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Method for rate pacing the network to improve Host system bus efficiency

IP.com Disclosure Number: IPCOM000004696D
Publication Date: 2001-Apr-12
Document File: 2 page(s) / 13K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for rate pacing a network to improve Host system bus efficiency. The benefits include improved efficiency, improved reliability from decreased packet loss, and effective implementation in the WAN environment.

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Method for rate pacing the network to improve Host system bus efficiency

Disclosed is a method for rate pacing a network to improve Host system bus efficiency. The benefits include improved efficiency, improved reliability from decreased packet loss, and effective implementation in the WAN environment.

The IEEE is defining the next generation 10 Gigabit Ethernet standard. The previous standard allowed for 1 Gigabit transmission, or through the use of trunking, higher speeds via multiple links. Few computer stations can handle the 10-Gbps bandwidth. A slower speed would be more manageable.

IEEE P802.3ae specifies a means of rate adaptation (pacing) to control the data throughput in a WAN implementation. The MAC is specified to output data at 10.0 Gbps, but a WAN implementation can only process data at 9.29 Gbps (see Figure 1). When extra idle characters are inserted, the MAC slows down the effective data rate. The WAN physical layer device (PHY) then removes the extra idle characters to achieve the 9.29 Gbps data rate. By expanding on this concept, the actual link runs at 10 Gbps but the MAC is paced down to a data rate that is more efficient for the Host system bus (see Figure 2).

Because very few I/O buses support a full-duplex 10-Gbps link, a subrate scheme is very useful. When an interface cannot support the high-speed transfer rate, packets may be dropped, causing lengthy retransmission delays.

The disclosed approach also enables a network to be scaled up as requirements for increased bandwidth occur. For example, an adapter designed to handle many different sub-rates based on a Host system bus could be swapped from a server with a 1-Gbps Host bus to a server with a 4-Gbps Host bus. This result is re-use and effectively scaling of the network server.

Fig. 1

Fig. 2

Disclosed anonymously