DLC8023 Device Manager Functions

The IEEE 802.3 Ethernet data link control (DLC8023) device manager and transport medium use two functional layers, medium access control (MAC) and logical link control (LLC), to maintain reliable link-level connections, guarantee data integrity, and negotiate exchanges of identification. Both connectionless (Type 1) and connection-oriented (Type 2) services are supported.

The Ethernet adapter and DLC8023 device handler can perform the following MAC functions:

• Managing the carrier-sense multiple access with collision detection (CSMA/CD) LLC algorithm
• Encoding and decoding the serial-bit stream data
• Receiving network-address checking
• Routing received frames based on the LLC Link Protocol Data Unit (LPDU) destination service access point (SAP) field
• Generating preamble
• Generating cyclic redundancy checks (CRC)
• Handling fail-safe time outs

The DLC8023 device manager can also perform the following LLC functions:

• Remote connection services
• Sequencing each link station on a given port
• Creating the network addresses on transmit frames
• Creating service access points addresses on transmit frames
• Creating IEEE 802.2 LLC commands and responses on transmit frames
• Recognizing and routing received frames to the proper SAP
• Servicing IEEE 802.2 LLC commands and responses on receive frames
• Handling frame sequencing and retries
• Handling fail-safe and inactivity time outs
• Handling reliability counters, availability counters, serviceability counters, error logs, and link traces