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CDC Network Control Model (NCM) sets the networking performance standard for high-speed, next-gen mobile devices. MCCI authored the Experimental NCM (ENCM) specification, and is the primary contributor to and technical editor of the released CDC NCM specification.

As network operators prepare to roll out LTE and WiMax communications networks, handset designers are turning to networked communications models to outperform yesterday's modem-based data communications. Although there are configurations in which a full-speed Windows device may need little more than MCCI's CDC Ethernet host-side drivers, tomorrow's radios will deliver content at a rate of 75-100 Mbps. For this kind of throughput, full-speed devices and full-speed technologies are not optimal.

For high-speed devices, turn to MCCI for seamless, high-quality, high-throughput 3G and 4G networking functionality. MCCI's embedded CDC NCM USB stack combines with MCCI's matching CDC NCM host-side drivers for the best design support. CDC NCM is based on MCPC Mobile Direct Line Model (MDLM). They use the semantics of CDC Ethernet Control Model (ECM). With CDC NCM, data flow to and from the handset is optimized.

At the most basic level, modem-based products are throughput-restricted because the modem protocol CDC ACM (Abstract Control Model) uses PPP-encapsulated IP frames to communicate with the host PC. CDC NCM eliminates the overhead of CDC ACM and maximizes data flow to the handset.

Once the switch from a modem architecture to a network architecture is made, the problem of frequent interrupts must be addressed because CDC Ethernet and CDC ECM transfer only a single frame per USB transfer. Every time a USB transfer finishes, the processor must stop what it is doing and service the interrupt. This is very costly in terms of performance and battery life. CDC NCM includes many Ethernet frames within a single USB transfer, thus reducing the interrupt burden substantially.

Further improvements brought by NCM:

• A standard way of imposing structure on the raw USB pipe data stream has been defined, so that Ethernet frames don't have to begin or end on packet boundaries.
• Highly efficient DMA (Direct Memory Access) is used to move data directly from the USB transfer buffers into the final application buffer, web browser, etc.
• Cache handling and interrupt loading are optimized across all standards for mobile platforms and communications. This makes CDC NCM a good remedy in situations where excessive control plane activity results in unstable connections.