US 7,548,560 B1Granted

Method and system for checking frame-length in fibre channel frames

AssigneeQLOGIC, Corporation

InventorsFrank R. Dropps, Ernest G Kohlwey, Edward C. Ross

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Abstract

Method and system for checking frame-length in a Fiber Channel frames is provided. The method includes extracting a R_CTL value from a Fiber Channel frame; comparing the extracted R_CTL value of the Fiber Channel frame with R_CTL values stored in a Content Addressable Memory Table; determining a maximum frame-length and a minimum frame-length of the Fiber Channel frame for the extracted R_CTL value from the Content Addressable Memory Table; and marking the Fiber Channel frame so that it can be discarded if the frame-length is less than the minimum frame-length of the Fiber Channel frame or greater than the maximum frame-length of the Fiber Channel frame. The system includes a processor that accesses a CAM stored in memory; and a receive port that extracts and compares a R_CTL value of the Fiber Channel frame.

Claims24

Dependent claims

A method for a port that receives Fibre Channel frames, comprising:

(a) storing a maximum frame length value and a minimum frame length value for each of a plurality of Fibre Channel frame type;
wherein the maximum frame length value and the minimum frame length value for each of the plurality of Fibre Channel frame type are associated with a R_CTL value, a field of a Fibre Channel frame header used for routing Fibre Channel frames;
(b) extracting a R_CTL value from a frame header of a Fibre Channel frame received at the port;
(c) comparing the extracted R_CTL value of the Fibre Channel frame with stored R_CTL values in step (a);
(d) if the extracted R_CTL value matches with a stored R_CTL value in step (c), then comparing a frame length of the received Fibre Channel frame with a maximum frame-length and a minimum frame-length associated with the extracted and matched R_CTL value;
(e) if the extracted R_CTL does not match with any stored R_CTL value in step (c), then comparing the frame length of the received Fibre Channel frame with a default maximum frame length value and a default minimum frame length value;
(f) based on the comparison in step (d) and step (e), determining if the received Fibre Channel frame is a long frame or a short frame;
wherein the received Fibre Channel frame is a long frame if the frame length of the received Fibre Channel frame is greater than the maximum frame length from step (d), if there was a match in step (c), or greater than the default maximum frame length from step (e), if there was no match in step (c);
and the received Fibre Channel frame is a short frame if the frame length of the received Fibre Channel frame is less than the minimum frame length from step (d), if there was a match in step (c), or less than the default minimum frame length from step (e), if there was no match in step (c);
and
(g) discarding the received Fibre Channel frame if the frame is a long frame or a short frame.

8 more elements

A Fibre Channel device element for receiving Fibre Channel frames, comprising:

a memory for storing a maximum frame length value and a minimum frame length value for each of a plurality of Fibre Channel frame type;
wherein the maximum frame length value and the minimum frame length value for each of the plurality of Fibre Channel frame type are associated with a R_CTL value, a field of a Fibre Channel frame header used for routing Fibre Channel frames;
and
a receive port that:
(a) receives a Fibre Channel frame;
(b) extracts a R_CTL value from the Fibre Channel frame;
(c) compares the extracted R_CTL value of the Fibre Channel frame with R_CTL values stored in the memory;
(d) if the extracted R_CTL value matches with a stored R_CTL value in (c), then compares a frame length of the received Fibre Channel frame with a maximum frame-length and a minimum frame-length associated with the extracted and matched R_CTL value;
(e) if the extracted R_CTL does not match with any stored R_CTL value in (c), then compares the frame length of the received Fibre Channel frame with a default maximum frame length value and a default minimum frame length value;
(f) based on the comparison in (d) and (e), determines if the received Fibre Channel frame is a long frame or a short frame;
wherein the received Fibre Channel frame is a long frame if the frame length of the received Fibre Channel frame is greater than the maximum frame length from (d), if there was a match in (c), or greater than the default maximum frame length from (e), if there was no match in (c);
and the received Fibre Channel frame is a short frame if the frame length of the received Fibre Channel frame is less than the minimum frame length from (d), if there was a match in (c), or less than the default minimum frame length from (e), if there was no match in (c);
and
(g) discards the received Fibre Channel frame if the frame is a long frame or a short frame.

11 more elements

A method for a network port for receiving and transmitting frames, comprising:

(a) storing a maximum frame length value and a minimum frame length value for each of a plurality of frame type;
wherein the maximum frame length value and the minimum frame length value for each of the frame type are associated with a field value used for routing frames received by the port;
(b) extracting the field value from a frame header of a frame received at the port;
(c) comparing the field value of the frame with stored field values in step (a);
(d) if the extracted field value matches with a stored value in step (c), then comparing a frame length of the received frame with a maximum frame length and a minimum frame length associated with the extracted and matched field value;
(e) if the extracted field value does not match with any stored field value in step (c), then comparing the frame length of the received frame with a default maximum frame length value and a default minimum frame length value;
(f) based on the comparison in step (d) and step (e), determining if the received frame is a long frame or a short frame;
wherein the received frame is a long frame if the frame length of the received frame is greater than the maximum frame length from step (d), if there was a match in step (c), or greater than the default maximum frame length from step (e) if there was match in step (c);
and the received frame is a short frame if the frame length of the received frame is less than the minimum frame length from step (d), if there was a match in step (c), or less than the default minimum frame length from step (e), if there was no match in step (c);
and
(g) discarding the received frame if the received frame is a long frame or a short frame.

8 more elements

Dependencies are inferred from the claim text.