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TCOM 5272 Telecomm Lab Dr. Mostafa Dahshan OU-Tulsa 4W 2 nd floor 660-3713 mdahshan@ou.edu Acknowledgments Most of the contents of this presentation are imported from Supplemental materials of the textbook Presentations of Dr. Anindya Das Introduction Course Objectives
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TCOM 5272Telecomm Lab Dr. Mostafa Dahshan OU-Tulsa 4W 2nd floor 660-3713 mdahshan@ou.edu M. Dahshan - TCOM5272
Acknowledgments • Most of the contents of this presentation are imported from • Supplemental materials of the textbook • Presentations of Dr. Anindya Das M. Dahshan - TCOM5272
Introduction • Course Objectives • Implementation of the theory • Improve knowledge in network devices management • Introduce some useful software tools • Schedule M. Dahshan - TCOM5272
Network Types • Local area networks (LANs) • Metropolitan area networks (MANs) • Wide area networks (WANs) M. Dahshan - TCOM5272
LAN (Local Area Network) • Interconnects computers, printers, other equipment • Consists of shared hardware and software resources in close physical proximity • Example: TCOM Department M. Dahshan - TCOM5272
MAN (Metropolitan Area Network) • Spans a greater distance than a LAN • Links multiple LANs within city or metropolitan region • Typically uses fiber-optic/wireless connections • Example: Campus LAN links to offices outside the campus M. Dahshan - TCOM5272
WAN (Wide Area Network) • Composed of two or more LANs or MANs • May have constituent LANs on different continents • Example: The Internet M. Dahshan - TCOM5272
NETWORK TOPOLOGIES M. Dahshan - TCOM5272
Network Topologies • Main topologies: • Bus • Ring • Star • Mesh • Hybrid topologies • star-bus • star-ring M. Dahshan - TCOM5272
Bus Topology • Consists of cables connecting PCs or file servers • Visualizes connections as chain links • Terminator attached to each end of bus cable segment • Media type (discussed later) • 10Base5 • 10Base2 M. Dahshan - TCOM5272
Bus Topology (2) • Advantages • Requires less cable than other topologies • Easy to extend bus with a workstation • Disadvantages • High management costs • Single defective node can take down entire network • Can become quickly congested with network traffic M. Dahshan - TCOM5272
Ring Topology • Continuous data path • Workstations attached to cable at points around ring • Transmitted data • Goes around ring to reach destination • Continues until ends at source node M. Dahshan - TCOM5272
Ring Topology (2) • Advantages • Easier to manage than bus • Handles high volume network better than bus • Suited to transmitting signals over long distances • Disadvantages • Expensive equipment and wiring • Fewer equipment options M. Dahshan - TCOM5272
Star Topology • Multiple nodes attached to central device (hub, switch, router) • Cable segments radiate from center like a star • Example: workstations connected to switch M. Dahshan - TCOM5272
Star Topology (2) • Advantages • Easier to manage, defective nodes quickly isolated • Easier to expand • Better equipment and high-speed options • Disadvantages • Failure of central device may cause network failure • Requires more cable than bus M. Dahshan - TCOM5272
Mesh Topology • Every node connected to every other node in network • Often used in MANs and WANs M. Dahshan - TCOM5272
Mesh Topology (2) • Advantages • Fault tolerance • Alternate communication paths • Disadvantages • Expensive M. Dahshan - TCOM5272
OSI MODEL M. Dahshan - TCOM5272
The ISO Reference Model • Fundamental network communications model • Product of two standards organizations • International Organization for Standardization (ISO) • American National Standards Institute (ANSI) • OSI is theoretical, not specific hardware or software • OSI guidelines analogized to a grammar M. Dahshan - TCOM5272
The ISO Reference Model (2) • Accomplishments • Enabling communications among LANs, MANs, WANs • Standardizing network equipment • Enabling backward compatibility to protect investments • Enabling development of software and hardware with common interfaces M. Dahshan - TCOM5272
The ISO Reference Model (3) M. Dahshan - TCOM5272
Layered Model • Reduces complexity • Standardizes interfaces • Facilitates modular engineering • Ensures interoperable technology • Accelerates evolution • Simplifies teaching & learning M. Dahshan - TCOM5272
Physical Layer • Transmit and receive signals • Network connectors • Signaling and encoding methods • Detection of signaling errors • Data transfer mediums • wire cable • fiber optics • radio waves M. Dahshan - TCOM5272
Data Link Layer • Format bits into frames • Frame: discrete unit of information • Contains control and address information • Does not contain routing information • Logical Link Control (LLC) • Initiates communication between two nodes • Media Access Control (MAC) • Provides physical addressing • Regulates access to the media M. Dahshan - TCOM5272
Network Layer • Packet logical addressing • Path determination • Route optimization • Addressing is done through routed protocols: IP, IPX, AppleTalk, DECnet • Path Selection is done using routing protocols: RIP, IGRP, EIGRP, OSPF, BGP M. Dahshan - TCOM5272
Transport Layer • Provides transparent flow of data • End-to-end recovery • Flow control and error control • Data segmentation • Ensures data received in order M. Dahshan - TCOM5272
Session Layer • Manages dialog between applications • Establishes, manages, terminates sessions • Determines communication type • Simplex • Half-duplex • Full-duplex M. Dahshan - TCOM5272
Presentation Layer • Provides data representation and code formatting • Translates between character codes • Compression and encryption • Example: Secure Sockets Layer (SSL) M. Dahshan - TCOM5272
Application Layer • Provides network services to applications • Remote access to printers • Message handling for electronic mail • Terminal emulation M. Dahshan - TCOM5272
Internet Standards • Specifications of network technologies • Ratified by the IETF • Begins as • Internet Draft (ID) • Request For Comments (RFC) • Not all RFCs are standards M. Dahshan - TCOM5272
Internet Standards (2) • Examples of full standard RFCs • RFC 791: Internet Protocol • RFC 793: Transmission Control Protocol • RFC 959: File Transfer Protocol • Full List www.apps.ietf.org/rfc/stdlist.html M. Dahshan - TCOM5272
PHYSICAL LAYER M. Dahshan - TCOM5272
Media Types • Coaxial cable: copper wire • Twisted-pair cable: copper wire • Fiber-optic cable: glass or plastic • Wireless: radio or microwaves M. Dahshan - TCOM5272
Coaxial Cables • Used in bus topologies • 10Base5 (thicknet, thickwire, RG8) • 10Base2 (thinnet, thinwire) M. Dahshan - TCOM5272
10Base5 • Transmission rate of 10 Mbps • Longest cable run 500 m • Two transmission types • Baseband: single channel • Broadband: multiple nodes on multiple channels M. Dahshan - TCOM5272
10Base5 (2) • Has relatively large 0.4-inch diameter • Copper or copper-clad aluminum conductor at core • Conductor surrounded by insulation • Aluminum sleeve wrapped around insulation • PVC or Teflon jacket covers aluminum sleeve M. Dahshan - TCOM5272
10Base5 (3) 10BASE5 vampire tap MAU transceiverSource: Wikimedia M. Dahshan - TCOM5272
10Base2 • Maximum speed 10Mbps • Wire up to 185 meters (almost 200) • Used for baseband data transmission M. Dahshan - TCOM5272
10Base2 (2) • Attached to bayonet connector (BNC) • BNC connected to T-connector • Middle of T-connector attached to NIC • Terminator may be attached to one end of T-connector M. Dahshan - TCOM5272
Twisted Pair Cables • Contains pairs of insulated copper wires • Outer insulating jacket covers wires • Communication specific properties • Copper wires twisted to reduce EMI and RFI • Length: up to 100 meters • Transmission speed: up to 10 Gbps M. Dahshan - TCOM5272
Twisted Pair Cables (2) • RJ-45 plug-in connector attaches cable to device • Less expensive and • more flexible than T-connectors M. Dahshan - TCOM5272
Twisted Pair Cables (3) • Two Types • Shielded (STP) • Unshielded (UTP) M. Dahshan - TCOM5272
Shielded Twisted Pair (STP) • Surrounded by braided or corrugated shielding • Shield reduces interference (EMI, RFI) • Interval of twists in each pair should differ • Connectors, wall outlets should be shielded • Have proper grounding • Used in strong interference environment • Expensive cable and equipment M. Dahshan - TCOM5272
Unshielded Twisted Pair (UTP) • Consists of wire pairs within insulated outer covering • No shield between wires and encasement • Most frequently used network cable • Reducing EMI and RFI • Twist interior strands (like STP) • Build media filter into network equipment M. Dahshan - TCOM5272
Unshielded Twisted Pair (UTP)(2) M. Dahshan - TCOM5272
Unshielded Twisted Pair (UTP)(3) • Fewer points of failure • Has no shield that can tear (up through Category 5e) • Connectors and wall outlets do not need shielding • Proper grounding not as critical to purity of signal M. Dahshan - TCOM5272
Fiber-Optic Cables • Glass or plastic fiber cores encased in glass tube (cladding) • Fiber cores and cladding are surrounded by PVC cover • Signal transmissions consist light (usually infrared) M. Dahshan - TCOM5272
Fiber-Optic Cables (2) • Advantages • Transmission speeds from 100 Mbps to over 100 Gbps • No EMI or RFI problems • Data travels by light pulse • Low attenuation • Secure from unauthorized taps M. Dahshan - TCOM5272
Fiber-Optic Cables (3) • Disadvantages • Fragile • Expensive • Requires specialized training to install • Cannot be used for analog communications M. Dahshan - TCOM5272
Fiber-Optic Cables (4) • Single-mode • Used for long-distance communication • 8-10/125 µm cable transmits one wave at a time • Communications signal is laser light • Multimode • Supports multiple waves (broadband) • Comes in two varieties • step index • graded index • Cable diameter between 50 and 115 microns • Source for multimode cable is LED M. Dahshan - TCOM5272