Packet forwarding is a packet relay from one network segment to another segment by a node in a computer network.
The Network layer in the Open Systems Interconnection (OSI) model is responsible for packet forwarding. The simplest forwarding model? -? Unicasting? -? Involves a relayed packet from a link to a link along a chain that leads from the source of the packet to its destination. However, other delivery strategies are usually used. Broadcasting requires packets to be duplicated and copies sent on multiple links for the purpose of sending copies to each device on the network. In practice, broadcast packages are not forwarded anywhere on the network, but only to devices within the broadcast domain, making broadcast relative terms. Less common than broadcasting, but perhaps from larger utilities and theoretical significance, is multicasting, in which packages are selectively duplicated and copies are sent to each set of recipients.
Network technology tends to support certain native forwarding models. For example, optical fibers and copper cables run directly from one machine to another to form a natural unicast medium - data transmitted at one end is received by only one machine at the other. However, as depicted in the diagram, nodes can forward packets to create a multicast or broadcast distribution of unicast media naturally. Similarly, traditional Ethernet (10BASE5 and 10BASE2, but not the more modern 10BASE-T) is a natural broadcasting medium - all the nodes are attached to one long cable and packets sent by one device are seen by every other device connected to the cable. Ethernet nodes implement unicast by ignoring packets that are not directly addressed to them. The wireless network is naturally multicast - all devices within the transmitter receiving radius can receive packets. Wireless nodes ignore packets addressed to other devices, but require forwarding to reach nodes beyond their receiving radius.
At the knot where some outbound links are available, the choice that, all, or whatever is used to forward the given package requires a decision process that, though simple in concept, is sometimes confusingly complex. Because forwarding decisions must be made for each packet handled by the node, the total time required for this can be a major limiting factor in overall network performance. Most of the design efforts of high-speed routers and switches have been focused on making quick switch decisions for a large number of packages.
The forwarding decision is generally made using one of two processes: routing, which uses information encoded in the device's address to infer its location on the network, or bridges, which does not make assumptions about where the address resides and is heavily dependent on broadcasting to find unknown locations. address. The large overhead of broadcasting has led to the dominance of routing in large networks, especially the Internet; bridging is mostly downgraded to a small network where broadcast overheads can be tolerated. However, since large networks typically consist of many small networks connected together, it is not appropriate to state that bridging is useless on the Internet; rather, its use is localized.
A network can use one of two different methods to forward packets: save-forward or bypass.
Video Packet forwarding
See also
- node-to-node data transfer
- Port forwarding
Maps Packet forwarding
References
Source of the article : Wikipedia
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