The term Ethernet refers to the family of local-area network (LAN) products covered by the IEEE 802.3 standard that defines what is commonly known as the CSMA/CD protocol. Four data rates are currently defined for operation over optical fiber and twisted-pair cables:
- 10 Mbps—10Base-T Ethernet
- 100 Mbps—Fast Ethernet
- 1000 Mbps and 10,000Mbps—Gigabit Ethernet
Ethernet is currently used for approximately 85 percent of the world's LAN-connected PCs and workstations. Ethernet is the major LAN technology because of the following characteristics:
- Is easy to understand, implement, manage, and maintain
- Allows low-cost network implementations
- Provides extensive topological flexibility for network installation
- Guarantees successful interconnection and operation of standards-compliant products, regardless of manufacturer
Carrier Sense Multi-Access/Collision Detection (CSMA/CD)
Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is the LAN access method used in Ethernet. When a device wants to gain access to the network, it checks to see if the network is free. If the network is not free, the device waits a random amount of time before retrying. If the network is free and two devices access the line at exactly the same time, their signals collide. When the collision is detected, they both back off and wait a random amount of time before retrying.
Ethernet Encapsulation Standards / Ethernet (802.3)
Fast Ethernet (802.3u)
Any of a number of 100-Mbps Ethernet specifications. Fast Ethernet offers a speed increase ten times that of the 10BaseT Ethernet specification, while preserving such qualities as frame format, MAC mechanisms, and MTU. Such similarities allow the use of existing 10BaseT applications and network management tools on Fast Ethernet networks.
Gigabit Ethernet (802.3z)
Gigabit Ethernet over copper (802.3ab)
Long-Reach Ethernet
The Cisco Long-Reach Ethernet (LRE) networking solution is the industry""s first end-to-end product line for delivering 5-15 Mbps speed over existing Category 1/2/3 wiring. With Ethernet-like performance that extends to 3,500-5,000 feet, LRE enables next-generation simultaneous voice, video and data services including high-speed Internet access, video streaming and IP telephony.
Speed / Duplex negotiation
UniDirectional Link Detection (UDLD)
10 Gigabit Ethernet
10 Gigabit Ethernet is basically a faster version of Ethernet. It uses the IEEE 802.3 Ethernet media access control (MAC) protocol, the IEEE 802.3 Ethernet frame format, and the IEEE 802.3 frame size. 10 Gigabit Ethernet is full duplex, just like full-duplex Fast Ethernet and Gigabit Ethernet; therefore, it has no inherent distance limitations. Because 10 Gigabit Ethernet is still Ethernet, it supports all intelligent Ethernet-based network services such as multiprotocol label switching (MPLS), Layer 3 switching, quality of service (QoS), caching, server load balancing, security, and policy-based networking. And it minimizes the user's learning curve by supporting familiar management tools and architectures.With a data rate of 10 Gb/s 10-Gigabit Ethernet offers a low-cost solution to the demand for higher bandwidth in the LAN, MAN, and WAN. The potential applications and markets for 10-Gigabit Ethernet are enormous, including enterprises, universities, telecommunication carriers, and Internet service providers.
Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is the LAN access method used in Ethernet. When a device wants to gain access to the network, it checks to see if the network is free. If the network is not free, the device waits a random amount of time before retrying. If the network is free and two devices access the line at exactly the same time, their signals collide. When the collision is detected, they both back off and wait a random amount of time before retrying.
Ethernet Encapsulation Standards / Ethernet (802.3)
Fast Ethernet (802.3u)
Any of a number of 100-Mbps Ethernet specifications. Fast Ethernet offers a speed increase ten times that of the 10BaseT Ethernet specification, while preserving such qualities as frame format, MAC mechanisms, and MTU. Such similarities allow the use of existing 10BaseT applications and network management tools on Fast Ethernet networks.
Gigabit Ethernet (802.3z)
Gigabit Ethernet over copper (802.3ab)
Long-Reach Ethernet
The Cisco Long-Reach Ethernet (LRE) networking solution is the industry""s first end-to-end product line for delivering 5-15 Mbps speed over existing Category 1/2/3 wiring. With Ethernet-like performance that extends to 3,500-5,000 feet, LRE enables next-generation simultaneous voice, video and data services including high-speed Internet access, video streaming and IP telephony.
Speed / Duplex negotiation
UniDirectional Link Detection (UDLD)
10 Gigabit Ethernet
10 Gigabit Ethernet is basically a faster version of Ethernet. It uses the IEEE 802.3 Ethernet media access control (MAC) protocol, the IEEE 802.3 Ethernet frame format, and the IEEE 802.3 frame size. 10 Gigabit Ethernet is full duplex, just like full-duplex Fast Ethernet and Gigabit Ethernet; therefore, it has no inherent distance limitations. Because 10 Gigabit Ethernet is still Ethernet, it supports all intelligent Ethernet-based network services such as multiprotocol label switching (MPLS), Layer 3 switching, quality of service (QoS), caching, server load balancing, security, and policy-based networking. And it minimizes the user's learning curve by supporting familiar management tools and architectures.With a data rate of 10 Gb/s 10-Gigabit Ethernet offers a low-cost solution to the demand for higher bandwidth in the LAN, MAN, and WAN. The potential applications and markets for 10-Gigabit Ethernet are enormous, including enterprises, universities, telecommunication carriers, and Internet service providers.
