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 level |
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Term
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| On a computer that receives data over a network, the process in which the device interprets the lower-layer headers and, when finished with each header, removes the header, revealing the net-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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| 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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| An OSI term to refer generically to a grouping of information by a particular layer of the OSI model. More specifically, an LxPDU would imply the data and headers as defined by Layer x |
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| A name for the IEEE Gigabit Ethernet standard that uses four-pair copper cabling, a speed of 1000Mbps, 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 100Mbps, and a maximum cable length of 100 meters |
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Definition
| The 10-Mbps baseband Ethernet specification using two pairs of twisted-pair cabling (one transmits, the other receives). Has a distance limit of approximately 100m per segment and is a part of the IEEE 802.3 specification |
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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 opposite end of the cable |
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Term
| carrier sense multiple access with collision avoidance (CSMA/CD) |
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Definition
| Carrier sense multiple access with collision avoidance. A media-access mechanism that defines how devices decide when they can send, with a goal of avoiding collisions as much as possible. IEEE WLANs use CSMA/CA |
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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 receive at the same time, allowed when both devices disable their CSMA/CD logic |
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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. They do not interpret the electrical signals as a frame of bits, so hubs are considered to be Layer 1 devices |
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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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| 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
| In Ethernet, a cable that connects the wire on pin 1 on one end of the cable to pin 1 on the other end of the cable, pin 2 to pin 2, 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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Definition
| An Ethernet that uses a switch so that the devices connected to one switch port do not have to contend to use the bandwidth available on another port |
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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 the current in opposite directions on each wire, reducing the interference between the two wires |
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Definition
| A set of all devices that receive broadcast frames originating from any device within the set. Devices in the same VLAN are in the same broadcast domain |
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Definition
| An Ethernet frame sent to destination address FFFF.FFFF.FFFF, meaning that the frame should be delivered to all hosts on that LAN |
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Definition
| A set of network interface cards (NICs) for which a frame sent by one NIC could result in a collision with a frame sent by any other NIC in the same collision domain |
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Definition
| One of three options for internal processing on some models of Cisco LAN switches in which the frame is forwarded as soon as possible, including forwarding the first bits of the frame before the whole frame is received |
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Term
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Definition
| The result of the LAN switch forwarding process for broadcasts and unknown unicast frames. Switches forward these frames out all interfaces, except the interface in which the frame arrived. Switches also forward multicasts by default, though this before can be changed |
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Term
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Definition
| Forwarding a frame 64 bits at a time, preventing collision fragments |
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Definition
| Process in LAN design by which every switch port connects to a single device, creating a separate collision domain per interface |
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Definition
| Process of breaking a large piece of data from an application in pieces appropriate in size to be sent through the network |
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Term
| Spanning Tree Protocol (STP) |
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Definition
| Bridge protocol that uses an algorithm to allow a switch to dynamically work around loops in a network topology |
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Term
| store-and-forward switching |
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Definition
| Internal processing option in which the Ethernet frame must be completely received before the switch can begin forwarding |
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Term
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Definition
| Ethernet frame whose destination MAC address is not listed in a switch's MAC address table, so the switch must flood the frame |
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Definition
| Group of devices, connected to one or more switches, with the devices grouped into a single broadcast domain through switch configuration |
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Term
| command-line interface (CLI) |
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Definition
| Interface that enables the user to interact with the operating system by entering commands and optional arguments |
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Term
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Definition
| TCP/IP application layer protocol that supports terminal emulation between a client and server, using dynamic key exchange and encryption to keep the communication private |
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Definition
| Where the user can use the most powerful and potentially disruptive commands on a router or switch |
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Definition
| Mode of the user interface to a router or switch in which the user can type only nondisruptive EXEC commands |
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Term
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Definition
| Where the user can type configuration commands that are then added to the device's currently used configuration file |
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Term
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Definition
| Name of the file that resides in the NVRAM memory, holding the device's configuration that will be loaded into RAM as the running-config file when the device is next reloaded or powered on |
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Definition
| Name of the file that resides in RAM memory, holding the device's currently used configuration |
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Definition
| Prompts the user for basic configuration information, resulting in new running-config/startup-config files |
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Definition
| LAN network design term that refers to a switch interface connected to end-user devices |
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Definition
| On a LAN switch, an interface that is currently using either 802.1Q or ISL trunking |
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Definition
| In Frame Relay, the physical serial link that connects a Frame Relay DTE device, usually a router, to a Frame Relay switch. It uses the same physical layer standards as do point-to-point leased lines |
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Term
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Definition
| Generic reference to network services, typically WAN services, in which the service examines the contents of the transmitted data to make some type of forwarding decision |
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Term
| Point-to-Point Protocol (PPP) |
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Definition
| Protocol that provides router-to-router and host-to-network connections over synchronous point-to-point and asynchronous point-to-point circuits |
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Term
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Definition
| An international standards data-link protocol that defines the capabilities to create a frame-switched (packet-switched) service, allowing DTE devices (typically routers) to send data to many other devices using a single physical connection to the device in question |
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Term
| High-Level Data Link Control (HDLC) |
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Definition
| A bit-oriented synchronous data link layer protocol developed by ISO |
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Definition
| Interfaces between network and application software. Also includes authentication services |
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Definition
| Defines the format and organization of data. Includes encryption |
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Definition
| Establishes and maintains end-to-end bidirectional flows between endpoints. Includes managing transaction flows |
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Definition
| Provides a variety of services between two host computers, including connection establishment and termination, flow control, error recovery, and segmentation of large data blocks into smaller parts for transmission |
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Definition
| Logical addressing, routing, and path determination |
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Definition
| Formats data into frames appropriate for transmission onto some physical medium. Defines rules for when the medium can be used. Defines means by which to recognize transmission errors |
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Term
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Definition
| Defines the electrical, optical, cabling, connectors, and procedural details required for transmitting bits, represented as some form of energy passing over a physical medium |
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