Patent ID: 6570890
Filing Date: 2003-05-27
Classification: H04L,H04M

Abstract:
In a local area network (LAN) adapted for packet switching using standard variable length Ethernet packets transmitted between devices over LAN segments connected in star topology to a Communication Switching Module (CSM), said devices each having a local clock and said CSM having a master clock,the method of transporting both delay sensitive information and user data packets concurrently over any one of said LAN segments between a said device and said CSM, said method comprising: segmenting said delay sensitive information and said user data packets at one end of the LAN segment; encapsulating the segmented delay sensitive information and the segmented user data packets into master Ethernet packets having a fixed length, each said master Ethernet packet having at least one fixed length constant bit rate (CBR) time slot portion and at least one fixed length data portion; determining the arrival of a new user data packet; establishing a data character sequence including at least one â€œsyncâ€  character and at least one character indicating the length of the new user data packet; encapsulating the data character sequence and segments of the new data packet into any available area remaining in the data portion of the master Ethernet packet being processed; transmitting the master Ethernet packets at a fixed constant rate over the LAN segment with a fixed interpacket gap (IPG); extracting the segmented delay sensitive information from the CBR time slot portions and the segmented user data packets from the data portions of the master Ethernet packet at the other end of the LAN segment; and re-assembling the delay sensitive information and the user data packets.