For a CCNA candidate, you almost certainly have some background in PC hardware and workstation support. If that’s the case, you’re already knowledgeable about loopback interfaces, especially 127.0.0.1, the loopback address assigned to a PC. More info https://www.certification-questions.com/
When you are learning about the distinct physical interfaces to your CCNA test – serial, ethernet, and BRI, among the others – there is one logical interface that you want to learn about, which is – you guessed it! – the loopback interface.
What is not as immediately clear is the reason why we utilize loopback interfaces on switches and routers to start with. A number of the Cisco router characteristics that may use loopbacks are intermediate and advanced features you’ll find out about on your CCNP and CCIE studies, however these attributes all come back to one fundamental concept: When the loopback interface on a router is down, then which usually means the router is inaccessible overall.
By comparison, a physical port does not indicate the router is out of commission. The physical interfaces on this router continue to be functional, although A router ethernet port may return. There is nothing physical that may go wrong, Because there is a loopback interface plausible.
As I said, you will find different Cisco router and change characteristics that use loopback ports as you scale the Cisco certification ladder. There is 1 misconception concerning Cisco loopback interfaces you would like to become clear on today. You are likely knowledgeable about loopback ports on a PC, and might even be aware that the address array 127.0.0.0 is reserved for loopback addressing.