Ethernet

Elements of the Ethernet System

physical medium used to carry Ethernet signals between computers

set of medium access control rules embedded in each Ethernet interface

Ethernet frame that consists of a set of bits used to carry data over the system.

Operation of Ethernet

CSMA/CD Protocol Collisions Best Effort Data Delivery

– High-level network protocols do this by establishing a reliable data transport service

Ethernet Frame and Ethernet Addresses

Ethernet Frame and Ethernet Addresses address fields variable size data field - carries 46-1,500

bytes of data error checking field - checks integrity of the

bits in the frame to make sure that the frame has arrived intact

Address Fields

48-bit addresses IEEE controls assignment of these

addresses Organizationally Unique Identifiers (OUIs)

– 24-bit identifier assigned to each organization that wishes to build Ethernet interfaces

– organization creates 48-bit addresses using assigned OUI as the first 24 bits of the address

High-Level Protocols and Ethernet Addresses High-level protocol software - e.g. TCP/IP

protocol suite Address Resolution Protocol (ARP)

Address Resolution Protocol (ARP) Resolve physical address