In-order delivery of frames during topology change
AssigneeBrocade Communications Systems, Inc.
InventorEzio Valdevit
Life of this patent
Estimating the term…
Abstract
A method and system is provided for in-order delivery of frames in Fiber Channel communication networks during topology change. When a topology change has rendered an old path between two switches or end devices infeasible, a new path is determined to replace the old path. To ensure in-order delivery of frames, the new path is activated only after the lapse of a hold-down period. The hold-down period may be calculated as the maximum time required for frames within the old path immediately prior to the topology change to reach the destination switch or device. The calculation may utilize information available from the Fiber Channel shortest path first (FSPF) protocol.
Claims25
A method for in-order delivery of frames in a Fibre Channel communication network system from a first communication device to a destination communication device, after a topology change in the communication network system has rendered infeasible a first path from the first communication device to the destination communication device, the method comprising:
- responsive to the topology change, deactivating the first path;
- determining a new path from the first communication device to the destination communication device;
- and
- alter the lapse of a hold-down period, activating the new path,
- wherein deactivating the first path comprises:
- clearing a transmit queue within the first communication device corresponding to the first path;
- and
- canceling an entry to a routing table for the first communication device directing frames destined for the destination communication device to the first path.
A method for in-order delivery of frames in a Fibre Channel communication network system from a first communication device to a destination communication device, after a topology change in the communication network system has rendered infeasible a first path from the first communication device to the destination communication device, the method comprising:
- responsive to the topology change, deactivating the first path;
- determining a new path from the first communication device to the destination communication device;
- and
- after the lapse of a hold-down period, activating the new path,
- wherein the hold-down period is a maximum allowable time the destination communication device can wait for a data frame transmitted from the first communication device before having to consider it missing.
A method for in-order delivery of frames in a Fibre Channel communication network system from a first communication device to a destination communication device, after a topology change in the communication network system has rendered infeasible a first path from the first communication device to the destination communication device, the method comprising:
- responsive to the topology change, deactivating the first path;
- determining a new path from the first communication device to the destination communication device;
- calculating the maximum time required for data frames within the first path immediately prior to the topology change to reach the destination communication device;
- and
- after the lapse of a hold-down period, activating the new path, wherein the hold-down period is the maximum time required for data frames within the first path immediately prior to the topology change to reach the destination device.
A method for in-order delivery of frames in a Fibre Channel communication network system from a first communication device to a destination communication device, after a topology change in the communication network system has rendered infeasible one or more of a plurality of existing paths from the first communication device to the destination communication device, the method comprising:
- responsive to the topology change, deactivating the plurality of existing paths;
- determining at least one feasible path from the first communication device to the destination communication device;
- calculating a maximum time required for data frames within the plurality of existing paths immediately prior to the topology change to reach the destination communication device;
- and
- after the lapse of a hold-down period, activating the at least one feasible path, wherein the hold-down period is the maximum time required for data frames within the plurality of existing paths immediately prior to the topology change to reach the destination device.
A system for in-order delivery of frames in a Fibre Channel communication network from a first communication device to a destination communication device, after a topology change in the communication network has rendered infeasible a first path from the first communication device to the destination communication device, the system comprising:
- a path computation module for determining a new path from the first communication device to the destination communication device;
- a timer for keeping track of the time lapsed since the topology change;
- a processing module for calculating a maximum time required for data frames within the first path immediately prior to the topology change to reach the destination communication device;
- and
- a routing logic module for,
- responsive to the topology change, deactivating the first path, and
- after the lapse of a hold-down period, activating the new path, wherein the hold-down period is the maximum time required for data frames within the first path immediately prior to the topology change to reach the destination device.
A computer program product for in-order delivery of frames in a Fibre Channel communication network system from a first communication device to a destination communication device, after a topology change in the communication network system has rendered infeasible a first path from the first communication device to the destination communication device, the product comprising:
- a computer usable medium;
- program code for, responsive to the topology change, deactivating the first path;
- program code for determining a new path from the first communication device to the destination communication device;
- and
- program code for, after the lapse of a hold-down period, activating the new path,
- wherein the hold-down period is a maximum allowable time the destination communication device can wait for a data frame transmitted from the first communication device before having to consider it missing.
Dependencies are inferred from the claim text.