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Computer network topology represents the network structure through the geometric relationship between nodes and communication lines in the network, reflecting the structural relationship between entities in the network. Mainly divided into six types: bus type, star type, tree type, ring type, mesh type and hybrid type.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
Computer Network Topology refers to the distribution and connection status of devices among the network composed of computers. Drawing them on the diagram becomes a topology diagram. Generally, the location of the equipment, the name type of the equipment, and the type of connection medium between the equipment should be indicated on the diagram. It is divided into two types: physical topology and logical topology.
Computer network topology refers to the topological configuration of the structure connected between communication subnet nodes. The network structure is represented by the geometric relationship between the nodes and communication lines in the network, reflecting the structural relationship of each entity in the network. .
Types of computer network topology:
1. Bus structure
Bus structure is a way to connect all end users using the same media or cable, that is, to connect The end user's physical media is shared by all devices
In a point-to-point link configuration, half-duplex operation requires only the use of simple mechanisms to ensure that the two end users take turns. In point-to-multipoint mode, access to the line is determined by polling from the control end. However, in a LAN environment, all data stations are equal and cannot adopt a point-to-multipoint approach. Instead, carrier sensing multiple access with collision detection is used (it is a media access method used in bus-sharing networks). , abbreviated as CSMA/CD).
This structure has the advantages of low cost, flexible network access for data end users, and the failure of a site or a certain end user does not affect the communication of other sites or end users.
The disadvantage is that only one end user can send data at a time, and other end users must wait to obtain the right to send. The media access acquisition mechanism is complex. However, due to simple wiring requirements and easy expansion, end user failure, additions and deletions do not affect the work of the entire network, so it is the easiest to use among LAN technologies.
2. Star structure
The star structure facilitates centralized control because communication between end users must pass through the central station. Due to this feature, it also brings advantages such as easy maintenance and security. When the end user equipment is shut down due to failure, it will not affect the communication between other end users. But the central system must have extremely high reliability, because once it is damaged, the entire system tends to be paralyzed.
3. Ring structure
Ring structure is commonly used in LAN. The transmission media in this structure goes from one end user to another until all end users are connected into a ring. This structure eliminates the end user's dependence on the central system when communicating. The characteristic of the ring structure is that each end user is connected to two adjacent end users, so there is a point-to-point link and operates in a one-way manner, divided into upstream end users and downstream end users. User N is the upstream user of user N 1, and N 1 is the downstream user of N. If the N 1 end needs to send data to the N end, it will almost take a full circle to reach the N end.
4. Hybrid topology
Hybrid topology is a network structure that combines a star structure or a ring structure and a bus structure. This topology can better meet the requirements of larger networks. The expansion solves the limitation of star network in transmission distance, and at the same time solves the limitation of bus network in the number of connected users.
5. Distributed structure
A network with a distributed structure interconnects computers distributed in different locations through lines. There is a point-to-point link between each device in the network. The distributed network structure has the following characteristics: due to the use of decentralized control, even if a certain part of the entire network fails, it will not affect the operation of the entire network, so it has high reliability; the shortest path algorithm is used for path selection , so the online delay time is small, the transmission rate is high, but the control is complicated; data links can be established directly between each node, and the information process is the shortest; it facilitates resource sharing within the entire network. The disadvantages are that the cables used to connect the lines are long and the cost is high; the network management software is complex; packet switching, path selection, and flow control are complex; this structure is not used in general LANs.
6. Tree structure network
The tree structure is a hierarchical centralized control network. Compared with the star structure, its total length of communication lines is shorter, the cost is lower, and the nodes are easy to expand. , it is more convenient to find paths, but in addition to leaf nodes and their connected lines, the failure of any node or its connected lines will affect the system.
7. Cellular topology
The cellular topology is a commonly used structure in wireless LANs. It is characterized by point-to-point and multi-point transmission through wireless transmission media (microwave, satellite, infrared, etc.). It is a wireless network suitable for city networks, campus networks, and enterprise networks.
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