Today, we’re going to look at OSI (Open System Interconnect). It is a network interconnection model published by ISO in 1985, which defines a seven-layer framework for network interconnection. Its contents are briefly described as follows:
We buy some network equipment for our offices or homes. Generally, there are three types of hubs, switches and routers that can be searched on websites such as JD.com. Here are the differences at the network level.
Hubs work at OSI Layer 1 (Physical Layer) and do nothing but transmit electrical signals to devices connected to them.
A switch is a layer 2 (link layer) device that is addressed by broadcasting on the same network segment and communicates with hosts on the same network segment using the MAC address of the target host. In addition, there is a type of switch on the market that has added routing capabilities, which we call a 3-layer switch.
A router is a 3-layer (transport-layer device) device that learns from each other to generate and maintain a routing table that is responsible for addressing and forwarding across network segments.
In future articles, we will cover some network protocols, services, and commands.
Here, please think about a problem first, usually we say that “the computer can not surf the Internet”, may be caused by what factors? How do you typically locate a problem?