Traditional PSTN routing relies on multiple transit providers between CPs. Each hop adds cost, latency, and points of failure. Transit providers charge for carrying traffic. This makes calls expensive and slow.

PSTN2 enables CPs to connect directly, eliminating middlemen. When CP1 wants to call CP2, they establish a direct media connection. No transit providers needed. No extra hops. Just source to destination.

How does CP1 find CP2? The PSTN2 directory provides this information. CP1 looks up the destination number, receives CP2's IP address and port, and connects directly. The directory is distributed, so queries are fast and reliable.

Direct routing eliminates transit fees. In tests, this reduced per-minute costs by 75%. For high-volume carriers, this means millions in savings annually. For consumers, it means lower prices. The savings are immediate and substantial.

Removing transit hops reduces latency by 75% or more. Traditional routing might traverse 5 to 7 hops. Direct routing uses 1 hop. Lower latency means better call quality, especially for real-time conversations and video calls.

During call setup, CPs exchange encryption keys. Each call gets unique SRTP keys generated fresh. The keys are negotiated using standard protocols. Once exchanged, all media is encrypted end-to-end between the CPs.

With direct routing and encryption, media never passes through untrusted networks unencrypted. Transit providers can't intercept calls. Governments can't wiretap without CP cooperation. Users get privacy by default, not as an optional add-on.

Direct connections allow better QoS management. CPs can negotiate codecs, bandwidth, and quality parameters directly. There's no lowest-common-denominator imposed by transit providers. This enables HD voice and video as standard features.

As more CPs adopt PSTN2, the benefits multiply. A network of 10 CPs enables 90 direct connections. A network of 100 CPs enables nearly 10,000 connections. Each new participant makes the network exponentially more valuable.

If a CP doesn't support PSTN2, calls fall back to traditional PSTN routing automatically. There's no failure mode. Users don't notice. But when both sides support PSTN2, they get the benefits: lower cost, lower latency, better quality, end-to-end encryption.

CPs can establish formal peering agreements for direct routing, just like internet peering. These agreements specify technical details, SLAs, and settlement rates if any. But unlike traditional telecom agreements, PSTN2 makes peering easy and automated.

Direct routing enables geographic optimization. If CP1 and CP2 both have presence in London, they can route calls through London even if their headquarters are elsewhere. This reduces international transit costs and improves quality.