What is Switch Virtual Interface (SVI)

Routers use interfaces or subinterfaces to interconnect multiple VLANs. Multilayer switches use SVIs for routing between VLANs.

In previous networks, the second layer was the fastest data transmission device, the router was relatively slow, physically removed and sent to other ports.

The goal of a network engineer is to maximize the distribution, distribution and distribution of distributors. They divide these layers into 2 layers, creating cyclical problems.

To solve this problem,

The engineers used a wooden protocol, but it still provides flexibility and accuracy in communication. With the advancement of technology, routers have become faster and cheaper, allowing wires to move faster.

Therefore, without affecting the operation of the network, the router moves to the middle and distribution layers. Users are divided into separate VLANs and subnets, and network engineers begin designing distribution schemes as tier 3 portals for VLAN use.

Thus, each distribution switch requires a unique IP address that matches the VLAN key. A 3-layer road is used between the port distribution and the main layer switch. Because two-layer topology does not have a single physical cycle, engineers do not rely on tree protocols.

We can also create multi-layer (SVI) and 2-layer virtual interfaces for VLANs. However, VLAN paths can only be created on a multi-layer transmitter (using 3 layers).

A powerful virtual interface is not a physical port, which is why it is called a virtual interface. It operates in a multi-layered key, such as a router interface, and can be configured as a router interface.

SVI offers this to all owners of VLAN 3 packet processing layers. When you need SVI configuration, make sure the key is a known VLAN.

The image above should contain the VLAN 100 and VLAN 200 keys, otherwise the SVI interface will remain the same. Reasons why we need SVI.

Provide a gateway for a VLAN.

         Assign a 3-layer IP connection to the transmitter.

         Support for marketing protocols and bridge configuration

Two VLANs require a VLAN using the Virtual Interface (SVI). Processing steps are as follows.

With the help of “IP routing” we create routes on the switch. If we do not do this online, we will not be able to communicate with other VLANs. With this command, the transmitter creates a source table of IP address information in the virtual interface.

We can check the IP configuration using the “IP Routing” and “Startup Configuration” commands. The following figure shows a dynamic root table.

As I said before, we can configure the Virtual Interface (SVI) interface for third and second layer switches, but the difference is “IP root”. In 2-layer switches we use the Virtual Interface (SVI) key for remote control.

We can test the interface with the command “Show the IP interface briefly”. It’s as if we used a command to test the router interface.

The command will display all ports and virtual interfaces. If we want to see all the ports and the VLAN interface, we can use the “show interface” command. If we need the interface we need, we can use a command with an interface ID, such as the “show vlan 100 interface”, which shows the configurations on the VLAN 100 interface. You can read my previous articles for other orders. .

Advantages and disadvantages

Powerful Virtual Interface (SVI) is faster than a router because not all are active and inactive.

You do not need external router links to access the Internet.

This removes the online limit because other transmission channels can be placed between the keys.


The downside to 3-layer keys is that they are very expensive.

InterVLAN onlineization, in other words, can be achieved between VLANs using the SVI root (switching to the virtual interface). We need a multi-layered transition here. 2-layer keys may have SVI, but only one. This is SVI contract management for VLAN 1.

For VLAN interconnection, we must first use the “ip routing” command in the multi-layer key for VLAN. By following this command, we can create a virtual interface for each VLAN and assign an IP address to that SVI (download the virtual interface). Then, a multi-layer switch is used to ensure communication between these VLANs.

One of the first concepts we know is SVI (Virtual Interface Exchange).

This virtual interface is, in fact, logical, with no physical port attached to it, but it acts as one layer, the other layer and the third layer.

SVI is usually described by VLAN as a portal of modern equipment in this transmission domain.

It performs 3 root layers for VLAN packages, which means that we can configure 3 layers (IP, ACL, QoS, etc.) on these interfaces.

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