Method and apparatus for guaranteed in-order delivery for FICON over SONET/SDH transport

A method of operating a transport interface for at least one local port associated with a first protocol in which frames are transmitted and received in order, said transport interface providing a mechanism to drop duplicate and/or out-of-order frames transported over a synchronous network that generates duplicate frames according to a second protocol, said method comprising:

• decapsulating a plurality of first protocol frames from one or more second protocol frames in received order after transport over said synchronous network from at least one remote port to said at least one local port;
• comparing sequence numbers in said received order, each sequence number inserted with each first protocol frame into said one or more second protocol frames, to determine duplicate and/or out-of order first protocol frames, wherein a control character inserted with each sequence number with each first protocol frame in said one or more second protocol frames is checked to determine if said sequence number is active for a corresponding first protocol frame;
• and
• generating a drop data strobe such that each said duplicate and/or out-of-order first protocol frames is dropped.

In a network system for transporting Generic Framing Protocol (GFP)-encapsulated Fibre Channel/FICON frames across a synchronous optical network (SONET) or synchronous digital hierarchy (SDH) transport network between first and second Fibre Channel/FICON ports, said first Fibre Channel/FICON port connected to said SONET/SDH transport network through a first transport interface and said second Fibre Channel/FICON port connected to said SONET/SDH transport network through a second transport interface, said first transport interface comprising:

• at least one integrated circuit configured to encapsulate Fibre Channel/FICON frames from said first Fibre Channel/FICON port into one or more transport frames in order for transport over said SONET/SDH network to said second Fibre Channel/FICON port;
• and to insert a sequence number in said order with each Fibre Channel/FICON frame into said one or more transport frames, said sequence number operative as an index for determining duplicate and/or out-of-order frames after transport over said SONET/SDH network, wherein a drop data strobe is generated for each said determined duplicate and/or out of order Fibre Channel/FICON frames, and wherein said at least one integrated circuit is further configured to insert a control character with said sequence number with each Fibre Channel/FICON frame into said one or more transport frames, said control character indicating said sequence number is active for a corresponding Fibre Channel/FICON frame.

In a network system for transporting Generic Framing Protocol (GFP)-encapsulated Fibre Channel/FICON frames across a synchronous optical network (SONET) or synchronous digital hierarchy (SDH) transport network between first and second Fibre Channel/FICON ports, said first Fibre Channel/FICON port connected to said SONET/SDH transport network through a first transport interface and said second Fibre Channel/FICON port connected to said SONET/SDH transport network through a second transport interface, said first transport interface comprising:

• means for encapsulating said plurality of Fibre Channel/FICON frames into one or more transport frames in order for transport over said SONET/SDH network from said first Fibre Channel/FICON port to said second Fibre Channel/FICON port;
• means for inserting a sequence number in said order with each Fibre Channel/FICON frame into said one or more transport frames said sequence number is used as an index for determining duplicate and/or out-of order frames after transport over said SONET/SDH network, wherein a drop data strobe is generated for each said determined duplicate and/or out of order Fibre Channel/FICON frames;
• and
• means for inserting a control character with said sequence number with each Fibre Channel/FICON frame into said one or more transport frames, said control character indicating said sequence number is active for a corresponding Fibre Channel/FICON frame.

In a network system for transporting Generic Framing Protocol (GFP)-encapsulated Fibre Channel/FICON frames across a synchronous optical network (SONET) or synchronous digital hierarchy (SDH) transport network between first and second Fibre Channel/FICON ports, said first Fibre Channel/FICON port connected to said SONET/SDH transport network through a first transport interface and said second Fibre Channel/FICON port connected to said SONET/SDH transport network through a second transport interface, said second transport interface comprising:

• means for decapsulating a plurality of Fibre Channel/FICON frames from one or more GFP frames after transport over said SONET/SDH network from said first Fibre Channel/FICON port to said second Fibre Channel/FICON port;
• means for comparing sequence numbers in received order, each sequence number inserted with each Fibre Channel/FICON frame into said one or more GFP frames, to determine duplicate and/or out-of order Fibre Channel/FICON frames;
• means for checking a control character inserted with each sequence number with each Fibre Channel/FICON frame in said one or more GFP frames to determine if said sequence number is active for a corresponding Fibre Channel/FICON frame;
• and
• means for generating a drop data strobe that causes a cyclic redundancy check for said duplicate and/or out-of-order Fibre Channel/FICON frames to fail such that each said duplicate and/or out-of-order Fibre Channel/FICON frames is dropped.