Please explain what is the difference between Via, From and Contact header in SIP INVITE and they these headers contain redundant information? Please don't give reference to RFC3261 because I have already read that but it didn't help!!
From Header
Parameter LineFrom: "HEISENBERG" <sip:7243683667@12.114.167.186;otg=3001atlngabu03t80051>;tag=gK0c237ea1
Via Header
Parameter LineVia: SIP/2.0/UDP 12.114.167.186:5060;branch=z9hG4bK0cB76a9694109bd6e64
Contact Header
Parameter LineContact: "HEISENBERG" <sip:7243683667@12.114.167.186:5060>
