Question: what is the difference between mgcp and h.323 voice gateway?
Answer: 323 gateway interfaces support the NFAS (Non-Facility Associated Signaling) feature, while MGCP gateways do not. The NFAS feature allows one Q. 931 D channel in a PRI to carry voice signaling for up to 20 PRIs. NFAS will allow more B channels in a PRI to accommodate additional phone calls.