Abstract:
In one embodiment, the present invention sends SNMP queries to sets and/or ranges of IP numbers to determine whether a network device exists at each IP number and whether the network device has IP forwarding capabilities. The set of IP numbers searched may be specified by specifying ranges or subnets or by providing a list of discrete IP numbers. When a new network device with IP forwarding capabilities is discovered, that network device is added to a list of discovered network devices. The list is displayed to the network manager. In one embodiment, in addition to discovering newly added devices via IP number polling, the invention also discovers newly added devices from SNMP messages (“traps”) broadcast by a newly added device. In one embodiment, each network device discovered as a result of a SNMP trap is added to the newly discovered device list.

Description:
FIELD OF THE INVENTION 
   The present invention relates to the field of data communications networks, and more particularly to a method and apparatus for automatically discovering network devices that have data forwarding capabilities. 
   BACKGROUND OF THE INVENTION 
   A data communications network transmits data among and between network devices (sometimes also referred to as “network elements” or “nodes”) physically and logically connected to the network. The physical configuration of a network changes as network devices are added or removed from the network and as physical connections between devices are made or changed. The logical configuration of a network changes as logical connections are established between communicating network devices utilizing the physical structure of the network. Network devices include devices that can send and/or receive data, as well as devices that can forward data. Network devices that can forward data are important in all but the very simplest networks. In most networks direct connections do not exist between most network devices. Instead, each network device is connected to a limited number of adjacent network devices. For network devices to be able to communicate when they are not physically connected, the two communicating network devices rely on intermediate network devices to forward communications between them. 
   Data is commonly transmitted over a data communications network in the form of discrete chunks of data referred to as “packets”. A string of data is broken up into packets at the sending network device and sent separately over the network to the receiving network device. The network device receives the individual packets and assembles them in the correct order to reconstruct the original data string. The particular manner in which packets are broken up and transmitted from one network device to another is defined as a “network protocol”. One prominent network protocol is the “Internet Protocol”, usually referred to by its acronym, “IP”, or as the “IP protocol.” Another protocol is called “Multi-Protocol Label Switching”, or “MPLS”. 
   Data communications networks are often conceptualized as comprising a hierarchy of communications “layers” that establish different types of connections between network devices. The more basic functions are provided at the lower layers, while successively more sophisticated functions are provided at successively higher layers. Different protocols are used to communicate between devices on each layer. Layering allows sophisticated communications functions to be built up using relatively simple protocols at each layer. 
   One common hierarchical network model is the so-called OSI “seven-layer” model. In the OSI model, each lower layer in the model provides communications capabilities or functions that are utilized by the next higher layer. A schematic illustration of the OSI seven-layer model is shown in  FIG. 2 . As shown in  FIG. 2 , the seven layers in the OSI model, beginning from the bottom, are physical layer  205 , data link layer  210 , network layer  215 , transport layer  220 , session layer  225 , presentation layer  230 , and application layer  235 . In relation to the OSI model, the IP protocol is commonly considered as being associated with the third layer, network layer  215 . 
   In an IP network, each sending and receiving device is assigned a 32-bit address. The address is usually written as a series of four “octets” (e.g., numbers within a range of 0-255) separated by periods. Examples of IP addresses are 127.0.0.1, 205.160.34.112, 23.1.99.244, etc. 
   Each IP packet sent over an IP network includes the sender&#39;s IP address and the recipient&#39;s IP address. The recipient&#39;s IP address is used to route the packet from the sending network device via intermediate network devices that have IP forwarding capabilities to the recipient network device. 
   An example of a simple network that illustrates IP forwarding is shown in  FIG. 1 . The network of  FIG. 1  includes two types of network devices: non-IP-forwarding devices  105 ,  110 ,  115  and  120  (represented by rectangles in  FIG. 1  and which may, for example, comprise personal computers or computer workstations), and IP-forwarding devices  125 ,  130 ,  135 ,  140 ,  145  and  150  (represented by circles in  FIG. 1  and which may, for example, comprise IP routers). The network devices in  FIG. 1  are interconnected by a various bi-directional connections or links  160 ,  162 ,  164 ,  166 ,  168 ,  170 ,  172 ,  174 ,  176 ,  178  and  180 , represented in  FIG. 1  by two-headed arrows. Links  160 - 180  may comprise direct physical connections between the adjacent network devices, or may comprise logical connections that involve intermediate devices but that are seen by the connected devices as direct connections. For example, network device  110  is connected to network device  130  via link  166 . That is, network device  110  knows that if it sends a communication via its interface port that is connected to link  166 , the communication will be received by network device  130 . It doesn&#39;t matter to network device  110  whether link  166  is a single physical connection or a series of physical connections. Logical links such as links  160 - 180  in  FIG. 1  that connect two network devices will be referred to sometimes herein as “IP links”. The term “IP links” as used herein includes logical links that use the IP protocol, as well as logical links utilizing other protocols, such as, for example, MPLS. 
   In the example network of  FIG. 1 , network device  110  is connected directly (via link  166 ) only to network device  130 . For network device  110  to communicate to any other network device, the IP forwarding capabilities of network device  130  must be used. 
   In  FIG. 1 , network device  130  has direct connections to three other network devices in addition to network device  110 , to which it is connected via link  166 . The other links are links  160 ,  168  and  176 , which connect network device  130  to network devices  125 ,  135  and  145 , respectively. Each of links  160 ,  166 ,  168  and  176  are typically connected to separate ports on network device  130 . Each port may be a separate physical interface, or two or more ports may share a single physical interface. Each port may have its own IP address assigned to it. In that case, network device  130 , as well of each of its ports, may have distinct IP addresses. 
   Network device  130  of  FIG. 1  has been defined to have IP forwarding capabilities. That means it must be able to receive an IP packet (intended for delivery to a network device other than network device  130 ) from one of the IP links it is connected to and forward it along at least one of the other the IP links it is connected to. In the general case where network device  130  is a typical router, network device  130  will be able to receive and forward IP packets from and to any of the IP links  160 ,  166 ,  168  and  176  it is connected to (provided the links are functioning). The other network devices  125 ,  135 ,  140 ,  145  and  150  with IP forwarding capabilities in the example of  FIG. 1  are similarly able to receive and forward IP packets from and to any of the IP links they are connected to. 
   If network device  110  wants to send a communication to, for example, network device  115 , there are a number of paths that the communication can take. The most direct path comprises links  166 ,  176 , and  178 . However, other paths include the path comprising links  166 ,  168 ,  174 ,  180  and  178 , and even the path comprising links  166 ,  160 ,  162 ,  174 ,  180  and  178 . 
   When network device  110  sends out IP packets to network device  115 , it does not know what path each of the packets will take. Network device  110  simply addresses the packet to network device  115  using network device  115 &#39;s IP number (namely 129.111.110.9 in the example of  FIG. 1 ), and sends it out over link  166  towards network device  130 . 
   What network device  130  does with the packet after it receives it depends on how network device  130  is configured. For example, network device  130  may be configured to forward any packet received from link  166  along link  176 . Alternatively, network device  130  may be configured to forward packets along links depending on the destination IP number of the packet. Network device  130  may also be programmed to monitor traffic along each link and to adapt its forwarding scheme to traffic conditions. 
   How each network device forwards packets depends on the capabilities and configuration of the particular network device. As is evident even from the simple network example of  FIG. 1 , it is important that network devices that do IP forwarding be properly configured to interoperate with each other to ensure that packets are correctly routed to their destination. 
   Configuration of network devices within a network comprises an aspect of network management. Network devices may be locally managed or remotely (centrally) managed. Local management of a network device may be accomplished using a workstation or terminal directly connected to the network device. Remote management of a network device may be accomplished from remote terminals or workstations that communicate with the network device via the network, provided the network device is provided with a management protocol that allows remote management. One protocol used for remote management of network devices is the Simple Network Management Protocol (SNMP). SNMP provides a set of commands and parameters that allow communication with and configuration of network devices. A person who is responsible for management of a network is commonly referred to as a “network manager.” Network management software systems provide tools to network managers that facilitate central management of often geographically dispersed network devices. 
   To be able to manage a network device, a network manager must know that the network device exists, how it is connected to the network and to other network devices, and what its capabilities are. In addition, the network device must have the capability of being remotely managed, the network management system used by the network manager must be able to communicate with the network device using the correct protocol, and the network manager must be apply to supply any required logins, passwords, or other security information. 
   The configuration of large networks often changes through the addition, removal and/or replacement of network devices. To properly manage large networks to ensure that IP packets are routed correctly over the network, the network manager must know when data forwarding network devices are added or removed. 
   In small local networks, for example those in which the entire network comprises only a handful of network devices, it is relatively easy for a network manager to physically inspect each network device and know from first hand inspection when a network device is added or removed. In large, geographically dispersed networks comprising hundreds of network devices, it would be extremely difficult for the network manager to know from a first hand inspection what the state of the entire network is at any given time. 
   A network being managed often comprises of a plurality of subnets. A subnet is a group of network devices belonging to a specific block or subset of IP addresses. For example, one type of subnet comprises IP numbers that share the first three octets, as for example 215.223.46.x (where “x” can be any number from 0 to 255). Larger subnets may share only the first two octets (e.g. 215.223.x.y). In addition to subnets, networks may also include individual IP numbers or ranges of IP numbers. A network manager generally will know which subnets are included in the network being managed. However, the network manager will not necessarily know beforehand the IP number of a network device to be added to a network, particularly if the IP number is not within one of the network&#39;s known subnets. 
   Some prior art network management systems provide tools that allow a network manager to gather certain information about network devices within the network managed by the network manager. For example, one prior art system allows a network manager to send queries to each possible IP number in a subnet or other range of IP numbers (“IP number polling”) to determine whether a network device is associated with that IP number. If a network device is found, it is automatically added to the network management system&#39;s database of managed network devices. This prior art network device discovery system can discover newly added network devices. However, it does not distinguish between network devices with IP forwarding capabilities and those without. Furthermore, it does not discover network devices outside of the range of IP numbers being searched, nor does it allow a network manager to exert control over which of the newly discovered network devices are to be managed by the network management system. 
   SUMMARY OF THE INVENTION 
   The present invention comprises a method and apparatus for automatic discovery of network devices with data forwarding capabilities. In one embodiment, the present invention sends SNMP queries to sets and/or ranges of IP numbers to determine whether a network device exists at each IP number and whether the network device has IP forwarding capabilities. The set of IP numbers searched may be specified by specifying ranges or subnets or by providing a list of discrete IP numbers. When a new network device with IP forwarding capabilities is discovered, that network device (identified by its IP number and SNMP description field) is added to a list of discovered network devices. The list is displayed to the network manager, who has the option of selecting none, one, or more than one of the network devices on the network device list for management by the network manager&#39;s network management system. In one embodiment, in addition to discovering newly added devices via IP number polling, the invention also discovers newly added devices from SNMP messages (“traps”) broadcast by a newly added device. In one embodiment, each network device discovered as a result of a SNMP trap is added to the newly discovered device list, regardless of whether or not the network device has data forwarding capabilities. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic of a data communications network that utilizes data forwarding. 
       FIG. 2  is a schematic of the OSI seven layer network model. 
       FIG. 3  is a flow chart showing an auto discovery process used in an embodiment of the invention. 
       FIG. 4  is a flow chart showing an auto discovery process used in an embodiment of the invention. 
       FIG. 5  is a flow chart showing an auto discovery process used in an embodiment of the invention. 
       FIG. 6  is a schematic of an apparatus comprising an embodiment of the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A method and apparatus for automatically discovering network devices with data forwarding capabilities is presented. In one or more embodiments, the invention comprises part of a network management system, such as, for example, the Alcatel 5620 Network Management System. In one or more embodiments, the invention is implemented by means of software programming operating on personal computers, computer workstations and or other computing platforms. In the following description, numerous specific details are set forth to provide a thorough description of the invention. However, it will be apparent to one skilled in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail so as not to obscure the invention. 
     FIG. 3  is a flow chart showing an auto discovery process used in an embodiment of the invention. This embodiment forms part of a network management system (NM) that comprises a number of tools to allow a network manager (user) to manage routing devices in a network environment. The NM provides a graphical user interface (GUI) that displays various views of the network and devices being managed, and that provides menus from which the network manager can select various network management operations. In one embodiment, the views that a user may select include a “physical map” that shows a graphical representation of the physical devices and connections in the network being managed (e.g., OSI layers  1  and  2 ) and an “IP map” that shows a graphical representation of network devices and connections at a higher layer (e.g., OSI layer  3 ). One of the operations that may be selected is the auto discovery process of  FIG. 3 . 
   As shown in  FIG. 3 , the process starts by a user launching the auto discovery process at step  300  (for example by selecting a “Discover” command from a pull-down menu). At step  302 , the discovery mode selected by the user is identified. In the embodiment of  FIG. 3 , the user can select either an “IP range” mode or a “configuration file” mode. In the “IP range” mode, the discovery process searches IP numbers within ranges specified by the user. In the “configuration file” mode, the discovery process searches IP numbers listed in a user supplied configuration file. 
   If the selected discovery mode is the “IP range” mode, the configuration information specified by the user for the IP range(s) to be searched is read at step  306 . In one embodiment, the configuration information for a range includes a starting IP address, an ending IP address, and SNMP information. The SNMP information includes the SNMP read community string, the remote port number to be used to connect to the SNMP agent at each IP address, a timeout value, a retry value, and a SNMP version number. 
   After the configuration information for the current range is read at step  306 , the first IP number in the range is selected at step  308 . A SNMP “get-request” command is sent to the selected IP number at step  310  using the SNMP configuration parameters identified at step  306 . A SNMP “get request” command is a request to the SNMP agent at the queried IP address to respond with identification information for any network device at that IP address. 
   At step  312  a determination is made as to whether a response from the queried IP address has been received within timeout and retry limits specified in the configuration information. 
   If no response is received within the applicable timeout and retry limits, a determination is made at step  314  as to whether the end of the IP range being searched has been reached. If the end of the IP range has not been reached, the process selects the next IP number in the range at step  316  and returns to step  310 . If the end of the IP range has been reached, the auto discovery process ends at step  318 . Alternatively, in embodiments in which a user may specify multiple IP ranges, instead of ending at step  318 , the process may go on to the next range and return to step  306 . 
   If a response to the SNMP “get request” message is received at step  312 , the response is inspected to see whether the SNMP reply identifies the responding device type as a router. If the device type specified in the SNMP reply is not a router, the process returns to step  314 . 
   If the device type specified in the SNMP reply is a router, a determination is made at step  324  as to whether the IP number for the responding device is already included in a managed devices database of the NM. The managed devices database is a database of all network devices that are currently being managed by the NM. If the IP number is already in the managed devices database, an error message is logged at step  326  and the process returns to step  314 . The error message indicates that the device discovered at the current IP number is already in the managed devices database. While the message is referred to as an error message, the message need not connote the occurrence of an error, but may simply serve as an indication of the discovery or re-discovery of a device already in the managed devices database. 
   If the current IP number is not in the managed devices database, a determination is made at step  328  as to whether the current IP address is already in the detected element list. The detected element list is a list of detected devices that have not yet been selected by the user to be managed by the NM. In one embodiment, the detected element list is persistent and cumulative, so that results of previous executions of the discovery process remain in the detected element list unless selected for management or deleted by the user. If the current IP address is already in the detected element list, the detected element&#39;s parameters as listed in the detected element list are compared to the parameters received in the response to the sent “get-request” command and updated as required at step  330 . The process then returns to step  314 . 
   If the current IP number is not in the detected element list, a new detected element having the parameters contained in the response to the “get-request” command is created at step  332 . The new detected element is then added to the detected element list at step  334 , and the process returns to step  314 . 
   Going back to step  302 , if the discovery mode specified by the user is “configuration file”, the process proceeds to the step  404  of  FIG. 4 . 
   The auto discovery process for the configuration file mode shown in  FIG. 4  is nearly identical to the auto discovery process for the IP range mode shown in  FIG. 3 , except that instead of incrementing through a range of IP numbers, the process increments through a user-supplied list of discrete IP numbers. On one embodiment, the configuration file contains a list of discrete IP numbers together with SNMP configuration parameters for each listed IP number. 
   From step  404  in  FIG. 4 , the process proceeds to step  406 , where the first IP address in the configuration file is selected. At step  408 , the corresponding SNMP parameters are read from the configuration file. In one embodiment, the SNMP configuration information for each IP number in the configuration file includes the SNMP read community string, the remote port number to be used to connect to the SNMP agent at that IP address, a timeout value, a retry value, and a SNMP version number. In one embodiment default values are used for any SNMP parameter missing from the configuration file. 
   After the configuration information for the current IP number is read at step  408 , a SNMP “get-request” command is sent to the selected IP number at step  410  using the SNMP configuration parameters identified at step  406 . 
   At step  412  a determination is made as to whether a response from the queried IP address has been received within timeout and retry limits specified in configuration parameters. 
   If no response is received within the applicable timeout and retry limits, a determination is made at step  414  as to whether the end of the configuration file has been reached. If the end of configuration file has not been reached, the process selects the next IP number in the configuration file and returns to step  408 . If the end of the configuration has been reached, the auto discovery process ends at step  418 . 
   If a response to the SNMP “get request” message is received at step  412 , the response is inspected to see whether the SNMP reply identifies the responding device type as router. If the device type specified in the SNMP reply is not a router, the process returns to step  414 . 
   If the device type specified in the SNMP reply is a router, the process at step  424  checks to see whether the IP number for the responding device is already included in the managed devices database of the NM. If the IP number is already in the managed devices database, an error message is logged at step  426  and the process returns to step  414 . The error message indicates that the device discovered at the current IP number is already in the managed devices database. While the message is referred to as an error message, the message need not connote the occurrence of an error, but may simply serve as an indication of the discovery or re-discovery of a device already in the managed devices database. 
   If the current IP number is not in the managed devices database, a determination is made at step  428  as to whether the current IP address is already in the detected element list. If the current IP address is already in the detected element list, the detected element&#39;s parameters as listed in the detected element list are compared to the parameters received in the response to the sent “get-request” command and updated as required at step  430 . The process then returns to step  414 . 
   If the current IP number is not in the detected element list, a new detected element having the parameters contained in the response to the “get-request” command is created at step  432 . The new detected element is then added to the detected element list at step  434 , and the process returns to step  414 . 
   In addition to the manually invoked discovery function of  FIGS. 3 and 4 , one or more embodiments of the invention comprise a discovery function that is automatically invoked via receipt of a SNMP notification by the NM. An embodiment of an auto discovery process invoked by a SNMP notification is shown in  FIG. 5 . 
   In the embodiment of  FIG. 5 , the SNMP port of the workstation or other system on which the NM is running is monitored at step  500  for SNMP notifications sent to the NM from SNMP network devices. Such notifications are sometimes referred to as SNMP “traps”. A network device may be configured to send a SNMP trap to the NM if the device is intended to be managed by the NM. In that case, the person installing and configuring the device may configure it to send the NM a SNMP trap once the device is installed on the network, when the device boots up, or at some other time or times. 
   When a SNMP notification is received at step  505 , a determination is made at step  510  as to whether the IP address of the device sending the SNMP notification is already contained in the NM&#39;s managed devices database. If the device is already included in the managed devices database, the process returns to step  500 . 
   If the device is not already contained in the managed devices database, a determination is made at step  515  as to whether the IP address of the device is already in the NM&#39;s detected element list. If the device is already included in the detected element list, the process returns to step  500 . 
   If the device is not already in the detected element list, a new detected element object is created in step  520 , and the new object, representing the new device, is added to the detected element list at step  525 . At this point the “type” attribute of the detected element object is specified as being “unknown.” 
   At step  530 , a determination is made as to whether the IP address for the device is included in a user specified auto discovery IP range or configuration file. If it is, the corresponding SMNP configuration parameters are extracted at step  535 , and a SNMP “get-request” message is sent to the device using the extracted SNMP configuration parameters at step  545 . If the IP address is not in an existing IP range or configuration file, default SNMP configuration parameters are obtained at step  540  and used for the SNMP “get-request” sent to the device at step  545 . 
   At step  550 , a determination is made as to whether a response to the SNMP “get-request” message has been received within the applicable timeout and retry limits. If no response is received, the process returns to step  500 . If a response is received, the attributes of the detected element object are updated with information from the response at step  555 . For example, if the response identifies the detected device as a router, the type attribute of the detected element object is changed from “unknown” to “router.” After the detected element object attributes are updated as appropriate at step  555 , the process returns to step  500 . 
   In one embodiment, the auto discovery process is launched from a graphic user interface referred to as an “Auto Discovery Window”. In one embodiment, the Auto Discovery Window comprises two panes. A top pane displays the IP range(s) or addresses to search, and the bottom pane displays the discovered elements. A menu bar provides access to various functions associated with the Auto Discovery Window. 
   
     
       
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
               First 
               Second 
                 
             
             
               level 
               level 
                 
             
             
               menu 
               menu 
               Description 
             
             
                 
             
           
           
             
               File 
               Exit 
               Closes the Auto Discovery Window. 
             
             
               Range 
               New 
               Displays a form enabling the user to create and 
             
             
                 
                 
               configure a new range. 
             
             
                 
               Edit 
               Displays a form enabling the user to edit the 
             
             
                 
                 
               configuration of the selected range. 
             
             
                 
                 
               This menu item is grayed out if no range is selected 
             
             
                 
                 
               or if the selected range is actively discovering 
             
             
                 
                 
               routing devices. Only single selection is supported 
             
             
                 
                 
               for this command. 
             
             
                 
               Delete 
               Deletes the selected Range. This command is grayed 
             
             
                 
                 
               out if no range is selected or if the selected range(s) 
             
             
                 
                 
               are actively discovering routing devices. 
             
             
                 
               Discover 
               Starts discovering supported routing devices for the 
             
             
                 
                 
               selected range(s). 
             
             
                 
                 
               This command is grayed out if no range is selected 
             
             
                 
                 
               or if the selected range(s) are already discovering 
             
             
                 
                 
               routing devices. 
             
             
                 
               Cancel 
               Stops discovering routing devices for the selected 
             
             
                 
                 
               range(s). 
             
             
                 
                 
               This command is grayed out if no range is selected 
             
             
                 
                 
               or if the selected range(s) are not actively discover- 
             
             
                 
                 
               ing routing devices. 
             
             
                 
               Log 
               Displays the associated log file for the selected 
             
             
                 
                 
               range. 
             
             
                 
                 
               This command is grayed out for the following 
             
             
                 
                 
               reasons: 
             
             
                 
                 
               No range is selected 
             
             
                 
                 
               More than one range is selected 
             
             
                 
                 
               No log file exists (A Discovery has never occurred 
             
             
                 
                 
               for this range.) 
             
             
                 
                 
               The selected range is actively discovering network 
             
             
                 
                 
               elements. 
             
             
               Element 
               Manage 
               Commits a Detected Network Element for 
             
             
                 
                 
               management within the 5620. 
             
             
                 
                 
               This command is grayed out if no Detected Network 
             
             
                 
                 
               Element is selected or if the selected element(s) are 
             
             
                 
                 
               not routing devices. 
             
             
                 
               View 
               Displays a form containing the configuration of the 
             
             
                 
               Configura- 
               Detected Network Element. 
             
             
                 
               tion 
               This command is grayed out if no Detected Network 
             
             
                 
                 
               Element is selected. 
             
             
                 
                 
               Only single selection is supported for this command. 
             
             
                 
               Delete 
               Deletes the selected Detected Network Elements. 
             
             
                 
                 
               This command is grayed out if no element is 
             
             
                 
                 
               selected or if the selected element(s) are in the 
             
             
                 
                 
               process of being committed for management within 
             
             
                 
                 
               the 5620. 
             
             
               View 
               Refresh 
               Refreshes the information displayed within the Auto 
             
             
                 
                 
               Discovery Window. 
             
             
               Help 
                 
               Display appropriate help page in a browser 
             
             
                 
             
           
        
       
     
   
   Table 1 lists the menu commands available to a user in the Auto Discovery Window in an embodiment of the invention. 
   The first column of Table 1 lists the first level menu commands. These are the commands that are normally displayed on the menu bar when no command has been selected. In the embodiment of Table 1, the available first level commands comprise “File”, “Range”, “Element”, “View” and “Help”. Selecting one of the first level menu commands displays a pull down menu of corresponding second level menu commands. 
   Under the “File” first level command, the second level command “Exit” is available. Selecting the “Exit” command closes the auto discovery window. 
   Under the “Range” first level command, the second level commands “New”, “Edit”, “Delete”, “Discover”, “Cancel” and “Log” are available. 
   Selecting the “New” command displays a form that allows the user to configure a new IP range for auto discovery. Table 2 shows the fields that are displayed in an IP range form in an embodiment of the invention. 
   
     
       
             
             
             
             
             
           
         
             
               TABLE 2 
             
             
                 
             
             
               Field 
               Required 
               Range 
               Default 
               Description 
             
             
                 
             
           
           
             
               Starting IP 
               YES 
               Class A to C. 
               0.0.0.0 
               The starting point 
             
             
               Address 
                 
               No Loopback or 
                 
               for the Discovery 
             
             
                 
                 
               broadcast 
             
             
                 
                 
               addresses. 
             
             
               Ending IP 
               YES 
               Class A to C. 
               0.0.0.0 
               The ending point 
             
             
               Address 
                 
               No Loopback or 
                 
               for the Discovery 
             
             
                 
                 
               broadcast 
             
             
                 
                 
               addresses. 
             
             
               SNMP Read 
               YES 
               Any valid string. 
               “public” 
               The SNMP Read 
             
             
               Community 
                 
                 
                 
               community string. 
             
             
                 
                 
                 
                 
               Only one commu- 
             
             
                 
                 
                 
                 
               nity string can be 
             
             
                 
                 
                 
                 
               specified per IP 
             
             
                 
                 
                 
                 
               range. 
             
             
               Remote Port 
               YES 
               1-64K 
               161 
               Remote port 
             
             
                 
                 
                 
                 
               number to use to 
             
             
                 
                 
                 
                 
               connect to the 
             
             
                 
                 
                 
                 
               SNMP agent at 
             
             
                 
                 
                 
                 
               each IP address. 
             
             
               Timeout 
               YES 
               Any valid 
               5000  
               SNMP Timeout 
             
             
                 
                 
               positive integer 
                 
               value (ms) 
             
             
                 
                 
               including zero. 
             
             
               Retries 
               YES 
               Any valid 
                3 
               Number of times 
             
             
                 
                 
               positive integer 
                 
               to attempt to 
             
             
                 
                 
               including zero. 
                 
               connect to the 
             
             
                 
                 
                 
                 
               SNMP agent at 
             
             
                 
                 
                 
                 
               each IP address. 
             
             
               SNMP 
               YES 
               v1, v2c 
               v1 
               Version of the 
             
             
               Version 
                 
                 
                 
               SNMP Agent. 
             
             
                 
             
           
        
       
     
   
   The IP range form of Table 2 comprises seven fields: “Starting IP Address”, “Ending IP Address”, “SNMP Read Community”, “Remote Port”, “Timeout”, “Retries” and “SNMP Version.” As shown in Table 2, all fields must contain values. Default values are supplied which are used if the user does not enter new values. 
   In some embodiments, the “New” command also allows the creation of a range of discrete IP numbers imported from a file. The file contains the parameters for each IP number shown in Table two, with the exception of the beginning and ending range addresses. 
   Turning back to Table 1, the next second level command available under the “Range” first level command is “Edit”. Selecting the “Edit” command displays a form that allows a user to edit the configuration of a selected range (i.e. if the user has selected a range from the IP range pane of the auto discovery window) using a form with the same fields as in Table 2. The “Edit” command is grayed out (making it not available to the user) if no range has been selected. Only one range at a time may be selected to use the “Edit” command. 
   The third second level command available under “Range” is “Delete”. Selecting the “Delete” command deletes the selected range(s). The “Delete” command is grayed out if no range is selected. 
   The fourth command available under “Range” is “Discover”. Selecting the “Discover” command begins the auto discovery process for the selected range(s). The “Discover” command is grayed out if no range is selected. 
   The fifth command available under “Range” is “Cancel.” Selecting the “Cancel” command stops the auto discovery process for the selected range(s). The “Cancel” command is grayed out if no range is selected or if no discovery process is taking place for the selected range(s). 
   The sixth and last second level command available under “Range” is “Log”. Selecting the “Log” command displays an associated log file for the selected range. The “Log” command is grayed out under any of the following circumstances:
         (a) No range is selected.   (b) More than one range is selected.   (c) No log file exists (no discovery process has yet taken place for the range).   (d) A discovery process for the range is actively taking place.       

   The next first level command after “Range” is “Element”. The second level commands available under “Element” include “Manage”, “View Configuration” and “Delete.” 
   The “Manage” command selects a discovered element from the discovered element list for management by the NM (also referred to as “committing” the selected element). In one embodiment, once an element is committed, the NM validates the element and displays the element in the NM&#39;s physical and logical network maps. The committed element is also removed from the detected element list. The “Manage” element is grayed out if no detected element is selected or if the selected element(s) are not IP forwarding (routing) devices. 
   The “View Configuration” command displays a form containing configuration information available for the selected element (the available information may include items not included in the information displayed in the detected element list). Table 3 shows the information displayed in an embodiment of the invention. The “View Configuration” command is grayed out if no element is selected. 
   
     
       
             
             
             
             
           
         
             
               TABLE 3 
             
             
                 
             
             
               Column 
               Values 
               Default 
               Description 
             
             
                 
             
           
           
             
               IP 
               N/A 
               IP Address of 
               The IP address of the 
             
             
                 
                 
               the device. 
               Detected Network 
             
             
                 
                 
                 
               Element. 
             
             
               Type 
               Unknown 
               Unknown 
               The type of Detected 
             
             
                 
               Routing 
                 
               Network Element. 
             
             
                 
               Non-routing 
             
             
                 
               Unsupported 
             
             
                 
               CPSS 
             
             
               Commit 
               Not Committed 
               Not Committed 
               The management status 
             
             
               Status 
               Requested 
                 
               of the Detected Network 
             
             
                 
               In Progress 
                 
               Element. Those network 
             
             
                 
               Not Applicable 
                 
               elements that are not to 
             
             
                 
               Not Available 
                 
               be managed through 
             
             
                 
                 
                 
               Auto Discovery have the 
             
             
                 
                 
                 
               “Not Applicable” status. 
             
             
                 
                 
                 
               A “Not Available” status 
             
             
                 
                 
                 
               is displayed if there is a 
             
             
                 
                 
                 
               failure to communicate 
             
             
                 
                 
                 
               with the network 
             
             
                 
                 
                 
               element. 
             
             
               SNMP 
               v1 
               v1 
               The SNMP version used 
             
             
               Version 
               v2c 
                 
               to communicate with the 
             
             
                 
                 
                 
               Detected Network 
             
             
                 
                 
                 
               Element. 
             
             
               SNMP Read 
               N/A 
               “public” 
               The SNMP Read 
             
             
               Community 
                 
                 
               Community String. 
             
             
               String 
             
             
               SNMP 
               N/A 
               The SNMP 
               The SNMP Description 
             
             
               Description 
                 
               Description of 
               of the network element. 
             
             
                 
                 
               the device, 
             
             
                 
             
           
        
       
     
   
   The final second level command available under “Element” is “Delete”. Selecting the “Delete” command deletes the selected element. The “Delete” command is grayed out if no element or more than one element are selected. 
   The two final first level menu commands are “View” and “Help”. Selecting the “View” command displays a single second level command, “Refresh”, that causes the information displayed in the Auto Discovery Window to be updated. Selecting the “Help” first level command displays a help information, for example via a help page in a browser. 
     FIG. 6  is a schematic of an apparatus comprising an embodiment of the invention. The embodiment of  FIG. 6  comprises a central processing unit (CPU)  600 , a display device  650 , a keyboard  680  and a mouse or trackball  690 . CPU  600  may, for example, comprise a personal computer or computer workstation containing one or more processors that execute computer software program instructions. In the embodiment of  FIG. 6 , CPU  600  comprises computer program instructions for a network management system  610 , which comprise computer program instructions  620  for analyzing messages received by CPU  600  via network communications interface  630 , which connects CPU  600  to network  640 . 
   Display device  660 , which may, for example, comprise a CRT or LCD computer display device, comprises a display area  655  for displaying graphical and textual information to a user. Display area  655  may also comprise a touch screen or other mechanism for accepting input from a user. In the embodiment of  FIG. 6 , display area  655  is divided into two panes or windows  660  and  670 . In one embodiment, window  660  comprises a discovery range window in which network address ranges for discovering network devices can be specified by a user and are displayed, while window  670  comprises a discovered devices window in which discovered devices are displayed and from which a user can select one or more of the listed devices for management. Display device  660  together with keyboard  680  and mouse or trackball  690  form a user interface that provides information to and accepts information from a user. 
   Thus, a method and apparatus for automatic discovery of network devices with data forwarding capabilities has been presented. Although the invention has been described using certain specific examples, it will be apparent to those skilled in the art that the invention is not limited to these few examples. For example, although the invention has been described with respect to network devices having IP forwarding capabilities, the invention is applicable to network devices having forwarding capabilities using other protocols as well, as for example, Multiple Protocol Label Switching (“MPLS”). Other embodiments utilizing the inventive features of the invention will be apparent to those skilled in the art, and are encompassed herein.