FIELD OF INVENTION
[0001] The present subject matter relates to communication systems and, particularly, but
not exclusively, to fibre channel communication systems.
BACKGROUN5 D
[0002] With the development of network technology, rate of data transmission have also
increased. Under the ever increasing growth of data transmission rates, conventional cable
transmission techniques are not sufficiently adequate to satisfy the upcoming data transmission
rates. Nowadays, fibre optic transmission technology has been intensively used for data
10 transmission applications as it offers, amongst other things, high rates of data transmission, large
data transmission capacity, and reliable data transmission.
[0003] Fibre Channel (FC) is a high-speed fibre optic network technology which is being
used to provide high speed data transmission capabilities. Communication through FC has been
standardized by a set of communication standards developed by the Technical Committee of the
15 International Committee for Information Technology Standards (INCITS), accredited by an
American National Standards Institute (ANSI). Fibre optics networks, also known as fibre
channel networks, utilize the FC standards for data transmission among communication devices,
such as workstations, mainframes, supercomputers, desktop computers, storage devices, displays
and other peripheral devices.
20 SUMMARY
[0004] This summary is provided to introduce concepts related to communication in a
fibre channel over Ethernet network. This summary is not intended to identify essential features
of the claimed subject matter nor is it intended for use in determining or limiting the scope of the
claimed subject matter.
25 [0005] In one implementation, a method to trace a fibre channel forwarder (FCF) in a
Fibre Channel over Ethernet (FCoE) network is described. The method includes identifying a
primary FCoE port of a Reverse N_Port ID Virtualization (R-NPIV) bridge to be non-functional,
where the primary FCoE port connects the R-NPIV bridge to an FCF in the FCoE network, and
where the R-NPIV bridge communicates data between FC nodes and the FCF based on one or
3
more sessions. The method also includes selecting at least one of the FCF and a secondary FCF,
from amongst one or more FCFs identified to be available on the primary FCoE port, for
communication of data where the one or more sessions with the FC nodes are not terminated.
The method further includes configuring a secondary FCoE port for connection with the at least
one of, the FCF and the secondary FCF, where the connection allows communication of dat5 a
between the FC nodes and the FCoE network; and updating information of the secondary FCoE
port with the FC nodes and with the at least one of the FCF and the secondary FCF.
[0006] In another implementation, a R-NPIV bridge for tracing a FCF in an FCoE
network is described. The R-NPIV bridge may include a processor and a communication module
10 coupled to the processor. The communication module may identify a primary FCoE port of a
Reverse N_Port ID Virtualization (R-NPIV) bridge to be non-functional, where the primary
FCoE port connects the R-NPIV bridge to an FCF in the FCoE network, and where the R-NPIV
bridge communicates data between FC nodes and the FCF based on one or more sessions. The
R-NPIV bridge may also include a tracing module coupled to the processor to select at least one
15 of the FCF and a secondary FCF, from amongst one or more FCFs identified to be available on
the primary FCoE port, for communication of data where the one or more sessions with the FC
nodes are not terminated. The R-NPIV bridge may also include a configuration module coupled
to the processor to configure a secondary FCoE port for connection with the at least one of, the
FCF and the secondary FCF, where the connection allows communication of data between the
20 FC nodes and the FCoE network; and update information of the secondary FCoE port with the
FC nodes and with the at least one of the FCF and the secondary FCF.
[0007] In one implementation a computer-readable medium having embodied thereon a
computer program for executing a method is also described. The method includes identifying a
primary FCoE port of a Reverse N_Port ID Virtualization (R-NPIV) bridge to be non-functional,
25 where the primary FCoE port connects the R-NPIV bridge to an FCF in the FCoE network, and
where the R-NPIV bridge communicates data between FC nodes and the FCF based on one or
more sessions. The method also includes selecting at least one of the FCF and a secondary FCF,
from amongst one or more FCFs identified to be available on the primary FCoE port, for
communication of data where the one or more sessions with the FC nodes are not terminated.
30 The method further includes configuring a secondary FCoE port for connection with the at least
one of, the FCF and the secondary FCF, where the connection allows communication of data
4
between the FC nodes and the FCoE network; and updating information of the secondary FCoE
port with the FC nodes and with the at least one of the FCF and the secondary FCF.
BRIEF DESCRIPTION OF THE FIGURES
[0008] The detailed description is described with reference to the accompanying figures5 .
In the figures, the left-most digit(s) of a reference number identifies the figure in which the
reference number first appears. The same numbers are used throughout the figures to reference
like features and components. Some embodiments of system and/or methods in accordance with
embodiments of the present subject matter are now described, by way of example only, and with
10 reference to the accompanying figures, in which:
[0009] Fig. 1 illustrates a Fibre Channel over Ethernet (FCoE) network environment
implementing a reverse N_Port ID Virtualization (R-NPIV) for communication between Fibre
Channel (FC) Nodes and a fibre channel forwarder (FCF) of the FCoE network, according to an
implementation of the present subject matter;
15 [0010] Fig. 2 illustrates a method of tracing the FCF in the FCoE network, according to
an implementation of the present subject matter.
[0011] It should be appreciated by those skilled in the art that any block diagrams herein
represent conceptual views of illustrative systems embodying the principles of the present
subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state
20 transition diagrams, pseudo code, and the like represent various processes which may be
substantially represented in computer readable medium and so executed by a computer or
processor, whether or not such computer or processor is explicitly shown.
DESCRIPTION OF EMBODIMENTS
[0012] Systems and methods for tracing a Fibre Channel Forwarder (FCF) in a Fibre
25 Channel over Ethernet (FCoE) network are described. In one implementation, the described
systems and methods may be implemented in interconnections of Fibre Channel (FC) networks
and Ethernet networks, to enable communication among the communication devices
communicating through FCoE networks and trace FCF in the FCoE network. The entities that
can implement the described method(s) may include, but are not limited to, routers, switches,
5
bridges, computers, portable devices, and the like. Further, the method may also be implemented
by devices capable of exchanging data to provide connectivity to different peripheral devices and
computing systems. Although the description herein is with reference to particular switches, the
methods and systems may be implemented in other devices, albeit with a few variations, as will
be understood by those skilled in the art5 .
[0013] Fibre Channel (FC) standards allow high-speed communication in a FC network
where data is generally communicated as frames while being transferred through communication
networks. FCoE, as defined by the T11 Technical Committee of International Committee for
Information Technology Standards (INCITS), is a computer network technology standardized to
10 enable transfer of FC frames over Ethernet networks. In operation, the FC frames communicated
by FC nodes are converted to Ethernet frames for communication over the Ethernet network. For
the sake of explanation, converted frames have been referred to as FCoE frames hereinafter, and
the Ethernet network transferring FCoE frames is referred to as an FCoE network. The
conversion of FC frames to FCoE frames is generally done by an interfacing entity, such as a
15 FCF which includes both, FC interfaces such as VF_Ports and the FCoE interfaces such as
N_Ports to communicate to the respective communication devices.
[0014] Further, in a FC network, in order to direct traffic between various destinations,
e.g., FC nodes and FC storage devices, one or more FC switches may be deployed. It would be
appreciated that an FC switch is a multi-port device where each port manages a simple point-to20
point connection between itself and its attached communicating devices. Each port can be
attached to a server, peripheral, I/O subsystem, bridge, hub, router, or even another FC switch.
An FC switch receives messages from one port and automatically routes it to another port.
Multiple calls or data transfers happen concurrently through the multi-port FC switch.
[0015] In some implementations, FC nodes or FC switches may connect to an FCoE
25 network, e.g., in particular to one or more FCFs, through a bridge. The bridge may be Reverse N
Port ID Virtualization (R-NPIV) device configured to enable communication between the FC
nodes and the FCFs. Such R-NPIV bridge may hereinafter be referred to as R-NPIV. The RNPIV
may convert FC frames received from the FC nodes into FCoE frames, and the FCoE
frames received from the FCoE network, or the FCF, into the FC frames. Upon receiving a
30 request from an FC node to connect to an FCF, the R-NPIV bridge may detect one or more FCFs
6
present in an FCoE and select one of such FCF to a Virtual Storage Area Network (VSAN) on
which the FC nodes may be connected. The selection may be based on different parameters, such
as A-bit value and priority value.
[0016] R-NPIV may connect to the FCFs of the FCoE network through a plurality of
available Fibre Channel over Ethernet (FCoE) ports. Usually, when an FCoE port in a particula5 r
FCoE VLAN goes down or becomes non-functional, the R-NPIV may declare the connected
FCF as non-functional and may terminate connections between the FC node and the
corresponding FCFs by taking appropriate actions. In one example, the R-NPIV may terminate
the connections by sending appropriate control packets to the FC nodes on behalf of the FCF.
10 [0017] Even though in such situations the FCF is functional and merely a FCoE port is
non functional, in order to continue the communication between the FC node and the FCFs, the
FC Node may have to re-initiate a fresh connection with the FCFs through the R-NPIV.
Therefore, the connection may have to be established afresh, which may pose inconvenience to
users. Also, significant amount of time and efforts may be invested in re-initiating the
15 communication between the FC node and the FCFs.
[0018] On the other hand, in another example, the R-NPIV bridge may wait for a
predefined time period before terminating the session between the FC node and the FCFs.
Therefore, if the FCoE port stays non-functional for more than the predefined time period, the RNPIV
bridge may declare the FCFs as non-functional, and may subsequently terminate the
20 session. However, this is a time-extensive process and may again cause inconvenience to the
users.
[0019] Therefore, in case of a non-functional FCoE port, the connectivity between the FC
nodes and the FCF may generally be terminated and a new session may have to be established.
Such initiation and establishment of new sessions may not only consume significant amount of
25 time, but may also causes unacceptable delays and loss of productivity due to connectivity loss.
[0020] According to an implementation of the present subject matter, systems and
methods for tracing a FCF in an FCoE network are described. In one implementation, the
described methods may be implemented by a bridge, such as a bridge with R-NPIV and e-tunnel
capabilities, and providing connectivity between FC nodes and FCF. For the sake of explanation,
30 the bridge has been referred to as R-NPIV hereinafter. In said implementation, the R-NPIV may
7
trace the FCF in situations such as a non-functional FCoE port. The implementation of the
described methods and systems, on one hand, eliminate any delay in situation of a non-functional
FCoE port, on the other hand, does not necessitate a re-establishment of a session between the
FC nodes and the FCF.
[0021] In operation, the R-NPIV of the present subject matter may be connected to on5 e
or more FCFs of the FCoE network through one or more FCoE ports, say a primary FCoE port.
Further, the R-NPIV may also be connected to one or more FC nodes through one or more FC
ports. The R-NPIV may detect and identify if the primary FCoE port, connected to the FCF,
becomes non-functional. In such situations, the R-NPIV may trace other FCFs through different
10 functional FCoE ports to connect to same FCF, prior to terminating the session with the FC
nodes. In other words, instead of terminating the session between the FC node and the FCF, the
R-NPIV may determine alternative paths, i.e., alternative FCoE ports, to reach to the FCF.
[0022] In one implementation of the present subject matter, the R-NPIV may trace all
FCFs identified by the R-NPIV on the primary FCoE port, through another functional FCoE port,
15 and may query them to establish a connection. In case a connection is established with a FCF,
say a secondary FCF, within a predetermined time period, the R-NPIV may determine the FCF
to be reachable and may configure a new functional FCoE port for communication between the
FC nodes and the secondary FCF. Therefore, the R-NPIV may allow an uninterrupted connection
between the FC node and the secondary FCF, but through the new functional FCoE port, say a
20 secondary FCoE port.
[0023] The secondary FCF may either be the FCF with which the R-NPIV was initially
connected to, or may be a different FCF already identified by the R-NPIV on the primary port. In
one implementation of the present subject matter, the R-NPIV may update the secondary FCoE
port details and may allow normal communication between the FC nodes and the secondary
25 FCF. Therefore, instead of terminating the session between the FC node and the FCF, an
alternative path may be identified by the R-NPIV.
[0024] In another implementation of the present subject matter, if the R-NPIV is unable
to establish a successful connection with a secondary FCF within the pre-determined time period,
the R-NPIV may terminate its session with the FC nodes. For the sake of explanation, such pre30
defined time period has been referred to as a FIP discovery advertisement interval.
8
[0025] It may happen that the R-NPIV may make predefined attempts within the FIP
discovery advertisement interval to trace an available FCF for connection prior to terminating the
session with the FC nodes. For example, the FIP discovery advertisement interval may be
defined to be 10 seconds and the R-NPIV may make 5 attempts to trace and establish a
connection with the secondary FCF. In another example, the FIP discovery advertisemen5 t
interval may be configured as 15 seconds and the R-NPIV may make at least 10 attempts prior to
terminating sessions with the FC nodes. Therefore, instead of terminating the session, the RNPIV
may make pre-defined attempts within the stipulated FIP discovery advertisement interval.
It would be appreciated that the time period and the number of attempts may be predefined and
10 may vary from one implementation to another.
[0026] Therefore, in accordance with the present subject matter, even when an FCoE port
becomes non-functional, a connection between the FC node and the FCF may not be terminated
if the FCF is determined to be reachable through any other FCoE port of the R-NPIV. Therefore,
the time and efforts to be invested in re-initiating the session are reduced. Further, the downtime
15 in case of breakdown of an FCoE port may also be avoided. Furthermore, the present subject
matter offers a quick technique for tracing the FCFs so that the FC node can connect through the
alternate ports quickly. In addition, convenience to users may also be ensured. The details of
establishment of connection between the FC node and the FCoE cloud are described with the
help of the following figures in greater detail.
20 [0027] It should be noted that the description merely illustrates the principles of the
present subject matter. It will thus be appreciated that those skilled in the art will be able to
devise various arrangements that, although not explicitly described herein, embody the principles
of the present subject matter and are included within its spirit and scope. Furthermore, all
examples recited herein are principally intended expressly to be only for explanation purposes to
25 aid the reader in understanding the principles of the invention and the concepts contributed by
the inventor(s) to furthering the art, and are to be construed as being without limitation to such
specifically recited examples and conditions. Moreover, all statements herein reciting principles,
aspects, and embodiments of the invention, as well as specific examples thereof, are intended to
encompass equivalents thereof.
9
[0028] The manner in which the systems and methods of the present subject matter shall
be implemented has been explained in details with respect to the Fig. 1 and 2. While aspects of
described systems and methods can be implemented in any number of different computing
systems, transmission environments, and/or configurations, the embodiments are described in the
context of the following exemplary system(s)5 .
[0029] It will also be appreciated by those skilled in the art that the words during, while,
and when as used herein are not exact terms that mean an action takes place instantly upon an
initiating action but that there may be some small but reasonable delay, such as a propagation
delay, between the initial action and the reaction that is initiated by the initial action.
10 Additionally, the word “connected” and “coupled” is used throughout for clarity of the
description and can include either a direct connection or an indirect connection.
[0030] Fig. 1 illustrates a communication network environment 100 implementing an RNIPV
bridge 102 to communicate between FC Nodes and an FCoE network 104, in accordance
with an embodiment of the present subject matter. For the sake of explanation, the R-NPIV
15 bridge 102 has been referred to as R-NPIV 102, hereinafter. In one implementation of the present
subject matter, the R-NPIV 102 may be coupled to one or more FC nodes 106-1, 106-2, …, 106-
N. The FC nodes 106-1, 106-2, …, 106-N have been individually referred to as FC node 106,
hereinafter. Further, the FC nodes 106-1, 106-2, …, 106-N have been common referred to as FC
nodes 106, hereinafter. Further, the R-NPIV 102 may also be connected to one or more FCFs,
20 108-1, 108-2, 108-3, 108-4, 108-N, individually and commonly referred to as FCF(s) 108, to
communicate data between the FC Nodes 106 and the FCoE network 104.
[0031] In one implementation of the present subject matter, the FCoE network 104
within the communication environment 100 may further be connected to a Storage Area Network
(SAN) 110 through another FCF 112. The FCF 112 may enable communication between FC
25 Storage devices 114-1, 114-2, 114-3, …, 114-N, and the FCoE 104. For the sake of explanation,
the FC Storage devices 114-1, 114-2, 114-3, …, 114-N have been individually referred to as
FCSD 114, and commonly referred to as FCSDs 114 hereinafter.
[0032] Although the description herein is with reference to R-NPIV 102, the methods
and systems may be implemented in other communication devices, such as gateways, routers,
30 switches, and bridges, albeit with a few variations, as will be understood by a person skilled in
10
the art. Moreover, although the implementation of the R-NPIVs 102 has been depicted in
reference to the FC nodes 106, the R-NPIVs 102 may also be implemented in SAN network 110,
as would be understood by those skilled in the art.
[0033] The FCoE network 104 may be a wireless, or a wired network, or a combination
thereof. The network 106 can be a collection of individual networks, interconnected with eac5 h
other and functioning as a single large network (e.g., the internet or an intranet). Examples of
such individual networks include, but are not limited to, Global System for Mobile
Communication (GSM) network, Universal Mobile Telecommunications System (UMTS)
network, Personal Communications Service (PCS) network, Time Division Multiple Access
10 (TDMA) network, Code Division Multiple Access (CDMA) network, Next Generation Network
(NGN), Public Switched Telephone Network (PSTN), and Integrated Services Digital Network
(ISDN). Depending on the technology, the FCoE network 104 includes various network entities,
such as gateways, routers; however, such details have been omitted for ease of understanding.
[0034] The FC Nodes 106 may be implemented in one or more FC networks. It would be
15 appreciated that the FC network may include one or more FC Nodes and may implement FC
standard to communicate data. Further, the FC Nodes 106 and the FCSD 114 may include
computing devices capable of communicating over the FC Networks based on FC standard.
Therefore, the FC Nodes 106 and the FCSD 114 may include computing devices, such as a
laptop computer, a desktop computer, a notebook, a workstation, a mainframe computer, a
20 server, and the like.
[0035] In one example, the R-NPIV 102 may include processor(s) 116. The processor
116 may be implemented as one or more microprocessors, microcomputers, microcontrollers,
digital signal processors, central processing units, state machines, logic circuitries, and/or any
devices that manipulate signals based on operational instructions. Among other capabilities, the
25 processor(s) 116 is also configured to fetch and execute computer-readable instructions stored in
a memory.
[0036] The functions of the various elements shown in the figure, including any
functional blocks labeled as “processor(s)”, may be provided through the use of dedicated
hardware as well as hardware capable of executing software in association with appropriate
30 software. When provided by a processor, the functions may be provided by a single dedicated
11
processor, by a single shared processor, or by a plurality of individual processors, some of which
may be shared. Moreover, explicit use of the term “processor” should not be construed to refer
exclusively to hardware capable of executing software, and may implicitly include, without
limitation, digital signal processor (DSP) hardware, network processor, application specific
integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) fo5 r
storing software, random access memory (RAM), non-volatile storage. Other hardware,
conventional and/or custom, may also be included.
[0037] The R-NPIV 102 may also include a memory 118. The memory 118 may be
coupled to the processor 116. The memory 118 can include any computer-readable medium
10 known in the art including, for example, volatile memory, such as static random access memory
(SRAM) and dynamic random access memory (DRAM), and/or non-volatile memory, such as
read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical
disks, and magnetic tapes.
[0038] Also, the R-NPIV 102 includes interface(s) 120. The interfaces 120 may include
15 proxy F_Ports 126 and proxy N_ports 128 to provide connectivity to FC nodes 104 and the FCFs
102. The interfaces 120 may also include a variety of software and hardware interfaces that allow
the R-NPIVs 102 to interact with different entities, or with each other. The interfaces 120 may
facilitate multiple communications within a wide variety of networks and protocol types,
including wire networks, for example, FCs, FCoEs, LAN, cable, etc., and wireless networks, for
20 example, WLAN, cellular, satellite-based network, etc.
[0039] Further, the R-NPIV 102 may include module(s) 122 and data 124. The modules
122, amongst other things, include routines, programs, objects, components, data structures, etc.,
which perform particular tasks or implement particular abstract data types. The modules 122 may
also be implemented as, signal processor(s), state machine(s), logic circuitries, and/or any other
25 device or component that manipulate signals based on operational instructions.
[0040] Further, the modules 122 can be implemented in hardware, instructions executed
by a processing unit, or by a combination thereof. The processing unit can comprise a computer,
a processor, a state machine, a logic array or any other suitable devices capable of processing
instructions. The processing unit can be a general-purpose processor which executes instructions
12
to cause the general-purpose processor to perform the required tasks or, the processing unit can
be dedicated to perform the required functions.
[0041] In another aspect of the present subject matter, the modules 122 may be machinereadable
instructions (software) which, when executed by a processor/processing unit, perform
any of the described functionalities. The machine-readable instructions may be stored on a5 n
electronic memory device, hard disk, optical disk or other machine-readable storage medium or
non-transitory medium. In one implementation, the machine-readable instructions can be also be
downloaded to the storage medium via a network connection.
[0042] In an implementation, the module(s) 122 includes a tracing module 130, a
10 communication module 132, a configuration module 134, and other module(s) 136. The other
module(s) 136 may include programs or coded instructions that supplement applications or
functions performed by the R-NPIV 102. In said implementation, the data 124 includes session
data 138, and other data 140. The other data 140, amongst other things, may serve as a repository
for storing data that is processed, received, or generated as a result of the execution of one or
15 more modules in the module(s) 122. Although the data 124 is shown internal to the R-NPIV 102,
it may be understood that the data 124 can reside in an external repository (not shown in the
figure), which may be coupled to the R-NPIV 102. The R-NPIV 102 may communicate with the
external repository through the interface(s) 120 to obtain information from the data 124.
[0043] In one implementation of the present subject matter, the configuration module 134
20 may configure the interfaces 120 such that the proxy F_Ports 126 may provide connectivity to
the FC nodes 106 and the proxy N_Ports 128 may be configured to function in either of a mixed,
FCF, or a trusted mode to communicate data packets with the FCF 108. Further, the
configuration module 134 may also configure a virtual SAN (VSAN) port which is mapped with
an FCoE virtual LAN (VLAN) where the configuration module 134 may intercept data packets
25 of the R-NPIV 102 for processing and modification.
[0044] The configuration module 134, in one example of the present subject matter, may
establish connection with one of the FCFs 108. To this end, the configuration module 134 may
determine all available FCFs 108. The configuration module 134 may then establish a connection
with one of such FCFs 108 to provide connectivity between the FC nodes 106 and the selected
30 FCF 108.
13
[0045] As depicted in Fig. 1, the R-NPIV 102 may include two different FCoE ports,
namely 1/2 and 2/2. The R-NPIV 102 may utilize the port 1/1 in forwarding state to establish
connection with one of the FCF 108 and communicate data packets between the FC node 106
and the FCF 108, and the other FCoE port 2/2 may be blocked by Spanning Tree Protocol (STP).
For the sake of explanation, the port 1/1 has been referred to as the primary FCoE port, and th5 e
port 2/2 has been refereed to as the secondary FCoE port, hereinafter.
[0046] In one implementation of the present subject matter, the primary FCoE port may
become non-functional, and the connection between the R-NPIV 102 and the FCF 108 may be
impeded. The communication module 132 may identify the primary FCoE port to be non10
functional and may identify a loss of communication between the R-NPIV 102, and the FCF 108.
[0047] The communication module 132 may communicate the non-functional state of the
primary FCoE port to the tracing module 130. In such situation of failure of the primary FCoE
port, the configuration module 134 may configure the secondary FCoE port in the forwarding
state, and the tracing module 130 may trace available FCFs 108 in the vicinity. The tracing
15 module 130 may send Unicast Discovery Solicitation (UDS) messages to all the FCSs 108 which
were earlier identified on the primary FCoE port.
[0048] The FCFs 108 which are reachable by the tracing module 130, through the
secondary FCoE port, may return an acknowledgement by sending a Unicast Discovery
Advertisement (UDA) message in response to any received UDS message. In one
20 implementation of the present subject matter, based on the received UDS, the configuration
module 134 may select a secondary FCF 108 to communicate data between the FC nodes 106 an
the FCoE network 104. Further, the configuration module 134 may also configure the secondary
FCoE port for communicating data between the FC nodes 106 and the FCF 108. Therefore,
based on establishment of a session between the FCF and the R-NPIV 102 through the secondary
25 port, without interrupting a session between the R-NPIV 102 and the FC nodes 106 allows reestablishment
of a connection to the FCF 108 without having to re-initiate session establishment
process.
[0049] In one implementation of the present subject matter, it may also occur that the
tracing module 130 may not receive any UDA message from the FCFs 108. In such situations,
30 the tracing module 130 may declare all the FCFs 108 to be non-functional and may terminate the
14
session with the FC nodes 106. The tracing module 130 may make predefined attempts to trace
an available FCF for connection, while waiting for a pre-defined time period in each attempt,
prior to terminating the session with the FC nodes 106. For example, the tracing module 130 may
make 5 attempts to establish a connection with the FCFs 108. Also, the tracing module 130 may
wait for a pre-determined time period, such as 10 seconds, prior to making another attempt o5 f
tracing the FCFs 108.
[0050] In another implementation, a pre-determined time period within which the FCFs
108 are expected to respond by sending the UDA, is hereinafter referred to as FIP discovery
advertisement interval, and a number of attempts for connecting to the FCFs may be predefined.
10 Therefore, in order to determine a UDS re-transmission time interval of the tracing module 130,
the following relation may be utilized:
UDS retransmission time interval
FIP discovery advertisement interval
Number of attempts
[0051] In one example, if the tracing module 130 is configured to make 10 attempts prior
to declaring the FCFs 108 as non-functional, and the FIP discovery advertisement interval is 10
seconds, the tracing module 130 may retransmit UDS after every 1 seconds to identify a FCF
15 108 in the vicinity.
[0052] Therefore, based on the described technique, the R-NPIV 102 may allow for
continuance of establishment sessions between the FC nodes 106 and the FCFs 108 which allow
reduction in time and efforts in re-initiating the session. Further, the downtime in case of
breakdown of the primary FCoE port may also be avoided. Furthermore, the present subject
20 method offers a quick technique for tracing the FCFs so that the FC node can connect through
secondary ports. In addition, convenience to users may also be ensured.
[0053] Fig. 2 illustrates a method 200 for tracing of a FCF in an FCoE network,
according to an embodiment of the present subject matter. The order in which the method 200 is
described is not intended to be construed as a limitation, and any number of the described
25 method blocks can be combined in any order to implement the method 200, or any alternative
methods. Additionally, individual blocks may be deleted from the method without departing
from the scope of the subject matter described herein. Furthermore, the method 200 can be
implemented in any suitable hardware, software, firmware, or combination thereof.
15
[0054] The method may be described in the general context of computer executable
instructions. Generally, computer executable instructions can include routines, programs, objects,
components, data structures, procedures, modules, functions, etc., that perform particular
functions or implement particular abstract data types. The method may also be practiced in a
distributed computing environment where functions are performed by remote processing device5 s
that are linked through a communications network. In a distributed computing environment,
computer executable instructions may be located in both local and remote computer storage
media, including memory storage devices.
[0055] A person skilled in the art will readily recognize that steps of the method can be
10 performed by programmed computers and programmable entities. Herein, some embodiments
are also intended to cover program storage devices, for example, digital data storage media,
which are machine or computer readable and encode machine-executable or computerexecutable
programs of instructions, where said instructions perform some or all of the steps of
the described method. The program storage devices may be, for example, digital memories,
15 magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically
readable digital data storage media. The embodiments are also intended to cover both
communication network and communication devices configured to perform said steps of the
exemplary methods.
[0056] Referring to Fig. 2, at block 202, a primary FCoE port may be identified to be
20 non-functional. In one implementation, the method may be implemented in a bridge, such as the
R-NPIV 102. The R-NPIV may include the primary FCoE port, along with other ports to connect
to one or more FCFs. The FCoE ports of the R-NPIV 102 may be configured as proxy N_ports to
provide Ethernet connectivity between the R-NPIV and the FCF.
[0057] At block 204, the R-NPIV 102 may send solicitation messages to the FCFs
25 identified to be connected to the primary FCoE port. The solicitation messages may be sent
through a different FCoE port of the R-NPIV 102. In one implementation of the present subject
matter, the solicitation messages may be UDS messages sent to identify FCFs.
[0058] At block 206, advertisement message are received from one or more FCFs in
response to the solicitation messages. In one implementation, UDA messages may be received in
30 response to the solicitation messages. The UDA messages may provide the R-NPIV 102 with
16
information about the presence of FCFs in the vicinity to be connected. It would be understood
that the FCFs from which the UDA messages are received may be one or more from amongst the
FCFs identified initially on the primary FCoE port of the R-NPIV.
[0059] At block 208, a secondary FCF is selected from amongst the FCFs from whom
the advertisement messages are received. In one implementation, the selection may be based o5 n
the UDA messages, where the FCF having compatible addressing capabilities may be selected.
[0060] At block 210, a secondary FCoE port is configured to communicate with the
secondary FCF and provide data communication capability between the FC nodes and the
secondary FCF.
10 [0061] At block 212, the details of the secondary FCoE port are updated in the records of
the R-NPIV 102, and are also shared with the FC nodes for the purpose of communication.
[0062] Although implementations for the present subject matter have been described in
language specific to structural features and/or methods, it is to be understood that the
implementations described are not necessarily limited to the specific features or methods
15 described. Rather, the specific features and methods are disclosed as mere explanations.

I/We claim:
1. A method to trace a fibre channel forwarder (FCF) in a Fibre Channel over Ethernet
(FCoE) network, the method comprising:
identifying a primary FCoE port of a Reverse N_Port ID Virtualization (R-NPIV)
bridge to be non-functional, wherein the primary FCoE port connects the R-NPIV bridg5 e
to an FCF in the FCoE network, and wherein the R-NPIV bridge communicates data
between FC nodes and the FCF based on one or more sessions;
selecting at least one of the FCF and a secondary FCF, from amongst one or more
FCFs identified to be available on the primary FCoE port, for communication of data
10 wherein the one or more sessions with the FC nodes are not terminated;
configuring a secondary FCoE port for connection with the at least one of, the
FCF and the secondary FCF, wherein the connection allows communication of data
between the FC nodes and the FCoE network; and
updating information of the secondary FCoE port with the FC nodes and with the
15 at least one of the FCF and the secondary FCF.
2. The method as claimed in claim 1, wherein the selecting further comprises:
sending solicitation messages to the one or more FCFs, wherein the solicitation
messages allow identification of available FCFs in the vicinity of the R-NPIV bridge,
20 and;
receiving advertisement messages from the one or more FCFs in response to the
solicitation messages, wherein the advertisement messages indicate availability of the one
or more FCFs.
25 3. The method as claimed in claim 2, wherein the solicitation messages are Unicast
Discovery Solicitation (UDS) messages.
18
4. The method as claimed in claim 2, wherein the advertisement messages are Unicast
Discovery Advertisement (UDA) messages.
5. The method as claimed in claim 2, wherein the advertisement messages are received
within a pre-defined FIP discovery advertisement interval5 .
6. The method as claimed in claim 2, wherein the solicitation messages are sent for a predefined
number of times if the advertisement message is not received within a pre-defined FIP
discovery advertisement interval.
10
7. The method as claimed in claim 6, wherein the solicitation messages are send after a time
period based on the pre-defined FIP discovery advertisement interval and the pre-defined number
of times.
15 8. A R-NPIV bridge (102) for tracing a FCF in a FCoE network, the R-NPIV bridge (102)
comprising:
a processor (116);
a communication module (132) coupled to the processor (116) to identify a
primary FCoE port of a Reverse N_Port ID Virtualization (R-NPIV) bridge to be non20
functional, wherein the primary FCoE port connects the R-NPIV bridge to an FCF in the
FCoE network, and wherein the R-NPIV bridge communicates data between FC nodes
and the FCF based on one or more sessions;
a tracing module (130) coupled to the processor (116) to select at least one of the
FCF and a secondary FCF, from amongst one or more FCFs identified to be available on
25 the primary FCoE port, for communication of data wherein the one or more sessions with
the FC nodes are not terminated; and
a configuration module (134) coupled to the processor (116) to:
19
configure a secondary FCoE port for connection with the at least one of,
the FCF and the secondary FCF, wherein the connection allows communication of
data between the FC nodes and the FCoE network; and
update information of the secondary FCoE port with the FC nodes and
with the at least one of the FCF and the secondary FCF5 .
.
9. The R-NPIV bridge (102) as claimed in claim 8, wherein the tracing module (130) is to
further:
send solicitation messages to the one or more FCFs, wherein the solicitation
10 messages allow identification of available FCFs in the vicinity of the R-NPIV bridge; and
receive advertisement messages from the one or more FCFs in response to the
solicitation messages, wherein the advertisement messages indicate availability of the one
or more FCFs.
15 10. The R-NPIV bridge (102) as claimed in claim 9, wherein the configuration module (134)
is to further configure the secondary FCoE port to send the solicitation messages after a predefined
time period, wherein the pre-defined time period is based on a FIP discovery
advertisement interval.
20 11. The R-NPIV bridge (102) as claimed in claim 9, wherein the tracing module (130) is to
further terminate the one or more sessions with the FC nodes if the advertisements are not
received within a pre-defined FIP discovery advertisement interval.
12. The R-NPIV bridge (102) as claimed in claim 9, wherein the communication module
25 (134) is to further communicate data with the FCoE network based on the existing sessions of the
FC nodes through the secondary FCoE port and the secondary FCF.
20
13. A computer-readable medium having embodied thereon a computer program for
executing a method, the method comprising:
identifying a primary FCoE port of a Reverse N_Port ID Virtualization (R-NPIV)
bridge to be non-functional, wherein the primary FCoE port connects the R-NPIV bridge
to an FCF in the FCoE network, and wherein the R-NPIV bridge communicates dat5 a
between FC nodes and the FCF based on one or more sessions;
selecting at least one of the FCF and a secondary FCF, from amongst one or more
FCFs identified to be available on the primary FCoE port, for communication of data
wherein the one or more sessions with the FC nodes are not terminated;
10 configuring a secondary FCoE port for connection with the at least one of, the
FCF and the secondary FCF, wherein the connection allows communication of data
between the FC nodes and the FCoE network; and
updating information of the secondary FCoE port with the FC nodes and with the
at least one of the FCF and the secondary FCF.
15 14. The computer-readable medium as claimed in claim 13, wherein the method further
comprises:
sending solicitation messages to the one or more FCFs, wherein the solicitation
messages allow identification of available FCFs in the vicinity of the R-NPIV bridge; and
receiving advertisement messages from the one or more FCFs in response to the
20 solicitation messages, wherein the advertisement messages indicate availability of the one
or more FCFs.