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Can switches interconnect different network segments? (with configuration steps)
May 23 , 2024 372

In network communication, the interconnection between different network segments is crucial. As one of the core equipments in the network, if the switch can realize the interconnection between different network segments, it will certainly provide more convenient and efficient support for network communication. However, it is obvious that not all switches can realize the interconnection of different network segments, such as Layer 2 switches.


Layer 2 switches work at the data link layer and forward data frames based on MAC addresses, and they must use routers to realize the interconnection between different network segments. Routers work at the network layer (Layer 3) and are able to route and forward packets based on IP addresses, which enables communication and interconnection of the entire network.

Layer 3 switches have more powerful network processing capabilities and support more complex network topologies and application scenarios. Not only can they learn MAC addresses and create forwarding tables, but they can also understand and process network layer addresses (such as IP addresses) and route and forward packets according to routing tables.

When a device sends a data frame to the switch, the switch learns the source MAC address of the data frame and associates it with the corresponding port. When the switch receives a data frame from a target device, it sends the data frame to the corresponding port according to the target MAC address, thus realizing direct communication between devices.

This interconnection between different network segments not only improves network performance, but also simplifies network management and enhances network security management, as well as enabling customized configurations based on network topology maps and requirements, and meeting network interconnection needs in different scenarios through flexible network design.

So in what scenarios is this interconnection between different network segments typically used?

First of all, this method is usually used in office network environment. When different departments or devices with different functions are in different network segments, the switch can connect these segments to realize the communication between departments or functions and improve work efficiency.

Secondly, this method is often used in large data centers. When different servers or storage devices are in different network segments, the switch connects these segments to realize the rapid exchange of data between servers or storage devices, thus meeting the high-speed transmission requirements of the data center network.

In addition, when there are different network segments between devices in different academic buildings or different campuses in the campus network, it is often possible to realize network communication within the campus or between departments through switch interconnection to provide efficient campus network services for all teachers and students.

In general, this type of interconnection between different network segments is suitable for office networks, large-scale data centers and campus networks, which can realize the interoperability between different networks within the same LAN, thus improving the access to information and operational efficiency.

So, how to configure this interconnection between different network segments? The engineers of Nethub Communications have given the following suggestions, which are recommended to be bookmarked by friends who need them!

How is this achieved? The overall idea is as follows:

1. 1. Segmenting VLANs on Layer 3 switches

Divide two VLANs, e.g. VLAN10, VLAN20, VLAN30

Configure the ip of the vlan

Set the gateway on the Layer 3 switch

This will enable the two devices to communicate with each other through the switch

The configuration code is shown below:

[SW1]vlan batch 10 20 30


[SW1]int g0/0/1

[SW1-GigabitEthernet0/0/1]p l a

[SW1-GigabitEthernet0/0/1]p d v 10


[SW1-GigabitEthernet0/0/1]int g0/0/2

[SW1-GigabitEthernet0/0/2]p l a

[SW1-GigabitEthernet0/0/2]p d v 20


[SW1-GigabitEthernet0/0/2]int g0/0/3

[SW1-GigabitEthernet0/0/3]p l a

[SW1-GigabitEthernet0/0/3]p d v 30



[SW1]int Vlanif 10

[SW1-Vlanif10]ip address 24


[SW1-Vlanif10]int Vlanif 20

[SW1-Vlanif20]ip address 24


[SW1-Vlanif20]int Vlanif 30

[SW1-Vlanif30]ip address 24


To sum up, Layer 2 switches need to be paired with routers to realize the purpose of interconnection between different network segments, while Layer 3 switches do not need to build routers to realize the interconnection between different network segments. When we build the network topology diagram, we should be flexible according to the actual situation and build the required network flexibly from the overall network structure and product budget.

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