Abstract:
The invention provides an improved method of exploring paths having multiple layers. Such paths may be through any of a number of types of networks, such as transportation networks, distribution networks, business structure networks, or telecommunication networks. The method initially displays in a path explorer view, the nodes and links of a first layer of the path in a linear configuration. Upon selection/deselection of a layer expander icon located near the first layer node at which the path traverses to the second layer, the method expands/collapses the second layer of nodes and links in a linear configuration which is parallel to, but offset from the first layer. The method further contemplates the display of a topology view which, in conjunction with the path explorer view, graphically displays a structure of a selected layer of the path, with the path visually distinguished therein.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to methods of exploring paths, and in particular to an improved method of exploring paths having multiple layers.  
         BACKGROUND OF THE INVENTION  
         [0002]    In many industries, it is desirable to view a path taken by a particular object, idea or signal, as it travels through for example, transportation, distribution, business or communication networks. Common examples include tracking of a courier package from an originating point to its destination, examining the travel of individuals through a transportation network, viewing a path a proposal may take within a business from conception through to final approval, or examining an assigned path of data traffic through a telecommunication network.  
           [0003]    Such paths typically consist of nodes and links, with nodes representing hubs, intersections, action points, sources, destinations, etc., and links representing the logical or actual transportation or communication links between the nodes. For example, in a communication network, the nodes may be communication devices such as routers or antenna base stations, while the links may be any means of communication between two nodes such as through copper wire, optical cable, or microwaves. In a transportation network, nodes may be airports, train stations, or shipping ports, while the links may be air routes, train routes or shipping routes.  
           [0004]    Many methods have been developed to view paths. One example is a geographic topology which displays nodes according to their geographic locations, as well as the links which connect the nodes. In one version, all nodes and all links are displayed, with the specific nodes and links comprising the path of interest highlighted in the geographic topology. In another version, only those nodes and links which make up the path of interest is displayed. Another example of a method of viewing paths is a logical topology, which is similar to the geographic topology except that the nodes are spatially arranged not according to their geographic locations, but in accordance with some other logical organization. A third example is a line view, wherein a path is represented by a simple linear representation of all of the nodes which comprise the path, with link representations therebetween.  
           [0005]    Each of the above methods are useful for viewing simple paths. However, where paths become complex, these methods may fail. One source of complexity is the sheer number of nodes and links which may comprise a path. Another source of complexity is the amount of information which must be displayed in respect of each of the nodes and links to be viewed.  
           [0006]    A third source of complexity is where the nodes are grouped into layers, wherein it may be desirable to know which nodes fall within which layer, and further, information respecting each layer may need to be viewed. One example of a network in which the nodes are grouped into layers is a distribution network, wherein the nodes may consist of source/destinations, storage facilities, trucking depots, and airports. In such a case, the nodes may be grouped into four distinct node layers, the first being a pick-up/delivery layer, the second being a storage layer, the third being a trucking layer, and the fourth being an air transportation layer. Thus a path from pick-up to delivery may progress from nodes in the pick-up/delivery layer, to the trucking layer, to the air transportation layer, to the storage layer, to the trucking layer, and back to the pick-up/delivery layer. Similarly, in a telecommunication network, node layers may include an IP (Internet Protocol) layer, a SONET (Synchronous Optical Network) layer, an SDH (Synchronous Digital Hierarchy) layer, an ATM (Asynchronous Transfer Mode) layer, and an optical layer. In a business plan network, node layers may include a planning committee layer, a finance layer, an engineering layer, and a marketing layer. Of course, there may exist sub-layers within each layer. For example, in the telecommunication context, there may be multiple SONET layers, grouped by geographic location, for example.  
           [0007]    Where nodes are grouped into layers, it may at times be desirable to view all nodes in the path, grouped according to the layer in which a particular node may belong. Other times, it may be desirable to omit nodes of a certain layer, allowing an individual to view only those layers of interest. Current solutions include identifying in a geographic or logical topology, or in a linear representation, nodes which belong in a particular layer using a distinctive colour, special icons, text, or by drawing a box around nodes comprising a node layer. However, such identifiers tend to clutter the path representation, and make it difficult to discern the node layers. Further, such solutions fail when a large number of nodes need to be viewed.  
         SUMMARY OF THE INVENTION  
         [0008]    In a broad aspect, the present invention provides a method in a computer system for displaying a representation of a path, wherein the path includes a plurality of nodes in a sequential order, each of the nodes being part of a first node layer or a second node layer. This method includes the steps of displaying in a path explorer view, a path representation comprising a first line of node icons, with each of these first line node icons representing a node of the first node layer; displaying a selectable layer expander icon; and upon a first selection of the layer expander icon, displaying in the path representation, a second line of node icons each representing a node of the second node layer, the second line being parallel to, and offset from the first line. The node icons are positioned in sequential order along the path representation. Optionally, upon a second selection of the layer expander icon, the second line of node icons will be erased from the path explorer view.  
           [0009]    In other aspects, the invention includes the option of displaying in conjunction with the path explorer view, a topology view which shows a structure of a node layer of the path. Further, the selection of a particular node layer, either by selecting designated icons in the path explorer view or the topology view may cause the structure of the selected node layer to be displayed in the topology view, with the nodes of which the path is comprised being visually distinguished.  
           [0010]    The present invention also contemplates a GUI (graphical user interface) embodying the method of the present invention, a computer-readable medium having stored thereon instructions for directing a host computer to implement the method of the present invention, as well as a computer system adapted to execute a path explorer application directing a computer to implement the method of the present invention.  
           [0011]    Advantageously, the present invention provides a method of viewing paths comprising multiple layers of nodes, which method allows a user to interactively view a large number of nodes, and the layers in which the nodes belong, clearly and easily. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    Preferred embodiments of the invention will now be described with reference to the attached drawings in which:  
         [0013]    [0013]FIG. 1 is a block diagram of a computer system attached to a network, which may be used to implement a preferred embodiment method of the present invention;  
         [0014]    [0014]FIG. 2 is a topological view of an exemplary path through a telecommunication network, said path being used to illustrate the preferred method embodiment of the present invention;  
         [0015]    [0015]FIG. 3 is an illustration of a display generated in accordance with the preferred embodiment method of the present invention, displaying a first line of node icons in a path explorer panel, and a topology of a first node layer in a topology panel;  
         [0016]    [0016]FIG. 4 is an illustration of the display of FIG. 3 wherein a network administrator has selected a layer expander icon in the path explorer panel;  
         [0017]    [0017]FIG. 5 is an illustration of the display of FIG. 4 wherein the network administrator has selected a third layer icon in the path explorer panel;  
         [0018]    [0018]FIG. 6 is an illustration of the display of FIG. 5 wherein the network administrator has selected a second line of node icons in the path explorer panel;  
         [0019]    [0019]FIG. 7 is an illustration of the display of FIG. 6 wherein the network administrator has selected a third line of node icons in the path explorer panel; and  
         [0020]    [0020]FIG. 8 is a flow chart illustrating the functionality behind the preferred embodiment method of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    A preferred embodiment of the method of the present invention will now be described in the context of a telecommunication network. In this example, the preferred embodiment method is used to interactively display information for a path through a telecommunication network having multiple layers such as IP, SONET and optical layers. The nodes are communication devices such as transmitters, routers, amplifiers, and receivers, while the links are the communication links between the nodes, most typically optical cable.  
         [0022]    However, before describing the preferred embodiment method, a demonstration of which is illustrated in FIGS. 3 through 7, an exemplary context for the application of the preferred embodiment method of the present invention will first be described with reference to FIG. 1, and an exemplary path to be explored using the preferred embodiment method will be described with reference to FIG. 2.  
         [0023]    [0023]FIG. 1 is a block diagram of a typical computer system used by a network administrator to administer a telecommunication network. In this illustration, the network  20  is connected to a data collector  22  which in turn is connected to a network database  24 . The network database  24  is then connected to a network management device, or NMD  26 .  
         [0024]    The data collector  22  is capable of collecting network information from the network  20 . Such network information may include for example, a level of traffic across nodes and links of the network, or status information representing the status of various nodes and links contained in the network  20 . Status information may include any alarms which may be detected at such nodes or links. The manner in which the data collector  22  collects network information from the network  20  is well known in the telecommunication field.  
         [0025]    Upon receipt of network information from the network  20 , the data collector  22  stores this network information in the network database  24 . The network database  24  may also have stored on it architectural, technical, or identification data for the network nodes and links, or various paths of data transmission in the network  20 .  
         [0026]    The NMD  26  has a network management processor  28  which is connected to a display  30 , and also to user input devices such as a mouse  32  and a keyboard  34 . If the display  30  is touch sensitive, then the display itself may also serve as a user input device. The processor  28  is also connected to a local database  36 . The NMD  26  is adapted to perform four functions. First, it executes the method of the present invention to interactively display a path of interest on the display  30 . Second, it processes data stored in the network database  24  as well as the local database  36 , in accordance with instructions received from a network administrator through the user input devices  32 ,  34 , to put it into a form suitable for display. Third, in some cases, the NMD  26  may request the data collector  22  to obtain certain specific information from the network  20 . Finally, the NMD  26  may manipulate the performance of the network  20 , for example by respecifying a different path of data transmission for a specific data stream.  
         [0027]    Although one exemplary context for the application of the preferred embodiment method of the present invention has been described in detail above, it is to be understood that the method may be used in other contexts. Notably, the computer system executing the method may be any system wherein a processor is connectable to a network or a database containing network information, and which is capable of displaying graphical information and receiving user inputs.  
         [0028]    An exemplary path which is the subject of the demonstration of the preferred embodiment method shown in FIGS. 3 through 7 will now be described with reference to FIG. 2, which shows a topology of this multi-layer path. Although the view shown in FIG. 2 is not part of the method of the present invention, it will be described with some detail since the same symbols are used in the preferred embodiment method depicted in FIGS. 3 through 7, and additionally, since such detail will assist in understanding the nature of the path which is the subject of the path exploration example shown in these later figures.  
         [0029]    [0029]FIG. 2 shows three topological views  40 ,  42  and  44  depicting three node layers, and the nodes and links of which each node layer is comprised. In this case, the three node layers are an IP layer  40 , a SONET layer  42  and an optical layer  44 . The IP layer  40  consists of five nodes, JA through JE, the SONET layer  42  consists of five nodes, WA through WE, and the optical layer  44  consists of six nodes, BA through BF. In this particular example, the three layers are distinguished by the technology used by the nodes which make up the layer. It is to be understood that in the telecommunication context, node layers may be distinguished by other features, geographic location for example.  
         [0030]    In FIG. 2, the nodes are represented by node icons ( 46  for example), while the links are represented by link lines ( 48  for example) connecting the node icons. Within each of the node icons is a symbol representing the technology used by the represented node. In this example, a circle ( 54  for example) is used to depict IP technology, a diamond ( 56  for example) for SONET technology, and a triangle ( 58  for example) for optical technology.  
         [0031]    Sometimes, a link between two nodes in a node layer of a particular technology may only be a logical link in the sense that there is no direct link of that technology between those two nodes. Such is the case between the two nodes JE and JD in the IP layer  40 . Although a link line  60  is shown between node icons JE and JD, a layer icon  62  bisecting this link line  60  indicates that it is the nodes of another technology layer through which traffic between the nodes JE and JD flows. This other technology layer is identified by a symbol within this layer icon  62 , in this case a diamond, indicating the SONET layer  42 . Thus, instead of flowing over a direct link, data traffic flowing between nodes JE and JD in this example flows through nodes and links of the SONET layer  42 .  
         [0032]    The same may be said of the link between nodes WD and WC of the SONET layer  42 . Again, a layer icon  65  appears between the node icons representing these two nodes, this time with a triangle symbol within. Thus, instead of flowing over a direct link, data traffic flowing between nodes WD and WC flows through nodes and links of the optical layer  44 .  
         [0033]    The actual path for data traffic represented by the logical link between nodes JE and JD in the IP layer is highlighted with outlining  64  in FIG. 2. As may be seen, this path has a sequential order of nodes over which it travels. First, the path travels from node JE in the IP layer  40  to node WE of the SONET layer  42 . The path then travels to node WD of the SONET layer  42  where another logical link is encountered. At this point, the actual path traverses to node BB of the optical layer  44 . After travelling over nodes BE, BD and BC of optical layer  44 , the path returns to the SONET layer  42  where it travels over nodes WC, WB and WA. Finally, the path returns to node JD of the IP layer  40 . It is this actual path of data transmission between nodes JE and JD which will be the subject of the demonstration of the preferred embodiment method of the present invention depicted in FIGS. 3 through 7, and discussed below.  
         [0034]    In this particular example, the path illustrated in FIG. 2 is a static one which has been assigned directly or indirectly by the network administrator for a particular stream of data traffic through the telecommunication network. Thus, information relating to the path structure is stored in the network database  24  which information is retrieved and processed by the network management processor  28  for display in accordance with the preferred embodiment method. Further, dynamic information such as the status of nodes and links on this static path may be retrieved by the data collector  22  from the network  20  as required, for use by the network management processor  28 . In other examples (not shown or discussed), the preferred embodiment method of the present invention may be used to display a dynamic path, such as in the pure IP context. In such a case, the network administrator would typically be viewing historic information for a path taken by a particular packet of data.  
         [0035]    The preferred embodiment method of the present invention will now be described with reference to the demonstration illustrated in FIGS. 3 through 7. Although the preferred embodiment method may have many additional features relevant to the administration of the network  20 , only those which are related to the present invention will be described below.  
         [0036]    In FIG. 3, a path explorer panel  70  and a topology panel  72  are displayed. These panels may be displayed as part of a larger network management application, or may comprise an application of their own. The particular path to be displayed in the path explorer panel  70  and the topology panel  72  may be selected through any of a number of well-known means. For example, the path may simply be selected out of a list of all paths in the network. Alternatively the network administrator may select to view a path affected by an alarm at a given node or link. In this demonstration, the network administrator has selected the path illustrated in FIG. 2, and described above.  
         [0037]    The path explorer panel  70  displays a path representation showing nodes of the selected path. These nodes are represented by node icons,  74  for example, which appear in the path explorer panel  70  in a sequential order from top to bottom, which sequential order corresponds to the order of the nodes in the selected path, as described above. The path representation is divided into multiple path segments along its length, in each of which appears a node icon.  
         [0038]    As shown in FIG. 3, the path explorer panel initially displays only node icons representing nodes of a first node layer, in this case, those of the IP layer in the selected path. These node icons  74  and  76 , representing nodes JE and JD of the IP layer respectively, appear in a first line  73  of node icons, in adjacent path segments. As with the node icons displayed in the topology of FIG. 2, each or the node icons  74 ,  76  have within them a symbol which identifies the technology associated with the represented node. In this case, the technology is IP, and as such circles  78  are shown inside the node icons  74 ,  76 . To the left of the node icons  74 ,  76  are alarm indicators  88 ,  90  each of which indicate an alarm state of the node represented by the associated node icon. In this case, each of the two nodes represented by the node icons  74 ,  76  have one warning alarm associated therewith. Of course, any coding may be used by the alarm indicators  88 ,  90  to indicate an alarm state. Further, in addition to, or instead of alarm indicators  88 ,  90  indicating the alarm state of the nodes, the path explorer panel may communicate other information concerning the nodes or the links between them, traffic capacity, location, or protection for example.  
         [0039]    Connecting the two node icons  74 ,  76  is a link line  80 . As discussed above, this particular link connecting nodes JE and JD is a logical link which traverses nodes of another technology layer. This fact is communicated by the presence of a layer icon  82  near the node icon representing the IP layer “traversing node”, or the last IP layer node in the sequential order before the path traverses to nodes of the other technology layer. In this case, the IP laser traversing node is node JE, and the layer icon  82  bisects the link line  80  immediately following the node icon  74  representing this node. To communicate the technology layer over whose nodes data traffic on the link between nodes JE and JD travels, a diamond symbol  84  is displayed within the layer icon  82 , indicating the SONET technology layer. The technology layer represented by this layer icon  82  is also indicated by the technology label “SONET” appearing beside the layer icon  82 .  
         [0040]    To the left of, and associated with the layer icon  82  is shown a selectable layer expander icon  86 , which in this case is a small triangle. That the triangle of this layer expander icon  86  points to the right indicates that selecting this layer expander icon  86  will cause to be expanded a second line of node icons representing nodes of the node layer represented by the associated layer icon  82  (discussed further below with reference to FIG. 4).  
         [0041]    The first line  73  of node icons is highlighted using a box outline  92 , labeled at its top right corner by a layer icon  94  whose symbol within (a circle), and label alongside  96  indicates that this node layer is an IP layer.  
         [0042]    Thus, the path explorer panel  70  shown in FIG. 3 informs the network administrator that the selected path consists of two IP nodes, JE and JD of the IP layer, and that the link between the two nodes is a logical link which travels over nodes of a SONET layer. Each of the two nodes JE and JD also have one warning alarm.  
         [0043]    To the right of the path explorer panel  70  is the topology panel  72 . The topology panel  72  in FIG. 3 is essentially the same as that appearing in the top panel of the topology displayed in FIG. 2 and as such will not be described in detail here. It is to be noted that as it is the first line  73  of nodes representing the IP layer which is highlighted  92  in the path explorer panel  70 , it is the topology of this IP layer which is displayed in the topology panel  72 . Further, those node icons  100  and  102  and link lines  104  of this topology representing nodes and links which are part of the selected path are highlighted in the topology panel  72 , again by outlining  98 . In this case, the network elements which are part of the selected path are the two nodes JE and JD represented by node icons  100  and  102 , and the link connecting the two, represented by the link line  104  connecting the two node icons  100  and  102 . Again, the presence of a layer icon  106  with a diamond within, near the node icon  100  representing the IP traversing node JE, in this case bisecting the link line  104 , indicates that the link between nodes JE and JD is a logical link which travels over the nodes of a SONET layer.  
         [0044]    In FIG. 4, the network administrator has selected the layer expander icon  86  representing the SONET layer in the path explorer panel  70  in FIG. 3. As a result, a second line  108  of node icons representing nodes of the SONET layer has been expanded in the path explorer panel  70 . Further, the layer expander icon  86  representing the SONET layer is now pointing down, indicating that the SONET layer has been expanded.  
         [0045]    In the illustrated example, the mechanism for this expansion is as follows. First, the number of path segments of which the path representation is comprised is increased by the number of SONET node icons to be displayed. Second, the IP node icons representing nodes which follow the IP traversing node JE are shifted down the path representation by this same number of path segments. Third, the second line  108  of node icons representing nodes of the SONET layer is displayed in the vacated path segments of the path representation.  
         [0046]    If the SONET layer expander icon  86  is now selected again, the second line  108  of node icons would be collapsed returning the path explorer panel  70  to the state shown in FIG. 3. In particular, the second line  108  of node icons would be erased, the IP node icons representing nodes which follow the IP traversing node JE would be shifted up the path representation by the number of SONET node icons erased, and the number of path segments of which the path representation is comprised would be decreased by the same number.  
         [0047]    The second line  108  of node icons is parallel to, and offset from the first line  73  of node icons to identify it as representing a different technology layer. Corresponding with the path illustrated in FIG. 2, the nodes of the SONET layer through which the path of interest passes are nodes WE, WD, WC, WB and WA. These nodes are represented once again by node icons ( 110  for example), this time with diamond symbols ( 112  for example) within, identifying the technology for these nodes as SONET. Alarm indicators  114 ,  116  are displayed to the left of some of the node icons  110  etc. of the second line  108 . In this case, the alarm indicators  114  and  116  of the second line  108  indicate that nodes WD and WB are both in an alarm state, with node WD having one major alarm, and node WB having two critical alarms.  
         [0048]    Link lines ( 118  and  120  for example) are displayed between each adjacent pair of node icons ( 74 ,  110 ,  122 , etc.) representing the links between the associated nodes. Connecting the two node icons  122  and  124  representing nodes WD and WC is a link line  126 . As discussed previously in the context of FIG. 2, this particular link connecting nodes WD and WC is a logical link which traverses nodes of a another technology layer. This fact is communicated by the presence of a layer icon  128  near the node icon representing the SONET layer “traversing node”, or the last SONET layer node in the sequential order before the path traverses to nodes of the other technology layer. In this case, the SONET layer traversing node is node WD, and the layer icon  128  bisects the link line  126  immediately following the node icon  122  representing this node. To communicate the technology layer over whose nodes data traffic on the link between nodes WD and WC travels, a triangle symbol  130  is displayed within the layer icon  128 , indicating the optical technology layer. The particular node layer represented by this layer icon  128  is also indicated by the “Optical” label appearing beside the layer icon  128 .  
         [0049]    To the left of this layer icon  128  appearing between the WD and WC node icons  122  and  124  is shown a selectable layer expander icon  132 , which is a small triangle. That the triangle of this optical layer expander icon  132  points to the right indicates that selecting this icon will cause to be expanded a third line of nodes representing nodes of the optical layer (discussed further below with reference to FIG. 5).  
         [0050]    The second line  108  of node icons is identified by a box  134 , labeled at its top right corner by a layer icon  136  whose symbol within (a diamond) indicates that this node layer is a SONET layer. The second line  108  of node icons is also identified by a layer-identifier label  138 .  
         [0051]    In FIG. 4, the box  134  identifying the second line  108  of node icons is in dashed lines, whereas the box  92  identifying the first line  73  of node icons remains in solid lines, indicating that notwithstanding the expansion of the node icons representing the SONET layer, it is still the IP layer which is selected in the path explorer panel  70 . As such, the topology panel  72  remains unchanged, still showing the IP layer.  
         [0052]    Thus, the path explorer panel  70  shown in FIG. 4 informs the network administrator that the path being displayed consists of the nodes JE, WE, WD, WC, WB, WA and JD, in that order. The nodes JE and JD are IP nodes of an IP node layer. The nodes WE, WD, WC, WB and WA are SONET nodes of a SONET node layer. The link between the two nodes WD and WC is a logical link which travels over nodes of an optical node layer.  
         [0053]    In FIG. 5, the network administrator has selected the layer expander icon  132  associated with the optical layer icon  128  between nodes WD and WC in the path explorer panel  70  in FIG. 4. As a result, a third line  140  of node icons representing nodes of the optical layer has been expanded in the path representation shown in the path explorer panel  70 . As such, this layer expander icon  132  is now pointing down, indicating that the optical layer has been expanded.  
         [0054]    In the illustrated example, the mechanism for this expansion is as follows. First, the number of path segments of which the path representation is comprised is increased by the number of optical node icons to be displayed. Second, both the SONET node icons representing nodes which follow the SONET traversing node WD, as well as the IP node icons representing nodes which follow the IP traversing node JE, are shifted down the path representation by this same number of path segments. Third, the third line  140  of node icons representing nodes of the optical layer is displayed in the vacated path segments of the path representation.  
         [0055]    If the optical layer expander icon  132  is now selected again, the third line  140  of node icons would be collapsed returning the path explorer panel  70  to the state shown in FIG. 4. In particular, the third line  140  of node icons would be erased, the SONET node icons representing nodes which follow the SONET traversing node WD, as well as the IP node icons representing nodes which follow the IP traversing node JE would be shifted up the path representation by the number of optical node icons erased, and the number of path segments of which the path representation is comprised would be decreased by the same number.  
         [0056]    The third line  140  of node icons is parallel to, and offset from the second line  108  of node icons to identify it as a separate line representing a different technology layer. Corresponding with the path illustrated in FIG. 2, the nodes of the optical layer through which the path of interest passes are nodes BB, BE, BD and BC. These nodes are represented once again by node icons ( 142  for example), this time with triangle symbols ( 144  for example) within, identifying the technology for these nodes as optical. In the case of the optical layer, there are no nodes which are part of the path of interest which are in an alarm state. As such, no alarm indicators appear to the left of the node icons ( 142  for example) of the third line  140 .  
         [0057]    Link lines ( 118 ,  120 ,  146  and  148  for example) are displayed between each adjacent pair of node icons ( 74 ,  110 ,  122 ,  142 , etc.) representing the links between the represented nodes. In this case, none of these links are logical links. As such, none of the link lines are bisected by a layer icon.  
         [0058]    The third line  140  of node icons is identified by a box  149 , labeled at its top right corner by a layer icon  150  whose symbol within (a triangle) indicates that this node layer is the optical technology layer. The third line  140  of node icons is also identified by a layer-identifier label  152 .  
         [0059]    In FIG. 5, the box  149  identifying the third line  140  of node icons is in dashed lines, whereas the box  92  identifying the first line  73  of node icons remains in solid lines, indicating that notwithstanding the expansion of the node icons representing the optical layer, it is still the IP layer which is selected in the path explorer panel  70 . As such, the topology panel  72  remains unchanged, still showing the IP layer.  
         [0060]    Thus, the path explorer panel  70  shown in FIG. 5 informs the network administrator that the path being displayed consists of the nodes JE, WE, WD, BB, BE, BD, BC, WC, WB, WA and JD, in that order, and that this path traverses across three technology layers, an IP layer, a SONET layer and an optical layer.  
         [0061]    In FIG. 6, the network administrator has selected the second line  108  of node icons in the path explorer panel  70 . As such, the box  134  around the second line  108  of node icons is now in solid, while the box  92  around the first line  73  of node icons is now in dashed lines. Further, the topology panel  72  now displays a topology of the SONET layer.  
         [0062]    The topology panel  72  in FIG. 6 is essentially identical to that appearing in the middle panel of the topology displayed in FIG. 2 and as such will not be described in detail here. Those node icons and link lines which are part of the path of interest are highlighted in the topology panel  72  by outlining  154 . In this case, the network elements in the SONET layer which are part of the path of interest are the nodes WA, WB, WC, WD and WE represented by node icons  156 ,  158 ,  160 ,  162  and  164 , and the links connecting adjacent nodes, represented by link lines  166 ,  168 ,  170  and  172 . The presence of a layer icon  178  near the node icon  162  representing the SONET traversing node WD, in this case between the WC and WD rode icons  160  and  162  indicates that the link between these two nodes is a logical link which travels over the nodes of another node another technology layer. The symbol within this layer icon  178  (a triangle) indicates that this other technology layer is the optical technology layer.  
         [0063]    To the left of the node icon  164  representing node WE, as well as the node icon  156  representing node WA are originating, and terminating IP layer icons  184  and  182  respectively. The Originating IP layer icon  184  appears near the SONET node icon  164  representing the first SONET layer node in the path, in this case node WE. The terminating IP layer icon  182  appears near the SONET node icon  156  representing the last SONET layer node in the path, in this case node WA. Each of the originating and terminating IP layer icons  184  and  182  respectively, have circle symbols therein, indicating that the path of interest arrives from nodes of the IP technology layer, and departs the SONET layer to nodes of the IP technology layer.  
         [0064]    If the network administrator would like to know which node of the IP Technology layer each of the nodes WA and WE may be adjacent to, by passing a mouse pointer over either of the originating or terminating IP layer icons  184  and  182 , the node icon in the path explorer panel  70  representing the adjacent node of the IP technology layer will be highlighted (not shown). In this case, if the mouse pointer is passed over the originating IP layer icon  184  near the WE node icon  164 , the JE node icon  74  in the path explorer panel  70  will be highlighted. If the mouse pointer is passed over the terminating IP layer icon  182  near the WA node icon  156 , the CD node icon  76  in the path explorer panel  70  will be highlighted.  
         [0065]    In FIG. 7, the network administrator has selected the third line  140  of node icons in the path explorer panel  70 . As such, the box  149  around the third line  140  of node icons is now in solid, while the box  134  around the second line  108  of node icons is now in dashed lines. Further, the topology panel  72  now displays a topology of the optical layer.  
         [0066]    The topology panel  72  in FIG. 7 is essentially identical to that appearing in the bottom panel of the topology displayed in FIG. 2 and as such will not be described in detail here. Those node icons and link lines representing elements which are part of the path of interest are highlighted in the topology panel  72  by outlining  186 . In this case, the network elements in the optical layer which are part of the path of interest are the nodes BB, BE, BD and BC represented by node icons  188 ,  190 ,  192  and  194 , and the links connecting adjacent nodes, represented by link lines  196 ,  198  and  200 .  
         [0067]    Above the node icon  188  representing node BB, as well as the node icon  194  representing node BC are originating, and terminating SONET layer icons  208  and  210  respectively. The originating SONET layer icon  208  appears near the optical node icon  188  representing the first optical layer node in the path, in this case node BB. The terminating SONET layer icon  210  appears near the optical node icon  194  representing the last optical layer node in the path, in this case node BC. Each of the originating and terminating SONET layer icons  208  and  210  respectively, have diamond symbols therein, indicating that the path of interest arrives from nodes of the SONET technology layer, and departs the optical layer to nodes of the SONET technology layer.  
         [0068]    If the network administrator would like to know which node of the SONET technology layer each of the nodes BB and BC may be adjacent to, by passing a mouse pointer over either of the originating or terminating SONET layer icons  208  and  210 , the node icon in the path explorer panel  70  representing the adjacent node of the SONET technology layer will be highlighted (not shown). In this case, if the mouse pointer is passed over the originating SONET layer icon  208  near the BB node icon  188 , the WD node icon  122  in the path explorer panel  70  will be highlighted. If the mouse pointer is passed over the terminating SONET layer icon  210  near the BC node icon  194 , the WC node icon  124  in the path explorer panel  70  will be highlighted.  
         [0069]    The information appearing in both the path explorer panel  70  and the topology panel  72  may also be manipulated by clicking on designated icons in the topology panel  72 . For example, if while the topology panel  72  is displaying the topology of the IP layer, as shown in FIG. 3, the network administrator were to click on the layer icon  106  representing the logical link between nodes JE and JD, then the network administrator would be selecting the node layer represented by that layer icon  106 , in this case the SONET layer. As a result, if it is not displayed already, the path representation displayed in the path explorer panel  70  would display the second line  108  of node icons representing nodes of the SONET layer, and this second line  108  of node icons would be highlighted. Furthermore, in the topology panel  72  would be displayed the topology of this SONET layer.  
         [0070]    Similarly, if while the topology panel  72  is displaying the topology of the SONET layer, as shown in FIG. 6, the network administrator were to click on the layer icon  178  representing the logical link between nodes WD and WC, then the network administrator would be selecting the node layer represented by that layer icon  178 , in this case the optical layer. As a result, if it is not displayed already, the path representation displayed in the path explorer panel  70  would display the third line  140  of node icons representing nodes of the optical layer, and this third line  140  of node icons would be highlighted. Furthermore, in the topology panel  72  would be displayed the topology of this optical layer.  
         [0071]    Alternatively, if while the topology panel  72  is displaying the topology of the SONET layer, as shown in FIG. 6, the network administrator were to click on one of the originating or terminating IP layer icons  184 ,  182  adjacent to either of nodes WE or WA, then the network administrator would be selecting the node layer represented by those layer icons, in this case the IP layer. As a result, the first line  73  of node icons in the path explorer panel  70  would be highlighted, and the topology panel  72  would display the topology of the IP layer.  
         [0072]    Similarly, if while the topology panel  72  is displaying the topology of the optical layer, as shown in FIG. 7, the network administrator were to click on one of the originating or terminating SONET layer icons  208 ,  210  adjacent to either of nodes BB or BC, then the network administrator would be selecting the node layer represented by that layer icon, in this case the SONET layer. As a result, the second line  108  of node icons in the path explorer panel  70  would be highlighted, and the topology panel  72  would display the topology of the SONET layer.  
         [0073]    Having described the appearance and panel interaction of a preferred embodiment method of the present invention, a particular example of functionality behind the operation of this preferred embodiment method will now be described with reference to the flowchart shown in FIG. 8. More generally, any functionality which is capable of transforming a database of network connectivity, element characteristics and performance information into displays such as exemplified herein may be employed.  
         [0074]    [0074]FIG. 8 shows a flow chart for the basic functionality of the preferred embodiment method of the present invention. Not all features described above are illustrated in FIG. 8, or described below.  
         [0075]    First, the network administrator using the method selects  220  a path of data travel across the network  20 . The processor  28  of the NMD  26  retrieves  221  from the local database  36  and the network database  24 , static and dynamic data relevant to then path, as necessary. Such data may include identification, architectural, technology layer and/or status information on the nodes and links of which the selected path is comprised. Next, the outlines of the path explorer panel  70  and the topology panel  72  are displayed  222  on the display  30 .  
         [0076]    The processor  28  then processes the data retrieved for the selected path, defines the nodes into technology layers, and displays  224  in the path explorer panel  70  the first line  73  of node icons and link lines representing the nodes and links of the IP layer for the selected path, and in the topology panel  72 , node icons and link lines also representing the nodes and links of the IP layer for the selected path. Such a display is exemplified in FIG. 3.  
         [0077]    Next, the processor  28  awaits  226  further input from the user.  
         [0078]    If the second, or SONET layer is selected, the second line  108  of node icons is displayed  228  in the path explorer panel  70  if it is not already displayed, and this second line  108  of node icons is highlighted. Further, depending on how the SONET layer was selected (as discussed in further detail above), the topology of the SONET layer may also be displayed  228  in the topology panel  72 . The SONET layer may be selected in any one of four ways. First, the layer expander icon  86  associated with the SONET layer icon  82  in the first line  73  of node icons in the path explorer panel  70 , as shown in FIG. 3, may be selected. Second, once displayed, the second line  108  of node icons in the path explorer panel  70 , may be selected. Third, while the topology panel  72  is displaying the topology of the IP layer, the layer icon  106  representing the SONET layer may be selected. Finally, while the topology panel  72  is displaying the topology of the optical layer, either of the originating or terminating SONET layer icons  208 ,  210  representing the SONET layer may be selected.  
         [0079]    If the optical layer is selected, the third line  140  of node icons is displayed  230  in the path explorer panel  70  if it is not already displayed, and this third line  140  of node icons is highlighted. Further, depending on how the optical layer was selected (as discussed in further detail above), the topology of the optical layer may also be displayed in the topology panel  72 . The optical layer may be selected in any one of three ways. First, the layer expander icon  130  associated with the optical layer icon in the second line  108  of node icons in the path explorer panel  70 , as shown in FIG. 4, may be selected. Second, once displayed, the third line  140  of node icons in the path explorer panel  70 , may be selected. Third, while the topology panel  72  is displaying the topology of the SONET layer, the layer icon  178  representing the optical layer may be selected.  
         [0080]    If the IP layer is selected, the first line  73  of node icons is highlighted  232  in the path explorer panel  70 . Further, depending on how the IP layer is selected (as discussed in further detail above), the topology of the IP layer may also be displayed  232  in the topology panel  72 . The IP layer may be selected in either of two ways. First, the first line  73  of node icons in the path explorer panel  70 , may be selected. Second, while the topology panel  72  is displaying the topology of the SONET layer, either of the originating or terminating IP layer icons  182 ,  184  representing the IP layer may be selected.  
         [0081]    Although in the foregoing description of a preferred embodiment method of the present invention, the functionality of, and information communicated by the displays of the method have been described in detail, it is to be understood that the particular functionality of the panels, the particular information displayed in each panel, and the manner in which the information is displayed may be altered without necessarily departing from the scope of the present invention which is defined in the claims which follow. Simply by way of example, although the node icons and layer icons have been shown having a particular appearance and shape, other appearances and shapes are of course possible. Further, different symbols other than those displayed in the illustrated examples may be used to indicate the relevant technology layers. Also, although visual distinguishing or highlighting of particular elements of the displays of the preferred embodiment method have been shown using outlining, other forms of visual distinguishing or highlighting may be used, shadowing, shading, or through use of different colours, for example. Additionally, although the path explorer and topology panels have been illustrated as being panels within a window, the relevant information may alternatively be displayed in any type of view, separate windows, or in a single panel for example.  
         [0082]    It is further to be understood that the data displayed in the figures are of course for illustrative purposes only, and that other data may be displayed using the method of the present invention. For example, the selected path may contain nodes of more or less than three technology layers. Further, the selected path may contain nodes of more than one node group of a given technology layer, which separate groups may be identified in the panels.  
         [0083]    As discussed above, although the preferred embodiment method of the present invention has been discussed in the context of a particular type of telecommunication application, it is to be understood that the present invention could also be used in other types of telecommunication applications, for example where telecommunication nodes are organized into layers using criteria other than technology, as well as in business plan applications, distribution applications, transportation applications, and any other application wherein it is desirable to view a path consisting of a number of nodes in multiple node layers. By way of example, the present invention could be used to view a path a shipment may take through a distribution network, wherein the nodes layers include a pick-up/delivery layer, a storage layer, a trucking layer, and an air transportation layer. Similarly, the present invention could be used to view the path a business proposal may take through a business plan network consisting of a planning committee layer, a finance layer, an engineering layer, and a marketing layer. In a transportation application, the present invention may be used to explore a path taken by an individual through a road transport layer, a rail transport layer, a water transport layer, and an air transport layer.  
         [0084]    Additionally, it is to be noted that the present invention also contemplates a GUI (graphical user interface) embodying the method of the present invention, a computer-readable medium having stored thereon instructions for directing a host computer to implement the method of the present invention (in the exemplary computer system illustrated in FIG. 1, the instructions stored on the computer readable medium may be stored on the local database  36 , and executed by the processor  28  of the NMD  26 ), as well as a computer system adapted to executed a path explorer application directing a computer to implement the method of the present invention.  
         [0085]    Finally, it is to be understood that the method of the present invention may be implemented for execution on a computer system using any suitable computer language, object-oriented computer language such as Java, for example.  
         [0086]    Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.