What level of work does the OSI seven - layer structure work with, hubs, switches, routers?
The router only forwards packets of a specific address, does not transmit packets that do not support routing protocols, and transmits unknown packets of network data, thereby preventing broadcast storms.Switches are generally used for LAN-WAN connections, switches to bridges, data link layer equipment, and some switches can also achieve third layers of switching. Routers are used for connections between WAN-WAN, which can solve packet forwarding between peers and act on the network layer. They simply accept input packets from a line and forward them to another line. The two lines may fall into different networks and adopt different protocols.
The network segment connected by the switch still belongs to the same broadcast domain, and the broadcast packet will be transmitted on all segments connected by the switch, and in some cases will lead to communication congestion and security vulnerabilities. The network segment connected to the router is assigned to different broadcast domains, and broadcast data does not pass through the router. Although more than third layers of switches have the function of VLAN, they can also segment the broadcast domain, but there is no communication between the sub broadcast domains, and the communication between them still requires routers.
A switch uses physical addresses, or MAC addresses, to determine the destination address of the forwarded data. The router is to use the ID number of different networks (ie IP address) to determine the address of data forwarding. The IP address is implemented in software that describes the network where the device is located, and sometimes these third levels are also referred to as protocol addresses or network addresses. MAC address is usually hardware comes, by the network card manufacturers to allocate, and has been cured to the network card, generally speaking, is not to be changed. The IP address is usually automatically assigned by a network administrator or system.
The original switch was a data link layer operating on the OSI / RM open architecture, that is, the second layer, and the router was originally designed to work on the network layer of the OSI model. Because the switch work in the second layer of OSI (data link layer), so its working principle is relatively simple, and the router in the third layer of OSI (network layer) protocol, can get more information, the router can make more intelligent forwarding decision.
