EP1535427A1 - Method, system and hub for loop initialization - Google Patents

Method, system and hub for loop initialization

Info

Publication number
EP1535427A1
EP1535427A1 EP03790972A EP03790972A EP1535427A1 EP 1535427 A1 EP1535427 A1 EP 1535427A1 EP 03790972 A EP03790972 A EP 03790972A EP 03790972 A EP03790972 A EP 03790972A EP 1535427 A1 EP1535427 A1 EP 1535427A1
Authority
EP
European Patent Office
Prior art keywords
loop
hub
loops
standby
redundant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03790972A
Other languages
German (de)
French (fr)
Inventor
Harri HYYTIÄINEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Oyj
Nokia Inc
Original Assignee
Nokia Oyj
Nokia Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nokia Oyj, Nokia Inc filed Critical Nokia Oyj
Publication of EP1535427A1 publication Critical patent/EP1535427A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/42—Loop networks
    • H04L12/437—Ring fault isolation or reconfiguration

Definitions

  • the present invention relates computer systems.
  • the present invention relates to a novel and improved method, system and hub for initializing redundant loop systems.
  • FC-AL Fibre Channel Arbitrated Loop
  • FC Fibre Channel
  • Fibre Channel in general exists in several topologies (point-to-point, fabric and loop) . Since the FC-AL is a loop topology in which the nodes are in logical circular so that data within loop may be usually passed through other nodes when two nodes are communicating. Removing a node may cut the path between nodes .
  • bypass circuitry is used to pass the data over such node. Usually the bypass circuitry is gathered into one entity called a Fibre Channel hub.
  • the hub can further have some intelli- gence and it can be controlled outside, therefore being called as a managed Fibre Channel hub.
  • the managed FC hub can for example be commanded to bypass any of the connected nodes (hub ports) .
  • Loop Initialization Primitive (LIP) isolation to limit its visibility in the loop.
  • Loop initialization action suspends normal operation of the loop while the entire population on the loop acquires or verifies the current port addresses and is assigned an AL_PA (Arbi- trated Loop Physical Address) .
  • AL_PA Arbi- trated Loop Physical Address
  • loop initialization disturbs the ongoing loop traffic.
  • the Fibre Channel systems have to take into account that loop initializations may happen and try to resend the data or otherwise handle the situation. This seems to be especially harmful for tape systems wherein repeating a command may spoil the logical structure of the data.
  • the present invention describes a method, system and hub for initializing a redundant loop system comprising a hub and plurality of nodes connected to the hub.
  • redundant describes computer or network system components, such as fans, hard disk drives, servers, switches, and telecommuni- cation links that are installed to back up primary resources in case of a failure.
  • the redundant loop system has to be initialized. These reasons comprise e.g. inserting a node into the loop, restart- ing a node within the loop, replacing a node of the loop or removing a node from the loop.
  • the present invention describes a solution for avoiding the disturbance of the initialization process to the ongoing loop traffic.
  • the loops in the redundant loop system are classified as being either in an active or standby state. However, at least one of the loops is in active state.
  • the classification is made for the initialization process of the redundant loop system. At other times, it is not necessary to maintain the classification but several loops can be used simultaneously, e.g. for load balancing purposes.
  • the loops of the redundant loop system are initialized so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized.
  • the initialized loop is set as a new active loop and the previous active loop as standby loop. Now the current active loop has been initialized and the previous active loop (now standby loop) is ready to be initialized.
  • the previous loop initialization process can also be applied when the redundant loop system comprises more than two loops. The process continues until all the loops have been initialized.
  • the loop initialization loop-by-loop is implemented so that the hub ports of the hub are controlled so that one or more standby loops are initialized at a time and, at the same time, at least one loop is in active state.
  • the re- dundant loop system is a Fibre Channel Arbitrated Loop .
  • the present invention has several advantages over the prior-art solutions.
  • the present invention fully isolates the loop initialization so that an ac- tive loop operation is not affected.
  • the present invention also provides an important part for implementing fluent hot swap procedure. This is an important feature especially in communication and telecommunication systems in which the amount of service breaks must be minimized.
  • Fig 1 is a physical view of a system configuration of the present invention
  • Fig 2 is a physical view of a system configuration of the present invention
  • Fig 3 is a logical view of the system configuratio of Figure 1 or 2 ,
  • Fig 4 is a logical wiring view of the system configuration of Figure 1 or 2
  • Fig 5 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is removed from the loop,
  • Fig 6 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is removed from the loop,
  • Fig 7 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop
  • Fig 8 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop
  • Fig 9 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is in- serted into the loop,
  • Fig 10 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop,
  • Fig 11 is a logical view of the system con- figuration of Figure 1 or 2 wherein server SRVB is inserted into the loop
  • Fig 12 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the. loop
  • server SRVB is inserted into the. loop
  • Fig 13 is an exemplary hub utilized in the present invention.
  • Figures 1 and 2 represent exemplary physical views of the blade disk configuration within which the present invention can be implemented.
  • the difference between Figure 1 and Figure 2 is that in Figure 1 also the chassis is redundant.
  • the blade disk configuration comprises redundant disks and servers.
  • the hubs HUB1 and HUB2 , servers SRVA and SRVB and hard disks HD1 and HD2 are separated between two chassis halves.
  • all the above-mentioned nodes are collected within one chassis halve.
  • Figures 1 and 2 describe redundant loop sys- terns, i.e. there exists two loops wherein for the initialization process, one of the loops has been defined as the active loop and the other one as the standby loop.
  • the dotted line represents one loop (FC-b) and the solid line (FC-a) the other.
  • FC-AL Fibre Channel Arbitrary
  • FIG. 3 represents a logical view of the system configuration of Figure 1 and 2.
  • Figure 3 comprises redundant FC-AL loops. Traffic in a loop will go in one direction through the nodes (disks or serv- ers of Figures 1 and 2) . However, traffic can be transmitted in full duplex mode (both nodes can send and receive at the same time) between two nodes although traffic is transmitted in one direction in the loop .
  • the solid line represents the active loop
  • FC-a and the dotted line (FC-b) the standby loop.
  • Figure 4 is a logical wiring view of the system configuration of Figure 1 and 2 and the logical view of Figure 3.
  • Figure 4 comprises hard disks HD1 and HD2 , hubs HUB1 and HUB2 and servers A and B. Each hard disk and server is connected to both of the hubs. Therefore, Figure 4 comprises two separate loops, FC-a (solid lines) and FC-b (dotted lines) .
  • Figures 5 and 6 represent an example in which server SRVB is removed.
  • Figure 5 represents a logical view of the configuration.
  • the logical wiring view of Figure 5 is represented in Figure 6.
  • Server SRVB ports are bypassed to keep the loops sound. Bypassed connections are shown with longer dotted lines.
  • Figures 7 - 12 represent an example in which server SRVB is inserted into the loops. At first, server SRVB is bypassed from both FC channels. This enables the procedure that the loops can be initialized one by one.
  • the logical wiring view of Figure 7 is represented in Figure 8 in which server SRVB ports are bypassed. Bypassed connections are shown with longer dotted lines.
  • server SRVB is bypassed from FC- a loop (active loop) meanwhile FC-b loop (standby loop) is being initialized. Bypassed connections are shown with longer dotted lines.
  • the logical wiring view of Figure 9 is represented in Figure 10. However, now server SRVB ports are bypassed in hub HUB2. The bypassed connection is shown with longer dotted lines.
  • Figure 11 represents the situation in which FC-b is already initialized and set in active state while FC-a is set in standby state. FC-a can now be initialized without any harmful effects on FC-b.
  • the logical wiring view of Figure 11 is represented in Figure 12.
  • both loops FC-a, FC-b
  • Figures 1 - 12 describe a redundant loop system comprising only two loops.
  • a redundant loop system may, of course, comprise more than two loops. Nevertheless, the initialization process is the same, i.e. initializing the redundant loop system so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized.
  • Figure 13 represents a hub comprising classifying means CM for classifying the loops as being ei- ther in an active or standby state, selecting means SEL for selecting one or more standby loops of the redundant loop system, initializing means INI for initializing the standby loop(s) and setting means SET for changing the state of a loop to active or standby.
  • the hub comprises controlling means CON for controlling the hub ports so that one or more standby loops are initialized at a time. With the controlling means the hub ports are set either in bypass or pass state.
  • the hub comprises also detecting means DET for detecting events that trigger the initialization process of the redundant loop system, the initialization process triggered by one of the following reasons: inserting a node into the loop, restarting a node within the loop, replacing a node of the loop or removing a node from the loop.
  • detecting means DET for detecting events that trigger the initialization process of the redundant loop system, the initialization process triggered by one of the following reasons: inserting a node into the loop, restarting a node within the loop, replacing a node of the loop or removing a node from the loop.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

The present invention describes a method and system for initializing a redundant loop system comprising one or more hubs, plurality of nodes connected to the hubs, wherein the redundant loop system comprises two or more loops. The loops in the redundant loop system are classified as being either in active or standby state. However, at least one of the loops is in active state. The classification is made for the initialization process of the redundant loop system. In the method, the redundant loop system is initialized so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized.

Description

METHOD, SYSTEM AND HUB FOR LOOP INITIALIZATION
FIELD OF THE INVENTION
The present invention relates computer systems. In particular, the present invention relates to a novel and improved method, system and hub for initializing redundant loop systems.
BACKGROUND OF THE INVENTION
A Fibre Channel Arbitrated Loop (FC-AL) is a media used to transfer commands and data e.g. between storage devices (like hard disks) and processor units
(like servers or workstations) . From the Fibre Channel
(FC) point of view both are nodes. Fibre Channel in general exists in several topologies (point-to-point, fabric and loop) . Since the FC-AL is a loop topology in which the nodes are in logical circular so that data within loop may be usually passed through other nodes when two nodes are communicating. Removing a node may cut the path between nodes . To prevent the FC-AL to be fully unusable when single node is removed, unpowered or broken, bypass circuitry is used to pass the data over such node. Usually the bypass circuitry is gathered into one entity called a Fibre Channel hub. The hub can further have some intelli- gence and it can be controlled outside, therefore being called as a managed Fibre Channel hub. The managed FC hub can for example be commanded to bypass any of the connected nodes (hub ports) .
Certain operations and incidents in the loop may cause the loop to initialize, which at least in some extent, may disturb the operation of the loop and hence excessive loop initializations are undesired. At least inserting a node and restarting a (processor) node will trigger loop initialization. Some commercial Fibre Channel hubs have, for example, features like Loop Initialization Primitive (LIP) isolation to limit its visibility in the loop. Loop initialization action suspends normal operation of the loop while the entire population on the loop acquires or verifies the current port addresses and is assigned an AL_PA (Arbi- trated Loop Physical Address) . Although the LIPs may sometimes happen fast, throughput-sensitive applications, such as video streaming and tape backups, are sensitive to hiccups.
The problem with the current loop solutions is that, e.g. in the Fibre Channel, loop initialization disturbs the ongoing loop traffic. The Fibre Channel systems have to take into account that loop initializations may happen and try to resend the data or otherwise handle the situation. This seems to be especially harmful for tape systems wherein repeating a command may spoil the logical structure of the data.
SUMMARY OF THE INVENTION
The present invention describes a method, system and hub for initializing a redundant loop system comprising a hub and plurality of nodes connected to the hub. In general, the term redundant describes computer or network system components, such as fans, hard disk drives, servers, switches, and telecommuni- cation links that are installed to back up primary resources in case of a failure.
There may be several reasons why the redundant loop system has to be initialized. These reasons comprise e.g. inserting a node into the loop, restart- ing a node within the loop, replacing a node of the loop or removing a node from the loop.
The present invention describes a solution for avoiding the disturbance of the initialization process to the ongoing loop traffic. In the method, the loops in the redundant loop system are classified as being either in an active or standby state. However, at least one of the loops is in active state. The classification is made for the initialization process of the redundant loop system. At other times, it is not necessary to maintain the classification but several loops can be used simultaneously, e.g. for load balancing purposes. The loops of the redundant loop system are initialized so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized. When the initialization process of the standby loop is over, in case the redundant loop system comprises two loops, the initialized loop is set as a new active loop and the previous active loop as standby loop. Now the current active loop has been initialized and the previous active loop (now standby loop) is ready to be initialized. The previous loop initialization process can also be applied when the redundant loop system comprises more than two loops. The process continues until all the loops have been initialized.
In one embodiment of the invention, the loop initialization loop-by-loop is implemented so that the hub ports of the hub are controlled so that one or more standby loops are initialized at a time and, at the same time, at least one loop is in active state.
In one embodiment of the invention, the re- dundant loop system is a Fibre Channel Arbitrated Loop .
The present invention has several advantages over the prior-art solutions. The present invention fully isolates the loop initialization so that an ac- tive loop operation is not affected.
The present invention also provides an important part for implementing fluent hot swap procedure. This is an important feature especially in communication and telecommunication systems in which the amount of service breaks must be minimized. BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are inclμded to provide a further understanding of the invention and constitute a part of this specification, illus- trate embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:
Fig 1 is a physical view of a system configuration of the present invention, Fig 2 is a physical view of a system configuration of the present invention,
Fig 3 is a logical view of the system configuratio of Figure 1 or 2 ,
Fig 4 is a logical wiring view of the system configuration of Figure 1 or 2,
Fig 5 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is removed from the loop,
Fig 6 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is removed from the loop,
Fig 7 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop, Fig 8 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop,
Fig 9 is a logical view of the system configuration of Figure 1 or 2 wherein server SRVB is in- serted into the loop,
Fig 10 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the loop,
Fig 11 is a logical view of the system con- figuration of Figure 1 or 2 wherein server SRVB is inserted into the loop, Fig 12 is a logical wiring view of the system configuration of Figure 1 or 2 wherein server SRVB is inserted into the. loop, and
Fig 13 is an exemplary hub utilized in the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Figures 1 and 2 represent exemplary physical views of the blade disk configuration within which the present invention can be implemented. The difference between Figure 1 and Figure 2 is that in Figure 1 also the chassis is redundant. In other words, the upper halves of the chasses are coupled and, correspondingly, the lower upper halves of the chasses are coupled. In both figures, the blade disk configuration comprises redundant disks and servers. In Figure 1, the hubs HUB1 and HUB2 , servers SRVA and SRVB and hard disks HD1 and HD2 are separated between two chassis halves. In Figure 2, all the above-mentioned nodes are collected within one chassis halve.
Figures 1 and 2 describe redundant loop sys- terns, i.e. there exists two loops wherein for the initialization process, one of the loops has been defined as the active loop and the other one as the standby loop. The dotted line represents one loop (FC-b) and the solid line (FC-a) the other. The configuration of Figure 1 has duplicated FC-AL (Fibre Channel Arbitrary
Loop) channel in backplane and FC-AL loops can be constructed from chassis halve elements. In a chassis halve, there are max. 6 blades and hence the loop consist of N * 6 blades (there may be empty blades as well) . Figure 3 represents a logical view of the system configuration of Figure 1 and 2. Figure 3 comprises redundant FC-AL loops. Traffic in a loop will go in one direction through the nodes (disks or serv- ers of Figures 1 and 2) . However, traffic can be transmitted in full duplex mode (both nodes can send and receive at the same time) between two nodes although traffic is transmitted in one direction in the loop . The solid line represents the active loop
(FC-a) and the dotted line (FC-b) the standby loop.
Figure 4 is a logical wiring view of the system configuration of Figure 1 and 2 and the logical view of Figure 3. Figure 4 comprises hard disks HD1 and HD2 , hubs HUB1 and HUB2 and servers A and B. Each hard disk and server is connected to both of the hubs. Therefore, Figure 4 comprises two separate loops, FC-a (solid lines) and FC-b (dotted lines) .
Figures 5 and 6 represent an example in which server SRVB is removed. Figure 5 represents a logical view of the configuration. The logical wiring view of Figure 5 is represented in Figure 6. Server SRVB ports are bypassed to keep the loops sound. Bypassed connections are shown with longer dotted lines. Figures 7 - 12 represent an example in which server SRVB is inserted into the loops. At first, server SRVB is bypassed from both FC channels. This enables the procedure that the loops can be initialized one by one. The logical wiring view of Figure 7 is represented in Figure 8 in which server SRVB ports are bypassed. Bypassed connections are shown with longer dotted lines.
In Figure 9, server SRVB is bypassed from FC- a loop (active loop) meanwhile FC-b loop (standby loop) is being initialized. Bypassed connections are shown with longer dotted lines. The logical wiring view of Figure 9 is represented in Figure 10. However, now server SRVB ports are bypassed in hub HUB2. The bypassed connection is shown with longer dotted lines.
Figure 11 represents the situation in which FC-b is already initialized and set in active state while FC-a is set in standby state. FC-a can now be initialized without any harmful effects on FC-b. The logical wiring view of Figure 11 is represented in Figure 12. In Figure 12, both loops (FC-a, FC-b) have been initialized. Figures 1 - 12 describe a redundant loop system comprising only two loops. A redundant loop system may, of course, comprise more than two loops. Nevertheless, the initialization process is the same, i.e. initializing the redundant loop system so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized.
Figure 13 represents a hub comprising classifying means CM for classifying the loops as being ei- ther in an active or standby state, selecting means SEL for selecting one or more standby loops of the redundant loop system, initializing means INI for initializing the standby loop(s) and setting means SET for changing the state of a loop to active or standby. Furthermore, the hub comprises controlling means CON for controlling the hub ports so that one or more standby loops are initialized at a time. With the controlling means the hub ports are set either in bypass or pass state. The hub comprises also detecting means DET for detecting events that trigger the initialization process of the redundant loop system, the initialization process triggered by one of the following reasons: inserting a node into the loop, restarting a node within the loop, replacing a node of the loop or removing a node from the loop. The aforementioned means are implemented in a way known to a man skilled in the art and are therefore not described in more detail .
In Figure 13, all the needed intelligence for one by one initialization process described in the present invention is accumulated in the hub. In other embodiments, the intelligence can be divided between the hub and the device managing the hub or the intelligence can be wholly placed in the managing device.
It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above, instead they may vary within the scope of the claims .

Claims

1. A method for initializing a redundant loop system comprising one or more hubs, plurality of nodes connected to the hubs, wherein the redundant loop sys- tem comprises two or more loops, wherein the method comprises the step of: initializing the redundant loop system when loop initialization is triggered; charac teri z ed in that the method further comprises the steps of: classifying the loops in the redundant loop system as being either in active or standby state, at least one of the loops being in active' state; and initializing the redundant loop system so that during the initialization process traffic is transferred via the active loop(s) while the standby loop(s) is/are initialized.
2. The method according to claim 1, char acteri zed in that the method further comprises the steps of: changing the state of one or more initialized standby loops to active; changing the state of one or more uninitialized active loops to standby; and initializing the uninitialized standby loop(s).
3. The method according to claim 1, char act er i z e d in that the redundant loop system is a Fibre Channel Arbitrated Loop.
4. The method according to claim 1, char - acter i z e d in that the initialization process is triggered by one of the following reasons : inserting a node into the loop; restarting a node within the loop; replacing a node of the loop; or removing a node from the loop.
5. The method according to claim 1, char ac t er i z ed in that when initialization of a loop is to be executed the method further comprises the step of : controlling the hub ports so that one or more standby loops are initialized at a time.
6. A system for initializing a redundant loop system comprising two or more loops, the system comprising: one or more hubs (HUB, HUB1, HUB2) ; plurality of nodes (SRVA, SRVB, HD1, HD2) con- nected to the hubs (HUB1, HUB2) , characteri z ed in that the system further comprises: classifying means (CM) for classifying the loops in the redundant loop system as being either in an ac- tive or standby state; selecting means (SEL) for selecting one or more standby loops of the redundant loop system; and initializing means (INI) for initializing the standby loop(s) .
7. The system according to claim 6, char act er i z ed in that the system comprises setting means (SET) for changing the state of a loop to active or standby.
8. The system according to claim 6, char - ac t e r i z e d in that the redundant loop system is a Fibre Channel Arbitrated Loop .
9. The system according to claim 6, char act er i z e d in that the system comprises detecting means (DET) for detecting events that trigger the initialization process of the redundant loop system, the initialization process being triggered by one of the following reasons : inserting a node into the loop; restarting a node within the loop; replacing a node of the loop; or removing a node from the loop.
10. The system according to claim 6, char act e ri z ed in that the system comprises controlling means (CON) for controlling the hub (HUB, HUB1, HUB2) ports so that one or more standby loops are ini- tialized at a time.
11. The system according to claim 6 c ar ac t eri z ed in that the system comprises a managing device for controlling the hub. (HUB, HUB1, HUB2).
12. A hub for a redundant loop system, wherein plurality of nodes (SRVA, SRVB, HDl, HD2) are connected to the hub (HUB, HUB1, HUB2), characteri zed in that the hub (HUB, HUB1, HUB2) further comprises: classifying means (CM) for classifying the loops as being either in an active or standby state, at least one of the loops being in active state; selecting means (SEL) for selecting a standby loop of the redundant loop system; and initializing means (INI) for initializing one or more standby loops.
13. The hub according to claim 12, char acte r i z ed in that the hub (HUB, HUB1, HUB2) comprises setting means (SET) for changing the state of a loop to active or standby.
14. The hub according to claim 12, char acter i z ed in that the redundant loop system is a Fibre Channel Arbitrated Loop.
15. The hub according to claim 12, char acteri z ed in that the hub (HUB, HUB1, HUB2) comprises detecting means (DET) for detecting events that trigger the initialization process of the redundant loop system, the initialization process being triggered by one of the following reasons: inserting a node into the loop; restarting a node within the loop; replacing a node of the loop; or removing a node from the loop.
16. The hub according to claim 12, characteri zed in that the hub (HUB, HUBl, HUB2) comprises controlling means (CON) for controlling the hub (HUB, HUBl, HUB2) ports so that one or more standby loops are initialized at a time.
17. The hub according to claim 12 , characteri zed in that a managing device -.connected to the hub (HUB, HUBl, HUB2) comprises controlling means (CON) for controlling the hub (HUB, HUBl, HUB2) ports so that one or more standby loops are initialized at a time.
EP03790972A 2002-08-30 2003-07-14 Method, system and hub for loop initialization Withdrawn EP1535427A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI20021553 2002-08-30
FI20021553A FI20021553A0 (en) 2002-08-30 2002-08-30 Method, system and hub for initiating a loop
PCT/FI2003/000565 WO2004021645A1 (en) 2002-08-30 2003-07-14 Method, system and hub for loop initialization

Publications (1)

Publication Number Publication Date
EP1535427A1 true EP1535427A1 (en) 2005-06-01

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Country Status (4)

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EP (1) EP1535427A1 (en)
AU (1) AU2003246745A1 (en)
FI (1) FI20021553A0 (en)
WO (1) WO2004021645A1 (en)

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6504817B2 (en) * 1997-03-31 2003-01-07 Hewlett-Packard Company Fiber channel arbitrated loop dynamic loop sizing

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004021645A1 *

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Publication number Publication date
WO2004021645A1 (en) 2004-03-11
FI20021553A0 (en) 2002-08-30
AU2003246745A1 (en) 2004-03-19

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