User-preferred instance analysis functions and benefits of layer-3 switches

At present, many network devices have three-tier switches. It can be seen that three-tier switches have become the first choice for many users. Here we mainly introduce the role of three-tier switches and the benefits of using three-tier switches. What I want to tell you in this article is that the layer-3 switch is very effective, not only looks beautiful, but also looks beautiful! So what is the role of layer-3 switches in the Construction of Campus Networks and urban education networks? What services does a layer-3 Switch provide for us?

What role does it bring to us? In order to answer this question well, we specially invited experts on layer-3 switches and school teachers to discuss the problem and finally got a satisfactory answer. Please have a good taste.

Role of a layer-3 Switch

◆ Layer-3 switching is indispensable for network backbone

A brief explanation: the Layer 7 Application Layer mainly provides user interfaces, which is the main implementation part of our program. The presentation layer on the sixth layer represents data and is mainly responsible for data encoding. For example: mpeg, midi, mp3. the fifth layer is mainly responsible for distinguishing data between applications so that they only interact with their applications without interfering with each other!

The fourth layer of the transmission layer is mainly responsible for data transmission, based on TCP trusted connections) and not based on connection UDP untrusted transmission mode is defined in this layer. It also includes data error correction TCP ). Layer 3 network layer provides network logic IP addresses, IPX ......), A route is defined at this layer to determine the data transmission path. Data Packets)

The Layer 2 data link layer provides MAC addresses, bridging and switching definitions at this layer, with error detection. Data frame) the first layer of the physical layer of Dongdong cable, voltage ......), The Hub is defined in this layer. BITs) layer-2 switches are based on mac addresses, frame layer-3 switches are based on IP addresses, and packet are similar to Routers. However, because ASIC is used, the speed is generally faster!

The role of a layer-3 Switch in many network devices cannot be described as the mainstay. In campus networks and urban education networks, three-layer switches are available in backbone networks, man backbone networks, and aggregation layers. In particular, three-layer switches must be used for core backbone networks, otherwise, thousands of computers on the entire network will be deployed in a sub-network, which is not only insecure, but also unable to isolate broadcast storms due to the inability to divide broadcast domains. Although traditional routers can be used to isolate broadcasts, their performance is not guaranteed. The performance of a layer-3 switch is very high. It provides both layer-3 routing and layer-2 switching network speed. Layer-2 switching is based on MAC addressing, while layer-3 switching is based on forwarding traffic of layer-3 addresses. In addition to the necessary routing decision processes, most data forwarding processes are handled by layer-2 switching, this improves the efficiency of packet forwarding.

Layer-3 switches implement the IP routing function by using a hardware exchange mechanism. The optimized routing software improves the routing efficiency and solves the routing speed problem of traditional routers. Therefore, it can be said that layer-3 switches have "vro functions and vswitch performance ".

◆ Layer-3 switching is indispensable for connecting subnets

If the number of computers on the same network exceeds a certain number, usually around 200, depending on the communication protocol), it is likely that the network transmission efficiency will be low due to a large number of broadcasts on the network. To avoid a broadcast storm caused by broadcasting on a large vswitch, You can further divide it into multiple virtual network VLANs ).

However, this will cause a problem: Communication Between VLANs must be implemented through routers. However, traditional routers cannot perform communication tasks between VLANs, because the Routing Capability of traditional routers is too weak compared with the network traffic of LAN.

In addition, the price of a gigabit router is unacceptable. If you use a layer-3 Switch to connect to different subnets or VLANs through a gigabit or 10-Gigabit port, after Dividing subnets economically, subnets must rely on routers for communication. Therefore, layer-3 switches are ideal devices for connecting subnets.

Benefits of using a layer-3 Switch

In addition to excellent performance, layer-3 switches have some features that traditional layer-2 switches do not have. These features can bring many benefits to the Construction of Campus Networks and urban education networks. The role of layer-3 switches is listed below.

◆ High scalability

When a layer-3 switch is connected to multiple subnets, The subnet only establishes a logical connection with the layer-3 Switch module. It does not need to add ports as traditional external routers do, this protects users' investment in Campus Networks and urban education networks. And meet the requirements of the school 3 ~ 5 years of rapid growth in network applications.

◆ Cost-effective

A layer-3 switch can connect to a large network and can basically replace some traditional routers, but the price is close to that of a layer-2 switch. Currently, the price of a M L3 switch is only tens of thousands, which is similar to that of a high-end L2 Switch.

◆ Built-in security mechanism

Like a common router, a layer-3 Switch has the access list function to implement one-way or two-way communication between different VLANs. If you set it in the access list, you can restrict users to access specific IP addresses, so that the school can prohibit students from accessing unhealthy sites. The access list can be used not only to prohibit internal users from accessing certain sites, but also to prevent illegal users outside the campus network and the city education network from accessing the network resources inside the campus network and the city education network, thus improving network security.