US 7,397,764 B2Granted

Flow control between fiber channel and wide area networks

AssigneeLucent Technologies Inc.

InventorsBabu Kalampukattussery Cherian, William R. Krieg, Shreedhara Maduvinakodi Ramegowda, Hemant Kumar KashinathRao Revankar, Andrew T. Schnable, Shiva Kumar Yenigalla

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Abstract

Multiple fiber channel (FC) storage area networks (SANs) are interconnected over wide-area networks (WANs) to form a long-distance (e.g., greater than about 10 km) distributed storage area network (DSAN) that includes FC to Internet Protocol (IP) over WAN (e.g., SONET or gigabit Ethernet (GE)) gateways that interwork the FC buffer-to-buffer and IP/WAN flow-control mechanisms appropriate to either the SONET or GE link layers using an additive increase, multiplicative decrease (AIMD) congestion avoidance algorithm. The gateways effectively spoof the FC buffer-to-buffer credit mechanism on the FC-interface side of the gateway, while using an IP Internet control message protocol (ICMP) quench mechanism on all WAN links and additionally the IEEE 802.3 pause packet flow control mechanism on gigabit Ethernet (GE) WAN links in combination, in both cases, with a rate-throttling mechanism at the FC<->IP converter.

Claims18

Dependent claims

A gateway for coupling a fiber channel (FC) network and a wide area network (WAN), comprising:

an FC interface adapted to interface with the FC network;
a WAN interface adapted to interface with the WAN;
a converter adapted to (1) convert FC data received by the FC interface into internet protocol (IP) over WAN (IP/WAN) data for transmission by the WAN interface to the WAN and (2) convert IP/WAN data received by the WAN interface into FC data for transmission by the FC interface to the FC network;
and
a flow-control manager adapted to control the rate at which the converter converts FC data into IP/WAN data, wherein:
if a backup is created in a queue of outgoing FC data in the FC interface as a result of the FC network withholding buffer credits for the FC interface, then (i) the FC interface communicates corresponding congestion information to the WAN interface, which causes (ii) the WAN interface to transmit WAN congestion information to the WAN to instruct the WAN to decrease the rate at which the WAN transmits IP/WAN data to the WAN interface;
and
if the WAN interface receives WAN congestion information from the WAN, then (i) the WAN interface communicates corresponding congestion information to the flow-control manager, which causes (ii) the converter to decrease the rate at which the converter converts FC data into IP/WAN data, which can create a backup in a queue of incoming FC data in the FC interface, in which case the FC interface will begin to withhold buffer credits for the FC network to decrease the rate at which the FC network transmits FC data to the FC interface.

5 more elements

A system comprising:

a fiber channel (FC) network;
a wide area network (WAN);
and
a gateway for coupling the FC network and the WAN, the gateway comprising:
an FC interface adapted to interface with the FC network;
a WAN interface adapted to interface with the WAN;
a converter adapted to (1) convert FC data received by the FC interface into internet protocol (IP) over WAN (IP/WAN) data for transmission by the WAN interface to the WAN and (2) convert IP/WAN data received by the WAN interface into FC data for transmission by the FC interface to the FC network;
and
a flow-control manager adapted to control the rate at which the converter converts FC data into IP/WAN data, wherein:
if a backup is created in a queue of outgoing FC data in the FC interface as a result of the FC network withholding buffer credits for the FC interface, then (i) the FC interface communicates corresponding congestion information to the WAN interface, which causes (ii) the WAN interface to transmit WAN congestion information to the WAN to instruct the WAN to decrease the rate at which the WAN transmits IP/WAN data to the WAN interface;
and
if the WAN interface receives WAN congestion information from the WAN, then (i) the WAN interface communicates corresponding congestion information to the flow-control manager, which causes (ii) the converter to decrease the rate at which the converter converts FC data into IP/WAN data, which can create a backup in a queue of incoming FC data in the FC interface, in which case the FC interface will begin to withhold buffer credits for the FC network to decrease the rate at which the FC network transmits FC data to the FC interface.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/426,819Filed 30 Apr 2003
Published: US 2004/0218531 A14 Nov 2004
Granted: 8 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04L 47/30
Flow control; Congestion control: in combination with information about buffer occupancy at either end or at transit nodes
H04L 47/10
Traffic control in data switching networks: flow control; Congestion control
H04L 47/12
Flow control; Congestion control: avoiding congestion; Recovering from congestion
H04L 47/39
Flow control; Congestion control: credit based