The routing protocol is located at the network layer. When a computer sends a packet, each layer of the network protocol stack on the network appends some information to it. Network layer protocols attach routing information, which may be a complete path through a network or some priority value that indicates which path the packet should take.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
The routing protocol is located at the network layer.
When a computer sends a packet, each layer of the network protocol stack on the network attaches some information to it. This information can be read by the peer layer protocol on the receiving end. These messages resemble parts of a communications session. Network layer protocols attach routing information, which may be a complete path through a network or some priority value that indicates which path the packet should take. The network layer information added by the sender can only be read by the router or the receiver's network layer protocol. Repeaters and bridges cannot recognize network layer information and can only transmit and forward packets.
Extended information:
The purpose of the network layer is to realize transparent transmission of data between two end systems. Specific functions include addressing and routing, and connection establishment. , maintain and terminate, etc. It provides services that eliminate the need for the transport layer to understand the data transmission and switching technologies in the network.
The network layer mainly provides services for the transport layer. In order to provide services to the transport layer, the network layer must use the services provided by the data link layer. The main role of the data link layer is to solve the communication problem between two directly adjacent nodes, but it is not responsible for solving the communication problem when the data passes through multiple transfer nodes in the communication subnet. Therefore, in order to realize the communication between the two terminals, The transparent transmission of data between systems allows the source data to transparently reach the destination through multiple transfer nodes in the communication subnet via the optimal path, so that the transport layer does not need to care about the network topology and the communication medium used. and switching technology, the network layer must have the following functions:
Packet and packet switching: Encapsulate the data messages received from the transport layer into packets (Packet, also called "packet") and then transmit them down to data link layer.
Routing: Use routing algorithms to select the most appropriate path for packets through the communication subnet.
Network connection multiplexing: Create logical links for the transmission of packets between nodes in the communication subnet, and multiplex multiple network connections on one data link (mostly using time division multiplexing technology).
Error detection and recovery: Generally, the header checksum in the packet is used for error checking, and the acknowledgment and retransmission mechanism is used for error recovery.
Service selection: The network layer can provide datagram and virtual circuit services for the transport layer, but the network layer of the Internet only provides datagram services for the transport layer.
Network management: manages the data communication process in the network, manages to transmit data from the source to the destination through several intermediate nodes, and provides the most basic end-to-end data transmission service for the transport layer.
Traffic control: Traffic shaping technology is used to achieve traffic control to prevent performance degradation of the communication subnet caused by excessive traffic.
Congestion control: When the data traffic of the network exceeds the rated capacity, network congestion will occur, causing the network's throughput capacity to drop sharply. Appropriate control measures are therefore required for diversion.
Network interconnection: Connect one network to another network to achieve cross-network communication between users.
Fragmentation and reassembly: If the packet to be sent exceeds the allowed length of the protocol data unit, the network layer of the source node will fragment the packet. After the fragments arrive at the destination host, the destination node The network layer is then reassembled into the original packet.
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