Automatic MAC control frame generating apparatus for LAN flow control

摘要

Pre-formatted MAC Control PAUSE frames are generated by a MAC device rather than by a switch. These may be automatically generated and transmitted upon the occurrence of a full or near full condition in the input buffer of the MAC device. The MAC device, upon receipt of a MAC Control PAUSE frame, allows a packet in the process of being transmitted to complete transmission prior to implementing the PAUSE. The MAC device is capable of generating MAC Control frames having any desired opcode. The parameter field associated with the MAC Control frame opcode is programmable. The destination address of the MAC Control frame is programmable. Automatic x-on/x-off is implemented. Flags may be set to enable/disable the IEEE 802.3x pause function in the MAC device and to override basic IEEE 802.3x operation in various ways.