Graceful port shutdown protocol for fibre channel interfaces
First Claim
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1. A method of gracefully shutting down an inter-switch link between a first switch and a second switch on a Fibre Channel network, the method comprising:
- (a) determining that the inter-switch link is to be shut-down;
(b) modifying forwarding parameters in the first switch to ensure that no further frames are forwarded from the first switch onto the inter-switch link and sending one or more communications to the second switch;
(c) sending a communication to the second switch informing it that the link is to be shut down;
(d) modifying forwarding parameters in the second switch to ensure that no frames are forwarded from the second switch onto the inter-switch link;
(e) ensuring that no frames remain queued in the first switch for transmission on the inter-switch link;
(f) receiving confirmation from the second switch that it is prepared for the inter-switch link to shut down; and
(g) shutting down the inter-switch link.
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Abstract
A port shutdown protocol coordinates among various components involved in the process of administratively bringing down a link at both ends of a link connecting two switches. Execution of the protocol avoids or reduces frame drops and/or reordering. In this protocol, peer switches perform various actions when bringing down an ISL in a synchronized manner. In one implementation, this protocol uses the Exchange Peer Protocol (EPP) as the underlying transport to carry the port shutdown protocol frames.
167 Citations
37 Claims
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1. A method of gracefully shutting down an inter-switch link between a first switch and a second switch on a Fibre Channel network, the method comprising:
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(a) determining that the inter-switch link is to be shut-down; (b) modifying forwarding parameters in the first switch to ensure that no further frames are forwarded from the first switch onto the inter-switch link and sending one or more communications to the second switch; (c) sending a communication to the second switch informing it that the link is to be shut down; (d) modifying forwarding parameters in the second switch to ensure that no frames are forwarded from the second switch onto the inter-switch link; (e) ensuring that no frames remain queued in the first switch for transmission on the inter-switch link; (f) receiving confirmation from the second switch that it is prepared for the inter-switch link to shut down; and (g) shutting down the inter-switch link. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 16, 17)
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9. A storage area network comprising:
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a first Fibre Channel switch; a second Fibre Channel switch; and an inter-switch link coupling the first and second Fibre Channel switches, wherein the first Fibre Channel switch comprises logic for (a) determining that the inter-switch link is to be shut-down; (b) modifying forwarding parameters in the first switch to ensure that no further frames are forwarded from the first switch onto the inter-switch link and sending one or more communications to the second switch; (c) sending a communication to the second switch informing it that the link is to be shut down; (d) ensuring that no frames remain queued in the first switch for transmission on the inter-switch link; (e) receiving confirmation from the second switch that it is prepared for the inter-switch link to shut down; and (f) shutting down the inter-switch link, wherein the second Fibre Channel switch comprises logic for (a) modifying forwarding parameters in the second switch to ensure that no frames are forwarded from second switch onto the inter-switch link; (b) ensuring that no frames remain queued in the second switch for transmission on the inter-switch link; and (c) sending a confirmation to the first switch that the second switch is prepared for the inter-switch link to shut down.
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10. A Fibre Channel switch, comprising:
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means for determining that an inter-switch link with a second Fibre Channel switch is to be shut down; means for modifying forwarding parameters to ensure that no further frames are forwarded from the switch onto the inter-switch link and sending one or more communications to the second Fibre Channel switch; means for sending a communication to the second switch informing it that the inter-switch link is to be shut down, wherein the communication comprises an indication that forwarding parameters in the second Fibre Channel switch be modified to ensure that no frames are forwarded from the second Fibre Channel switch onto the inter-switch link; means for ensuring that no frames remain queued on the switch for transmission on the inter- switch link; means for receiving confirmation from the second Fibre Channel switch that it is prepared for the inter-switch link to shut down; and means for shutting down the inter-switch link.
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11. A computer program product comprising a tangible storage medium on which is provided instructions for gracefully shutting down an inter-switch link between a first switch and a second switch on a Fibre Channel network, the instructions comprising:
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determining that the inter-switch link is to be shut down; modifying forwarding parameters to ensure that no further frames are forwarded from the first switch onto the link and sending one or more communications to the second switch; sending a communication to the second switch informing it that the link is to be shut down, wherein the communication comprises an indication that forwarding parameters in the second switch be modified to ensure that no frames are forwarded from the second switch onto the inter-switch link; ensuring that no frames remain queued on the first switch for transmission on the inter- switch link; receiving confirmation from the second switch that it is prepared for the inter-switch link to shut down; and shutting down the inter-switch link. - View Dependent Claims (12, 13, 14, 15, 18, 19, 20)
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21. A Fibre Channel switch, comprising:
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a port for connecting to an inter-switch link with a second Fibre Channel switch; and at least one processor configured to do the following; determining that the inter-switch link is to be shut down; modifying forwarding parameters to ensure that no further frames are forwarded from the switch onto the inter-switch link and sending one or more communications to the second Fibre Channel switch; sending a communication to the second switch informing it that the inter-switch link is to be shut down, wherein the communication comprises an indication that forwarding parameters in the second Fibre Channel switch be modified to ensure that no frames are forwarded from the second Fibre Channel switch onto the inter-switch link; ensuring that no frames remain queued on the switch for transmission on the inter-switch link; receiving confirmation from the second Fibre Channel switch that it is prepared for the inter-switch link to shut down; and shutting down the inter-switch link. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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30. A line card operable for use in a Fibre Channel switch, the line card comprising:
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an interface for communicating with a Fibre Channel switch; a port for connecting to an inter-switch link with a second Fibre Channel switch; and at least one processor configured to do the following; determine that the inter-switch link is to be shut down; modify forwarding parameters to ensure that no further frames are forwarded from the switch onto the inter-switch link and sending one or more communications to the second Fibre Channel switch; send a communication to the second switch informing it that the inter-switch link is to be shut down, wherein the communication comprises an indication that forwarding parameters in the second Fibre Channel switch be modified to ensure that no frames are forwarded from the second Fibre Channel switch onto the inter-switch link; ensure that no frames remain queued on the switch for transmission on the inter- switch link; receive confirmation from the second Fibre Channel switch that it is prepared for the inter-switch link to shut down; and shut down the inter-switch link. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37)
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Specification