Abstract:
The present invention provides a slot identification strategy for an optical cross-connect platform which facilitates replacement or repair of field replaceable units by a servicing technician. The slot identification strategy is comprised of three components: (a) functional group naming; (b) functional group numbering; and (c) functional group colour coding. Like components are placed together in functional groups and given alpha, numeric and colour labels to ensure minimal errors when identifying and removing a specified field replaceable unit in need of servicing. In an environment which cannot tolerate errors, the identification strategy integral to the present invention maximizes a human&#39;s ability to perceive colours and alpha-numeric labels, thereby allowing a technician to quickly and accurately locate a component on the cross-connect platform.

Description:
BACKGROUND  
         [0001]    1. Field of Invention  
           [0002]    The invention relates to data networking and in particular to an apparatus and method for assisting technicians with error prevention and pathfinding in an optical cross connect switch.  
           [0003]    2. Related Prior Art  
           [0004]    In an effort to support high bandwidth services to an increasing user base, data transport networks have become increasingly complex. Optical networks have been seen by many as the architecture which can provide the increased capacity required. As shown in FIG. 1, one such optical architecture has a user  10  connecting to an optical metropolitan area network (MAN)  12  which connects to an optical long haul network  14 . In the long haul network, Dense Wavelength Division Multiplexing (DWDM) switches  16  operating in the 10 Gbps range are coupled with optical amplifiers (not shown) to provide an optical transport system that is scalable to 1.6 terabits per second over a single strand of fiber and which can transport optical signals up to 4000 km without electrical regeneration. MAN switching is accomplished by multi-rate, multi-service SONET bandwidth management platforms and open air laser systems which consist of a mesh network of rooftop nodes that communicate with each other through free-space laser beams. Additionally, a network management function  18  facilitates service assurance, customer care &amp; billing and service activation among other services. It will be understood by those in the art that FIG. 1 represents only one optical networking solution and is not meant to restrict the present invention. The present invention is useful in any optical network which includes a cross-connect platform.  
           [0005]    In the architecture of FIG. 1, where the MAN  10  connects to the long haul network  14 , an optical cross-connect platform  20  is provided. The Nortel Networks OPTera Connect HDX Connection Manager™ is an example of such a device. It is a multi-terabit optical cross-connect platform serving a high capacity, high performance optical network. It allows interconnection of hundreds of routers, ATM and SONET/SDH switches, as well as transparent wavelength services, at rates up to 40 Gbps. Along with physical fiber connectivity, this cross-connect platform provides full management of Add/Drop, Transit as well as Pass-Through traffic.  
           [0006]    Like optical cross-connect platforms of this type, the amount of data (and corresponding users) which are managed by the device is staggering. Typically these devices comprise a plurality of line cards with each line card supporting as many as 10,000 users. Each line card is physically connected to, among other components, a power module. Historically, the line card and power module were co-located for ease of servicing by a technician. The line cards gather optical fiber groups and cross-connect them through a midplane to switching cards located on the opposing side of the backplane. In an attempt to increase the number of fibers cross-connected while maintaining the smallest possible footprint for the cross-connect platform, it became necessary to separate the power servicing module from its associated line card. This served to free up more space on the midplane to terminate and cross-connect fiber.  
           [0007]    However, this reconfiguration was problematic because it raised the potential for technician error when servicing the cross-connect platform. More specifically, there existed the potential for the wrong power servicing module to be shut down when a particular line card required servicing or replacement. In the event that a power servicing module was incorrectly shut down, the result would be catastrophic, given the number of users&#39; serviced by its associated line card. This problem also existed in respect of other components positioned on optical cross-connect platform  20  which had physically separate power servicing modules. A solution was required to minimize the potential for such an error while allowing quick, error free location of the associated component to be serviced.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention serves to overcome the deficiencies of the prior art by providing a slot identification strategy which allows a technician to effectively associate a component on a optical cross-connect platform with its&#39; differently located power servicing module. Additionally, the present invention ensures that a technician can quickly and accurately locate a component on the optical cross-connect platform which may need to be replaced.  
           [0009]    The identification strategy is comprised of three components: (a) functional group naming; (b) functional group numbering; and (c) functional group colour coding. With respect to (a), each group of components (e.g. power service modules) on the cross-connect platform is represented by a unique alpha identifier on both the slot where the component is housed and on the component itself. With respect to (b), each functional group of components is represented by a different number series. Finally, with respect to (c), each functional group is marked with a different colour bar or graphic pattern to provide a visual cue for immediate grouping of related components. The power service module functional grouping has additional markings which identify by alpha, numeric and colour code indicators the component associated with the power service module.  
           [0010]    In one broad aspect of the invention there is provided an optical cross-connect platform comprising: power service modules; shelf controller cards; fans; routing, synchronization and protection modules; and port cards, wherein a selected one of the power servicing modules is associated with a selected one of the shelf controller cards, fans, routing, synchronization and protection modules or port cards; and wherein the power service modules, shelf controller cards, fans, routing, synchronization and protection modules and port cards form functional groups, and wherein each power service module and its associated shelf controller card, fan, routing, synchronization and protection module or port card share at least one identifier.  
           [0011]    In another broad aspect of the invention, there is provided in an optical cross-connect platform comprising power service modules, shelf controller cards, fans, routing, synchronization and protection modules and port cards, a method of providing error prevention and pathfinding comprising: connecting a selected one of the power service modules to a selected one of the shelf controller cards, fans, routing, synchronization and protection modules or port cards; grouping the power service modules, shelf controller cards, fans, routing, synchronization and protection modules and port cards into co-located functional groups; assigning each power service module and its associated shelf controller card, fan, routing, synchronization and protection module or port card at least one common identifier; and using the at least one common identifier, correlating a selected one of the shelf controller cards, fans, routing, synchronization and protection modules or port cards with its associated power service module.  
           [0012]    In yet another broad aspect of the invention there is provided a method of error prevention and pathfinding in an optical cross-connect platform, the cross-connect platform comprising power service modules, shelf controller cards, fans, router, synchronization and protection modules and port cards, wherein a selected one of the power service modules is associated with a selected one of the shelf controller cards, fans, router, synchronization and protection modules or port cards, and wherein the power service modules, shelf controller cards, fans, router, synchronization and protection modules and port cards are co-located to form functional groups; and wherein each power service module and its associated shelf controller card, fan, routing, synchronization and protection module or port card share at least one identifier, the method comprising: locating a selected one of the power service modules, shelf controller cards, fans, routing, synchronization and protection modules or port cards in less than 4 seconds.  
           [0013]    The advantages of the present are now clearly evident. Using the apparatus and method of the present invention, components within the optical cross-connect platform can be readily identified to facilitate replacement or repair by a servicing technician. Search time is reduced and the numbers of search errors are minimized. In addition, shut down of the proper power service module associated with the component to be replaced or serviced is enhanced by providing alpha, numeric and colour identifiers which provide mental triggers to the technician when correlating the component to be serviced to its associated power service module. Ergonomically speaking, the identification strategy integral to the present invention maximizes a human&#39;s ability to perceive colours and labels, thereby ensuring minimal errors in an environment which cannot tolerate errors. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    These and other features of the preferred embodiments of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein:  
         [0015]    [0015]FIG. 1 depicts a typical optical network;  
         [0016]    [0016]FIG. 2 depicts the port side of an optical cross-connect platform;  
         [0017]    [0017]FIG. 3 depicts the power service module functional grouping;  
         [0018]    [0018]FIG. 4 depicts the shelf controller card functional grouping;  
         [0019]    [0019]FIG. 5 depicts the fan functional grouping;  
         [0020]    [0020]FIG. 6 depicts the router, synchronization and protection module functional grouping;  
         [0021]    [0021]FIG. 7 depicts the port card functional grouping; and  
         [0022]    [0022]FIG. 8 depicts the switch side of an optical cross-connect. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    Referring to FIG. 2, the port side of an optical cross-connect platform  20  is depicted. The port side comprises power service modules (PSM)  22 , shelf controller cards (SC)  24 , fans  26 , routing, synchronization and protection modules (RSP)  28  and port cards  30 . Additionally, fiber management trays  32  may be included. Similar components are placed together to form a functional group (e.g. power service module functional grouping  34 ) the purpose of which we will be described later. As will be appreciated by those skilled in the art, each the components discussed above are separately housed in a bay or slot to facilitate easy removal, replacement and/or repair. Generically, such components are referred to as field replaceable units (FRU). As will also be appreciated by those skilled in the art, a selected one of the power service modules serves as the power source of an associated SC  24 , fan  26 , RSP  28  or port card  30 .  
         [0024]    Referring to FIG. 3, the power service module functional grouping  34  is shown. In this functional grouping each of the slots housing the power service modules are given an alpha and numeric label, generally depicted at  36 . More specifically, each slot is assigned a consecutive number beginning at number  101  and each slot is also labeled with the generic acronym “PSM”. This generic acronym is also indicated on the actual power service module as shown generally at  38 . To facilitate correlation between a selected PSM  22  and its associated SC  24 , fan  26 , RSP module  28  or port card  30 , additional labeling has been provided, as depicted generally at  40 . Each of the PSMs  22  associated with an SC  24 , fan  26 , RSP  28  or port card  30  functional grouping are placed together in sub-groups as indicated at  42 ,  44 ,  46  and  48  respectively. Each of these sub-groups are given alpha, numeric and colour identifiers, specifying the specific component within a functional group with which the PSM  22  is associated e.g. the PSMs  22  associated with shelf controller card functional group are identified using a red bar  50 , a number (i.e.  201  to  203 ), and the acronym associated with the shelf controller, SC. The colours assigned to the sub-groups are red, blue, brown and purple for the SCs, fans, RSP and port cards respectively. It will be understood by those skilled in the art that the colour combination may be varied without departing from the scope of the invention. Any colour combination in which each functional group is distinctive and visually captivating will suffice. It will also be understood by those skilled in the art that the alpha and numeric slot label may be combined with the functional group labeling to provide a combined label e.g. PSM  101  for SC  201  with a red colour bar would serve to identify PSM  101  and the PSM associated with SC  201 .  
         [0025]    [0025]FIG. 4 depicts the shelf controller card functional grouping. As shown in the drawing, the slots housing the shelf controller cards are given an alpha and numeric label, generally depicted at  52 . More specifically, each slot is assigned a consecutive number beginning at number  201  and each slot is also labeled with the generic acronym “SC”. This generic acronym is also indicated on the actual shelf controller card as shown generally at  54 . Finally, there is a red bar  56  which is the unique colour code assigned to the shelf controller card functional grouping  
         [0026]    [0026]FIG. 5 depicts the fan functional grouping. As shown in the drawing, the slots housing the fans are given an alpha and numeric label, generally depicted at  58 . More specifically, each slot is assigned a consecutive number beginning at number  301  and each slot is also labeled with the generic label “Fan”. This generic label is also indicated on the actual fan as shown generally at  60 . Finally, there is a blue bar  62  which is the unique colour code assigned to the fan functional grouping.  
         [0027]    [0027]FIG. 6 depicts the routing, synchronization and protection (RSP) module functional grouping. As shown in the drawing, the slots housing the RSP modules are given an alpha and numeric label, generally depicted at  64 . More specifically, each slot is assigned a consecutive number beginning at number  401  and each slot is also labeled with the generic acronym “RSP”. This generic acronym is also indicated on the actual RSP module as shown generally at  66 . Finally, there are the brown bars  68 ,  70  which represent the unique colour code assigned to the RSP module functional grouping.  
         [0028]    [0028]FIG. 7 depicts the port card functional grouping. As shown in the drawing, the slots housing the port cards are given an alpha and numeric label, generally depicted at  72 . More specifically, each slot is assigned a consecutive number beginning at number  501  and each slot is also labeled with the generic label “Port”. This generic label is also indicated on the actual port card as shown generally at  74 . Finally, there is a purple bar  76  which is the unique colour code assigned to the port card functional grouping  
         [0029]    Looking at optical cross-connect platform  20  in its entirety, it can be seen that the functional groupings are labeled using the numbering series  100  to  500  which are read from left to right and top to bottom. That is to say that as the PSM functional group is given 100 series numbers, the SC card functional group is given 200 series numbers, the fan functional group is given 300 series numbers, the RSP module functional grouping is given 400 series numbers and the port card functional group is given 500 series numbers. In addition to the identification strategy used in each functional group, the overall layout and numbering scheme of the functional groups also facilitates quick and error free location of a particular component by a technician by presenting the labeling information in a manner which corresponds to text presented on the page of a book in the English language.  
         [0030]    In operation, when the Network Operations Center determines that a specific FRU requires replacement, they notify the appropriate field technician. The technician uses the page-like layout of the optical cross-connect labeling along with the three identification layers to quickly scan the cabinet and locate the FRU to be serviced. For example, if “Fan 301” were to be replaced, the technician would be quickly directed to the fan functional grouping using the blue colour indicator and the generic “Fan” label positioned on each fan FRU. Once the technician had been directed to the functional grouping, they would identify the specific fan to be removed using the alpha and numeric “Fan 301” label provided on the slot housing the unit.  
         [0031]    In most cases, prior to removing a component for observation the power service module associated with the component is shut off. Using the present invention, the technician is first directed to power service module functional grouping using the generic acronym “PSM” positioned on each power supply module FRU. After having located the functional grouping, the technician would then locate the specific power service module associated with the component (SC, fan, RSP or Port Card) to be removed using the alpha, numeric and colour code associated with the specific power service module e.g. “PSM for fan 301” label highlighted with a blue line, as described in relation sub-group  44  of FIG. 3.  
         [0032]    In addition, the identification strategy integral to the present invention may be used on the switch side of optical cross-connect platform  20 . As shown in FIG. 8, the switch side comprises a switch card functional grouping  78 , a fan functional grouping  80  and a power service module functional grouping  82 . The numeric labeling on the front would be continued on the rear side with the switch card functional grouping being assigned 600 series numbers, the fan functional grouping being assigned 700 series numbers and the power service module functional grouping being assigned 800 series numbering. Alternately, the series numbers could range from 100 to 300. In addition to the series numbering, the switch card functional grouping  78  and the fan functional grouping  82  would be assigned respective uniquely coloured bar identifiers. All functional groupings would have unique alpha and numeric identifiers positioned on a respective component slot, with the alpha identifier positioned on the associated component e.g. “Switch 601” would appear beside the first switch card with “Switch” indicated on the first switch card; “Fan 701” would appear beside the first fan with “Fan” indicated on the first fan unit; and “PSM 801” would appear beside the power service module with “PSM” indicated on the first power service module. Similar to the front side, the individual components of the switch card and fan functional groupings could be correlated to a specific power service module by grouping the power service modules into switch card or fan sub-groups, and providing each power service module with unique alpha, numeric and colour identifiers e.g. “PSM for Fan 701” would be listed against “PSM 801” and contained within the fan sub-group bordered by a blue bar.  
         [0033]    Tests were conducted with both inexperienced and experienced technicians, where participants were asked to locate specific slots identified by the tester. Participants were advised that the optical connect platform had two sides: a “Port side” and a “Switch Side”. For the Port Side, two possible panel arrangements A and B were provided while for the Switch Side, three possible panel arrangements C, D and E were provided. For each panel arrangement, four testing sequences were identified to participants. For example, on Panel A, the first testing sequence was as follows:  
                                                     Elapsed   Done           Slot Location Task   Time   Correctly       Panel “A” (Port Side)   (Seconds)   (✓or X)   Comments                                Fan, 303       Power Service Module, 101       Port card, 512       Shelf Controller, 201       RSP Module, 402       Power Service Module, 122       Port card, 501       Shelf Controller, 202       Power Service Module, 107       Port card, 516       Fan, 301       Power Service Module, 112       RSP Module, 401       Power Service Module, 118       Fan, 302       Port card, 510                  
 
         [0034]    For panel E, the first testing sequence was as follows:  
                                                     Elapsed   Done           Slot Location Task   Time   Correctly       Panel “E” (Switch Side)   (Seconds)   (✓or X)   Comments                                Switch Card, 606       Power Service Module, 806       Switch Card, 601       Power Service Module, 801       Power Service Module 804       Fan, 701       Power Service Module, 807       Switch Card. 604       Switch Card, 602       Power Service Module, 811       Fan, 702                  
 
         [0035]    As indicated in the table, the speed at which the participants were able to locate the slots and their accuracy were measured. The results of the testing follow:  
                                                             Port Side, all types combined                                Total Observations:   80                           FAN   PSM   PORT   SC   RSP       NUMBER OF CASES   63   80   64   16   32       MINIMUM   0.51   0.47   0.51   0.41   1       MAXIMUM   8.27   4.73   7.38   3.17   10.44       RANGE   7.76   4.26   6.87   2.76   9.44       MEAN   1.694   2.16   2.38   1.686   2.371       VARIANCE   1.483   0.672   1.609   0.632   2.98       STANDARD DEV   1.218   0.82   1.269   0.795   1.726       STANDARD ERROR   0.153   0.92   0.159   0.199   0.305       SKEWNESS (G1)   2.949   0.649   1.785   0.271   3.316       KURTOSIS (G2)   12.123   0.809   4.241   −0.844   13.062       SUM   106.71   172.76   152.32   26.98   75.87       C.V.   0.719   0.38   0.533   0.472   0.728       MEDIAN   1.3   2.1   2.115   1.645   1.865                  
 
         [0036]    [0036]                                                     Switch Side, all variables together                                Total Observations:   64                   FAN   PSM   SWITCHES       N OF CASES   32   64   64       MINIMUM   0.51   0.93   0.68       MAXIMUM   2.94   4.62   3       RANGE   2.43   3.69   2.32       MEAN   1.417   1.936   1.551       VARIANCE   0.364   0.599   0.282       STANDARD DEV   0.603   0.774   0.531       STANDARD ERROR   0.107   0.097   0.066       SKEWNESS (G1)   0.715   1.043   0.681       KURTOSIS (G2)   0.048   1.187   0.269       SUM   45.35   123.9   99.26       C.V.   0.426   0.4   0.342       MEDIAN   1.335   1.875   1.47                    
         [0037]    It will be understood by those skilled in the art that although the error prevention and pathfinding apparatus and method have been described in relation to an optical cross-connect platform, the concept is applicable to any communications platform containing functionally disparate and interconnected components where the need for speedy fault isolation exists while ensuring that the potential for technician error is minimized. These other communication platforms are also meant to be included within the spirit of the invention.