Interoperate / Scale / Interconnect

At this time VoIP gateway products do not seamlessly interoperate. The reason for this is basically due to the newness of the VoIP protocols. Since most of the VoIP protocols came out of the data networking world, they are immature with respect to telephony and the protocols must evolve to handle all of the contingencies of the voice world.

Like the rest of the current VoIP industry, NACT is not interoperable with any other VoIP vendor. Any IP networks using the IPAX family must be private. In the meantime, NACT's IPAX performs all PSTN signaling inter-working, meaning it interfaces with any of the current PSTN signaling protocols and can convert them to VoIP calls. It can stand alone as a Class 4 Tandem switch.

Equipment Scalability

Early VoIP vendors produced small gateways that had a capacity of 1, 2, 4, 8 or 12 T1 or E1 digital spans for PSTN interconnection. The vendors explained that scalability was achieved by stacking these small boxes. In reality this simply introduced inefficiencies well known in the PSTN world as "small trunk groups" and did not truly achieve scalability. Scalability requires non-blocking among all PSTN trunks and VoIP channels at the same location, and small boxes cannot produce true scalability.

NACT's Pico IPAX can start you out small, a minimum of 2 T1/E1 spans. When it is time to grow, however, NACT's standard IPAX has a non-blocked capacity of 80 T1 (64E1) spans in a single box. The Dual IPAX provides two IPAX gateways in a single cabinet for minimum footprint. Multiple gateways can be managed by the Master Control Unit (MCU) softswitch for a total 320-span capacity at a single cluster.

Seamless PSTN Carrier Interconnection

All VoIP network systems do not interconnect seamlessly with the PSTN. This greatly hinders VoIP network service providers from successfully interoperating because most of the telephony information carried by PSTN networks is not transported by VoIP protocols. VoIP protocols such as H.323, MGCP, or SIP do not transport and/or use most existing PSTN network telephony information, which prevents the seamless interconnection with existing PSTN networks.

Since most voice calls originate and terminate in circuit-switched networks, end-to-end SS7 signaling is extremely important in order to preserve telephony information and to seamlessly interoperate with PSTN networks. The NACT IPAX interoperates with all PSTN protocols and performs conversion to VoIP protocols internally; it is the perfect interface between PSTN and VoIP-only carriers.