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New Member

Switching

Came across SVI, similar to VLAN. got twisted and confused. Why it is used? detailed explanation would be appreciated

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New Member

Traditionally, switches send

Traditionally, switches send traffic only to hosts within the same broadcast domain (Single VLAN) and routers handled traffic between different broadcast domains (Different VLANs). This meant that network devices in different broadcast domains could not communicate without a router.

With SVIs the switch will use virtual Layer 3 interface to route traffic to other Layer 3 interface thus eliminating the need for a physical router.

VLANs reduce the load on a network by dividing a LAN into smaller segments and keeping local traffic within a VLAN. However, because each VLAN has its own domain, a mechanism is needed for VLANs to pass data to other VLANs without passing the data through a router.

The solution is to use switched virtual interface – SVI. An SVI is normally found on switches (Layer 3 and Layer 2). With SVIs the switch recognizes the packet destinations that are local to the sending VLAN and switches those packets and packets destined for different VLANs are routed.

There is one-to-one mapping between a VLAN and SVI, thus only a single SVI can be mapped to a VLAN. In default setting, an SVI is created for the default VLAN (VLAN1) to permit remote switch administration.

 

Hope this helps.

2 REPLIES
Cisco Employee

Hi, SVI is nothing but

Hi,

 

SVI is nothing but Switched Virtual interface for a particular vlan (Virtual LAN). Through vlan you define broadcast boundary and it can be pure layer 2 only. But if you want to assign any ip address for management purpose or may be for routing purpose for a vlan on a switch then we create a SVI interface with command "interface <vlan-id>". 

 

Regards,

Akash

New Member

Traditionally, switches send

Traditionally, switches send traffic only to hosts within the same broadcast domain (Single VLAN) and routers handled traffic between different broadcast domains (Different VLANs). This meant that network devices in different broadcast domains could not communicate without a router.

With SVIs the switch will use virtual Layer 3 interface to route traffic to other Layer 3 interface thus eliminating the need for a physical router.

VLANs reduce the load on a network by dividing a LAN into smaller segments and keeping local traffic within a VLAN. However, because each VLAN has its own domain, a mechanism is needed for VLANs to pass data to other VLANs without passing the data through a router.

The solution is to use switched virtual interface – SVI. An SVI is normally found on switches (Layer 3 and Layer 2). With SVIs the switch recognizes the packet destinations that are local to the sending VLAN and switches those packets and packets destined for different VLANs are routed.

There is one-to-one mapping between a VLAN and SVI, thus only a single SVI can be mapped to a VLAN. In default setting, an SVI is created for the default VLAN (VLAN1) to permit remote switch administration.

 

Hope this helps.

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