a. What authentication mechanisms are common on IP telephones? b. What does SIP Identity ensure? c. How can eavesdropping be thwarted? d. What sound quality problem may encryption create? e. Why do...

a. What authentication mechanisms are common on IP telephones? b. What does SIP Identity ensure? c. How can eavesdropping be thwarted? d. What sound quality problem may encryption create? e. Why do firewalls have problems with typical VoIP traffic? f. For SIP signaling, what port has to be opened on firewalls? g. Describe firewall port openings for VoIP transport. h. Why is NAT traversal problematic? i. How are VLANs useful in VoIP?