471 2003-3 8 TCP/IP Internet Protocol Suite (cont.) ISO/OSI model OSI: Open System Interconnect Introduced by ISO (International Standards organizations) in late 1970s TCP/IP protocol suiteOSI model Dominant network architecture currently Dominated data communication before 1990 ProtocolsNot protocol; a model for designing network architecture Intensively used and tested in Internet Never fully implemented 5 layers7 layers
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Notes-2 CMPT 471 2003-3 9 TCP/IP Internet Protocol Suite (cont.) TCP/IP addressing Physical address defined by WAN or LAN Ethernet uses 48-bit physical address Internet (IP) address : 32-bit (IPv4) Different address formats in different networks Port address : 16-bit End objective of internet communication is a process communicating with another process Port address: the label assigned to a process
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Notes-2 CMPT 471 2003-3 10 TCP/IP Internet Protocol Suite (cont.) Relationship of layers & addresses Processes TCP IP & other protocols Underlying physical networks Transport layer Application layer Network layer Data link layer Physical layer UDP Port address IP address Physical address
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Notes-2 CMPT 471 2003-3 11 TCP/IP Internet Protocol Suite (cont.) Features Network technology independence Independent of any vendor’s hardware Universal interconnection Every computer is assigned a universally unique address End-to-end acknowledgement Provide acknowledgement between original source and final destination Application protocol standards Include standards for many applications, e.g., email, file transfer, remote login
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Notes-2 CMPT 471 2003-3 12 TCP/IP Internet Services Application-level services World Wide Web Email File transfer Remote login Network-level services Connectionless packet delivery Reliable stream transport
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Notes-2 CMPT 471 2003-3 13 Underlying Physical Technologies LAN Ethernet LAN: most widely used Token Ring LAN Wireless LAN Fiber Distributed Data Interconnect (FDDI) LAN WAN ARPANET NSFNET ANSNET ATM (asynchronous transfer mode)
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Notes-2 CMPT 471 2003-3 14 Ethernet Evolution 10Base5 (Thick Ethernet) 10 Mbps, cable < 500m 10Base2 (Thin-wire Ethernet) 10 Mbps, cable < 200m 10Base-T (Twisted pair Ethernet) 10 Mbps, connection between a hub and a computer < 100m 100Base-T (Fast Ethernet) 100 Mbps Gigabit Ethernet 1 Gbps
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Notes-2 CMPT 471 2003-3 15 Thick Ethernet Coaxial cable: ½ inch diameter Host interface card: plug into computer bus Transceiver: translate analog electrical signals to / from digital form AUI (attachment unit interface) cable: control transceiver operation transceiver Ethernet cable AUI cable Host interface
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Notes-2 CMPT 471 2003-3 16 Thin-Wire Ethernet Coaxial cable: thinner, less expensive, more flexible (thinnet cable) Replace costly transceiver with high speed digital circuit Direct connection from computer to network Computer contains both host interface and circuit that connects to the cable Thinnet cable
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Notes-2 CMPT 471 2003-3 17 Twisted Pair Ethernet Reduce cost by replacing coaxial cable with unshielded copper wire Connect computer to hub using four pairs of wires
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Notes-2 CMPT 471 2003-3 18 Ethernet Properties Shared bus All stations connect to a single, shared communication channel Support broadcast All stations receive every transmission Best-effort delivery No error checking or tracking Distributed access control No central authority to grant access
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Notes-2 CMPT 471 2003-3 19 Ethernet Hardware Address Ethernet address: a 48-bit number Fixed on Ethernet interface hardware Also called: hardware address, physical address, media access (MAC) address Address assigning Ethernet hardware manufactures purchase blocks of Ethernet addresses, and then, Assign the addresses in sequence to the Ethernet interface hardware No two hardware interfaces have the same Ethernet address: universally unique Host interface filters incoming packets based on their destination addresses
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Notes-2 CMPT 471 2003-3 20 Ethernet Frame Format Ethernet Frame: packet that is transmitted on Ethernet Format Preamble Dest. Addr Src. Addr Frame Type Frame Data CRC 866246~15004 Unit: octet (byte) Preamble: for synchronization CRC: Cyclic Redundancy Check, for error detection
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