Networking principle of high-level switches

layer 3 routing

usually, a normal switch works only at the data link layer, and a router works at the network layer. a powerful layer 3 switch can work at both the data link layer and the network layer and forward packets based on mac address or ip address. however, it should be noted that the layer 3 switch does not completely replace the router because it is mainly used to communicate between vlans on two different subnets, rather than complex path selection for data transmission.

network management function

the degree of management supported by a switch reflects the manageability and operability of the device.Networking principle of high-level switches is an important topic of CCIE Security Lab learning.a switch with network management can monitor the traffic of each port, set the rate of each port, and close/open the port connection. by monitoring the switch ports, it is easy to distinguish the network traffic and quickly define the network faults, which improves the manageability of the network.

port aggregation

this is a kind of encapsulation technology. it is a point-to-point link. both ends of the link can be switches, switches, and routers, and can be hosts and switches or routers. port-based trunking allows switches and switches, switches and routers, hosts and switches or routers to transmit simultaneously through two or more ports to provide higher bandwidth and greater throughput. network capabilities.

cascading mode of switch networking structure

this is the most common networking method, which is connected through the cascade port (uplink) on the switch. note that the switch cannot be cascaded indefinitely. if a certain number of switches are cascaded, the broadcast storm will eventually cause a serious drop in network performance. the structure diagram is as follows.

port aggregation mode

we have already touched the characteristics of port aggregation. this method is equivalent to cascading multiple ports at the same time. it provides higher interconnect bandwidth and line redundancy, which makes the network have certain reliability. the structure diagram is as follows.

stacking method

the stacking of switches is the fastest and most convenient way to expand ports. at the same time, the bandwidth after stacking is several times that of the single switch port. however, not all switches support stacking, depending on whether the switch's brand and model support stacking; and also need to use dedicated stacking cables and stacking modules; finally, the switches in the same stack must be the same brand. the structure diagram is as follows.

layered approach

this method is generally applied to a relatively complex network structure and can be divided into access layer, aggregation layer, and core layer according to functions. the structure diagram is as follows.