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Definition
| The IEEE standard that describes, among other things, bridging and STP (Spanning Tree Protocol). |
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Definition
| The IEEE standard that specifies how VLAN and trunking information appear in frames and how switches and bridges interpret that information. |
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Definition
| he IEEE standard that describes RSTP (Rapid Spanning Tree Protocol), which evolved from STP (Spanning Tree Protocol) |
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Definition
| The interface on a switch used for an end node. Devices connected to access ports are unaware of VLAN information. |
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Definition
| A switch that provides functions between Layer 4 and Layer 7 of the OSI model. |
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Definition
| A synonym for motherboard, often used in the context of switches and routers. |
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Term
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Definition
| The most efficient route from one node on a network to another. Under optimal network conditions, the best path is the most direct path between two points. However, when traffic congestion, segment failures, and other factors create obstacles, the most direct path might not be the best path. |
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Term
| BGP (Border Gateway Protocol) |
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Definition
| A distance-vector routing protocol capable of considering many factors in its routing metrics. BGP, an Exterior Gateway Protocol, is the routing protocol used on Internet backbones. |
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Term
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Definition
| A combination of a 2-byte priority field and a bridge's MAC address, used in STP (Spanning Tree Protocol) to select a root bridge. |
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Definition
| A router that connects to autonomous LAN with an exterior network--for example, the router that connects a business to it's ISP. |
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Definition
| A connectivity device that operates at the Data Link layer (Layer 2) of the OSI model and reads header information to forward packets according to their MAC addresses. Bridges use a filtering database to determine which packets to discard and which to forward. Bridges contain one input and one output port and separate network segments. |
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Term
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Definition
| A type of circuit used by a computer's motherboard to transmit data to components. Most new Pentium computers use buses capable of exchanging 32 or 64 bits of data. As the number of bits of data a bus handles increases, so too does the speed of the device attached to the bus. |
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Definition
| A switch that provides functions between Layer 4 and Layer 7 of the OSI model |
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Definition
| The time it takes for a router to recognize a best path in the event of a change or network outage |
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Definition
| In the context of routing metrics, the value assigned to a particular route as judge by the network administrator. The more desirable the path, the lower its cost. |
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Term
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Definition
| A switching mode in which a switch reads a frame's header and decides where to forward the data before it receives the entire packet. Cut-through mode is faster, but less accurate, than the other switching method, store-and-forward mode. |
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Definition
| The software that enables an attached device to communicate with the computer's operating system. |
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Definition
| The simplest type of routing protocols, these determine the best route for data based on the distance to a destination. Some distance-vector routing protocols, like RIP, only factor in the number of hops to the destination, while others take into account latency and other network characteristics. |
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Term
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Definition
| A method of routing that automatically calculates the best path between two nodes and accumulates this information in a routing table. If congestion or failures affect the network, a router using dynamic routing can detect the problem and reroute data through a different path. Modern networks primarily use dynamic routing. |
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Term
| EGP (Exterior Gateway Protocol) |
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Definition
| A routing protocol that can span multiple, autonomous networks. BGP and EIGRP are examples of Exterior Gateway Protocols. |
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Term
| EIGRP (Enhanced Interior Gateway Routing Protocol) |
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Definition
| A routing protocol developed in the mid-1980s by Cisco Sytems that has a fast convergence time and a low network overhead, but is easier to configure and less CPU-intensive than OSPF. EIGRP also offers the benefits of supporting multiple protocols and limiting unnecessary network traffic between routers. |
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Definition
| A popular tool for viewing and modifying network interface properties on Linux computers. |
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Definition
| A circuit board used to connect a device to a computer's motherboard. |
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Definition
| see expansion board. Expansion slot A receptacle on a computer's motherboard that contains multiple electrical contacts into which an expansion board can be inserted. |
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Definition
| a router that directs data between nodes outside a given autonomous LAN, for example, routers used on the Internet's backbone |
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Definition
| A collection of data created and used by a bridge that correlates the MAC addresses of connected workstations with their locations. A filtering database is also known as a forwarding table. |
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Definition
| A device (either a router or a computer running special software) that selectively filters or blocks traffic between networks. Firewalls are commonly used to improve data security. |
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Definition
| A combbination of networking hardware and software that connects two dissimilar kinds of networks. Gateways perform connectivity, session management, and data translation, so they must operate at multiple layers of the OSI model. |
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Term
| GBIC (Gigabit interface converter) |
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Definition
| A standard type of modular interface designed in the 1990s for Gigabit Ethernet connectiosn. GBICs may contain RJ-45 or fiber-optic cable ports (such as LC, SC, or ST). They are inserted into a socket on a connectivity device's backplane. |
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Term
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Definition
| The feature of a component that allows it to be installed or removed without disrupting operations. |
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Term
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Definition
| A connectivity device that retransmits incoming data signals to its multiple ports. Typically, hubs contain one uplink port, which is used to connect to a network's backbone. |
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Term
| IGP (Interior Gateway Protocol) |
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Definition
| A routing protocol, such as RIP, that can only route data within an autonomous (internal) network. |
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Term
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Definition
| A router that directs data between nodes on an autonomous LAN. |
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Term
| IS-IS (Intermediate System to Intermediate System) |
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Definition
| A link-slate routing protocol that uses a best-path algorithm similar to OSPFs. IS-IS was originally codified by ISO, which referred to routers as "intermediate systems," thus the protocol's name. unlike OSPF, IS-IS is deigned for use on interior routers only. |
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Term
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Definition
| A switch capable of interpreting data at Layer 3 (Network layer) of the OSI model. |
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Term
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Definition
| A switch capable of interpreting data at Layer 4 (Transport Layer) of the OSI model. |
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Term
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Definition
| A type of routing protocol that enables routers across a network to share information, after which each router can independently map the network and determine the best path between itself and a packet's destination node. |
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Term
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Definition
| A connector used for troubleshooting that plugs into a port (for example, a serial, parallel, or RJ-45 port) and crosses over the transmit line to the receive line, allowing outgoing signals to be redirected back into the computer for testing. |
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Term
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Definition
| A nic that is integrated into a computer's motherboard, rather than connected via an expansion slot or peripheral bus. |
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Term
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Definition
| A port that is integrated into a computer's motherboard. |
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Term
| OSPF (Open Shortest Path First) |
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Definition
| A routing protocol that makes up for some of the limitations of RIP and can coexist with RIP on a network. |
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Term
| PCIe (PCI component Interconnect Express) |
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Definition
| A 32-bit bus standard capable of transferring data at up to 1 Gbps per data path, or lane, in full-duplex transmission. PCIe is commonly used for expansion board NICs. |
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Term
| RIP (Routing Information Protocol) |
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Definition
| The oldest routing protocol that is still widely used, RIP is a distance-vector protocol that uses hop count as its routing metric and allows up to only 15 hops. It is considered an IGP. Compared with older, more modern, routing protocols, RIP is slower and less secure. |
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Term
| RIPv2 (routing Information Protocol version 2) |
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Definition
| An updated version of the original RIP routing protocol, which makes up for some of its predecessor's overhead and security flaws. However, RIPv2's packet forwarding is still limited to a maximum 15 hops. |
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Term
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Definition
| The single bridge on a network selected by the Spanning Tree Protocol to provide the basis for all subsequent path calculations. |
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Term
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Definition
| A multiport device that operates at Layer 3 of the OSI model and uses logical addressing information to direct data between networks or segments. Routers can connect dissimilar LANs and WANs running at different transmission speeds and using a variety of Network layer protocols. They determine the best path between nodes based on traffic congestion, available versus unavailable routes, load balancing targets, and other factors. |
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Term
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Definition
| The method used by routing protocols to determine the best path for data to follow over a network. Routing metrics may be calculated using any of several variables, including number of hops, bandwidth, delay, MTU, cost, and load. |
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Term
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Definition
| The means by which routers communicate with each other about network status. Routing protocols determine the best path for data to take between nodes. |
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Term
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Definition
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Term
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Definition
| A database stored in a router's memory that maintains information about the location of hosts and best paths for forwarding packets to them |
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Term
| RSTP (Rapid Spanning Tree Protocol) |
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Definition
| As described in IEEE's 802.1W standard, a version of the Spanning Tree Protocol that can detect and correct for network changes much more quickly. |
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Term
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Definition
| An erroneously shortened packet |
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Term
| SFP (small form-factor pluggable) transceiver |
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Definition
| A standard hot-swappable network interface used to link a connectivity device's backplane with fiber-optic or copper cabling. SFPs are known as mini GBICs because they perform a similar function as GBICs, but have a smaller profile. Current SFP standards enable them to send and receive data at up to 10 Gbps. |
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Term
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Definition
| A technique in which a network administrator programs a router to use specific paths between nodes. Because it does not account for occasional network congestion, failed connections, or device moves and requires manual configuration, static routing is not optimal. |
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Term
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Definition
| A method of switching in which a switch reads the entire data frame into its memory and checks it for accuracy before transmitting it. Although this method is more time consuming than the cut-through method, it allows store-and-forward switches to transmit data more accurately. |
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Term
| STP (Spanning Tree Protocol) |
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Definition
| A switching protocol defined in IEEE 802.1d. STP operates in the Data Link layer to prevent traffic loops by calculating paths that avoid potential loops and by artificially blocking links that would complete a loop. Given changes to a network's links or devices, STP recalculates its paths. |
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Term
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Definition
| A connectivity device that logically subdivides a network into smaller, individual collision domains. A switch operates at the Data Link layer of the OSI model and can interpret MAC address information to determine wheter to filter (discard) or forward packets it receives. |
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Term
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Definition
| The interface on a switch capable of managing traffic from multiple VLANs |
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Term
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Definition
| The aggregation of multiple logical connections in one physical connection between connectivity devices. In the case of VLANs, a trunk allows two switches to manage and exchange data between multiple VLANs. |
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Term
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Definition
| A port on a connectivity device, such as a hub or switch, used to connect it to another connectivity device. |
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Term
| VLAN (virtual local area network) |
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Definition
| A network within a network that is logically defined by grouping its devices' switch ports in the same broadcast domain. A VLAN can consist of any type of network node in any geographic location and incorporate nodes connected to different switches. |
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Term
| VTP (VLAN trunking protocol) |
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Definition
| Cisco's protocol for exchanging VLAN information over trunks. VTP allows one switch on a network to centrally manage all VLANs. |
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