Loopback Addressing

A logical interface
Always up
Reachable over redundant paths
Ideal for administrative use
A software interface.
- Behaves like a regular interface, but it is always always up
Lets say that you got a switch with 10 VLANs, if this switch is routing, it will have 10 IP's
You will pool the device maybe once a minute.
Which of these 10 IP's do we store in the network management station?
Because loopback is always up, we can advertise it trough dynamic routing.
You put an IP address on your loopback, nobody can get there but you can ping it
With this one IP address, we can put this one IP in every single device and advertise it through dynamic routing.
We can always reach our loopbacks.

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Advertise loopback trhough dynamic routing.