Ethernet Ethernet What is Ethernet LAN standards Ethernet

Ethernet

Ethernet • What is Ethernet? • LAN standards • Ethernet framing • Ethernet topologies • Ethernet devices • Ethernet cabling • CSMA /CD

What is Ethernet? • A set of specifications for LAN communication • Covers Layer 1 and Layer 2 of OSI model • Most widely used LAN implementation today

Ethernet Evolution

Ethernet Specifications • Physical layer specifications include– Signaling and encoding type – Cabling type, length and connectors – Topologies • Data link layer specifications – Media Access Control – Framing

LAN Standards

Ethernet Frame Structure

Ethernet Topologies • Physical layer topologies – Bus – Star

Ethernet Devices • Hubs/repeaters – Single broadcast and collision domain • Bridge – Single broadcast domain – Multiple collision domains • Switch – Single broadcast domain – except with VLANs • VLANs are broadcast dmains – Multiple collision domains

Ethernet Devices • Routers – Segment broadcast domains to contain broadcasts – Provide packet forwarding from one broadcast domain (aka VLAN; aka subnet) to another

Network Device Domains Hub Bridge Switch Router Collision Domains: 1 4 Broadcast Domains: 1 1 4 4 1 4

Ethernet Cabling • Coaxial – Used in bus topology – 10 Base 2 (thinnet); 10 Base 5 (thicknet) • Twisted pair – Used in star topology – Cat 3, 5, 6

Ethernet Cabling • Twisted pair – Straight through • Host to switch • Router to switch – Crossover • Switch/hub to switch/hub • PC/router to PC/router

UTP Implementation Crossover Cable 10 Base. T/ 100 Base. T Crossover Hub/Switch Pin 1 2 3 4 5 6 7 8 Label RD+ RDTD+ NC NC TDNC NC Crossover Cable 8 1 1 8 8 1 br w g b w w o w br b g o 8 w ww w br b g br o b 1 o g Some wires on cable ends are crossed

MAC Address Components

MAC Addresses

CSMA/CD