Question : Problem: need the loopback?

related question with some background:
http://www.experts-exchange.com/Networking/Q_21554049.html

all my routers have loopback addresses and id like to get rid of them to free up the network they are taking up.  i cant find anything thats referencing the loopback interface, but id like to get some input here before i go ripping them out.

Answer : Problem: need the loopback?

Are you running any routing protocols? If so, you're better off keeping your loopback interface(s) configured (you *could* carefully reconfigure the loopback IPs on all routers, but keep something in place) so your routing protos behave, from what I've seen in Cisco documentation, since loopbacks are often used as the router ID.  Here's some references:

  Preventing Duplicate EIGRP Router IDs:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800949ab.shtml
  Troubleshooting Duplicate Router IDs with OSPF:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080117102.shtml  --> quote: "OSPF automatically prefers a loopback interface over any other kind, ..."

You can find info on Cisco's website by searching for "loopback router id "

HTH