How to Classify and Select Network Switches?
Switches are widely used in weak current network projects to transmit various types of data. In this article, we will discuss what factors we should consider when classifying and selecting switches.
1. Classification of switches
● Network structure: access Layer Switches, aggregation layer switches and core layer switches
● OSI model: Layer 2 Switch, Layer 3 switch, Layer 4 switch, Layer 5 switch, Layer 6 switch, Layer 7 switch.
● Manageability of switches: The difference between managed switches and unmanaged switches lies in their support for network management protocols such as SNMP and RMON.
2. Main factors to consider when choosing a switch
● Backplane bandwidth and Layer 2/3 switching throughput.
The backplane bandwidth of a switch is the maximum amount of data that can be throughput between the switch interface processor or interface card and the data bus. The backplane bandwidth marks the total data exchange capability of the switch, in Gbps, also called switching bandwidth. Therefore, only modular switches (with expandable slots that can flexibly change the number of ports) have this concept. Fixed-port switches do not have this concept, and the backplane capacity and switching capacity of fixed-port switches are equal.
How to calculate backplane bandwidth?
Calculation formula: Number of ports*corresponding port rate*2 (full duplex mode)
For example, 24-port 100M+2-port Gigabit switch
The backplane bandwidth is: 24*2*100+2*2*1000=8.8Gbps
● Switching capacity and forwarding capability
Since the switching engine is the core of packet forwarding of the modular switch, this indicator can truly reflect the performance of the switch. For fixed-port switches, the switching engine and the network interface template are integrated, so the forwarding performance parameters provided by the manufacturer are the forwarding performance of the switching engine. This indicator is the key to determining the performance of the switch. For equipment that supports layer 3 switching, the manufacturer will provide the layer 2 forwarding rate and layer 3 forwarding rate respectively. Generally, bps is used for layer 2 capabilities and pps is used for layer 3 capabilities. For modular switches using different architectures, these two parameters The meaning is different. However, for ordinary LAN users, they only care about these two indicators, which are the key indicators that determine the performance of the system. For large campus network and metropolitan area network users, it makes sense to discuss the architecture of the switch and the third layer optimization algorithm.
● VLAN type and number.
● Number and type of switch ports.
● Support protocols and methods for network management. Switches are needed to provide more convenient and centralized management.
● Qos, 802.1q priority control, whether to support 802.1X and 802.3X.
● Whether stacking is supported.
● Parameters such as the switch's switching cache, port cache, main memory, and forwarding delay.
● Line speed forwarding, routing table size, access control list size, support for routing protocols, support for multicast protocols, packet filtering methods, machine expansion capabilities, etc. are all parameters worth considering and should be investigated based on actual conditions.
Established in 2010, TST is a global R&D manufacturer in smart networking and PoE solutions. We offer a wide range of cutting-edge products such as PoE switches, POE injector, industrial switches, and Power over Ethernet (PoE) modules, as well as tailored ODM/OEM services. TST is dedicated to providing professional and unique security surveillance transmission products and services to create value for its customers.