EP0772323A2
Expired / Lapsed
EP
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Method and apparatus for tracking buffer availability
Assignee: McData Corp
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Filing: 1996-09-19
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Granted: —
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Expires: 2016-09-19
Abstract
Abstract The appts includes a number of interconnected fabric ports each including a number of receive buffers for storing frames received from an NPort. A receive credit counter counts the number of frames that the NPort is currently allowed to transmit at one time. A smart credit counter counts the number of receive buffers available to receive frames from the NPort. A status/control logic on the FPort transmits a receiver ready signal to the N port when the FPort is ready to receive another frame. The status/control logic includes a transmit credit counter located on each NPort that counts the number of frames that the NPort is currently allowed to transmit to the FPort at one time.
Inventors
- 👤 Dwayne Bennett
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 14:18
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/10; H04L49/104; H04L49/105; H04L49/107; H04L49/30; H04L49/3081; H04L49/35; H04L49/356; H04L49/357; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L2012/5678; H04L2012/5681; H04L49/351
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
170 words
A fibre channel switch apparatus for interconnecting a plurality of devices having node ports (N_ports), comprising: a plurality of interconnected fabric ports (F_ports), each further comprising: a plurality of receive buffers (432, 434, 436, 438) for storing frames received from an N_port, a receive credit counter (480) for counting the number of frames that the N_port is currently allowed to transmit at one time, and a smart credit counter (482) for counting the number of receive buffers available to receive frames from the N_port, status/control logic on the F_port for transmitting a receiver ready signal to the N_port when the F_port is ready to receive another frame, the status/control logic further comprising: a transmit credit counter (142) located on each N_port for counting the number of frames that the N_port is currently allowed to transmit to the F_port at one time, wherein the transmit credit counter is decremented by one after a frame is transmitted to an F_port and incremented by one upon the receipt of the receiver ready signal.
Claim 2
Dependent Claim
47 words
The fibre channel switch apparatus as claimed in claim 1, wherein the transmit credit counter (142) is initialized at login at a number corresponding to the maximum number of frames that the N_port can transmit to the F_port without receiving the receiver ready signal from the F_port.
Claim 3
Dependent Claim
34 words
The fibre channel switch apparatus as claimed in claim 2, wherein the N_port is only allowed to transmit a frame to the F_port if the transmit credit counter has a value greater than 0.
Claim 4
Dependent Claim
51 words
The fibre channel switch apparatus as claimed in claim 3, wherein each receive credit counter (480) is initialized at login with an initial value defined as the login receive buffer-to-buffer credit (login rx_bb_credit) corresponding to the maximum number of frames that the N_port can transmit to the F_port at one time.
Claim 5
Dependent Claim
42 words
The fibre channel switch apparatus as claimed in claim 4, wherein the difference between the current value of the smart credit counter (482) and the login receive buffer-to-buffer credit is the number of spare buffers (432, 434, 436, 438) on the F_port.
Claim 6
Dependent Claim
84 words
The fibre channel switch apparatus as claimed in claim 5, wherein, upon receipt of a frame, the current value of the smart credit counter (482) is compared to the login receive buffer-to-buffer credit, and if the smart credit counter (482) value is greater than the login receive buffer-to-buffer credit, the status control logic sends the receiver ready signal to the N_port, and wherein, both the receive credit counter (480) and the smart credit counter (482) are decremented by one upon receipt of the frame.
Claim 7
Dependent Claim
25 words
The fibre channel switch apparatus as claimed in claim 6, wherein upon receipt of the receiver ready signal, the transmit credit counter (145) is incremented.
Claim 8
Dependent Claim
97 words
The fibre channel switch apparatus as claimed in claim 6, wherein upon receipt of a frame: if the value of the smart credit counter (482) is less than or equal to the login receive buffer-to-buffer credit, then the number of available buffers is limited to the current count of the receive credit counter (480), and wherein, both the receive credit counter (480) and the smart credit counter (482) are decremented by one upon receipt of the frame, and wherein, the receiver ready signal is generated and sent to the N_port upon forwarding the frame to another F_port.
Claim 9
Dependent Claim
55 words
The fibre channel switch apparatus as claimed in claim 8, wherein upon forwarding the frame to another F_port, the smart credit counter (482) and the receive credit counter (480) are incremented as long as the current count of the receive credit counter (480) is less than the initial value of the receive credit counter (480).
References Cited (Backward Citations)
No citation records indexed.
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