Regarding sub-interfaces

[Vijeth]

Hi,
The question I am asking may be very trivial, What are sub-interfaces ?
(Advantages, use cases, configuring sub-interfaces etc., )
Any pointers to previous posts or web resources would be much appreciated !!

Thanks,
Vijeth

[Olaf Borowski]

Vijeth,
Subinterfaces are logical interfaces on a physical link. Example: Ethernet 0/1 is the physical interface. You can create logical interface on that physical interface. Example: Ethernet 0/0.1 and 0/0.2
You can now apply IP-addresses to both of those logical interfaces even if they are on the same physical link. You can also apply ACL's (access control lists) to filter traffic between the (sub)-interfaces.
If you don't need physically separate interfaces, you can logically build subinterfaces that share the bandwidth of the physical interface.
If you need specifics, you have to tell us on what device you are using/configuring.

Hope this helps.