Index[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] gatekeepers 2nd 3rd gateways case study gateway-to-gateway calls (H.323) PIMG protocols H.323 MGCP SIP registration resolution glare global synchronization GoS (grade of service) ground start signaling 2nd Group Call Pickup feature (IP Phone) grouping CCMs |