signaling protocols / IP telephony / LAN / implementing VoIP technologies / two separate protocols / Linux / IP / Lightweight Directory Access Protocol / instant messaging / operating system / Quality of Service / UDP / operating systems / WAN / TCP/IP / MGCP / following protocols / circuit-switched / encryption / H.248 / PSTN / load balancing / WLAN / audio VoIP Protocols / Proxy Server / Firewall / media protocols / signaling protocol / video conferencing / Network Address Translation / VoIP protocols / H.323 / 2 VoIP Overview VoIP Protocols VoIP technologies / VOIP / Wireless LAN / using two separate protocols / /