Comprehensive assessment of Gigabit switch performance

Generally in our evaluation of equipment selection, we should pay attention to the following aspects: Product type, the product support gigabit port density and type, product performance, product after-sales service, product management characteristics and product safety and reliability. When making a purchase, remind the user to pay attention to the following key parameters:

Port

Application: According to the combination of ports at present there are three kinds, pure hundred-gigabit port products, hundred trillion and gigabit port mixed products, pure gigabit products, each product application of the network environment are different, if it is applied to the core backbone network, the best choice for all gigabit products, if it is on the backbone of the network, select Hundred Trillion + Thousand trillion of mixed products, if it is edge access, the budget a little more on the choice of mixed products, less than the budget, directly using the original pure hundred trillion products.

Performance metrics: Switch port performance metrics refer to the number of packets per second that each port can handle. The larger the value, the stronger the switch performance. To purchase a workgroup switch, it is recommended that you choose a 10/100mbps switch with 24 or 48 ports, and if you take into account the overall performance of the upgrade, with the hundred trillion + gigabit mixed is also a good choice, the central switch is recommended to select a fixed port of the pure 1000Mbps switch.

The market is currently capable of providing hundred gigabit + gigabit hybrid port Gigabit switch products and pure Gigabit Switch products.

Throughput

The maximum theoretical value of throughput is called wire speed, which means that the switch has sufficient capacity to handle data packet forwarding at full speed to all sizes, and gigabit switch products should reach the wire speed. Many (such as Speed Networks 2400 series) such as gigabit switch products can reach the full speed. However, this metric is of little practical significance for stackable 10m/100m edge switches.

Forwarding Rate

The forwarding rate is a very important parameter of the switch, which fundamentally determines the forwarding rate of the switch. The forwarding rate is usually expressed as "MPPs" (million Packet per Second, million packets/sec), that is, the forwarding rate per second. Forwarding technology can be divided into storage and forwarding and pass-through forwarding, the majority of gigabit switches are currently supporting storage and forwarding. While pass-through forwarding, although less delay but will bring the Exchange network garbage packets, so generally applicable to the network link quality better, less error packet network environment under the application. SPEED Networks's 2400-series Gigabit switch products are both storage and forwarding technologies.

Back Plate Bandwidth

Backplane bandwidth refers to the maximum amount of data that can be throughput between a switch interface processor or an interface card and an information bus. Since all communication between ports is done via Backplane, the bandwidth available to all backplane is the bottleneck of concurrent communication between ports. The larger the bandwidth, the greater the available bandwidth to each communication port, the faster the data exchange speed, and the smaller the bandwidth, the smaller the available bandwidth to each communication port, and the slower the data exchange speed. Therefore, the larger the backplane bandwidth, the faster the transfer rate of the switch.

Cache

Each switch maintains a MAC address table that records the corresponding relationship between the MAC address and the port, which forwards the access request directly to the corresponding port according to the MAC address. The more the number of MAC addresses stored, the higher the speed and efficiency of data forwarding, and the stronger the ability of anti MAC address overflow supply.

Number of MAC addresses

Caching is used to temporarily store data waiting to be forwarded. If the cache size is small, when concurrent traffic is large, the data is discarded, causing network traffic to fail. Only large cache capacity can provide better overall performance in the event of multicast and broadcast traffic, while ensuring maximum possible throughput. At present, almost all low-cost switches use a shared memory structure, sharing switch memory from all ports, balancing Network load and preventing packet loss.

Management features

Now switch vendors generally provide management software or meet the remote management of third-party management software switches. Generic switches Meet SNMP MIB I/MIB II statistical management capabilities, while complex gigabit switches increase support for RMON active monitoring through the built-in RMON group (Mini&rmon). Some switches also allow external Rmon to monitor the network condition of the optional port.

Virtual Local Area Network

By dividing the LAN into VLAN segment of virtual network, it can strengthen network management and network security, and control unnecessary data broadcasting. In a virtual network, a broadcast domain can be a virtual network segment that consists of a set of arbitrarily selected MAC addresses. In this way, the division of workgroup in the network can break through the geographical limitation in the shared network, and it is divided completely according to the management function. Good products at present can provide a more detailed function of the virtual network division.