Digital loop diagnostic port test before insertion
View Patent ↗Methods and associated hub arrangements are described for use in diagnosis and recovery in high performance digital loops such as, for example, those seen in Fibre Channel systems. In one system having a hub configured for interconnection of a plurality of stations as part of a digital system such that digital data flows between the stations based on operational status of the system, an arrangement forms part of the hub which arrangement is connectable at points within the hub and between at least two different pairs of the stations for monitoring certain characteristics of the data in a way which provides for non-invasive identification of one or more conditions related to the operational status of the system.
1. In a Fibre Channel system configured for interconnection of a plurality of stations as part of a digital system using a main loop such that digital data flows between the stations on the main loop through a Fibre Channel hub based on operational status of the system, said Fibre Channel hub being configured for interconnection of said stations using a series of ports which interface with said main loop, each station being operatively coupled to one of said ports such that each one of said stations is selectively insertable in the main loop via the ports to cause said digital data to flow through the stations and such that each one of the stations is selectively and individually bypassable with respect to the main loop while the station is operatively coupled to one of the ports to prevent said digital data from flowing through each of the stations, the improvement comprising:
an arrangement forming part of the hub and part of at least one selected station configured for sending a set of loop-back test data from the selected station to the hub when the selected station is operatively coupled to one of the ports and, thereafter, looping the set of loop-back test data, at least partially through a diagnostics loop separate from the main loop, back to the selected station in a loop-back mode in a way which confirms operation of the selected station using the port into which the selected station is operatively coupled and which also confirms the operation of at least a portion of said hub.
2. The arrangement according to claim 1 further configured for entering said loop-back mode at least after a new station has been initially operatively coupled to one of said ports.
3. The arrangement according to claim 1 further configured to operate in said loop-back mode using diagnostic means connectable at points within the hub and between at least two different pairs of the stations for monitoring certain characteristics of said set of loop-back data in a way which, without affecting an operation of the main loop, provides for confirmation of an operation of said portion of the hub and of an operation of the port into which the selected station is operatively coupled.
4. The arrangement according to claim 3 wherein said diagnostic means includes the diagnostics loop separate from the main loop and connected between the stations and further includes analysis means, said diagnostics loop being configured for selectively copying the set of loop-back data from one of said points on the main loop at a time and, thereafter, for transmitting the copied digital data to said analysis means.
5. The arrangement according to claim 1 wherein said arrangement is configured for initially maintaining an operatively coupled station in a bypassed condition with respect to said main loop during said loop-back mode while verification of certain aspects of the operation of the inserted station is performed whereby connection of a defective operatively coupled station with the main loop is prevented.
6. In a Fibre Channel system configured for interconnection of a plurality of stations as part of a digital system using a main loop such that digital data flows between the stations on the main loop through a Fibre Channel hub, said Fibre Channel hub being configured for interconnection of said stations using a series of ports interfaced with said main loop, each station being operatively coupled to a respective one of said ports such that each one of said stations is selectively insertable in the main loop when operatively coupled to one of the ports to cause said digital data to flow through the stations, a method of inserting a selected station in the main loop, said method comprising the steps of:
a) positioning the selected station as being operatively coupled to an available one of the ports;
b) maintaining the selected station disconnected from the main loop;
c) while the selected station is disconnected from the main loop, performing a loop-back test which verifies integrity if the selected station by looping a set of loop-back test data at least partially through a diagnostic loop separate from the main loop; and
d) connecting the selected station to the main loop only after the integrity of the selected station has been verified using the main loop-external loop-back test.
7. The method according to claim 6 including the step of providing a notification in a predetermined way if the selected station is not connected to the main loop within a specified period of time following insertion of the selected station into the available port.
8. The method according to claim 7 wherein said notification is provided at a remote location with respect to said Fibre Channel hub.
9. In a Fibre Channel system which interconnects a plurality of stations in a loop using at least a first hub as part of a digital system such that digital data flows between the stations on the loop and through the hub or hubs based on operational status of the system, each station being configured such that, upon receipt of a Loop Initialization Primitive (LIP) F 7 ordered set, the station will transmit a burst of LIP F 7 followed by 15 ms of idle characters, a method of identifying an unknown hub requesting insertion in the loop, said method comprising the steps of:
a) transmitting one burst of LIP F 7 from the first hub to the unknown hub;
b) within 15 ms of ending transmission of the LIP F 7 burst, transmitting on the loop an ARB FB from said first hub;
c) if the Arbitrate Primitive (ARB) FB returns to the first hub, requesting identification information from the unknown hub using said loop; and
d) if the unknown hub responds to the information identification request, using the first hub to receive a predetermined set of identification information from the unknown hub.
10. The method according to claim 9 wherein said step of requesting identification from the unknown huh is performed using ordered sets prior to insertion of the unknown hub.
11. The method according to claim 9 wherein said identification information is a serial number assigned to the unknown hub.
12. In a Fibre Channel system which interconnects a plurality of stations in a loop using at least a first hub as part of a digital system such that digital data flows between the stations on the loop and through the hub or hubs based on operational status of the system, each station being configured such that, upon receipt of Loop Initialization Primitive (LIP) F 7 , the station will transmit a burst of LIP F 7 followed by 15 ms of idle characters, a method of identifying an unknown station requesting attachment to the loop, said method comprising the steps of:
a) transmitting one burst of LIP F 7 from the first hub to the unknown station;
b) within 15 ms of ending transmission of the LIP F 7 burst, transmitting on the loop an Arbitrate Primitive (ARB) FB from said first hub; and
c) if the ARB FB does not return to the first hub, providing an indication that the unknown station is an attaching station.