Patent Number: 6,167,054

Title: Method and apparatus providing programmable thresholds for full-duplex flow control in a network switch

Abstract: A network having a shared memory architecture for storing data frames has a set of programmable thresholds that specify when flow control should be initiated on full-duplex network ports. The network switch includes a queue for storing free frame pointers that specify available memory locations in an external memory for storing data frames received from a network station. The network switch takes a frame pointer from a free buffer queue for each received data frame, and stores the received data frame in the location in external memory specified by the frame pointer while a decision making engine within the switch determines the appropriate destination ports. Flow control is initiated based on the number of available frame pointers by transmitting a PAUSE frame having a selected PAUSE interval to a transmitting network station. Specifically, a full-duplex port will output a PAUSE frame having a short, medium, or long programmed pause interval if the free buffer pool of available frame pointers falls below a high, medium, or low programmable threshold, respectively. The switch thus provides flexibility in generating variable-length PAUSE control frames to minimize wasting network bandwidth.

Inventors: Simmons; Philip (San Jose, CA), Erimli; Bahadir (Mountain View, CA), Sang; Jinqlih (Fremont, CA), Chow; Peter Ka-Fai (San Jose, CA), Crayford; Ian (San Jose, CA), Kadambi; Jayant (Milpitas, CA), Kerstein; Denise (Mountain View, CA), Runaldue; Thomas Jefferson (San Jose, CA)

Assignee: Advanced Micro Devices, Inc.

International Classification: H04L 12/28 (20060101); H04L 012/28 ()

Expiration Date: 12/26/2017