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Administrative Distance
Administrative distance (AD) or route preference is a number of arbitrary unit assigned to dynamic routes, static routes and directly-connected routes. The value is used in routers to rank routes from most preferred (low AD value) to least preferred (high AD value).Cisco Systems (2013),What is Administrative Distance? retrieved 14 September 2013 When multiple paths to the same destination are available in its routing table, the router uses the route with the lowest administrative distance. Router vendors typically design their routers to assign a default administrative distance to each kind of route. For example, on Cisco routers, routes issued by the Open Shortest Path First routing protocol have a lower default administrative distance than routes issued by the Routing Information Protocol. This is because, by default on Cisco routers, OSPF has a default administrative distance of 110 and RIP has a default administrative distance of 120. Administrative distance values can, howe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbitrary Unit
In science and technology, an arbitrary unit (abbreviated arb. unit, '' see below'') or procedure defined unit (p.d.u.) is a relative unit of measurement to show the ratio of amount of substance, intensity, or other quantities, to a predetermined reference measurement. The reference measurement is typically defined by the local laboratories or dependent on individual measurement apparatus. It is therefore impossible to compare "1 arb. unit" by one measurer and "1000 arb. unit" by another measurer without detailed prior knowledge on how the respective "arbitrary units" were defined; thus, the unit is sometimes called an unknown unitThe unit only serves to compare multiple measurements performed in similar environment, since the ratio between the measurement and the reference is a consistent and dimensionless quantity independent of what actual units are used. Units of such kind are commonly used in fields such as physiology to indicate substance concentration, and spectroscopy to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Routing
Dynamic routing, also called adaptive routing, is a process where a router can forward data via a different route for a given destination based on the current conditions of the communication circuits within a system. The term is most commonly associated with data networking to describe the capability of a network to 'route around' damage, such as loss of a node or a connection between nodes, so long as other path choices are available. Dynamic routing allows as many routes as possible to remain valid in response to the change. Systems that do not implement dynamic routing are described as using static routing, where routes through a network are described by fixed paths. A change, such as the loss of a node, or loss of a connection between nodes, is not compensated for. This means that anything that wishes to take an affected path will either have to wait for the failure to be repaired before restarting its journey, or will have to fail to reach its destination and give up the journ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Privileged Exec Mode
Privileged may refer to: Film and television * ''Privileged'' (TV series), a 2008 US television series * ''Privileged'' (film), a 1982 Hollywood film Other uses * Immunologically privileged site, a body location where immune response to antigens is non-destructive or suppressed * Privileged motion, a motion of parliamentary procedure * Privileged group, an economics term * Privileged pattern In music a privileged pattern is a motive, figure, or chord which is repeated and transposed so that the transpositions form a recognizable pattern. The pattern of transposition may be either by a repeated interval, an interval cycle, or a st ..., a musical motive, figure, or chord which is repeated and transposed See also * Privilege (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing Redistribution
Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone network (PSTN), and computer networks, such as the Internet. In packet switching networks, routing is the higher-level decision making that directs network packets from their source toward their destination through intermediate network nodes by specific packet forwarding mechanisms. Packet forwarding is the transit of network packets from one network interface to another. Intermediate nodes are typically network hardware devices such as routers, gateways, firewalls, or switches. General-purpose computers also forward packets and perform routing, although they have no specially optimized hardware for the task. The routing process usually directs forwarding on the basis of routing tables. Routing tables maintain a record of the routes to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Next Hop Resolution Protocol
The Next Hop Resolution Protocol (NHRP) is an extension of the ATM ARP routing mechanism that is sometimes used to improve the efficiency of routing computer network traffic over Non-Broadcast, Multiple Access (NBMA) Networks. It is defined in IETF RFC 2332, and further described in RFC 2333. It can be used by a sender to determine a route with the fewest hops to a receiver. The protocol differs from ARP-type protocols in that it allows routing optimization across multiple IP subnets. NHRP is implemented by means of next-hop servers across IP subnets. The NHRP forms a part of the Multiprotocol Encapsulation over ATM (MPOA) protocol as described in RFC 2684. It also plays a role in Cisco's Dynamic Multipoint Virtual Private Network. A limitation of NHRP is its inability to improve multicast In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On Demand Routing
On-Demand Routing ("ODR") is an enhancement to Cisco Discovery Protocol (CDP), a protocol used to discover other Cisco devices on either broadcast or non-broadcast media. With the help of CDP, it is possible to find the device type, the IP address, the Cisco IOS The Internetworking Operating System (IOS) is a family of proprietary network operating systems used on several router and network switch models manufactured by Cisco Systems. The system is a package of routing, switching, internetworking, and ... version running on the neighbor Cisco device, the capabilities of the neighbor device, and so on. In Cisco IOS software release 11.2, ODR was added to CDP to advertise the connected IP prefix of a stub router via CDP. This feature takes an extra five bytes for each network or subnet, four Bytes for the IP address, and one byte to advertise the subnet mask along with the IP. ODR is able to carry Variable Length Subnet Mask (VLSM) information. External links ODR Cisco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exterior Gateway Protocol
An exterior gateway protocol is an IP routing protocol used to exchange routing information between autonomous systems. This exchange is crucial for communications across the Internet. Notable exterior gateway protocols include Exterior Gateway Protocol (EGP), now obsolete, and Border Gateway Protocol Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. BGP is classified as a path-vector routing protocol, and it make ... (BGP). By contrast, an interior gateway protocol is a type of protocol used for exchanging routing information between gateways (commonly routers) within an autonomous system (for example, a system of corporate local area networks). This routing information can then be used to route network-level protocols like IP. References Internet protocols Internet Standards Routing protocols {{Compu-network-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IS-IS
Intermediate System to Intermediate System (IS-IS, also written ISIS) is a routing protocol designed to move information efficiently within a computer network, a group of physically connected computers or similar devices. It accomplishes this by determining the best route for data through a packet switching network. The IS-IS protocol is defined in ISO/IEC 10589:2002 as an international standard within the Open Systems Interconnection (OSI) reference design. The Internet Engineering Task Force (IETF) republished IS-IS in , but that RFC was later marked as ''historic'' by because it republished a draft rather than a final version of the (International Organization for Standardization) ISO standard, causing confusion. IS-IS has been called "the ''de facto'' standard for large service provider network backbones." Description IS-IS is an interior gateway protocol, designed for use within an administrative domain or network. This is in contrast to exterior gateway protocols, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IGRP
Interior Gateway Routing Protocol (IGRP) is a distance vector interior gateway protocol (IGP) developed by Cisco. It is used by routers to exchange routing data within an autonomous system. IGRP is a proprietary protocol. IGRP was created in part to overcome the limitations of RIP (maximum hop count of only 15, and a single routing metric) when used within large networks. IGRP supports multiple metrics for each route, including bandwidth, delay, load, and reliability; to compare two routes these metrics are combined into a single metric, using a formula which can be adjusted through the use of pre-set constants. By default, the IGRP composite metric is a sum of the segment delays and the lowest segment bandwidth. The maximum configurable hop count of IGRP-routed packets is 255 (default 100), and routing updates are broadcast every 90 seconds (by default). IGRP uses protocol number 9 for communication.{{cite web , url=https://www.iana.org/assignments/protocol-numbers/protocol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIGRP
Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers. In 2013 Cisco decided to allow other vendors freely implement limited version of EIGRP with some of its associated features such as High Availability (HA), while withholding other EIGRP features such as EIGRP stub, needed for DMVPN and large-scale campus deployment, exclusively for themselves. Information needed for implementation was published with informational status as in 2016, which did not make it into an Internet Standards Track specification and allowed Cisco to retain control of the EIGRP protocol. EIGRP is used on a router to share routes with other routers within the same autonomous system. Unlike other well known routing protocols, such as RIP, EIGRP only sends incremental updates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisco Systems
Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, software, telecommunications equipment and other high-technology services and products. Cisco specializes in specific tech markets, such as the Internet of Things (IoT), domain security, videoconferencing, and energy management with leading products including Webex, OpenDNS, Jabber, Duo Security, and Jasper. Cisco is one of the largest technology companies in the world ranking 74 on the Fortune 100 with over $51 billion in revenue and nearly 80,000 employees. Cisco Systems was founded in December 1984 by Leonard Bosack and Sandy Lerner, two Stanford University computer scientists who had been instrumental in connecting computers at Stanford. They pioneered the concept of a local area network (LAN) being used to connect distant c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static Routing
Static routing is a form of routing that occurs when a router uses a manually-configured routing entry, rather than information from dynamic routing traffic. In many cases, static routes are manually configured by a network administrator by adding in entries into a routing table, though this may not always be the case. Unlike dynamic routing, static routes are fixed and do not change if the network is changed or reconfigured. Static routing and dynamic routing are not mutually exclusive. Both dynamic routing and static routing are usually used on a router to maximise routing efficiency and to provide backups in case dynamic routing information fails to be exchanged. Static routing can also be used in stub networks, or to provide a gateway of last resort. Uses Static routing may have the following uses: * Static routing can be used to define an exit point from a router when no other routes are available or necessary. This is called a default route. * Static routing can be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
