Abstract:
A method and fibre channel switch element is provided for isolating a defective device that is coupled to a fibre channel arbitrated loop. The method includes, isolating a port if a loop initialization primitive (“LIP”) is detected from a device coupled to the arbitrated loop; configuring the device and acquiring an AL_PA; determining if the device is sending LIPs; and isolating the device if the device continues to send LIPs. The switch element includes, a port having an isolation state machine that allows the switch element to isolate a device whose behavior may result in disruption of other devices in the network. The state machine may also configure a device after detecting disruptive parameters from the device and perform diagnostic operations on the device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority under 35 USC Section 119(e), to the following provisional patent applications: 
   Ser. No. 60/487,876 filed on Jul. 16, 2003; 
   Ser. No. 60/487,887 filed on Jul. 16, 2003; 
   Ser. No. 60/487,875 filed on Jul. 16, 2003; 
   Ser. No. 60/490,747 filed on Jul. 29, 2003; 
   Ser. No. 60/487,667 filed on Jul. 16, 2003; 
   Ser. No. 60/487,665 filed on Jul. 16, 2003; 
   Ser. No. 60/492,346 filed on Aug. 4, 2003; and 
   Ser. No. 60/487,873 filed on Jul. 16, 2003. 
   The disclosures of the foregoing applications are incorporated herein by reference in their entirety. 

   BACKGROUND 
   1. Field of the Invention 
   The present invention relates to networks, and more particularly to prevent disruptions in networks. 
   2. Background of the Invention 
   In a common-access network, every attached network device detects all traffic on the network, and each device determines through network-specific hand shaking when to claim data from the network. Examples of common-access networks include Ethernet, Fibre Channel—Arbitrated Loop (FC-AL), and Token-Ring. 
   Because each device detects all traffic on a common-access network, certain behaviors from a single network device would disrupt all network devices. For example, a FC-AL device may initiate loop initialization and disrupt all traffic in FC-AL. Similarly; a beaconing condition would disrupt all traffic on a Token-Ring network. 
   Hence, isolation of disruptive events (or devices) is a challenge for modern networks. The following introduces Fibre Channel standards/terminology and also describes some of the challenges that a FC-AL topology faces in this context. 
   Fibre channel is a set of American National Standard Institute (ANSI) standards, which provide a serial transmission protocol for storage and network protocols such as HIPPI, SCSI, IP, ATM and others. Fibre channel provides an input/output interface to meet the requirements of both channel and network users. 
   Fibre channel supports three different topologies: point-to-point, arbitrated loop and fibre channel fabric. The point-to-point topology attaches two devices directly. The arbitrated loop topology attaches devices in a loop. The fibre channel fabric topology attaches host systems directly to a fabric, which are then connected to multiple devices. The fibre channel fabric topology allows several media types to be interconnected. 
   Fibre channel is a closed system that relies on multiple ports to exchange information on attributes and characteristics to determine if the ports can operate together. If the ports can work together, they define the criteria under which they communicate. 
   In fibre channel, a path is established between two nodes where the path&#39;s primary task is to transport data from one point to another at high speed with low latency, performing only simple error detection in hardware. 
   FC-AL is one fibre channel standard (incorporated herein by reference in its entirety) that establishes the protocols for an arbitrated loop topology. Conventional elements in a FC-AL topology are not robust and do not provide an efficient way to identify, isolate and manage loop traffic. 
   One such problem is shown in system  210  of  FIG. 2B . System  210  includes a fibre channel element (or a switch)  216  that couples host systems  213 - 215  to storage systems  217  and  218 . Storage system  217  and  218  include redundant array of independent disks (RAID)  211  and  219  coupled via plural input/output (“I/O”) modules ( 212 ) and RAID controllers  201 A and  201 B. If drive  219  is defective, it may disrupt all traffic in common-access network  220 . This can result in loop failure and lower performance of the overall network. To discover the defective device in a common-access network, the system administrator may have few options other than removing devices until the network disruption ceases. 
   Another example is shown in  FIG. 2A , where a RAID controller  201  is coupled to two different loops  209 A and  208 A via links  209  and  208  in a disk array system  200 . Each loop has a small computer systems interface (SCSI) enclosure services (“SES”) module  202  and  202 A. SES modules  202  and  202 A comply with the SES industry standard that is incorporated herein by reference in its entirety. 
   Port Bypass Circuit (or PBC) modules  203  (and  206 ) couple plural disks (for example,  204 ,  202 B and  207 ) and link  205  couples the PBC modules. 
   If drive  202 B, which is dual ported, fails then both loops  209 A and  208 A are disrupted. Again, conventional techniques will require that storage  202 A be removed and a bypass command issued to all drives, which takes the entire array off-line. Each device is attached and detached to investigate the reason for a link failure. Then all the drives, except the faulty drive are re-attached and loop activity is restored. This system of trial and error is labor intensive and inefficient. 
   Therefore, what is required is a process and system that can identify, isolate and manage loop faulty devices in common access networks, including the FC-AL topology. 
   SUMMARY OF THE INVENTION 
   In one aspect of the present invention, a method for isolating a defective device that is coupled to a fibre channel arbitrated loop in a network is provided. The method includes, isolating a port if a loop initialization primitive (“LIP”) is detected from a device coupled to the arbitrated loop; configuring the device and acquiring an AL_PA; determining if the device is sending LIPs; and isolating the device if the device continues to send LIPs. The method also includes connecting the device to the network if the device stops sending LIPs after it is configured. 
   In another aspect of the present invention, a fibre channel switch element having more than one port for connecting devices in a network is provided. The switch element includes, a port having an isolation state machine that allows the switch element to isolate a device whose behavior may result in disruption of other devices in the network. The state machine may also configure a device after detecting disruptive parameters from the device and perform diagnostic operations on the device. 
   In yet another aspect of the present invention, a network for connecting devices is provided. The network includes a fibre channel switch element including a port having an isolation state machine that allows the switch element to isolate a device whose behavior may result in disruption of other devices in the network. 
   This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiments thereof concerning the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing features and other features of the present invention will now be described with reference to the drawings of a preferred embodiment. In the drawings, the same components have the same reference numerals. The illustrated embodiment is intended to illustrate, but not to limit the invention. The drawings include the following Figures: 
       FIG. 1  shows a block diagram of a storage area network; 
       FIGS. 2A-2B  show disruptive configurations that use the adaptive aspects of the present invention; 
       FIGS. 3A-3C  show block diagrams of various system level configurations, according to one aspect of the present invention; 
       FIG. 4  shows a block diagram of a switch element, according to one aspect of the present invention; 
       FIGS. 5A and 5B  (jointly referred to as  FIG. 5 ) show a block diagram of a transmission protocol engine, according to one aspect of the present invention; 
       FIGS. 6A and 6B  show block diagrams for a diagnostic module and a SES module, according to one aspect of the present invention; 
       FIGS. 6C-6I  show various block diagrams used to reduce disruption in common access networks, according to one aspect of the present invention; 
       FIG. 7  shows process flow diagram for assigning an AL_PA to a device without disrupting all other devices, according to one aspect of the present invention and 
       FIG. 8  shows a process flow diagram for isolating a disruptive device and assigning an AL_PA to the device, according to one aspect of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Definitions: 
   The following definitions are provided as they are typically (but not exclusively) used in the fibre channel environment, implementing the various adaptive aspects of the present invention. 
   “AL_PA”: Arbitrated loop physical address. 
   “FC-AL”: Fibre channel arbitrated loop process described in FC-AL standard. 
   “Fibre channel ANSI Standard”: The standard describes the physical interface, transmission and signaling protocol of a high performance serial link for support of other high level protocols associated with IPI, SCSI, IP, ATM and others. 
   “FC-1”: Fibre channel transmission protocol, which includes serial encoding, decoding and error control. 
   “FC-2”: Fibre channel signaling protocol that includes frame structure and byte sequences. 
   “FC-3”: Defines a set of fibre channel services that are common across plural ports of a node. 
   “FC-4”: Provides mapping between lower levels of fibre channel, IPI and SCSI command sets, HIPPI data framing, IP and other upper level protocols. 
   “LIP”: Loop initialization protocol primitive. 
   “L_Port”: A port that contains Arbitrated Loop functions associated with the Arbitrated Loop topology. 
   “PBC”: Port Bypass Circuit. 
   “SES”: SCSI Enclosure Services. 
   “TPE”: Transmission Protocol Engine, a controller that operates at the FC-1 level. 
   To facilitate an understanding of the preferred embodiment, the general architecture and operation of a fibre channel system will be described. The specific architecture and operation of the preferred embodiment will then be described with reference to the general architecture of the fibre channel system. 
     FIG. 1  is a block diagram of a fibre channel system  100  implementing the methods and systems in accordance with the adaptive aspects of the present invention. System  100  includes plural devices that are interconnected. Each device includes one or more ports, classified as node ports (N_Ports), fabric ports (F_Ports), and expansion ports (E_Ports). Node ports may be located in a node device, e.g. server  103 , disk array  105  and storage device  104 . Fabric ports are located in fabric devices such as switch  101  and  102 . Arbitrated loop  106  may be operationally coupled to switch  101  using arbitrated loop ports (FL_Ports). 
   The devices of  FIG. 1  are operationally coupled via “links” or “paths”. A path may be established between two N_ports, e.g. between server  103  and storage  104 . A packet-switched path may be established using multiple links, e.g. an N-Port in server  103  may establish a path with disk array  105  through switch  102 . 
     FIG. 3A  shows a block diagram of the top-level architecture for system  300  according to one aspect of the present invention. System  300  includes system  307  (a Fibre Channel element) operationally coupled to an array of storage devices  307 A that is coupled to a RAID controller  301 . RAID system  301 A is coupled to switch  303  that is coupled to various computing systems ( 304 - 306 ). System  308 ,  309 ,  310 ,  311  and  312  coupled to storage devices  308 A,  309 A,  310 A,  311 A and  312 A, are similar to  307 / 307 A configuration. 
   System  307  (or  308 - 312 ) allows faulty disks to be easily segregated. For example, if a drive  313  in string  311 A is faulty, then system  311  allows drive  313  to be separated, while normal traffic in arrays  301 A and  310 A continues. 
     FIG. 3B  shows how system  307  operationally couples RAID controller  301  and  302  to disk array  315  (similar to  307 A) via loop  314 , according to one aspect of the present invention. Both RAID controllers have access to all the drives. 
     FIG. 3C  shows plural system  307  coupled to RAID controllers  301  and  302  to provide access to arrays  315 ,  317  and  318  using loops  314  and  316 , according to one aspect of the present invention. 
     FIG. 4  is a block diagram of an 18-port ASIC FC element  400 A (also referred to as system  307 ) according to one aspect of the present invention. FC element  400 A provides various functionality in an FC-AL environment, including without limitation, FC element  400 A operates as a loop controller and loop switch using switch matrix  408 , in accordance with the FC-AL standard. 
   FC element  307  of the present invention is presently implemented as a single CMOS ASIC, and for this reason the term “FC element” and ASIC are used interchangeably to refer to the preferred embodiments in this specification. Although  FIG. 4  shows 18 ports, the present invention is not limited to any particular number of ports. 
   System  400 A provides a set of port control functions, status indications, and statistics counters for monitoring the health of the loop and attached devices, diagnosing faults, and recovering from errors. 
   ASIC  400 A has 18 ports where 16 ports are shown as numeral  405  while a host port  404  and cascade port  404 A are shown separately for convenience only. These ports are generic to common Fibre Channel port types, for example, L_Ports. 
   For illustration purposes only, all ports are drawn on the same side of ASIC  400 A in  FIG. 4 . However, the ports may be located on any side of ASIC  400 A. This does not imply any difference in port or ASIC design. Actual physical layout of the ports will depend on the physical layout of the ASIC. 
   Each port has transmit and receive connections to switch matrix  408  and includes transmit protocol engine  407  and a serial/deserializer  406 . Frames enter/leave the link  405 A and SERDES  406  converts data into 10-bit parallel data to fibre channel characters. 
   Switch matrix  408  dynamically establishes a connection for loop traffic. Switch matrix  408  includes a global arbiter (hence switch matrix  408  is also referred to as SGA  408 ) that provides lower latency and improved diagnostic capabilities while maintaining full Fibre Channel Arbitrated Loop (FC-AL) compliance. 
   Switch matrix  408  provides a quasi-direct architecture in the form of a buffer-less Switch Matrix. Switch matrix  408  includes data multiplexers that provide a path to each port. In one aspect, twenty multiplexers may be used. In one aspect, data is 16 bits wide plus the internal “K” control signal and two parity bits. 
   At power-up, SGA  408  is setup in a flow-through configuration, which means all ports send what was received on host port  404 . When a valid LIP sequence occurs, SGA  408  configures the switch to a complete loop configuration for the address selection process. During normal data transfer on the loop, SGA  408  reconfigures the switch data-path to connect the active ports in what appears as a smaller loop, which lowers the latency but still emulates FC-AL functionality to all entities on the loop. 
   During loop configuration, SGA  408  configures the switch data-path to include a snooping port that walks through each port during the LIP physical address assignment to track each port&#39;s assigned arbitrated loop physical address (AL_PA). This snooping process is called the ‘LIP walk’. When the LIP process is done, the firmware records the “port to AL_PA” map in an internal table built in SGA  408 . During normal data transfer mode, SGA  408  monitors arbitration requests, open requests, and close primitives to determine which ports have traffic that must be forwarded. The ports that have traffic for the loop provide the necessary information to create the connection points for the switch data-path. The inactive ports are provided the primitive ARB(F0). 
   SGA  408  selects the arbitration winner, from all the arbitrating ports, according to Fibre Channel Arbitrated Loop (FC-AL) rules. For ports, which detect arbitration, the AL_PA is looked up in a Port Address Table to see if the arbitration request is valid for that port. Due to the unique purpose of port  0  (Host port  404 ), port  0  never needs to win arbitration, but can detect that the arbitration winner is outside a range, or with ARB(F0)/IDLE show that devices outside system  307  are not arbitrating at a given time. 
   For arbitration detect on host port  404  to be considered valid the “ArbPS0” cannot match an AL_PA in the internal Port Address Table, which means that the source address is not in a particular system  307 . For ports seeking a valid arbitration, the AL_PA determines which arbitrating device has highest priority; and typically, the port with the lowest AL_PA value is always selected as the winner. 
   SGA  408  creates a direct loop connection between source and destination devices. This connection methodology avoids the delay associated with data having to pass from one disk drive member of the loop to the next until the data has completed traversing the loop. In one aspect, the following formula evaluates performance of a loop connection:
 
Latency (word times)= n *(2*8)+disk+host=16 n+ 12
 
   Where n is the number of systems  307  that comprise the FC loop, 6 is the latency of the disk drive that is part of the loop connection and 6 is typically the latency of the attached host. 
   System  307  includes plural  12 C ( 12 C standard compliant) interfaces  412 - 413  that allow system  307  to couple to plural I 2 C ports each having a master and slave capability. 
   System  307  also includes a general purpose input/output interface (“GPIO”)  415 . This allows information from system  307  to be analyzed by any device that can use GPIO  415 . Control/Status information  419  can be sent or received through module  415 . 
   System  307  also includes a SPI module  414  that is used for parallel to serial and serial to parallel transfer between processor  400  firmware and flash memory  421  in the standard Little Endian format. 
   System  307  also includes a Universal Asynchronous Receiver/Transmitter (“UART”) interface  418  that converts serial data to parallel data (for example, from a peripheral device modem or data set) and vice-versa (data received from processor  400 ) complying industry standard requirements. 
   System  307  can also process tachometer inputs (received from a fan, not shown) using module  417 . Processor  400  can read the tachometer input via a tachometer rate register and status register (not shown). 
   System  307  provides pulse width modulator (“PWM”) outputs via module  416 . Processor  400  can program plural outputs. Timer module  411  is provided for monitoring and controlling various timers for various switch operations. 
   System  307  also includes two frame manager modules  402  and  403  that are similar in structure. Processor  400  can access runtime code from memory  420  and input/output instructions from read only memory  409 . 
   Module  402  (also referred to as the “diag module  402 ”) is a diagnostic module used to transfer diagnostic information between a FC-AL and the firmware of system  307 . 
   Diag module  402  is functionally coupled to storage media (via ports  405 ) via dedicated paths outside switch matrix  408  so that its connection does not disrupt the overall loop. Diag module  402  is used for AL_PA capture during LIP propagation, drive(s) (coupled to ports  405 ) diagnostics and frame capture. 
   Module  403  (also referred to as “SES module  403 ”) complies with the SES standard and is functionally coupled to host port  404  and its output is routed through switch matrix  408 . SES module  403  is used for in-band management services using the standard SES protocol. 
   When not bypassed, modules  402  and  403  receive primitives, primitive sequences, and frames. Based on the received traffic and the requests from firmware, modules  402  and  403  maintain loop port state machine (LPSM) ( 615 ,  FIG. 6B ) in the correct state per the FC-AL standard specification, and also maintain the current fill word. 
   Based on a current LPSM  615  state (OPEN or OPENED State), modules  402  and  403  receive frames, pass the frame onto a buffer, and alert firmware that a frame has been received. Module  402  and  403  follow FC-AL buffer to buffer credit requirements. 
   Firmware may request modules  402  and  403  to automatically append SOF and EOF to the outgoing frame, and to automatically calculate the outgoing frame&#39;s CRC using CRC generator  612 . Modules  402  and  403  can receive any class of frames and firmware may request to send either fibre channel Class 2 or Class 3 frames. 
   Port Management Interface (PMIF)  401  allows processor  400  access to various port level registers, SerDes modules  406  and TPE Management Interfaces  509  ( FIG. 5 ). PMIF  401  contains a set of global control and status registers, receive and transmit test buffers, and three Serial Control Interface (SCIF) controllers (not shown) for accessing SerDes  406  registers. 
     FIGS. 6A and 6B  show block diagrams for module  402  and  403 . It is noteworthy that the structure in  FIGS. 6A and 6B  can be used for both modules  402  and  403 .  FIG. 6B  is the internal data path of a FC port  601  coupled to modules  402 / 403 . 
   Modules  402  and  403  interface with processor  400  via an interface  606 . Incoming frames to modules  402  and  403  are received from port  601  (which could be any of the ports  404 ,  404 A and  405 ) and stored in frame buffer  607 . Outgoing frames are also stored in frame buffer  607 . Modules  402  and  403  have a receive side memory buffer based on “first-in, first-out” principle, (“FIFO”) RX_FIFO  603  and transmit side FIFO TX_FIFO  604  interfacing with a Random access FIFO  605 . A receive side FIFO  603  signals to firmware when incoming frame(s) are received. A transmit side FIFO  604  signals to hardware when outgoing frames(s) are ready for transmission. A frame buffer  607  is used to stage outgoing frames and to store incoming frames. Modules  602  and  602 A are used to manage frame traffic from port  601  to buffers  603  and  604 , respectively. 
   Modules  402  and  403  use various general-purpose registers  608  for managing control, status and timing information. 
   Based on the AL_PA, modules  402  and  403  monitor received frames and if a frame is received for a particular module ( 402  or  403 ), it will pass the frame onto a receive buffer and alert the firmware that a frame has been received via a receive side FIFO  603 . Modules  402  and  403  follow the FC-AL buffer-to-buffer credit requirements using module  616 . Modules  402  and  403  transmit primitives and frames based on FC-AL rules. Firmware pre-sends the SOF and then appends the cyclic redundancy code (“CRC”) generated by module  612 , and the EOF generated by Module  613 . 
   Overall transmission control is performed by module  611  that receives data, SOF, EOF and CRC. A word assembler module  609  is used to assemble incoming words, and a fill word module  610  receives data “words” before sending it to module  611  for transmission. Transmit Buffer control is performed by module  614 . 
     FIG. 5  shows a block diagram of the transmission protocol engine (“TPE”)  407 . TPE  407  maintains plural counters/registers to interact with drives coupled to ports  405 . Each TPE  407  interacts with processor  400  via port manager interface  401 . 
   Each Fibre Channel port of system  400 A includes a TPE module for interfacing with SerDes  406 . TPE  407  handles most of the FC-1 layer (transmission protocol) functions, including 10B receive character alignment, 8B/10B encode/decode, 32-bit receive word synchronization, and elasticity buffer management for word re-timing and TX/RX frequency compensation. 
   SerDes modules  406  handle the FC-1 serialization and de-serialization functions. Each SerDes  406  port consists of an independent transmit and receive node. 
   TPE  407  has a receive module  500  (that operates in the Rx clock domain  503 ) and a transmit module  501 . Data  502  is received from SERDES  406  and decoded by decoding module  504 . A parity generator module  505  generates parity data. SGA interface  508  allows TPE to communicate with switch  514  or switch matrix  408 . Interface  508  (via multiplexer  507 ) receives information from a receiver module  506  that receives decoded data from decode module  504  and parity data from module  505 . 
   Management interfaces module  509  interfaces with processor  400 . Transmit module  501  includes a parity checker  511 , a transmitter  510  and an encoder  512  that encodes 8-bit data into 10-bit data. 10-bit transmit data is sent to SERDES  406  via multiplexer  513 . 
   Port Management Interface (PMIF)  401  allows processor  400  access to various port level registers, SerDes modules  406  and TPE Management Interfaces  509  (MIFs). PMIF  401  contains a set of global control and status registers, receive and transmit test buffers, and three Serial Control Interface (SCIF) controllers (not shown) for accessing SerDes  406  registers. 
   In one aspect of the present invention, module  402 / 403  includes an Isolation State Machine to prevent disruptive behaviors.  FIG. 6C  shows an example of an Isolation State Machine (“ISM”)  402 A, which isolates disruptive device, as illustrated in  FIG. 6I . ISM  402 A can also function in a diagnostic mode as a diagnostic state machine ( 402 B,  FIGS. 6D and 6J  (diagnostic state machine as  402 D, used interchangeably), and as a configuration state machine  402 C ( FIGS. 6E and 6K ). 
     FIG. 6F  shows ISM  402 A, diagnostic (“diag”) state machine  402 B and configuration state machine  402 C as separate components. It is noteworthy that the functionality of the foregoing state machines may all be included in one state machine. 
   If a network device is disruptive, diag module  402  connects the device to Isolation State Machine  402 A to prevent disruptions to the other devices ( FIG. 6I ), and may opt to perform diagnostics on the suspected device. 
   If the system can determine the cause and correct the fault, the system may correct the problem and move the corrected network device back to the operating network. The faulty device would stay in-place during this process of isolation, diagnosis and correction. 
     FIG. 6I  shows ISM  402 A isolating device  616 , while  FIG. 6J  shows diag state machine  402 D diagnosing device  616 . 
     FIG. 6K  shows a configuration state machine  402 C interacting with a device  616  that needs to be set-up. 
     FIG. 7  shows process steps of how to assign an AL_PA to a device without disrupting all other devices, according to one aspect of the present invention. In step S 700 , the process is either transferring data or is monitoring the network. 
   In step S 701 , the process determines if a LIP is received. If a LIP is received, then in step S 702 , ISM  402 A isolates the port (via TPE  407 ). If not, the process goes back to step S 700 . 
   In step S 703 , the process determines if the device (for example,  616 ) has been configured before. If the device is not configured, then the device ( 616 ) is configured in step S 705  (as described below with respect to  FIG. 8 ). If the device ( 616 ) has been configured before, the device is still configured (in step S 704 , as described below with respect to  FIG. 8 ), followed by additional diagnostics using device-specific commands in step S 706 . 
   In step S 707 , the process determines if the device (for example,  616 ) is still sending LIPs. If yes, the device is isolated from the network in step S 709 . If the device is not sending LIPs, then it is connected to the network in step S 708 . 
   In certain networks, device configuration and initialization is disruptive to all network devices. For instance, when a FC-AL device initializes, it normally needs to acquire an AL_PA. This process of acquiring an AL_PA is disruptive and requires all network devices to stop any on-going data transfer until the AL_PA assignment has completed and then restart the previous data transfers. 
   Module  402 / 403  prevents device-configuration disruptions on an operational network, even when new devices are inserted. In addition, the present invention would also prevent disruptions when a faulty device is disconnected from the system, and a replacement device is connected in the place of the faulty device. In such a case, Configuration State Machine  402 C can isolate the replacement device and configure the device identically to that of the replaced device. 
   As an example, suppose a FC-AL device is initializing and thus sends LIP primitives in order to acquire an AL_PA. To prevent disruption, the system would isolate the device and assign an AL_PA to the device as discussed below with respect to  FIG. 8  process steps. 
   Turning in detail to  FIG. 8 , in step S 800 , the process is either transferring data or is monitoring the network. If a LIP is detected in step S 801 , the process isolates the port in step S 802 . In step S 803 , the process determines if the device has been configured. If yes, then the process goes to  FIG. 7 . If not, then in step S 804  the device is configured per FC-AL standard. 
   In step S 805 , the process determines if the device is still sending LIPs. If yes, then the process goes to  FIG. 7 , otherwise the device is connected back to the network in step S 806 . 
   Diagnostics and device configuration need not be restricted to knowledge contained in system  307  or module  402 / 403 .  FIG. 6H  shows an external control means  617  that can be used for acquiring data to/from Isolation State Machine  402 A (i.e. Diagnosis/Configuration State Machine), for example UART  418  or GPIO  415  may be used for external control  617 . 
   Control and diagnostic information may also be shared with an in-band state machine  402 D ( FIG. 6G ) located within module  403 , in one aspect of the present invention. 
   Although the present invention has been described with reference to specific embodiments, these embodiments are illustrative only and not limiting. Many other applications and embodiments of the present invention will be apparent in light of this disclosure and the following claims.