Abstract:
Embodiments of the present invention provide a tool for maintaining and analyzing portions of an optical network. In some embodiments, a tool is provided that provides a map of sections of an optical network. Additionally, details on the performance and operations of the network elements forming a section of an optical network may also be provided. Embodiments of the invention may collect and use performance and operation statistics which were collected by network elements for other purposes. An algorithm collates the collected data to generate a map of optical links of an optical network. Through use of the map, data structures providing detailed information about the network can be populated. Embodiments of the invention provide a maintenance and analysis tool which may enable optical network administrators to save time, effort and costs and provide increased customer satisfaction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to optical networks and, more particularly, to methods and apparatus for the maintenance and analysis of an optical network. 
     2. Description of Related Art 
     Due to increased data traffic over public and private networks, fuelled in part by the rapid acceptance and reliance on the public Internet and the world wide web, the deployment of optical networks or optical network links has increased substantially. Further, due to the large bandwidth that is provided by these networks, any circumstance which detrimentally affects network performance will, in most instances, affect a tremendous amount of data. Additionally, due to the increased use of networking and data communication in general, users have developed an increased reliance on network availability. Moreover, users of data networks, including users of optical networks, have increasingly become less tolerant of any performance degradation or network down time. 
     With the increased deployment and use of optical networks comes an increased need for maintenance of these networks. The types of maintenance may include, for example, the need to assess a network&#39;s performance, troubleshooting, etc. 
     In many optical networks, maintenance and network performance assessment is performed manually. While a list of the network components or elements forming an optical network are typically known, the performance and configuration of each network element, which may change over time, is generally difficult to obtain. Current techniques to determine optical network performance and configuration require a high degree of understanding of the network&#39;s operations and methodology. Additionally, as a result of manual steps required to gather, format and validate statistics collected for an optical network, there is a tremendous opportunity for errors to result. Moreover, manually performing these operations is extremely time consuming. It is estimated that analyzing an optical network comprising a forty (40) element ring may require approximately forty hours of time. As a result, this manual procedure of network analysis and maintenance is often unacceptable for a variety of reasons: the cost in time and money is too high, customers or users of the network usually require a quicker response and the quality of the analysis is often suspect due to the likelihood of errors caused by manually performing the analysis. 
     Additionally, due to difficulties in locating and employing qualified personnel to perform such maintenance and analysis, required or desired maintenance is often delayed or not performed. Moreover, without robust and accurate analysis, it is extremely difficult to “tune” or optimize an optical network for a customer. 
     Use of specially designed monitoring software which could be installed at each network element has been considered. However, use of such software may detrimentally impact the operation of the element itself. Moreover, the installation and maintenance of such monitoring software at each element in a network may result in additional maintenance and cost requirements. 
     Accordingly, it would be desirable to provide an optical network maintenance tool which addresses at least some of these shortcomings. 
     SUMMARY OF THE INVENTION 
     Advantageously, embodiments of the present invention provide an optical network maintenance tool which provides identification of elements forming parts of the network and, through utilization and analysis of data collected from each network element, an analysis of system configuration and performance can be provided. 
     Network elements, in many instances, individually collect data regarding optical fiber terminating at the network element. Embodiments of the present invention retrieve portions of the data collected in the normal course by network elements. This retrieved data may then be processed by embodiments of the present invention to generate a map of portions of an optical network. This map can then be populated with additional data relating to network element configuration and performance statistics of the optical fibers which terminate at the network element. This map can then be used by a wide variety of personnel in assessing the maintenance and operations of the mapped portions of the optical network. 
     In one aspect of the invention there is provided a method of mapping an optical network. The optical network comprising a plurality of network elements (NEs), some adjacent pairs of NEs of the plurality of NEs communicating using optical fibers and one or more of the some adjacent pairs forming optical links. The method comprising: identifying NEs which, together with optical fibers therebetween, form an optical link; organizing statistical data retrieved from each identified NE into a map which corresponds to the physical layout of the optical link. 
     In a further aspect of the invention there is provided a method for facilitating management of an optical network. The method comprising: over a network, querying a plurality of NEs for identification information; and correlating the identification information to identify NEs communicating over an optical link. 
     In a further aspect of the invention there is provided a computer readable medium operable to provide instructions for directing a processor to map a portion of an optical network. The instructions directing the processor to: identify NEs which, together with optical fibers therebetween, form an optical link; organize statistical data retrieved from each identified NE into a map which corresponds to the physical layout of the optical link. 
     In a further aspect of the invention there is provided an apparatus for generating a map of a portion of an optical network. The optical network comprising a plurality of network elements (NEs), some adjacent pairs of NEs of the plurality of NEs communicating using optical fibers and one or more of the some adjacent pairs forming optical links. The apparatus comprising: memory adapted to store computer readable instructions and code; a network interface adapted to communicate with a data network; a processor in communication with the memory and the network interface, the processor adapted to retrieve and execute the instructions and code from the memory adapting the processor to: identify NEs which, together with optical fibers therebetween, form an optical link; and organize statistical data retrieved from the NEs identified using the network interface into a map which corresponds to the physical layout of the optical link. 
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more clearly understood with reference to the following detailed description read in conjunction with the drawings, in which: 
         FIG. 1  is a schematic illustration of a portion of an optical network embodying aspects of the present invention; 
         FIG. 2  is a schematic illustration of a portion of  FIG. 1 ; 
         FIG. 3  is a schematic illustration of a portion  FIG. 2 ; 
         FIG. 4  is a exemplary of computer terminal embodying further aspects of the invention, the computer terminal communicating with portion of the optical network of  FIG. 1 ; 
         FIG. 4A  is exemplary of further aspects of the computer terminal illustrated in  FIG. 4 ; 
         FIG. 5  is exemplary of data output resulting from communications between the computer terminal of FIG.  4  and network elements of  FIG. 2 ; 
         FIG. 6  is a schematic of a mapping of optical network of  FIG. 1  performed by the computer terminal of  FIG. 4 ; 
         FIG. 7  is a flow chart of operations performed by the computer terminal of  FIG. 4 ; and 
         FIG. 8  is a more detailed flow chart of a portion of the operations illustrated in FIG.  5 . 
     
    
    
     DETAILED DESCRIPTION 
     Illustrated in  FIG. 1  is optical network  100  which embodies aspects of the present invention. Optical network  100  includes a Synchronized Optical NETwork (SONET) portion  120  and an Optical Service Channel (OSC) portion  130 . As persons of ordinary skill in the art are aware, network elements (NEs) forming part of the SONET layer are generally unaware of the OSC layer, and vice versa. SONET network  120  includes various SONET lines  104  and SONET section  106  (two such sections,  106 A and  106 B, are illustrated). SONET lines  104  and sections  106  enable communication between SONET NEs  102  (three such NEs being illustrated— 102 A,  102 B and  102 C). 
     OSC network  130  includes optical links  108  (two such links,  108 A an  108 B, are illustrated) and computer terminal  110 . As illustrated in  FIG. 1 , computer  110  communicates with portions of links  108  through network  112 . Network  112  may be a conventional data network such as, for example, a public internet, private internet, Ethernet, WAN, LAN or Public Switched Telephone Network (PSTN). 
     An OSC transmits a data communications channel (DCC) to NEs that do not process SONET overhead. The OSC also provides orderwire and power optimizer functionality and, in some instances, allows remote access for Operations, Administration, Maintenance and Provisioning (OAM&amp;P) activities. 
     Communication between computer terminal  110  and an individual OSC NE of optical link  108  may use conventional networking protocols such as telnet, Ethernet, IP or the like. In the exemplary embodiment of  FIG. 1  computer terminal  110  communicates over a conventional PSTN using a modem. Alternatively, computer terminal  110  may connect directly to an OSC NE using, for example, serial communication. 
     An exemplary optical link—optical link  10 A—is illustrated in greater detail in FIG  2 . Optical link  108 A includes a number of NEs communicating over the OSC. These OSC NEs  202  (four are illustrated in FIG.  2 — 202 A,  202 B,  202 C and  202 D) are in communication using optical fibers  204  (three optical fiber segments are illustrated— 204 A,  204 B and  204 C). Optical link  108 A is illustrated as having only a single optical fiber  204  for communication between adjacent OSC NEs  202 . However, as those of ordinary skill in the art will appreciate, many optical links  108  are provisioned with two optical fibers connecting adjacent OSC NEs  202 . Tpically, in such a configuration, two optical fibers  204  are provisioned between adjacent OSC NEs  202  to provide a level of redundancy. In the description herein, the optical links  108  described herein include only a single fiber between adjacent OSC NEs  202 . However, embodiments of the invention are equally applicable to adjacent OSC NEs  202  connected by one, two or more optical fibers  204 . 
     As will be appreciated by those of ordinary skill in the art, OSC NEs  202  are not “visible” to SONET NEs  102  (FIG.  1 ). The purpose of  FIG. 1  is provide an overview of an optical network  100  and the inclusion of both SONET NEs  102  (which are more common and more commonly appreciated) and the OSC NEs  202 . The embodiment of the maintenance tool described herein is adapted to assist in the maintenance and analysis of a portion of optical network  100 , namely the OSC optical links  108 . 
     Referencing  FIGS. 2 and 3 , an OSC NE  202  includes a circuit pack group (CPG)  320  which receives optical signals from optical fibers  204 . A CPG  310  receives optical signals from an optical fiber  204 , amplifies and conditions received signals, and re-transmits these optical signals on an optical fiber  204 . Each optical fiber  204  is used for bi-directional communication. Consequently, two bands of optical signals—a red band (having wavelengths of approximately 1547.50-1561.00 nm) and a blue band (having wavelengths of approximately 1527.50-1542.50 nm)—are transmitted on each optical fiber  204 . As will be appreciated by those of ordinary skill in the art, an OSC NE  202  may be configured as a terminating end of an optical link  108  (such as OSC NEs  202 A and  202 D) or as a Mid-Span Access (MSA) element (such as OSC NEs  202 B and  202 C). Accordingly, a single OSC NE  202  may communicate with an adjacent OSC NEs  202  using one, two or more optical fibers  204 . 
     A CPG  320  receives incoming optical signals from the red band  308 A and in the blue band  310 A. Received optical signals  308 A and  310 A are amplified by amplifiers  304 A and  304 B, respectively. For bi-directional optical fibers  204  using more than one waveband, these amplifiers are sometimes known in the art as Multi-wavelength Optical Repeaters (MORs). A CPG  320  may provide additional signal conditioning. The type of signal conditioning provided is configurable and is known in the art as the facility  306  of the CPG  320 . 
     Once a received red or blue band optical signal  308 A,  310 A has been amplified and (possibly) conditioned, the output red and blue band optical signals are output as red band output signals  308 B and blue band output signals  310 B. 
     As will be appreciated by those of ordinary skill in the art, OSC NEs  202  can, and often are, configured to collect data (e.g., statistics and other information) regarding the optical signals (red and blue bands) received, amplified (and, possibly, conditioned) and output on optical fibers  204 . In the preferred embodiment, each OSC NE  202  will maintain records or data relating to communication with other OSC NEs  202  forming part of an optical link  108  (e.g., the identities of other OSC NEs, optical fiber performance, etc.). Additionally, each OSC NEs  202  will also preferably be suitably configured or modified to enable retrieval of the records maintained. 
     Embodiments of the invention include conventional OSC NEs  202  preferably modified to communicate with computer terminal  110  over network  112  as described herein. However, if OSC NEs  202  are not configured to communicate remotely with computer terminal  110 , each OSC NEs  202  should be configured to enable retrieval of records maintained through other methods (e.g., serial link communication). 
     Computer terminal  110 , an embodiment of which is illustrated in  FIG. 4 , includes a processor  110  in communication, via a suitable bus, with input/output (I/O) card  404 , memory  416  and network interface (I/F)  414 . Memory  416  may include both volatile memory  406  and persistent memory or storage  408 . 
     Processor  110  is a central processing unit (CPU) and associated chip set suitable to perform the operations attributed to computer terminal  110  described herein. For example, processor  402  may be implemented using a conventional processor such as Intel Pentium-class processor, reduced instruction set computer (RISC) chip or the like. Additionally, and as will be appreciated by those of ordinary skill in the art, one or more CPUs may be employed in alternative embodiments. Memory  406  may include conventional RAM, ROM, FLASH and other similar suitable storage devices for storing computer instructions, code and temporary data registers. Persistent storage  408  may include both internal and external storage devices such as fixed or hard disk drives, ZIP™ disks, optical storage devices (e.g., DVD-RAM, RW-CD, etc.) and the like. Memory  406  and persistent storage  408 , in part or in whole, operate as a computer readable medium for the storage and retrieval of computer instructions and codes which adapt processor  402  to perform the functions and operations described herein. 
     Network I/F  414  enables communication between computer terminal  110  and other networking devices (e.g., OSC NEs  202 ) over a suitable network connection such as network  112  (FIG.  1 ). In the exemplary embodiment, network I/F  414  is a modem, Ethernet card or other suitable device for enabling communication with network  112  (FIG.  1 ). Alternatively, computer terminal  110  may communicate with other networking devices directly over a suitable link such as an RS- 232  cable. In such an embodiment, network I/F  414  may be embodied in a serial port. 
     I/O card  404  provides a suitable interface between a user and computer terminal  110  and enables computer terminal  110  to receive computer instructions, code or the like. Accordingly, I/O card  404  communicates with input/output devices  410  which may include a keyboard, a mouse, a display or the like. I/O card  404  may be adapted to receive user instructions in the form of keyboard entries or mouse clicks indicative of user selections. Additionally, I/O card  404  provides an interface between computer terminal  110  and an external computer readable medium  412  which may be embodied in a diskette, CD-ROM or the like. 
     Memory  416  is illustrated schematically and in greater detail in FIG.  4 A. As will be appreciated by those of ordinary skill in the art, the functional delineations illustrated in  FIG. 4A  may be altered and functions combined or separated as required. Memory  416 , which may include both volatile and persistent memory  406 ,  408 , includes an operating system (O/S)  420 , communication software (S/W)  430 , maintenance tool S/W  440  and a data portion  450 . 
     O/S  420  may be implemented using a conventional operating system such as, for example, Microsoft™ Windows™ 98, 2000 ME, NT, Linux, Unix or the like. 
     Communication S/W  430  operates in conjunction with O/S  420  and maintenance tool  440  to enable communication between computer terminal  110  ( FIGS. 1 and 4 ) and OSC NEs  202  through network  112  or, in an alternative embodiment, through direct serial communication. In the illustrated embodiment, communication S/W  430  operates to utilize the hardware facilities of network I/F  414 . Accordingly, communication S/W  430  in the illustrated embodiment may include known communication protocols such as the telnet, Ethernet or Internet protocols. Additionally or alternatively, communication S/W  430  may include software to operate a modem. 
     Maintenance tool  440  is, in the exemplary embodiment, software instructions or codes which, when retrieved from memory  416  and executed by processor  402  adapt processor  402  to perform the functions described herein including those illustrated as flow charts in  FIGS. 7-8 . 
     In  FIGS. 7 and 8  (with reference to  FIGS. 4 ,  4 A,  5  and  6 ) maintenance tool  440  adapts processor  402  to perform operations  700 . Hereinafter description of the exemplary embodiment will refer to operations and functions performed by maintenance tool  440 . While it is more accurate to indicate that the computer readable instructions or codes (illustrated in flow charts of  FIGS. 7 and 8 ) which form maintenance tool  440  are retrieved from memory  416  and executed by processor  402  thus adapting processor  402  to perform these functions, to be more concise these operations and functions will be attributed directly to maintenance tool  440 . 
     During operations  700 , maintenance tool  440  will operate to communicate with and collect data from each OSC NE  202  that forms part of optical network  100  (FIG.  1 ). Communication between maintenance tool  440  and an OSC NE  202  is facilitated through operation of communication S/W  430  and network I/F  414 . Communication between maintenance tool  440  and the OSC NEs  202  may be conducted in a serial or parallel manner. That is, maintenance tool  440  may first communicate with and collect data from a first OSC NE  202 . Subsequent to communication with a first OSC NE  202 , maintenance tool  440  may then repeat the communication and collection with a second OSC NE  202 . This communication and collection may then be repeated as necessary. Alternatively, maintenance tool  440  may communicate with and collect data from more than one OSC NE  202  simultaneously or contemporaneously (i.e., in parallel). In the exemplary embodiment, maintenance tool  440  operates to communicate with and collect data from a plurality of OSC NEs  202  serially. 
     Regardless of the communication protocols used to establish communication or whether communication with OSC NEs  202  is established in a serial or parallel fashion, data is collected from each OSC NE  202  (S 702 ). The data collected from each OSC NE  202  is used by maintenance tool  440  to determine the identity of each OSC NE  202  in a single band (i.e., red or blue band) forming part of a single optical link  108 . Once the identities of the OSC NEs  202  for a single optical link  108  are determined, maintenance tool  440  uses this identity information to associate information related to the red band of a single optical link  108  with the information related to the corresponding blue band thus forming an “optical link pair” (S 704 ). Using the information of the optical link pair, maintenance tool  440  forms a map or detailed description of the entire optical link  108  which can then be presented to a user (S 706 ). 
     As described above, data used, in part, by maintenance tool  440  to generate a detailed map of optical links in optical network  100  is collected from individual OSC NEs  202 . The data or information collected is, in the exemplary embodiment, data that is typically generated and stored by each OSC NEs  202  for various other purposes. Accordingly, in one aspect of the present invention, data required by maintenance tool  440  can be accessed using conventional tools. For example, in optical networks employing OSC NEs from Nortel Networks Ltd. of Brampton, Canada, data required by maintenance tool  440  can be accessed by using a tool known as the Multi-wavelength Optical Repeater Facility (MORF) software. As will be appreciated by those of ordinary skill in the art, other software from other suppliers of OSC NEs or custom software could be employed to retrieve similar data from OSC NEs. However, in the embodiments described herein, reference will be made to the MORF software which forms part of or is used by maintenance tool  440 . 
     Using a list of the network addresses, network IDs or physical locations of the individual OSC NEs  202  (which may be manually provisioned into memory  416  of computer terminal  110 —FIG.  4 ), maintenance tool  440  will establish communication with each OSC NE  202  (S 702 ). During communication, maintenance tool  440 , through utilization of the MORF software (or other suitable software), will query and retrieve data records maintained by each NE  202 . The data retrieved from an OSC NE  202  will generally include, but not be limited to, data  500  illustrated in FIG.  5 . 
     Data for fields  502 ,  504  and  506  can be obtained using the MORF software with the following command lines: “morf pwrm disptr g 0  red” (which generates data  500  for the red band) and “morf pwrm disptr g 0  blue” (which generates data  500  for the blue band). 
     Data  500  includes information or indicia pertaining to the identity  502  (e.g., NE ID) of each OSC NE  202  with which the queried NE has communicated, the identity of the CPG  504  corresponding to each identified NE and the configuration  506  of the amplifier (or MOR). Rows of data  508  (having data fields NE ID  502 , MOR CPG  504  and MOR configuration  506 ) are retrieved from each OSC NE  202  forming part of optical network  100  (FIG.  1 ). Since a single OSC NE  202  may operate as a mutli-span access unit, a single OSC NE  202 , in a non-redundant optical link (i.e., an optical link with only one optical fiber connecting adjacent NEs), may service more than one optical fiber  204 . Consequently, a single OSC NE  202  may be identified twice in data  500  retrieved from a single OSC NE  202 —once for each optical fiber  204  serviced. For those NEs listed twice in data field  502  of data  500 , one amplifier  304  ( FIG. 3 ) will be configured as an MSA pre-amplifier (MSAPre) and the other amplifier  304  will be configured as an MSA post-amplifier (MSAPost) in column  506 . 
     As will be explained below, other data, in addition to that collected from fields  502 ,  504  and  506 , will also be collected from each OSC NE  202  and stored for later processing in memory  416 . This data can be obtained through the MORF software using the following command lines: “morf pwrm disptp g 0  red” (which returns data relating to power measurements and, more particularly to input red power, reflected blue power, input OSC power, total input power, output red power, output OSC power, total output power, input LOS threshold and input shut-off threshold) and “morf pwrm disptp g 0  blue” (which returns similar data for the blue band). Other calls to the MORF software may be made to collect additional data from the queried OSC NE  202 . These calls may include, for example, “morf pwrm dispor g 2  red” or “morf pwrm dispor g 2  blue” (each of which returns data relating to output optical return loss, optical return loss threshold and optical reflectometer state relating to the specified color band); “morf sig qrgp G 0  red” and “morf sig qrgp g 0  blue” (each of which returns data relating to amplifier configuration, fiber type, power control mode, input shut-off mode, color band output optical reflectometer, total output power target, peak output power target, input LOS threshold, input shut-off threshold, optical return loss threshold, mid-stage access partner and output power lock for the respective color band); and “morf sig disptp” (which returns data relating to output optical return loss). 
     Since an OSC NE  202  will only communicate with other OSC NEs  202  forming part of the same optical link  108 , maintenance tool  440 , having retrieved data  500  from each OSC NE  202  forming at least part of optical network  100  (FIG.  1 ), collates the data collected to determine the OSC NE members of optical links  108  for each band (red or blue). This collation may be performed by selecting one OSC NE  202  of an optical link  108 . For the selected OSC NE  202 , data  500  retrieved will identify one or more (and usually all) members of its optical link  108 . By accessing similar data for each of these members identified in data  500  (and the data  500  retrieved from those OSC NEs  202  identified by the data from the selected OSC NE and so on), a complete listing of the members of a single optical link  108  can be generated. Accordingly, a listing  600  ( FIG. 6 ) of each OSC NE  202  forming optical links  108  can be generated. This process can then be repeated for other OCS NEs  202  forming other optical links  108 . 
     It should be noted that listing  600  provides an excellent cross-check against the initial listing of addresses OSC NEs  202  forming optical network  100 . If, for whatever reason, modifications or alterations to optical network  100  (and, more particularly, the OSC portion) have been made without updating the initial listing of OSC NE  202  addresses used by maintenance tool  440 , listing  600  can identify this problem. As described above, listing  600  will be generated from records maintained by each OSC NE  202 . These records include the NE ID of other OSC NEs which have communicated with the selected OSC NE. Accordingly, the records used to generate listing  600  may include NE IDs which did not form part of the initial listing but which identify NEs which have communicated with a selected OSC NE  202 . Any discrepancy between the initial listing and listing  600  will, in some embodiments, result in maintenance tool  440  updating the initial listing for future reference; contacting any OSC NE  202  missing from the initial listing, and collecting any desired information. Alternatively, maintenance tool  440  may indicate the discrepancy to a user of maintenance tool  440  by way of message, alarm or the like. 
     Since the MORF software used by maintenance tool  440  is waveband specific, data corresponding to optical links  108  will be separated into data corresponding to the red band portion of optical links  108  (illustrated in  FIG. 6  as red band optical link data structures  604 —a data structure representing three red band optical links are illustrated as data structures  604 A,  604 B and  604 C) and the blue band portion of optical links  108  (illustrated in  FIG. 6  as blue band optical link data structure  606 —data structures representing three blue band optical links are illustrated as data structures  606 A,  606 B and  606 C). 
     Each data structure  604 ,  606  will include data blocks  608 ,  610 , respectively, corresponding to individual OSC NEs  202  which form part of an optical link  108 . As will be appreciated, data structures  604 ,  606  may vary in the number of data blocks  608 ,  610  depending upon the number of OSC NEs  202  which form part of a corresponding optical link  108 . For example, the red band data structure  604  corresponding to optical link  108 A ( FIG. 1 ) will include four data blocks  608 —one for each of the four OSC NEs  202  illustrated. A similar number of data blocks  610  will be included in the blue band data structure  606  corresponding to optical link  108 A. In contrast, the red and blue band data structures  604 ,  606  corresponding to optical link  108 B will each include only three data blocks  608 ,  610 , respectively. Accordingly, the size (i.e., the number of data blocks) in a selected data structure  604 ,  606  may differ from the size another data structure  604 ,  606 . 
     A data structure for a single band portion of single optical link (e.g.,  604 A or  606 A) will initially include a data block  608 ,  610  representing the OSC NE ID (from field  502 — FIG. 5 ) and the MOR CPG number (from field  504 —FIG.  5 ). In combination these two fields of data will uniquely identify one amplifier  304  ( FIG. 3 ) of a single OSC NE  202  (FIG.  2 ). 
     In addition to generating data blocks  608 ,  610  and arranging these data blocks in data structures  604 ,  606  based on color band for each optical link  108 , maintenance tool  440  arranges for the data blocks  608 ,  610  of data structures  604 ,  606  to be organized in an order which mimics or corresponds to the physical layout of the corresponding optical link  108 . Structures  604 ,  606  are arranged based on the data received from the “morf pwrm disptr g 0  red” and “morf pwrm disptr g 0  blue” commands. 
     Once the red and blue band optical link data structures  604 ,  606  have been generated and the data blocks  608 ,  610  contained therein are organized to mimic the physical layout of a corresponding optical link  108 , maintenance tool  440  performs operation S 704  ( FIG. 7 ) to associate the two band data structures  604 ,  606  which form a single optical link  108 . Operation S 704  is illustrated in greater detail in the flow chart of FIG.  8 . 
     Operation S 704  is performed by maintenance tool  440  once for each red band optical link data structure  604  generated in S 702 . Accordingly, and in the exemplary embodiment, a loop (S 804 -S 826 ), having a counter (i) set to zero (S 802 ) that is incremented by one for each pass through the loop (S 826 ), is performed for each band optical link data structure  604 . Once the value of “i” exceeds the number of red band data structures (S 804 ), operations S 704  terminate. 
     For each i th  red band data structure  604 , a second loop (S 808 - 824 ) is performed. The second loop is performed at most once for each blue band data structure  606  by using a second counter “j”. Like the first loop, the second loop terminates once the counter “j” has exceeded the number of blue band data structures  606  (S 808 ). The second loop may also terminate early (i.e., prior to counter “j” exceeding the number of blue band data structures  604 ) if a blue band data structure  606  is identified which corresponds to the i th  red band data structure  604  (S 824 ). If, during a pass through the second loop, maintenance tool  440  determines that the j th  blue band data structure  606  is the same size (i.e., has the same number of data blocks  610 ) as the i th  red band data structure  604  (S 810 ), a third loop (S 816 - 822 ) is performed using a counter “k”. If, however, the size of the j th  blue band data structure  606  is different from the size of the i th  red band data structure  604 , counter “j” is incremented (S 812 ) and the second loop repeats until a blue band data structure  606  having the same size as the i th  red band data structure  604  is identified. 
     If the j th  blue band data structure  606  is the same size as red band data structure  604 , the third loop (S 816 - 822 ) is performed once for each k th  data block  608 ,  610  in the corresponding data structures  604 ,  606 . During the third loop, the OSC NE IDs and the CPGs (which were previously retrieved in S 702 — FIG. 7 ) for each data block are compared. If, for each k th  data block  608  in the i th  red band data structure  604 , there exists a data block  610  in the identified j th  blue band data structure  606  which has the same NE ID and CPG (S 822 ), then the two data structures  604 ,  606  are associated with each other since both data structures refer to the same optical link  108  (S 824 ). In this circumstance, the second and third loops terminate, the counter “i” is incremented by one (S 826 ) and the first, second and third loops repeat for the remaining red band data structures  604 . 
     As a consequence of operation S 704  and, more particularly operations S 802 -S 828 , for each optical link  108 , which transmits red and blue band data signals, the corresponding one red band data structure  604  and corresponding one blue band data structure  606  of a single optical link  108  will be associated with each other. 
     However, and as indicated above, in some optical networks redundant optical fibers are sometimes used to provide additional security and availability. In such a redundant optical network, adjacent pairs of OSC NEs  202  communicate via two (or more) optical fibers  204 . As a result of this redundancy, a single optical link  108  may be associated with more than one pair of corresponding red and blue band data structures  604 ,  606  (i.e., for a single redundant system which has two optical fibers  204  connecting adjacent pairs of OSC NEs  202 , there would be two pairs of red and blue band data structures  604 ,  606 ). Accordingly, in some embodiments of the present invention, it may be desirable to associate all pairs of red and blue band optical structures for the same optical link  108 . The association of all pairs of red and blue band optical structures for the same optical link  108  may be enabled by using an algorithm similar to that illustrated in FIG.  8 . 
     As indicated above, in addition to the NE ID, CPG number and MOR configuration data collected from fields  502 ,  504  and  506  (FIG.  5 ), other data is also collected by maintenance tool  440  and stored in memory  416  of computer terminal  110 . This stored data, previously unused, is used to populate each of data blocks  408 ,  410  with performance and configuration data for each OSC NE  202  associated with data blocks  408 ,  410  (S 706 ). 
     If desired, the data blocks  408 ,  410  can then be output to a user in a desired format. This may, for example, include displaying the results in textual or graphical form on output device  110  (FIG.  1 )(e.g., a display or printing device), outputting the data to a computer readable format such as memory  416 , medium  412  ( FIG. 4 ) or the like. For example, a graphical representation of the individual links may be presented on a display by I/O card  404  (FIG.  4 ). By passing a pointer (through use of a mouse) over any graphical representation of an OSC NE  202 , a user may be presented with a “pop-up” message box containing all or some of the performance and maintenance statistics relating to the selected OSC NE. Alternatively, output to memory  416  or medium  412  may be provided in a format that is readable by other computer applications such as Microsoft™ Excel™. In this latter instance, a comma or tab delimited format may be preferred. 
     As will be appreciated by those of ordinary skill in the art, an optical network is provided which includes a tool (e.g., maintenance tool  440 ) which enables simple, remote and easy to use analysis of portions of the optical network. Embodiments of the invention are estimated to provide significant cost and time savings over known maintenance and analysis methods. Additionally, embodiments of the present invention reduce the errors (as compared the manual system), timely responses to maintenance and analysis and, additionally, requires relatively little user skills or involvement. 
     While one (or more) embodiment(s) of this invention has been illustrated in the accompanying drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the invention. All such modifications or variations are believed to be within the scope of the invention as defined by the claims appended hereto.