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What are sub interfaces?
A subinterface is a virtual interface created by dividing one physical interface into multiple logical interfaces. A sub-interface in a Cisco Router uses the parent physical interface for sending and receiving data. Subinterfaces are used for a variety of purposes.
How do you create a subinterface?
To configure additional IP interfaces over the VLAN major interface:
- Create a new VLAN subinterface by adding a unique subinterface number to the interface identification command. host1(config-if)#interface fastEthernet 4/1.2.
- Assign a VLAN ID for the subinterface.
- Assign an IP address and mask.
How do I create a subinterface on a Cisco switch?
To create a VLAN subinterface, use the interface command in XR Config mode. To delete a subinterface, use the no form of this command. Physical interface or virtual interface followed by the subinterface path ID.
How many subinterfaces can be configured on an interface?
You can partition one physical interface into up to 4094 different subinterfaces, one for each VLAN. We recommend that you use the VLAN ID as the subinterface number when you configure the subinterface.
What is a VLAN sub interface?
A dot1q VLAN subinterface is a virtual Cisco IOS interface that is associated with a VLAN ID on a routed physical interface. A parent interface is a physical port. Subinterfaces can be created only on Layer 3 physical interfaces.
What is the minimum no of interfaces in a router?
TCP/IP’s first requirement for a router is that the machine must have at least two network interfaces installed, as introduced in “Network Interfaces”. As long as one of the network interfaces is not disabled, the router automatically “talks” to the RDISC and RIP protocols.
How many sub interfaces are there?
You can partition one physical interface into up to 4094 different subinterfaces, one for each VLAN.
Why do we use encapsulation dot1q?
As 802.1q encapsulation inserts an additional field into the Ethernet frame, Frame Check Sequence(FCS) is recalculated. All switches support 802.1q encapsulation. VLAN implementations have shown an increase in the performance, scalability and security of the entire network.