Ho to choose the suitable layer 3 Ethernet switch

Nowadays, the traditional switching system has become increasingly unaffordable for strict network security. With the development of enterprises, the choice of new network products to set up a network has become the most urgent need of modern enterprises. The emergence of large switches such as Layer 3 switch has changed the traditional switching system phenomenon.

Modern LAN infrastructure needs to provide a new solution to data transmission through network boundaries, which requires a brand new device with the functions of both Layer 2 switches and LAN routers, and with less latency than traditional LAN routers. Usually, we call it a Layer 3 switch.

Currently, Layer 3 switches are showing a strong growth trend and are replacing routers in LANs. Their huge market potential is attracting a large number of domestic and foreign vendors to join the competition. Happily, domestic vendors have developed their ASIC chips and network management software in critical technologies, thus providing a vast space for users to choose the brand. Currently, the leading vendors in the market are Cisco, 3Com, Extreme, Foundry, Avaya, Nortel, Enterasys, D-Link, Huawei, and TCL. In the face of such a variety of brands, How users choose the suitable Layer 3 switch becomes a complex problem.

For selecting a Layer 3 switch, the focus in choosing a Layer 3 switch varies from user to user because the network structure and application will be different. However, for users, the following aspects are generally essential to note.

Focus on throughput at complete configuration

As with any electronic product, when selecting a Layer 3 switch, the first step is to analyze the performance metrics of various products. However, in the face of many technical indicators such as switching capacity (Gbps), backplane bandwidth (Gbps), processing power (Mpps), throughput (Mpps), etc., it is best to hold on to the indicator “throughput at full configuration” because users generally cannot measure other technical indicators. Still, throughput is an indicator that users can directly measure and verify using test instruments such as Smart Bits and IXIA.

Distributed switches are better than centralized switches

Different switches use different switch technologies, which can be divided into two main categories: centralized and distributed. The traditional bus-type switch structure module is centralized, and the modern switch matrix module is distributed. Due to the increasing amount of audio, video, and data information running in the enterprise Intranet, it makes it more demanding on the processing capability of the switch. It is wise to use distributed Layer 3 switches to achieve high-speed non-blocking switching under the condition of high port density. Because the bus type switch module still can’t avoid conflict in the Ethernet environment, the matrix type precisely avoids the conflict phenomenon during port switching.

Focus on delay and delay jitter indicators

Almost all enterprise Intranets are high-speed LANs, and one of their purposes is to transmit large-capacity multimedia data such as audio and video. And these large-capacity multimedia data packets are most jittery due to long delay and packet loss. The latency of some traditional centralized switches is as high as 2ms, while the latency of some modern distributed switches is only about 10ms, which is hundreds of times different from each other. The reasons for high latency usually include blocking the design of the switch structure and excessive use of buffering, etc. Therefore, attention to latency requires attention to the product’s modular system.

Stable performance

Layer 3 switches are mostly used in the backbone and aggregation layer. If the performance is not stable, it will affect most of the hosts of the network system or even the entire network system. Therefore, only the durable Layer 3 switches can ensure the continuous, reliable, secure, and regular operation of the network system.  So you can determine this through many metrics such as throughput, latency, frame loss rate, address table depth, wire-end blocking, and all-in-one functionality, as well as market application surveys.

Secure and reliable

As the core equipment of the network, the Layer 3 switch is naturally an essential target of hacker attacks, which requires the Layer 3 switch to include in the scope of network security protection. Of course, the “security and safety” mentioned here should consist of the software and hardware of the Layer 3 switch. Therefore, from the “security” point of view, it is essential to have a layer 3 switch that supports excellent performance and no security vulnerability firewall function. From the “reliability” point of view, because objectively, no product can guarantee that it will not fail, and whether it can quickly switch to a suitable device in case of failure is a matter of concern.

In addition, in the hardware to consider redundancy capabilities, such as power, management modules and ports and other vital components support redundancy, which is particularly important for users such as telecommunications, finance, and other high requirements for security and reliability. There is also the way of heat dissipation, such as cooling fans and different settings are reasonable.

Finally, for broadband operators, the authentication function is also an important aspect to examine. Previously, the switch is for businesses, and the network is directly connected out, no need for authentication. Instead, broadband operators need to confirm whether the user is on record. A window appears when the user accesses the Internet and enters a user name and password to pass authentication. The broadband operator’s Layer 3 switch should also support some particular protocols such as 802.1x to achieve authentication.

Fully functional

The product should meet the current needs and meet the needs of a period in the future, thus giving users a value-added space. For example, when the company increases the number of employees, you can plug in optical modules to expand without eliminating the original equipment. There are also features such as multicast, QoS, port trunking (Port Trunking), 802.1d spanning tree (Spanning Tree), and whether to support RIP, OSPF, and other routing protocols are very important for Layer 3 switches.

Take multicast as an example. In VOD applications, if a group of users simultaneously VOD a program with multicast protocol can ensure that the switch in the high-density video stream VOD very smooth data processing. On the contrary, if the switch does not support multicast protocol, the occupied bandwidth is quite large.

Then the QoS function can be divided into different levels according to the diverse needs of users, which can enable broadband operators to bill by port traffic, thus providing various services to different users. In addition, the access list function. If you divide the VLAN in the access layer, it is impossible to communicate between users of other VLANs because it is based on the second layer of VLAN. If you want to communicate, you must go through the third layer. For example, the finance department and the marketing department of an enterprise generally do not communicate with each other, if a user needs to access, the network administrator can make a simple command-line setting through the Layer 3 switch to enable normal communication between VLANs, which is the access list function. It is a function ported from the router to the Layer 3 switch, enabling one-way or two-way communication between different VLANs. If an external IP address is always found to send useless packets to its network, it can be set in the access list to prohibit it from sending packets.

Final Words

The vendor’s service, ease of use, and cost-effectiveness of the Layer 3 switch are also crucial considerations. The critical thing is that you need to consider the project and your situation.