The CopperStream™ protocol stack handles the MAC, Link Layer Control, Convergence and Management Layers.

MAC sub-layer
The MAC sub-layer is responsible for managing access to the physical media using a Media Access protocol. The MAC sub-layer supports both phone and coax media, and presents a single interface to the upper communication layers.

The MAC protocol is a highly efficient synchronous MAC that uses CSMA/CA techniques, under master control, to avoid collisions by pre-planning the timing of all media access requests. The protocol is very efficient, achieving above 80% user throughput and supporting different types of services including isochronous constant and variable bit-rate streaming services such as HDTV and SDTV video, audio and telephony, and asynchronous best-effort data services such as broadband data.

MAC highlights:

• Synchronous MAC protocol
• Master-controlled peer-to-peer communication
• High protocol efficiency
  • Collision avoidance
  • Service oriented (media access plan per device and per service)
  • Over 80% effective throughput achievable
• Quality of Service (QoS)
• Supports both relative (priority-based) and guaranteed (parameter-based) QoS
• Provides service quality in unpredictable environments
• Dynamic Bandwidth Allocation (DBA™)
• Traffic classification filters for service identification

Link Layer Control (LLC) sub-layer
The LLC sub-layer performs link control functions. In particular, it is responsible for managing information concerning network connections, for enforcing Class of Service (CoS) and Quality of Service (QoS) constraints defined for the various system data flows and for ensuring robust data transmission. The LLC sub-layer supports extensive local and remote management and diagnostic features such as the DSL forums TR-069 recommendations.

Convergence sub-layer
The CopperStream™ protocol stack supports interfaces and bridging to external protocols through the convergence sub-layer. The convergence sub-layer is a protocol-specific sub-layer that maps various transport layer protocols into the native primitives of the LLC sub-layer.