THE ETHERNET FAMILY

Flashcards covering key vocabulary terms related to Ethernet technology, its standards, frame format, and operations, based on the provided lecture notes.

Ethernet

The most common LAN technology, an open standard known for its cost-effectiveness, scalability, and reliability.

IEEE 802.3

The IEEE standard that defines Ethernet, modifying the original DIX standard published in 1985.

OSI Model

A conceptual framework explaining network functions, with which the IEEE Ethernet reference model is designed to interoperate.

Data Link Layer

The second layer of the OSI model, which in Ethernet includes the Logical Link Control (LLC) (802.2) and Media Access Control (MAC) (802.3) sublayers.

Physical Layer

The first layer of the OSI model, define by Ethernet, including specifications for connections and cable types.

DIX Standard

The first Ethernet standard published in 1980 by DEC, Intel, and Xerox.

Ethernet Frame

The specific format in which data is encapsulated by the Ethernet protocol for transmission, typically ranging from 64 to 1518 bytes.

Preamble and Start of Frame Delimiter (SFD)

An 8-byte field at the beginning of an Ethernet transmission (7 bytes Preamble, 1 byte SFD) used to synchronize the NIC for receiving a frame, not considered part of the frame length.

Destination MAC Address

A 6-byte field in an Ethernet frame that identifies the physical address of the node intended to receive the frame.

Source MAC Address

A 6-byte field in an Ethernet frame that identifies the physical address of the node that originated the frame.

Length/Type Field

A 2-byte field in an Ethernet frame that, depending on the standard (DIX or IEEE 802.3), either indicates the type of encapsulated upper layer protocol or the length of the frame data.

Data and Pad (Payload)

The field in an Ethernet frame (46 to 1500 bytes) containing the encapsulated Layer 3 data (e.g., an IPv4 packet), padded with null characters if the total frame length is less than the minimum 64 bytes.

Frame Check Sequence (FCS)

A 4-byte field at the end of an Ethernet frame containing the result of a Cyclic Redundancy Check (CRC), used by the receiving node to detect transmission errors.

Payload (802.3 & 802.11)

Refers to the 'data' portion of the frame (frame body), also known as the Service Data Unit (SDU).

MTU (Maximum Transmission Unit)

Refers to the maximum size of the Payload that can be transmitted.

Minimum Ethernet Frame Size

64 Bytes, inclusive of destination/source MAC, Length/Type, Data and Pad, and FCS.

Maximum Ethernet Frame Size

1518 Bytes, inclusive of destination/source MAC, Length/Type, Data and Pad, and FCS.

10BASE-T

An Ethernet standard utilizing twisted pair cable, Manchester encoding, supporting up to 100m over a star topology with a 10 Mbps data rate.

Gigabit Ethernet

An enhancement to Ethernet (IEEE 802.3z, 802.3ab, 802.3ah) supporting faster data rates (1 Gb/s) while maintaining backwards compatibility.

4D-PAM5

A signaling method used in Gigabit Ethernet for copper cabling.

1000Base-T

A Gigabit Ethernet standard that operates over Category 5e or better twisted pair copper cable, with a 100m limit.

1000Base-LX

A Gigabit Ethernet standard using fiber optic cable, supporting single-mode fiber up to 5km and multimode fiber up to 500m.

1000Base-SX

A Gigabit Ethernet standard primarily using shorter wavelength (850 nm) over multimode fiber, supporting 50µm fiber up to 500m and 62.5µm fiber up to 250m.

Frame Bursting

A MAC layer enhancement in Gigabit Ethernet that allows for sending multiple frames consecutively, effectively avoiding the overhead of CSMA/CD in high-speed networks.

Jumbo Frames

Ethernet frames larger than the standard 1518-byte limit, supported up to 9720 Bytes in Gigabit Ethernet, designed to reduce overhead for large data transfers but only work on LANs.

Auto-Negotiation

An Ethernet operation that allows networked devices to automatically agree on the best common transmission parameters, such as speed and duplex mode.

Auto-MDIX (Automatic Medium-Dependent Interface Crossover)

An Ethernet feature that automatically detects the required cable connection type (crossover or straight-through) and adjusts the interface accordingly.

Power over Ethernet (PoE)

A technology that allows network cables to carry electrical power to powered devices along with data.