Abstract:
A management system for use in a communication monitoring system, exchanging communication check information between external devices, and monitoring communication in the network, the management system including an information manager for managing topology information about each of a number of network apparatuses, representative information about a representative external device connected to a network apparatus connected to the management system, and adjacent information about one or more external devices adjacent to each of the external devices; and an information notifier for notifying each of the external devices of the topology information, the representative information, and the adjacent information supplied from the information manager.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-204614, filed on Aug. 7, 2008, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a communication monitoring method of monitoring network communication, a communication monitoring system, a management system, and an external device. 
         [0004]    2. Description of the Related Art 
         [0005]    To check end-to-end network communication, the network communication is monitored by use of a probe connected to an edge router at the border of the network. 
         [0006]      FIG. 1  illustrates a system configuration of one example of an existing communication monitoring system. In this drawing, edge routers  2   a  to  2   f  in a network  1  are connected to probes  3 a to  3 f, respectively. The edge router  2   a  is connected to an operation system (OPS)  4  managing the network  1 . 
         [0007]    The probe  3   a  connected to the edge router  2   a  checks communication with all of the other probes  3   b  to  3   f  through the network  1 . As a result of the checking, when detecting a communication break, the probe  3   a  notifies the operation system  4  of the communication break. The other probes  3   b  to  3   f  check communication in a similar way. When a communication break is detected, the communication break is notified to the operation system  4 . 
         [0008]    One example of a mechanism for consolidating the management of monitoring results is disclosed in Japanese Unexamined Patent Application Publication No. 2001-282761. With this mechanism, if a health check server and each terminal of a distributed system cannot communicate with one another and the management of health check results is unable to be consolidated, the health check server is changed. 
         [0009]    In the illustrated existing communication monitoring system, for example, if there is a failure in the path between the edge routers  2   c  and  2   a  being a notification path from the probe  3   c  to the operation system  4  and a communication break occurs between the probes  3   c  and  3   a,  the probe  3   c  cannot send a notification of confirmation of communication to the operation system  4 . 
         [0010]    In addition, because a notification to the operation system  4  employs a user datagram protocol (UDP) packet, the notification may be discarded and lost within the network  1 . One approach to addressing this is to employ a transmission control protocol (TCP) packet. With this approach, however, a retry repeatedly occurs when a communication break is present, and this results in a significant load on the network  1 . 
         [0011]    There are other possible approaches to addressing the above problems. For example, a network different from the network  1  may be constructed to be used for a communication path to the operation system  4 , or alternatively, the network  1  may be used in an in-band manner by employing a network routing technique. 
         [0012]    However, the construction of a different network significantly increases the cost of equipment, and this causes poor economics. With the in-band approach employing a routing technique, because an edge router performs routing for a notification as a result of checking communication, the edge router has an increased load. Additionally, to provide a notification as a result of checking communication in an in-band manner, a high-performance edge router capable of processing an increased amount of processing is necessary, and this leads to poor economics. Furthermore, if the edge router has a silent failure, such as one undetectable by the edge router, routing does not work and the operation system  4  cannot be notified of the communication break. 
         [0013]    The present invention is made to solve the above problems. It is an object of a communication monitoring system disclosed herein to provide a method and system of notifying a communication break in an in-band manner without causing poor economics. 
       SUMMARY 
       [0014]    A management system for use in a communication monitoring system, the communication monitoring system connecting each of a plurality of network apparatuses at a border of a network to an external device, connecting a predetermined network apparatus of the plurality of network apparatuses to a management system for the network, exchanging communication check information between the external devices, and monitoring communication in the network, the management system comprises: information managing means for managing topology information about each of the plurality of network apparatuses, representative information about a representative external device connected to a network apparatus connected to the management system, and adjacent information about one or more external devices adjacent to each of the external devices; and information notifying means for notifying each of the external devices of the topology information, the representative information, and the adjacent information supplied from the information managing means. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a system configuration of one example of an existing communication monitoring system; 
           [0016]      FIG. 2  is a system configuration of a communication monitoring system according to one embodiment; 
           [0017]      FIG. 3  is a functional diagram of an operation system according to one embodiment; 
           [0018]      FIG. 4  is a functional diagram of a probe according to one embodiment; 
           [0019]      FIG. 5  illustrates probe information that contains OPS information according to one embodiment; 
           [0020]      FIGS. 6A and 6B  illustrate a communication check request packet and a communication check reply packet, respectively, according to one embodiment; 
           [0021]      FIG. 7  illustrates one state of a communication check table; 
           [0022]      FIG. 8  is an illustration for use in describing a communication break; 
           [0023]      FIG. 9  illustrates another state of the communication check table; 
           [0024]      FIG. 10  illustrates a communication check notice packet according to one embodiment; 
           [0025]      FIG. 11  illustrates another communication check notice packet according to one embodiment; 
           [0026]      FIG. 12  illustrates a sequence of notifying probe information according to one embodiment; 
           [0027]      FIG. 13  illustrates a sequence of checking communication (OK) according to one embodiment; 
           [0028]      FIG. 14  illustrates a sequence of checking communication (NG) according to one embodiment; and 
           [0029]      FIG. 15  illustrates a sequence of checking communication (NG). 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    Embodiments are described below with reference to the drawings. 
       Summary of Embodiments 
       [0031]    The present embodiment has a configuration described below to allow an operation system to be notified of a communication break even if a notification path from a probe to the operation system is broken. Communication information between a representative probe connected to an edge node connected to the operation system and each of a number of probes is contained in a communication check request packet for each of the probes, and thus the probes share a path in which the probes and the edge node can communicate with each other. Each of the probes retains a communication status with the representative probe in its communication check table, and a notification of a communication break is sent and relayed using the communication check table. That is, (1) A probe adjacent to an operation system is set as a representative probe, and the operation system notifies probes of adjacent probe information; (2) Each of the probes checks communication with the representative probe and retains communication status; (3) A communication status between a probe and the representative probe is contained in a communication check request packet regularly exchanged between the probes, and the communication status is notified to one or more adjacent probes; and (4) In notifying the operation system of a communication break, if communication with the representative probe is in a broken state, the communication break is notified to the operation system via an adjacent probe. 
       &lt;Configuration of Communication Monitoring System&gt; 
       [0032]      FIG. 2  illustrates a system configuration of a communication monitoring system according to one embodiment. In this drawing, edge routers  12   a  to  12   f  in a network  11  are connected to probes  13   a  to  13   f,  respectively. The edge router  12   a  is connected to an operation system (OPS)  14  managing the network  11 . 
         [0033]    The probe  13   a  checks communication with all of the other probes  13   b  to  13   f  through the network  11 . When detecting a communication break, the probe  13   a  notifies it to the operation system  14 . Each of the other probes  13   b  to  13   f  checks communication in a similar way. When detecting a communication break, the probe detecting the communication break notifies it to the operation system  14 . 
         [0034]    The operation system  14  retains topology information indicating the connection relationship between network components (e.g., routers) included in the network  11  and also topology information indicating the connection relationship between probes. The operation system  14  has representative probe information and adjacent probe information about each of the probes. 
         [0035]    Information about the probe  13   a  connected to the edge router  12   a  connected to the operation system  14  (containing an IP address) is the representative probe information. Information about a second probe connected to a second edge router adjacent to a first edge router connected to a first probe (containing an IP address) is the adjacent probe information for the first probe. The IP address of the operation system is OPS information. 
       &lt;Configuration of Operation System&gt; 
       [0036]      FIG. 3  illustrates a functional diagram of the operation system  14  according to one embodiment. In this drawing, a topology management function  21  manages topology of probes. That is, the topology management function  21  stores in advance topology information about the probes  13   a  to  13   f  and the representative probe information and the adjacent probe information about each of the probes  13   a  to  13   f  in an internal memory  21   a.  The topology management function  21  notifies each of the probes  13   a  to  13   f  of probe information containing OPS information (topology information, representative probe information, and adjacent probe information). 
         [0037]    Information about the probe  13   a  connected to the edge router  12   a  connected to the operation system  14  (containing an IP address) is the representative probe information. Information about a second probe connected to a second edge router adjacent to a first edge router connected to a first probe (containing an IP address) is the adjacent probe information for the first probe. The IP address of the operation system is OPS information. 
         [0038]    A communication failure management function  22  manages communication failure information notified by the probes  13   a  to  13   f  and notifies it to a failure management function  25 . 
         [0039]    A transmission function  23  sends a packet of the probe information containing OPS information (topology information, representative probe information, and adjacent probe information) to each of the probes  13   a  to  13   f.    
         [0040]    A reception function  24  receives a packet of the communication failure information from each of the probes  13   a  to  13   f  and notifies it to the communication failure management function  22 . 
         [0041]    The failure management function  25  manages a failure occurring in the network  11  and shows a managed failure to an operator using, for example, a display and a printer. 
       &lt;Configuration of Probe&gt; 
       [0042]      FIG. 4  illustrates a functional diagram of a probe  13  having the same configuration as in the probes  13   a  to  13   f  according to one embodiment. 
         [0043]    In this drawing, a communication management function  31  generates a communication check request packet for probes in the network  11  managed by a probe management function  32 . The communication check request packet is sent to the probes by a transmission function  34 . The communication management function  31  checks a communication check reply packet received by a reception function  35  and stores it as communication check result information in a database (DB)  36 . When a communication check reply packet in response to the communication check request packet is not acquired in a predetermined period of time, the communication management function  31  detects a communication break and generates a communication check notice packet indicating a notification of the communication break. The communication check notice packet is sent to the operation system  14  by the transmission function  34 . 
         [0044]    The probe management function  32  stores probe information containing OPS information notified by the operation system  14  in a communication check table  36   a  of the database  36 . 
         [0045]    When receiving a communication check notice packet, a relay function  33  generates a communication check notice packet to be sent to the operation system  14 , and the communication check notice packet is sent to the operation system  14  by the transmission function  34 . 
         [0046]    The transmission function  34  sends a communication check request packet and a communication check notice packet. 
         [0047]    The reception function  35  receives a communication check request packet or a packet of probe information containing OPS information and checks the type of a received packet. When the packet is a communication check reply (Type=Reply), the reception function  35  notifies the communication management function  31 . When the packet is a communication check notice (Type=Notice), the reception function  35  notifies the relay function  33 . In the case of probe information, the reception function  35  notifies the probe management function  32 . 
       &lt;Notification of Probe Information&gt; 
       [0048]      FIG. 5  illustrates probe information containing OPS information according to one embodiment. The probe information is transmitted from the operation system  14  to all of the probes  13   a  to  13   f  as indicated by the arrows illustrated in  FIG. 2  for example, upon start-up of the communication monitoring system. The probe information is set in the communication check table  36   a  in the database  36  of each of the probes  13   a  to  13   f.    
         [0049]    In  FIG. 5 , the OPS information indicates the IP address of the operation system  14 . In the communication check target probe information, for a probe (e.g.,  13   a ) among all of the probes  13   a  to  13   f  connected to the network, the IP address and the property of each of the other probes (e.g.,  13   b  to  13   f ) are set. The property “R” represents a representative probe. The property “N” represents an adjacent probe, and the number subsequent to “N” represents the priority. The smaller the number, the higher the priority. 
       &lt;Communication Check&gt; 
       [0050]    After probe information containing OPS information supplied from the operation system  14  is set in the communication check table  36   a,  each of the probes  13   a  to  13   f  sends a communication check request packet to all of the probes indicated in the communication check target probe information in the communication check table  36   a  and receives a communication check reply packet in response to the request. 
         [0051]      FIGS. 6A and 6B  illustrate a communication check request packet and a communication check reply packet, respectively, according to one embodiment. 
         [0052]    In the communication check request packet illustrated in  FIG. 6A , the source address (SA), destination address (DA), type (Type=Request), code, checksum, and communication status between a probe and the representative probe are set. 
         [0053]    In the communication check reply packet illustrated in  FIG. 6B , the source address (SA), destination address (DA), type (Type=Reply), code, checksum, and message (communication status) are set. 
         [0054]    Each of the probes stores the communication status between the probe and the representative probe set in the communication check request packet received from an adjacent probe in the status to representative probe field in the communication check table  36   a  illustrated in  FIG. 7 . For a probe (sender) from which the communication check reply packet is received, “OK” is stored in the communication field in the communication check table  36   a  illustrated in  FIG. 7 . 
         [0055]      FIG. 7  illustrates one example state of the communication check table  36   a  of the probe  13   c  after the probe  13   c  transmits and receives communication check request packets. The table includes the IP address field, the communication field, the property field, and the status to representative probe field with respect to the operation system  14  (OPS information) and with respect to the probes  13   a,    13   b,  and  13   d  to  13   f  (communication check target probe information), which are the probes other than the probe  13   c.    
         [0056]    In  FIG. 7 , the communication check reply packets are received from all of the probes  13   a,    13   b,  and  13   d  to  13   f  other than the probe  13   c,  and thus all of the communication fields thereof indicates “OK.” The adjacent probes  13   d,    13   e,  and  13   f  can communicate with the representative probe, and the status to representative probe fields thereof indicate “OK.” 
         [0057]    Here, as illustrated in  FIG. 8 , when a communication break occurs between the edge routers  12   a  and  12   c,  the communication check table  36   a  of the probe  13   c  detecting the communication break is illustrated in  FIG. 9 . In  FIG. 9 , the communication field corresponding to the probe  13   a  (representative probe) indicates “NG”, which represents the occurrence of a communication break. 
         [0058]    The probe  13   c  detecting the communication break with respect to the representative probe sends the communication check notice packet illustrated in  FIG. 10  to the probe  13   d.  The probe  13   d  has the highest priority among the adjacent probes having “OK” in the status to representative probe field in the communication check table  36   a.    
         [0059]    In the communication check notice packet illustrated in  FIG. 10 , the source address (SA), destination address (DA), type (Type=Notice), code, checksum, communication source probe address, and communication destination probe address are set. Here, the source address (SA) is the address of the probe  13   c  detecting the communication break, and the destination address (DA) is the address of the adjacent probe  13   d.  The communication source probe address is the address of the probe  13   c,  and the communication destination probe address is the address of the probe  13   a.    
         [0060]    When receiving the above-described communication check notice packet illustrated in  FIG. 10 , the probe (adjacent probe)  13   d  converts the communication check notice packet illustrated in  FIG. 10  into the communication check notice packet illustrated in  FIG. 11  using the relay function  33  and sends it to the operation system  14 . 
         [0061]    In  FIG. 11 , the source address (SA) is the address of the probe (adjacent probe)  13   d,  and the destination address (DA) is the address of the operation system  14 . The settings of the type (Type=Notice), code, checksum, communication source probe address, and communication destination probe address are the same as in  FIG. 10 . 
       &lt;Sequence of Notifying Probe Information&gt; 
       [0062]      FIG. 12  illustrates a sequence of notifying probe information. In this drawing, in step S 1 , the topology management function  21  reads the representative probe information, adjacent probe information, and OPS information with respect to a probe and supplies the read information to the transmission function  23 . In step S 2 , the transmission function  23  generates a packet of the above probe information containing the OPS information and sends it to the relevant probe (e.g.,  13   f ). 
         [0063]    In step S 3 , the reception function  35  of the destination probe  13   f  receives the packet of the probe information containing the OPS information and notifies the probe management function  32 . In step S 4 , the probe management function  32  stores the probe information containing the OPS information in the communication check table  36   a  of the database  36 . 
       &lt;Sequence of Checking Communication&gt; 
       [0064]      FIG. 13  illustrates a sequence of checking communication (OK) according to one embodiment. 
         [0065]    In this drawing, in step S 11 , the communication management function  31  of, for example, the probe  13   c  generates a communication check request packet for, for example, the probe  13   b  managed by the probe management function  32  and notifies the transmission function  34 . In step S 12 , the transmission function  34  sends the communication check request packet to that probe. 
         [0066]    In step S 13 , the reception function  35  of the destination probe  13   b  receives the communication check request packet and notifies the communication management function  31 . In step S 14 , the communication management function  31  stores the communication status between itself (the probe  13   b ) and the representative probe or probe  13   c  in the status to representative probe field in the communication check table  36   a.    
         [0067]    In step S 15 , the communication management function  31  generates a communication check reply packet to be sent in response to the communication check request packet and notifies the transmission function  34 . In step S 16 , the transmission function  34  sends the communication check reply packet to the probe  13   c,  which is the return destination. 
         [0068]    In step S 17 , the reception function  35  of the return-destination probe  13   c  receives the communication check reply packet and notifies the communication management function  31 . In step S 18 , the communication management function  31  stores “OK” in the communication field corresponding to the probe being the sender of the received communication check reply packet in the communication check table  36   a.    
         [0069]      FIGS. 14 and 15  illustrate a sequence of checking communication (NG) according to one embodiment. 
         [0070]    In  FIG. 14 , in step S 21 , the communication management function  31  of, for example, the probe  13   c  generates a communication check request packet for, for example, the probe  13   b  managed by the probe management function  32  and notifies the transmission function  34 . In step S 22 , the transmission function  34  sends the communication check request packet to that probe. 
         [0071]    If communication between the edge routers  12   c  and  12   b  in the network  11  is broken, and a communication check reply packet is not received from the probe  13   b  to the probe  13   c  even after a predetermined period of time has passed after the transmission of the communication check request packet from the probe  13   c  toward the probe  13   b,  in step S 24 , the communication management function  31  of the probe  13   c  stores “NG” in the communication field corresponding to the probe  13   b,  to which the communication check request packet has been sent, in the communication check table  36   a.    
         [0072]    In step S 25 , the communication management function  31  refers to the communication field corresponding to the representative probe  13   a  having the property “R” in the communication check table  36   a  to check the status of the communication with the representative probe  13   a.  After that, in step S 26 , the communication management function  31  determines whether the status of the communication with the representative probe  13   a  is “OK.” When it is “OK,” in step S 27 , the communication management function  31  generates the communication check notice packet illustrated in  FIG. 11  and notifies the transmission function  34 . In step S 28 , the transmission function  34  sends the communication check notice packet to the operation system  14 . 
         [0073]    In step S 29 , the reception function  24  of the operation system  14  receives the communication check notice packet and notifies the communication failure management function  22 . 
         [0074]    In step S 26 , when the status of the communication with the representative probe  13   a  is “NG,” the processing proceeds to step S 30  illustrated in  FIG. 15 . In step S 30 , the communication management function  31  refers to the status to representative probe field in the communication check table  36   a  and checks the status to the representative probe with respect to the adjacent probes. 
         [0075]    Then, in step S 31 , the communication management function  31  generates the communication check notice packet illustrated in  FIG. 10  for the probe  13   d  having the highest priority among the adjacent probes having “OK” in the status to representative probe field in the communication check table  36   a  and notifies the transmission function  34 . In step S 32 , the transmission function  34  sends the communication check notice packet to the adjacent probe  13   d.    
         [0076]    In step S 33 , the reception function  35  of the probe  13   d  receives the above communication check notice packet and notifies the relay function  33 . In step S 34 , the relay function  33  converts the communication check notice packet illustrated in  FIG. 10  into the communication check notice packet illustrated in  FIG. 11  and sends it to the operation system  14 . 
         [0077]    In step S 35 , the reception function  24  of the operation system  14  receives the communication check notice packet and notifies the communication failure management function  22 . 
         [0078]    With the above embodiment, the communication status between the probes can be reliably notified to the operation system without use of an advanced routing technology in a network. This facilitates the introduction of the communication monitoring system. In addition, the use of the in-band system, which does not require an advanced routing technology, eliminates the necessity of investment in a network. 
         [0079]    A communication break caused by a silent failure, which is undetectable by an edge router itself, can also be identified by exchange of a communication check request packet and a communication check reply packet. Accordingly, even if a silent failure occurs, a path that connection is confirmed can be selected. Even when a probe notifies the operation system of the communication break using a TCP packet, resending does not occur, and it can prevent an excessive load on the network.