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Open Shortest Path First
Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single Autonomous system (Internet), autonomous system (AS). OSPF gathers link state information from available routers and constructs a topology map of the network. The topology is presented as a routing table to the internet layer for routing packets by their destination IP address. OSPF supports Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) networks and is widely used in large enterprise networks. IS-IS, another LSR-based protocol, is more common in large Network service provider, service provider networks. Originally designed in the 1980s, OSPF version 2 is defined in RFC 2328 (1998). The updates for IPv6 are specified as OSPF version 3 in RFC 5340 (2008). OSPF supports the Classless Inter-Domain Routing (CIDR) addressing model. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing Protocol
A routing protocol specifies how routers communicate with each other to distribute information that enables them to select paths between nodes on a computer network. Routers perform the traffic directing functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer. Routing algorithms determine the specific choice of route. Each router has a prior knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network. The ability of routing protocols to dynamically adjust to changing conditions such as disabled connections and components and route data around obstructions is what gives the Internet its fault tolerance and high availability. The specific characteristics of routing protocols include the manner in which they avoid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dijkstra's Algorithm
Dijkstra's algorithm ( ) is an algorithm for finding the shortest paths between nodes in a weighted graph, which may represent, for example, a road network. It was conceived by computer scientist Edsger W. Dijkstra in 1956 and published three years later. Dijkstra's algorithm finds the shortest path from a given source node to every other node. It can be used to find the shortest path to a specific destination node, by terminating the algorithm after determining the shortest path to the destination node. For example, if the nodes of the graph represent cities, and the costs of edges represent the distances between pairs of cities connected by a direct road, then Dijkstra's algorithm can be used to find the shortest route between one city and all other cities. A common application of shortest path algorithms is network routing protocols, most notably IS-IS (Intermediate System to Intermediate System) and OSPF (Open Shortest Path First). It is also employed as a subroutine in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicast Address
A multicast address is a logical identifier for a group of hosts in a computer network that are available to process datagrams or frames intended to be multicast for a designated network service. Multicast addressing can be used in the link layer (layer 2 in the OSI model), such as Ethernet multicast, and at the internet layer (layer 3 for OSI) for Internet Protocol Version 4 (IPv4) or Version 6 (IPv6) multicast. IPv4 IPv4 multicast addresses are defined by the most-significant bit pattern of ''1110''. This originates from the classful network design of the early Internet when this group of addresses was designated as ''Class D''. The CIDR notation for this group is . The group includes the addresses from to . The address range is divided into blocks each assigned a specific purpose or behavior. ;Local subnetwork :Addresses in the range of to are individually assigned by IANA and designated for multicasting on the local subnetwork only. For example, the Routing Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicast
In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from physical layer point-to-multipoint communication. Group communication may either be application layer multicast or network-assisted multicast, where the latter makes it possible for the source to efficiently send to the group in a single transmission. Copies are automatically created in other network elements, such as routers, switches and cellular network base stations, but only to network segments that currently contain members of the group. Network assisted multicast may be implemented at the data link layer using one-to-many addressing and switching such as Ethernet multicast addressing, Asynchronous Transfer Mode (ATM), point-to-multipoint virtual circuits (P2MP) or InfiniBand multicast. Network-assisted multicast may also be im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 makes routing decisions based on paths, network policies, or rule-sets configured by a network administrator. BGP used for routing within an autonomous system is called Interior Border Gateway Protocol (iBGP). In contrast, the Internet application of the protocol is called Exterior Border Gateway Protocol (EBGP). History The genesis of BGP was in 1989 when Kirk Lougheed, Len Bosack and Yakov Rekhter were sharing a meal at an IETF conference. They famously sketched the outline of their new routing protocol on the back of some napkins, hence often referenced to as the “Two Napkin Protocol”. It was first described in 1989 in RFC 1105, and has been in use on the Internet since 1994. IPv6 BGP was first defined in in 1994, and it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing Information Protocol
The Routing Information Protocol (RIP) is one of the oldest distance-vector routing protocols which employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination. The largest number of hops allowed for RIP is 15, which limits the size of networks that RIP can support. RIP implements the split horizon, route poisoning, and holddown mechanisms to prevent incorrect routing information from being propagated. In RIPv1 routers broadcast updates with their routing table every 30 seconds. In the early deployments, routing tables were small enough that the traffic was not significant. As networks grew in size, however, it became evident there could be a massive traffic burst every 30 seconds, even if the routers had been initialized at random times. In most networking environments, RIP is not the preferred choice of routing protocol, as its time to converge and scalability are poo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of IP Protocol Numbers
This is a list of the IP protocol numbers found in the 8-bit ''Protocol'' field of the IPv4 header and the 8-bit ''Next Header'' field of the IPv6 header. It is an identifier for the encapsulated protocol and determines the layout of the data that immediately follows the header. Because both fields are eight bits wide, the possible values are limited to the 256 values from 0 (0x00) to 255 (0xFF), of which just over half had been allocated Protocol numbers are maintained and published by the Internet Assigned Numbers Authority (IANA). {, class="wikitable" , - ! class="nomobile" , Hex ! Protocol Number !! Keyword !! Protocol !! References/ RFC , - , style="text-align:right" class="nomobile" , 0x00 , style="text-align:right" , 0 , HOPOPT , IPv6 Hop-by-Hop Option , , - , style="text-align:right" class="nomobile" , 0x01 , style="text-align:right" , 1 , ICMP , Internet Control Message Protocol , , - , style="text-align:right" class="nomobile" , 0x02 , style="te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Control Protocol
The Transmission Control Protocol (TCP) is one of the main communications protocol, protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliability (computer networking), reliable, ordered, and error detection and correction, error-checked delivery of a reliable byte stream, stream of octet (computing), octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the transport layer of the TCP/IP suite. Transport Layer Security, SSL/TLS often runs on top of TCP. TCP is Connection-oriented communication, connection-oriented, meaning that sender and receiver firstly need to establish a connection based on agreed parameters; they do this through three-way Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Datagram Protocol
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in Network packet, packets) to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths. UDP is a connectionless protocol, meaning that messages are sent without negotiating a connection and that UDP does not keep track of what it has sent. UDP provides checksums for data integrity, and port numbers for addressing different functions at the source and destination of the datagram. It has no Handshake (computing), handshaking dialogues and thus exposes the user's program to any Reliability (computer networking), unreliability of the underlying network; there is no guarantee of delivery, ordering, or duplicate protection. If error-correction facilities are needed at the network interface level, an applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Protocol
Transport (in British English) or transportation (in American English) is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelines, and space. The field can be divided into infrastructure, vehicles, and operations. Transport enables human trade, which is essential for the development of civilizations. Transport infrastructure consists of both fixed installations, including roads, railways, airways, waterways, canals, and pipelines, and terminals such as airports, railway stations, bus stations, warehouses, trucking terminals, refueling depots (including fuel docks and fuel stations), and seaports. Terminals may be used both for the interchange of passengers and cargo and for maintenance. Means of transport are any of the different kinds of transport facilities used to carry people or cargo. They may include vehicles, riding animals, and pack animals. Vehicles may inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Route Summarization
A supernetwork, or supernet, is an Internet Protocol (IP) network that is formed by aggregation of multiple networks (or subnets) into a larger network. The new routing prefix for the aggregate network represents the constituent networks in a single routing table entry. The process of forming a supernet is called supernetting, prefix aggregation, route aggregation, or route summarization. Supernetting within the Internet serves as a strategy to avoid fragmentation of the IP address space by using a hierarchical allocation system that delegates control of segments of address space to regional Internet registries. This method facilitates regional route aggregation. The benefits of supernetting are efficiencies gained in routers in terms of memory storage of route information and processing overhead when matching routes. Supernetting, however, can introduce interoperability issues and other risks. Overview In IP networking terminology, a supernet is a block of contiguous subnetw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
