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US 7,600,035 B2Granted
Dynamic link distance configuration for extended fabric
AssigneeBrocade Communications Systems, Inc.
InventorsNagaraj Lalsangi, Balakrishma Wusirika
Life of this patent
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Abstract
A method to dynamically allocate credits for a particular port to port link based on measured link distance during the initial interswitch link configuration process. An apparatus implementing such method or a software upgrade to retrofit existing switches.
Claims27
A method to dynamically allocate credits to a port in a Fibre Channel network, the method comprising:
- connecting a first port on a first device to a second port on a second device to form a link;
- the first port sending a unique signal to a second port and starting a timer;
- the first port receiving the unique signal returned from the second port and stopping the timer;
- and
- allocating credits according to the time elapsed on the timer,
- wherein allocating credits according to the time elapsed on the timer includes:
- calculating the distance according to the time elapsed on the timer;
- and
- allocating credits corresponding to the distance between the first and second ports, and
- wherein calculating the distance according to the time elapsed on the timer uses the following formula:
- distance=(LRT_LATENCY*3)/(20*RI) Eq.(1)
- where distance is the link distance in km;
- LRT_LATENCY is the time lapse between timer stops and starts, in microseconds and
- RI is the refractive index of glass (worst case) in the fiber optic connecting the two ports.
11 more elements
A device for use in a Fibre Channel network, comprising:
- a Fibre Channel port for connection to another Fibre Channel port,
- a timer coupled to the Fibre Channel port, and
- a control module coupled to the Fibre Channel port and the timer, wherein the control module is operable to send and receive a unique signal through the Fibre Channel port,
- wherein the control module is operable to tell the time elapsed between sending the unique signal and receiving the unique signal, using the timer,
- wherein the control module is operable to allocate a number of credits based on the time elapsed between sending the unique signal and receiving the unique signal, and wherein the number of credits allocated is determined by formula:
- Number of credits=(LRT_LATENCY*LINE_RATE*100)/MAX_FRAME_SIZE+K,
- where LRT_LATENCY is the time lapse between timer stops and starts, in microseconds,
- LINE_RATE is the raw data rate of the link in Gb/sec,
- MAX_FRAME_SIZE is the maximum size of a frame transmitted by the ports, and
- K is a constant provided to allow for intradevice latencies.
7 more elements
A Fibre Channel switch for an information network, said switch comprising:
- a first Fibre Channel port and a second Fibre Channel port, the first port for connection to another Fibre Channel port and the second port for connection to another Fibre Channel port;
- a memory;
- a timer coupled to the first port;
- and
- a control module coupled to the first port and the timer, wherein the control module is operable to send and receive a unique signal through the first port,
- wherein the control module is operable to tell the time elapsed between sending the unique signal and receiving the unique signal, using the timer,
- wherein the control module is operable to allocate a number of credits to the first port based on the time elapsed between sending and receiving the unique signal, and
- wherein the number of credits allocated is determined by formula:
- Number of credits=(LRT_LATENCY*LINE_RATE*100)/MAX_FRAME_SIZE+K,
- where LRT_LATENCY is the time lapse between timer stops and starts, in microseconds,
- LINE_RATE is the raw data rate of the link in Gb/sec,
- MAX_FRAME_SIZE is the maximum size of a frame transmitted by the ports, and
- K is a constant provided to allow for intradevice latencies.
10 more elements
A Fibre Channel network comprising:
- a first switch including:
- a first port;
- a timer;
- and
- a first control module coupled to the first port and the timer;
- and,
- a second switch including:
- a second port connected to the first port on the first switch, and
- a second control module,
- wherein the first control module is operable to send and receive a unique signal through the first port,
- wherein the first control module is operable to tell the time elapsed between sending the unique signal and receiving the unique signal, using the timer,
- wherein the first control module is operable to allocate a number of credits to the first port based on the time elapsed between sending and receiving the unique signal;
- wherein the second port is operable to receive and return the unique signal, and
- wherein the number of credits allocated is determined by formula:
- Number of credits=(LRT_LATENCY*LINE_RATE*100)/MAX_FRAME_SIZE+K,
- where LRT_LATENCY is the time lapse between timer stops and starts, in microseconds,
- LINE_RATE is the raw data rate of the link in Gb/sec,
- MAX_FRAME_SIZE is the maximum size of a frame transmitted by the ports, and
- K is a constant provided to allow for intraswitch latencies.
16 more elements
A Fibre Channel network system comprising:
- a first node;
- a second node;
- a first switch including:
- a first port;
- a third port coupled to the first node;
- a timer;
- and
- a first control module coupled to the first port and the timer,
- a second switch including;
- a second port connected to the first port on the first switch;
- a fourth port coupled to the second node;
- and
- a second control module,
- wherein the first control module is operable to send and receive a unique signal through the first port,
- wherein the first control module is operable to tell the time elapsed between sending the unique signal and receiving the unique signal, using the timer,
- wherein the first control module is operable to allocate a number of credits to the first port based on the time elapsed between sending and receiving the unique signal,
- wherein the second port is operable to receive and return the unique signal, and
- wherein the number of credits allocated is determined by formula:
- Number of credits=(LRT_LATENCY*LINE_RATE*100)/MAX_FRAME_SIZE+K
- where LRT_LATENCY is the time lapse between timer stops and starts, in microseconds,
- LINE_RATE is the raw data rate of the link in Gb/see,
- MAX_FRAME_SIZE is the maximum size of a frame transmitted by the ports, and
- K is a constant provided to allow for intraswitch latencies.
20 more elements
Dependencies are inferred from the claim text.