Network Topologies & Standards

Network Topologies & Standards Vivian Arzola

Overview • Preliminary Terms • Hardware Basics • Topologies • Channel Access Methods • Standards

Preliminary Terms • Node – interconnected devices in a computer network • e.g. terminals, computers, printers, scanners, servers, repeaters, routers, etc. • Link – Physical medium connecting two nodes • cable • wireless • Packet – small block of data transmitted at one time • header • data • trailer

Hardware Basics • Wireless Transmission Media: • Radio • Infrared • Microwave • Lightwave (laser)

Hardware Basics… • Copper cables • Coaxial (thick/thin) • Twisted Pair (STP/UTP)

Hardware Basics… • Coaxial cable

Hardware Basics… • Twisted Pair

Hardware Basics… • Fiber Optic Cable • Single Mode • Multimode

Hardware Basics… • Multimode Fiber Optic Cable

Topologies • Point-to-Point • Multipoint (Broadcast) • dedicated physical connections • impractical for LAN’s • used for long-distance networks

Topologies… • Tree Topology (point-to-point)

Topologies… • Point-to-Point • Multipoint (Broadcast) • dedicated physical connections • impractical for LAN’s • used for long-distance networks • shared communication channel • requires coordinating use (delays) • reduces cost

Topologies… • Bus Topology

Topologies… • Ring Topology

Topologies… • Star Topology

Channel Access Methods… (preventing collisions!) • Carrier Sense Multiple Access (CSMA) • checks for electrical activity before transmission • Carrier Sense Multiple Access with Collision Detection (CSMA/CD) • supports collision recovery • binary exponential backoff

Channel Access Methods… (preventing collisions!) • Polling • delays • single point of failure • no monopolization • Token-Passing • zero collisions • equal access • great performance on high traffic networks

Channel Access Methods… (preventing collisions!) • Demand Priority • can assign priorities • costly • single point of failure

Standards

Standards…

Questions?

Network Topologies & Standards