Term
| adjacent-layer interaction |
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Definition
| the general topic of how on one computer, two adjacent layers in a networking architectural model work together, with the lower layer providing services to the higher layer. |
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Term
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Definition
| On a computer that recieves data over a network, the process in which the device inerprets the lower-layer headers and, when finished with each header, removes the header, revealing the next-higher-layer PDU. |
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Term
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Definition
| The placement of data from a higher-layer protocol behind the header (and in some cases, between a header and trailer) of the next-lower-layer protocol. For example, an IP packet could be encapsulated in an Ethernet header and trailer before being sent over an Ethernet. |
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Definition
| A term referring to a data-link header and trailer, plus the data encapsulated between the header and trailer. |
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Term
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| A generic term referring to any set of protocols and standards collected into a comprehensive grouping that, when followed by the devices in a network, allows all the devices to communicate. Examples include TCP/IP and OSI. |
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| A logical grouping of information that includes the network layer header and encapsulated data, but specifically does not include any headers and trailers below the network layer |
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Term
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| An OSI term to refer generically to a grouping of information by a particular layer of the OSI model. More specifically, LxPDU would imply the data and headers as defined by Layer x. |
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Term
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Definition
| The communication between two networking devices for the purpose of the functions defined at a particular layer of a networking model, with that communication happening by using a header defined by that layer of the model. The two devices set values in the header, send the header and encapsulated data, with the receiving device(s) interpreting the header to decide what action to take. |
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Term
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Definition
| In TCP, a term used to describe a TCP header and its encapsulated data (also called a L4PDU). Also in TCP, the process of accepting a large chunk of data from the application layer and breaking it into smaller pieces that fit into TCP segments. In Ethernet, a segment is either a single Ethernet cable or a single collision domain (no matter how many cables are used). |
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Definition
Application, Presentation, Session, Transport, Network, Data Link, Physical
Please Do Not Take Sausage Pizzas Away!
(Layers 1 - 7) |
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Term
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Definition
| A name for the IEEE gigabit ethernet standards that uses four-pair copper cabling, a speed of 1000 Mbps (1 Gbps), and a maximum cable length of 100 meters |
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Definition
| A name for the IEEE Fast Ethernet standard that uses two-pair copper cabling, a speed of 100 Mbps, and a maxium cable length of 100 meters |
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Term
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Definition
| The 10-Mbps baseband Ethernet specification using two pairs of twisted-pair cabling (Categories 3,4, or 5): One pair transmits data and the other receives data. 10Base-T, which is part of the IEEE 802.3 specification, has a distance limit of approximately 100m (328 ft) per segment |
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Term
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Definition
| An Ethernet cable that swaps the pair used for transmission on one device to a pair used for receiving on the device on the oppposite end of the cable. In 10BASE-T and 100BASE-TX networks, this cable swaps the pair at 1,2 to pins 3,6 on the other end of the cable, and the pair at pins 3,6 to pins 1,2 as well |
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Term
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Definition
| carrier sense multiple access collision detect. A media-access mechanism in which devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. if two devices transmit at once, a collision occurs and is detected by all colliding devices. this collision subsequently delays retransmissions from those devices for some random length of time. |
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Term
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Definition
| Generically, any communication in which two communicating devices can concurrently send and receive data. In Ethernet LANs, the allowance for both devices to send and recieve at the same time, allowed when both devices disable their CSMA/CD logic |
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Term
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Definition
| Generically, any communication in which only one device at a time can send data. In Ethernet LANs, the normal result of the CSMA/CD algorithm that enforces the rule that only one device should send at any point in time. |
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Term
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Definition
| A LAN device that provides a centralized connection point for LAN cabling, repeating any received electrical signal out all other ports, thereby creating a logical bus. Hubs do not interpret the electrical signals as a frame of bits, so hubs are considered to be Layer 1 devices. |
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Term
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Definition
| The documentation and implementation of which wires inside a cable connect to each pin position in any connector. |
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Term
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Definition
| A field in LAN header that identifies the type of header that follows the LAN header. Includes the DIX ethernet Type field, the IEEE 802.2 DSAP field, and the SNAP protocol Type field. |
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Term
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Definition
| An ethernet that uses a hub, or even the original coaxial cabling, which results in the devices having to take turns sending data, sharing the available bandwidth. |
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Term
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Definition
| cable that connects the wire on pin1 on one end of the cable to pin 1 on the other end of the cable, and so on. |
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Definition
| A network device that filters, forwards, and floods Ethernet frames based on the destination address of each frame. |
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Term
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Definition
| An ethernet that uses a switch, and a particularly not a hub, so that the devices connected to one switch port do not have to contend to use the bandwidth available on another port. The term contrast with shared ethernet in which the devices must share bandwidth, whereas switched Ethernet provides much more capacity, as the devices do not have to share the available bandwidth. |
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Term
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Definition
| transmission medium consisting of two insulated wires, with the wires twisted around each other in a spiral. An electrical circuit flows over the wire pair, with interference between the two wires. |
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