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… 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…
Standards…
Standards…
Questions?