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Link State Packet
Link State Packet (LSP) is a packet of information generated by a network router in a link state routing protocol that lists the router's neighbors. Link state packets can be further defined as special datagrams that determine the names of and the cost or distance to any neighboring routers and associated networks. They are used to efficiently determine what the new neighbor is, if a link failure occurs, and the cost of changing a link if the need arises. LSPs are queued for transmission, and must time out at about the same time. They must be acknowledged, and can be distributed throughout the network, but cannot use the routing database. Developing Link State Packets When Information needed for exchange is collected, a router then builds a packet containing all the data. The packet starts with the identity of the sender, followed by a sequence number and age, and a list of neighbors. For each neighbor, the delay to that neighbor is given. Building a link state packet is usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Router
A router is a computer and networking device that forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination node. The most familiar type of IP routers are home and small office routers that forward IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, connect large business or ISP networks to powerful core routers that forward data at high speed along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Link State
Link-state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the others being distance-vector routing protocols. Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS). The link-state protocol is performed by every ''switching node'' in the network (i.e., nodes which are prepared to forward packets; in the Internet, these are called routers). The basic concept of link-state routing is that every node constructs a ''map'' of the connectivity to the network in the form of a graph, showing which nodes are connected to which other nodes. Each node then independently calculates the next best logical ''path'' from it to every possible destination in the network. Each collection of best paths will then form each node's routing table. This contrasts with distance-vector routing protocols, which work by having each node shar ... [...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] |
Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet (information Technology)
In telecommunications and computer networking, a network packet is a formatted unit of Data (computing), data carried by a packet-switched network. A packet consists of control information and user data; the latter is also known as the ''Payload (computing), payload''. Control information provides data for delivering the payload (e.g., source and destination network addresses, error detection codes, or sequencing information). Typically, control information is found in packet Header (computing), headers and Trailer (computing), trailers. In packet switching, the Bandwidth (computing), bandwidth of the transmission medium is shared between multiple communication sessions, in contrast to circuit switching, in which circuits are preallocated for the duration of one session and data is typically transmitted as a continuous bit stream. Terminology In the seven-layer OSI model of computer networking, ''packet'' strictly refers to a protocol data unit at layer 3, the network layer. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Number
A sequence number is a consecutive number in a sequence of numbers, usually of real integers (natural numbers). Sequence numbers have many practical applications. They can be used, among other things, as part of serial numbers on manufactured parts, in case management, or in databases as a surrogate key for registering and identifying unique entries in a table (in which case it is used as a primary key). Examples Historically, the Norwegian Mapping Authority have used sequence numbers for land registration as a placeholder in cases where an organization number or national identity number have not been known. In elections in Norway, sequence numbers are used in the duplicate check to prevent votes being counted twice or to detect duplicate ballots. An example of a sequence number being used as a surrogate key is the ''snr'' number used by Statistics Norway since 1970, which uniquely identifies a person even if their social security number changes. The snr number will then be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flooding (computer Networking)
Flooding is used in computer network Routing, routing algorithms in which every incoming packet (information technology), packet is sent through every outgoing link except the one it arrived on. Flooding is used in Bridging (networking), bridging and in systems such as Usenet and peer-to-peer file sharing and as part of some routing protocols, including Open Shortest Path First, OSPF, Distance Vector Multicast Routing Protocol, DVMRP, and those used in ad-hoc wireless networks (WANETs). Types There are generally two types of flooding available, uncontrolled flooding and controlled flooding. In ''uncontrolled flooding'' each node unconditionally distributes packets to each of its neighbors. Without conditional logic to prevent indefinite recirculation of the same packet, broadcast storms are a hazard. ''Controlled flooding'' has its own two algorithms to make it reliable, SNCF (Sequence Number Controlled Flooding) and RPF (reverse-path forwarding). In SNCF, the node attache ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
OSPF
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 (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 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. Concepts OSPF is an interior gateway protocol (IGP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Link-state Advertisement
The link-state advertisement (LSA) is a basic communication means of the OSPF routing protocol for the Internet Protocol (IP). It communicates the router's local routing topology to all other local routers in the same OSPF area. OSPF is designed for scalability, so some LSAs are not flooded out on all interfaces, but only on those that belong to the appropriate area. In this way detailed information can be kept localized, while summary information is flooded to the rest of the network. The original IPv4-only OSPFv2 and the newer IPv6-compatible OSPFv3 have broadly similar LSA types. Types The LSA types defined in OSPF are as follows: The opaque LSAs, types 9, 10, and 11, are designated for upgrades to OSPF for application-specific purposes. For example, OSPF-TE has traffic engineering extensions to be used by RSVP-TE in Multiprotocol Label Switching Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to th ... [...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] |
