How to correctly select a broadband network switch

Broadband Network switches are quite common, So I studied how to correctly select a broadband network switch. Here I will share it with you, hoping it will be useful to you. The storage and forwarding technology requires the broadband network switch to decide how to forward after receiving all data packets. In this way, the broadband network switch can check the integrity and correctness of data packets before forwarding. It has the following advantages: No incomplete data packet forwarding reduces potential unnecessary data forwarding. Its disadvantage is that the forwarding rate is slower than that of direct forwarding. Therefore, the storage and forwarding technology is more suitable for the network environment with common link quality.

Backplane throughput and buffer size

Backplane throughput is also called the maximum bandwidth. The unit is the number of packets passed per second (pps), which indicates the maximum data volume that can be transferred between the processor of the broadband network switch interface or the interface card and the data bus. The higher the bandwidth of A vswitch, the stronger the ability to process data. The maximum theoretical value is the line rate. That is, a broadband network switch can process data packet forwarding buffers of all sizes at full speed. It is also called the packet buffer size. It is a data queue mechanism, A broadband network switch is used for speed matching between different network devices. Data sent by a device with a high speed can be stored in the buffer until it is processed by a slow device. The buffer size is calculated by the buffer scheduling algorithm. A large buffer space requires a relatively large amount of addressing time. If the buffer space is too small, packet loss may occur in the case of congestion.

Latency

Switch latency refers to the interval between the time when the switch receives the data packet and the time when it begins to copy the data packet to the destination port. There are many factors that affect the latency, such as forwarding technology and buffer size. Vswitches using the forward-through technology have fixed latency. The bandwidth network switch that uses the storage and forwarding technology starts to forward data packets only after it receives the complete data packets. Therefore, its delay is related to the packet size. Latency has a serious impact on real-time and non-real-time video and voice information in the three-in-one network, which may lead to non-synchronous pictures and voice.

Management Functions

To facilitate management by network administrators and control access switches by users, generally, the switch should support the snmp mib I/MIB II statistical management function to meet the requirements of common network management software such as OPENVIEW, SUN Solstice Domain Manager, or IBM Network Management (NetView) Remote Management Switch. Complex vswitches also support the active RMON monitoring function through the built-in RMON group (mini-RMON. You can also use the WEB page or CLI to remotely monitor devices to implement common management functions such as fault management, performance management, configuration management, and security management.

MAC address table size and MAC address type

Each port or device connecting to the LAN requires a MAC address, which is used by other devices to locate a specific port and update the route table and data structure. The MAC address table size reflects the number of nodes supported by the device. A single MAC address type switch connects to an end user or a non-bridging device, and cannot connect to the network segments of multiple network devices such as a hub. A multi-MAC address switch can store multiple MAC addresses on each port with strong support for multiple nodes.

Extension tree

To ensure network security, redundant backup links are often provided for key data links. Because the switch is actually a multi-port transparent bridge device, the "topology ring" problem is caused. The switch uses the extended Tree Protocol algorithm to let every bridging device in the network know each other and automatically prevents the Topological Ring. Switch and disconnect a port in the detected "Topological Ring" to eliminate the "Topological Ring" and maintain the integrity of the topology tree in the network.

Full Duplex

The full-duplex port can send and receive data at the same time, but this requires that both the switch and connected devices support full-duplex operation. Vswitches with full-duplex functions can achieve high throughput (twice the single-mode port throughput), avoid collision, and break through the length limit of CSMA/CD links, the length limit of the communication link is only related to the physical media. In addition, it is best to enable full/half-duplex automatic conversion of switch ports.

High-speed port Integration

A broadband network switch can provide a high-bandwidth "pipe" (fixed port, optional module, or multi-link tunnel) to meet the switching needs of the bandwidth network switch traffic and the upper-level trunk. Prevents trunk communication bottlenecks. Such as FDDI, ATM, and G bit optical module.

Maximum number of VLANs

This parameter reflects the maximum number of VLANs supported by a device. The maximum number of VLANs supported by a broadband network switch (over 1024) is sufficient to meet the needs of general enterprises. VLAN Division should follow the 802.1Q standard.

Scalability Configuration

Rack slots, expansion slots, maximum number of stacks, 10/100/M Ethernet ports, maximum number of ATM ports, maximum number of SONET ports, maximum FDDI ports, and maximum number of power supplies the hardware indicators directly reflect the expansion capability of the broadband network switch and the interconnection capability with other backbone network devices.

Different users have different requirements in their selection, such as implementing access control (ACL) and QoS for data streams) bandwidth management, various control and service policies, packet filtering, Server Load balancer, and layer-3 Switch support for various routing protocols.

In short, users should carefully examine the various functions of Switches during network planning, design, and selection of switches. Especially with the ever-changing exchange technology, more and more broadband network switches integrate new functions of other network devices, with its superior performance and price ratio, it has become a new favorite of users. Especially in some industries, switch selection should be more careful and comprehensive. This article briefly describes the choice of vswitches based on actual work and common engineering cases, it helps readers to design networks, select and use broadband switches.