Ethernet Standards
A standard provides detailed specifications for Physical layer media and interfaces.
- a standard must define:
- cable and connector specifications
- schemes for modulation and encoding
- Ethernet standard dominates the wired LAN product market
IEEE 802.3 Ethernet
- IEEE 802.3 Ethernet standards are widely used on LANs and WANs
- maintained by the Institute of Electrical and Electronics Engineers (IEEE)
- provide assurance that network cabling will meet the bandwidth requirements of applications
- copper cable is used to transmit electrical signals
- cable between two nodes creates a low voltage electrical circuit between the interfaces on the nodes
- 2 main types of copper cable:
- copper cable suffers from high attenuation
- signal quickly loses strength over long links
- twisted pair category standards define what bandwidth it supports up to a given distance
- Other types of Ethernet work over fiber optic cabling
- Fiber uses pulses of light to communicate data
Naming
- 802.3 Ethernet specifications are named using a 3 part xBASE-y convention:
- x = nominal speed or bit rate
- in megabits per second (Mbps) or gigabits per second (Gbps)
- signal mode
- baseband or broadband
- all mainstream Ethernet types use baseband
- y = designator for media type (cable type)
- x = nominal speed or bit rate
Example
- 10BASE-T denotes:
- works at 10 Mbps (10)
- uses baseband signal (BASE)
- runs over twisted pair copper cabling (-T)
- 100BASE-T refers to Fast Ethernet
- works at 100 Mbps
- baseband
- over copper twisted pair cabling