AU781354B2 - SNMP network management system and management method thereof - Google Patents

Description

S&FRef: 533546

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: NEC Corporation 7-1, Shiba Minato-ku Tokyo Japan Yasushi Higuchi Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 SNMP Network Management System and Management Method Thereof The following statement is a full description of this invention, including the best method of performing it known to me/us:- W- 1 Austraia Docurnens received o:

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1F- -12 Batch No: 5845c 1 SNMP NETWORK MANAGEMENT SYSTEM AND MANAGEMENT METHOD

THEREOF

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to an SNMP network management system for conducting network management using an SNMP (Simple Network Management Protocol) and, more particularly, to an SNMP network management system for conducting management regarding a Trap which is transmitted from an SNMP agent to an SNMP manager and a management method thereof.

DESCRIPTION OF THE RELATED ART .ii :In a conventional SNMP network management system of this kind, there exists on an SNMP manager no mechanism for determining whether all Traps transmitted from an SNMP agent to an SNMP manager are received or not.

The above-described conventional network management system has the following problems.

oeeeo First, since there exists on an SNMP manager no 0:00.: mechanism for determining whether all the Traps are received or not as described above, Traps failing to reach the SNMP manager are abandoned.

Under these circumstances, as a method of restoring a discrepancy in a state between an SNMP manager and an SNMP agent caused by Trap omission 2 (phenomenon that a Trap transmitted from an SNMP agent fails to reach an SNMP manager), there is a technique of making a Get Request to all the SNMP agents with respect to all MIB (Management Information Base) objects.

Such a conventional technique, however, has a shortcoming that the higher the number of SNMP agents or MIB objects is, the more the time is required for making the state of the SNMP manager and that of the SNMP agent coincide with each other.

Conventional techniques of conducting retransmission of a Trap in order to cope with a Trap omission disclosed in Patent official Gazettes include that of Japanese Patent Laying-Open (Kokai) No. Heisei 9-101929 and that of Japanese Patent Laying-Open (Kokai) 15 No. heisei 11-177552.

Although both of the techniques recited in the Gazettes ("Trap Transmission Device" and "TRAP Management Method and Device Using SNMP") are analogous to the present invention, they are clearly different from the present invention having a structure enabling a plurality of successive Trap omissions to be appropriately handled in that they fail to cope with a plurality of successive Trap omissions (differs from the present invention also in a manner of realizing retransmission of a Trap). Therefore, neither the relevant conventional techniques nor combinations thereof can obtain the present invention.

3 Taking the above-described problems into consideration, a need exists to provide an SNMP network management system capable of reliably preventing a Trap omission (also appropriately coping with a plurality of successive Trap omissions) by determining existence/non-existence of a Trap omission to conduct retransmission of Traps failing to reach an SNMP manager and a management method thereof.

SUMMARY

According to the first aspect of the invention, an SNMP network management system for conducting management of a network using an SNMP comprises an SNMP protocol processing unit in an SNMP agent 15 for receiving a Get Request/Set Request from an SNMP manager and responding to the Get Request/Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing unit in the 20 SNMP agent for, when a Set Request received by the SNMP protocol processing unit in the SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing unit in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, 4 an SNMP protocol processing unit in the SNMP manager for, when receiving either a Trap or a Get Response having a Trap Current Number from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question/the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing unit in the SNMP manager for, when a Trap omission is detected by the SNMP protocol processing unit in the SNMP manager, referring to data relating to items to be managed for the SMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting the SNMP protocol processing unit in the SNMP manager to transmit the Set Request.

In the preferred construction, the SNMP network management system further comprises an item to be managed data storage unit in the SNMP agent for storing data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP agent, a Trap retransmission log data storage unit in the SNMP agent for storing Trap retransmission log data 5 preserved for retransmitting a Trap which has been transmitted to the SNMP manager, and an item to be managed data storage unit in the SNMP manager for storing, with respect to each SNMP agent, data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP manager.

In another preferred construction, the SNMP protocol processing unit in the SNMP agent includes an SNMP Get Request/Set Request reception unit for receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation unit responsive to a Get Request requesting a state value of a Trap Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission unit for transmitting a Get Response generated by the SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation unit for generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing 6 unit based on Trap retransmission log data, and an SNMP Trap transmission unit for transmitting a Trap generated by the SNMP Trap generation unit to the SNMP manager.

In another preferred construction, the SNMP protocol processing unit in the SNMP manager includes an SNMP Get Request/Set Request transmission unit for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception unit for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis unit for, when a Get Response having a Trap Current Number from an SNMP agent is received by the SNMP Get Response reception unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state e: value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the 20 comparison, recognizing "generation of Trap omission", an SNMP Trap reception unit for receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis unit for, when a Trap from an SNMP agent is received by the SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in 7 data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission".

In another preferred construction, the SNMP protocol processing unit in the SNMP agent includes an SNMP Get Request/Set Request reception unit for receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation unit responsive to a Get Request requesting a state value of a Trap Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission unit for transmitting a Get Response generated by the SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation unit for generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing unit based on Trap retransmission log data, and an SNMP Trap transmission unit for transmitting a Trap generated by the SNMP Trap generation unit to the .o o oooo 20 ooo2 8 SNMP manager, and the SNMP protocol processing unit in the SNMP manager includes: an SNMP Get Request/Set Request transmission unit for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception unit for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis unit for, when a Get Response having a Trap Current Number from an SNMP i agent is received by the SNMP Get Response reception unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP i manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception unit for receiving a Trap transmitted from the SNMP agent, and 20 an SNMP Trap analysis unit for, when a Trap from an SNMP agent is received by the SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of 9-

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According to the second aspect of the invention, an SNMP network management system for conducting management of a network using an SNMP comprises an SNMP protocol processing unit in an SNMP agent for receiving a Set Request from an SNMP manager and responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing unit in the SNMP agent for, when a Set Request received by the SNMP protocol processing unit in the SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing unit in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing unit in the SNMP manager for, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing unit in the SNMP manager for, when a Trap omission is detected by the SNMP protocol processing unit in the SNMP manager, 0*

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10 referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting the SNMP protocol processing unit in the SNMP manager to transmit the Set Request.

In the preferred construction, the SNMP network management system further comprises an <item to be managed data storage unit in the SNMP agent for storing data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP agent, a Trap retransmission log data storage unit in 15 the SNMP agent for storing Trap retransmission log data preserved for retransmitting a Trap which has been transmitted to the SNMP manager, and an item to be managed data storage unit in the SNMP manager for storing, with respect to each SNMP agent, data 20 relating to items, to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP manager.

According to the third aspect of the invention, an SNMP network management method of conducting management of a network using an SNMP comprises an SNMP protocol processing step of receiving a Get Request/Set Request from an SNMP manager and 11 responding to the Get Request/Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing step of, when a Set Request received by the SNMP protocol processing step in an SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing step in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing step of, when receiving either a Trap or a Get Response having a Trap Current Number from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question/the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing step in the SNMP manager of, when a Trap omission is detected by the SNMP protocol processing step in the SNMP manager, referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting the SNMP e o 2 oo oo 2 oeoo oo oo 12 protocol processing step in the SNMP manager to transmit the Set Request.

In the preferred construction,the SNMP protocol processing step in a program for the SNMP agent includes an SNMP Get Request/Set Request reception step of receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation step of, in response to a Get Request requesting a state value of a Trap Current Number from the SNMP manager, generating a Get Response having the Trap Current Number and in response to a Set Request requesting Trap retransmission from the SNMP manager, generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission step of transmitting a Get Response generated by the SNMP Get Response generation step to the SNMP manager, an SNMP Trap generation step of generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing step based on Trap retransmission log data, and an SNMP Trap transmission step of transmitting a Trap generated by the SNMP Trap generation step to the SNMP manager.

In another preferred construction, the SNMP 13 protocol processing step in a program for the SNMP manager includes an SNMP Get Request/Set Request transmission step of transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception unit for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis step of, when a Get Response having a Trap Current Number from an SNMP agent is received by the SNMP Get Response reception step, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within an item to be managed data storage unit in the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception step of receiving a Trap transmitted from the SNMP agent, and 20 an SNMP Trap analysis step of, when a Trap from an SNMP agent is received by the SNMP Trap reception step, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of 14 Trap omission".

In another preferred construction, the SNMP protocol processing step in a program for the SNMP agent includes an SNMP Get Request/Set Request reception step of receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation step of, in response to a Get Request requesting a state value of a Trap Current Number from the SNMP manager, generating a Get Response having the Trap Current Number and in response to a Set Request requesting Trap retransmission from the SNMP manager, generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission step of •transmitting a Get Response generated by the SNMP Get Response generation step to the SNMP manager, S.an SNMP Trap generation step of generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing step based on Trap retransmission log data, and an SNMP Trap transmission step of transmitting a Trap generated by the SNMP Trap generation step to the SNMP manager, and the SNMP protocol processing step in a program 15 for the SNMP manager includes: an SNMP Get Request/Set Request transmission step of transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception step of receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis step of, when a Get Response having a Trap Current Number from an SNMP agent is received by the SNMP Get Response reception step, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception step of receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis step of, when a Trap from an SNMP agent is received by the SNMP Trap reception 20 step, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission" According to the fourth aspect of the invention, 16 an SNMP network management method of conducting management of a network using an SNMP comprises an SNMP protocol processing step in an SNMP agent of receiving a Set Request from an SNMP manager and responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing step in the SNMP agent of, when a Set Request received by the SNMP protocol processing step in the SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing unit in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing step of, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing step of, when a Trap omission is detected by the SNMP protocol processing step in the SNMP manager, referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a S* 20 o 2 17 0 0 0 0* start number and an end number of a Trap group whose retransmission is to be requested for the Trap in question and requesting the SNMP'protocol processing unit in the SNMP manager to transmit the Set Request.

According to another aspect of the invention, a computer readable memory storing an SNMP network management program for controlling a computer to conduct management of a network using an SNMP, the SNMP network management program comprising computer program code for an SNMP protocol processing function for receiving a Get Request/Set Request from an SNMP manager and responding to the Get Request/Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing function for, when a Set Request received by the SNMP protocol processing function in an SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing function in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing function for, when receiving either a Trap or a Get Response having a Trap Current Number from the SNMP agent, detecting a Trap omission based on a comparison between a state value of 00 0 0 00 ooo 0000 *o o o 0 00 20 eeoc 0 0 0 2 0 00 0 0000 18 the Trap Current Number designated by the Trap in question/the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing function in the SNMP manager for, when a Trap omission is detected by the SNMP protocol processing function in the SNMP manager, referring to data relating to items to be managed for the SMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting the SNMP protocol processing function in the SNMP manager to transmit the Set Request.

15 According to another aspect of the invention, a computer readable memory storing an SNMP network management program for controlling a computer to conduct management of a network using an SNMP, the SNMP network management program comprising S 20 computer program code for S.an SNMP protocol processing function in an SNMP agent for receiving a Set Request from an SNMP manager and responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing unit in the SNMP agent for, when a Set Request received by the SNMP protocol processing function in the SNMP agent relates to a 19 Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing the SNMP protocol processing function in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing function for, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing function for, 15 when a Trap omission is detected by the SNMP protocol processing function in the SNMP manager, referring to data relating to items to be managed for the SNMP agent in question within 0* the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose .e 20 retransmission is to be requested for the Trap omission in question and requesting the SNMP protocol processing function in the SNMP manager to transmit the Set Request.

Other features and advantages of the present invention will become clear from the detailed description given herebelow.

BRIEF DESCRTPTTON OF THE DRAWTNrS 20 The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only.

In the drawings: Fig. 1 is a block diagram showing a structure of an SNMP network management system according to a first embodiment of the present invention; Fig. 2 is a flow chart showing processing of "operation related to detection of a Trap omission and Trap retransmission based on a Get Response" in the SNMP network management system shown in Fig. 1; 15 Fig. 3 is a flow chart showing processing of "operation related to detection of a Trap omission and •Trap retransmission based on Trap reception" in the SNMP network management system shown in Fig. 1; Fig. 4 is a diagram showing a specific example of an MIB defined and used in the SNMP network management system shown in Fig. 1; Fig. 5 is a diagram showing a specific example of data of an item to be managed in an item to be managed data storage unit of an SNMP agent in Fig. 1; Fig. 6 is a diagram showing a specific example of Trap retransmission log data in a Trap retransmission log data storage unit of the SNMP agent in Fig. 1; 21 Fig. 7 is a sequence diagram for use in explaining specific operation of the SNMP network management system illustrated in Fig. 1 (sequence diagram showing Get Request/Get Response transmission and reception processing between the SNMP manager and each SNMP agent); Fig. 8 is a sequence diagram for use in explaining specific operation of the SNMP network management system illustrated in Fig. 1 (sequence diagram showing processing of detecting one Trap omission and conducting retransmission of the Trap in response to a Get Response); Fig. 9 is a sequence diagram for use in explaining specific operation of the SNMP network S 15 management system illustrated in Fig. 1 (sequence diagram showing processing of detecting a plurality of Trap omissions and conducting retransmission of a group of Traps based on a Get Response); Fig. 10 is a sequence diagram for use in explaining specific operation of the SNMP network management system illustrated in Fig. 1 (sequence diagram showing processing of detecting one Trap omission and conducting retransmission of the Trap in response to Trap reception); Fig. 11 is a sequence diagram for use in explaining specific operation of the SNMP network management system illustrated in Fig. 1 (sequence 22 diagram showing processing of detecting a plurality of Trap omissions and conducting retransmission of a group of Traps in response to Trap reception); Fig. 12 is a block diagram showing a structure of an SNMP network management system according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the present invention will be discussed hereinafter in detail with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled 15 in the art that the present invention may be practiced without these specific details. In other instance, wellknown structures are not shown in detail in order to unnecessary obscure the present invention.

(1)First Embodiment Fig. 1 is a block diagram showing a structure of an SNMP network management system according to the first embodiment of the present invention.

With reference to Fig. 1, the network management system according to the present embodiment includes an SNMP manager 1 and an arbitrary number, at least one, of SNMP agent 2 connected by a WAN (Wide Area Network) or a LAN (Local Area Network).

23 The SNMP manager 1 includes an SNMP protocol processing unit 11, a message request processing unit 12 for conducting processing of requesting transmission of a message (Get Request and Set Request), a Trap retransmission request processing unit 13 included in the message request processing unit 12 for conducting processing of requesting retransmission of a Trap, an item to be managed data storage unit 14 for storing, with respect to each SNMP agent 2, data of an item to be managed which holds state values (one of which is a state value of Trap Current Number) of an item to be managed of an MIB object as internal storage data of the SNMP manager i, and a Trap accumulation data storage unit 15 for accumulating a Trap received from each SNMP *i 15 agent 2 for each SNMP agent 2.

*The SNMP protocol processing unit 11 includes an SNMP Get Request/Set Request transmission unit 111 for *ee.e* transmitting a Get Request/Set Request to the SNMP agent S. 2, an SNMP Get Response reception unit 112 for receiving a Get Response from the SNMP agent 2, an SNMP Get Response analysis unit 113 for analyzing a Get Response received by the SNMP Get Response reception unit 112, an SNMP Trap reception unit 114 for receiving a Trap from the SNMP agent 2, and an SNMP Trap analysis unit 115 for analyzing a Trap received by the SNMP Trap reception unit 114.

The SNMP agent 2 includes an SNMP protocol 24 0 0 0 0 *0 processing unit 21, a Set Request analysis processing unit 22 for analyzing the contents of a Set Request received from the SNMP manager 1, an item to be managed data storage unit 23 for storing data relating to items to be managed which holds state values (one of which is a state value of Trap current number) of an item to be managed of an MIB object as internal storage data of the SNMP agent 2, and a Trap retransmission log data storage unit 24 for storing log data of a Trap (Trap retransmission log data) preserved for conducting retransmission of a Trap sent to the SNMP manager 1.

The SNMP protocol processing unit 21 includes an SNMP Get Request/Set Request reception unit 211 for receiving a Get Request/Set Request from the SNMP manager 1, an SNMP Get Response generation unit 212 for generating a Get Response for responding to a Get Request/Set Request received by the SNMP Get Request/Set Request reception unit 211, an SNMP Get Response transmission unit 213 for transmitting a Get Response generated by the SNMP Get Response generation unit 212 to the SNMP manager 1, an SNMP Trap generation unit 214 for generating a Trap (including a Trap to be retransmitted) and an SNMP Trap transmission unit 215 for transmitting a Trap generated by the SNMP Trap generation unit 214 to the SNMP manager 1.

Fig. 2 is a flow chart showing processing related to detection of a Trap omission and Trap retransmission o0 0 0 0 0.00 0 0* 0 20 0000 00 00 *.0o 0 0 0 0000 25 based on a Get Response in the SNMP network management system according to the present embodiment. The processing is composed of the Get Request transmission step S201, the Get Request reception step S202, the Get Request recognition step S203, the Get Response generation step S204, the Get Response transmission step S205, the Get Response reception step S206, the Trap omission generation/non-generation determination step S207, the Trap retransmission request processing unit notification step S208, the Set Request generation step S209, the Set Request transmission step S210, the Set Request reception step S211, the Set Request recognition step S212, the retransmission target Trap group start number/end number obtaining step S213, the Get Response 15 generation instructing step S214, the Get Response go p.

generation step S215, the Get Response transmission step S216, the retransmission target Trap group generation requesting step S217, the retransmission target Trap group generation step S218, the retransmission target S 20 Trap group transmission step S219, the retransmission target Trap group reception step S220 and the Trap I Current Number state value updating step S221.

Fig. 3 is a flow chart showing processing related 0000 to detection of a Trap omission and Trap retransmission based on Trap reception in the SNMP network management system according to the present embodiment. The processing is composed of the Trap reception step S301, 26 the Trap omission generation/non-generation determination step S302, the Trap retransmission request processing unit notification step S303, the Set Request generation step S304, the Set Request transmission step S305 and the same processing as that of Steps S211 to S221 in Fig. 2.

Fig. 4 is a diagram showing a specific example of an MIB defined and used in the SNMP network management system according to the present embodiment.

The MIB objects include a Trap Current Number object which is an object representing the number of accumulated Traps (in some cases, indicated as trap or TRAP) transmitted by the SNMP agent 2, a Trap Request Start No. object which is an object representing the e g 15 start number of a Trap group to be retransmitted (the number of the leading Trap of the Trap group in question), a Trap Request End No. object which is an object representing the end number of a Trap group to be retransmitted (the number of the last Trap of the Trap "0 0 0 20 group in question), a Trap Number object which is a target object to which a value of a Trap Current Number

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O: is set in a Trap (Trap PDU) and a Trap Time Stamp object which is an object representing a time of transmission of a Trap by the SNMP agent 2.

As a Trap defined by this MIB, there are an alarm Activated Trap (Trap having as the Specific Trap Number) to be transmitted when a failure occurs and an 27 alarm Recovered Trap (Trap having as the Specific Trap Number) to be transmitted when a failure is recovered.

The item to be managed data storage unit 14 in the SNMP manager 1 and the item to be managed data storage unit 23 in the SNMP agent 2 have data relating to items to be managed based on such an MIB described above.

The Trap accumulation data storage unit 15 in the SNMP manager 1 and the Trap retransmission log data storage unit 24 in the SNMP agent 2 hold data of a Trap defined by such an MIB as described above.

Fig. 5 is a diagram showing a specific example of item to be managed data in the item to be managed data storage unit 23.

The data relating to items to be managed has, for each object defined by the above-described MIB, an object name (Object Name), an object identifier (Object ID (Identification)) and a state value (Value).

Fig. 6 is a diagram showing a specific example of 20 Trap retransmission log data in the Trap retransmission S" log data storage unit 24.

The Trap retransmission log data has Index, Specific Trap Number, Trap Number and Trap Time Stamp (m and n in Fig. 6 are positive integers).

Figs. 7 to 11 are sequence diagrams for use in explaining specific operation of the SNMP network management system according to the present embodiment.

28 Next, with reference to Figs. 1 to 11, operation of thus structured SNMP network management system according to the present embodiment will be described in detail.

First, description will be made of operation related to detection (sensing) of a Trap omission and Trap retransmission based on a Get Response (See Fig. 2).

As illustrated in Fig. 7, from the SNMP manager 1 to each SNMP agent 2 (in Fig. 7, each of SNMP agents 2 to N denotes a positive integer), a Get Request for obtaining a state value (Value) of the Trap Current Number object is sequentially and periodically transmitted (the SNMP manager 1 transmits a Get Request for the Trap Current Number object of the SNMP agent 2 15 at fixed intervals to conduct polling).

05 More specifically, the SNMP Get Request/Set Request transmission unit 111 in the SNMP protocol processing unit 11 within the SNMP manager 1 periodically transmits a Get Request for the Trap *055 *500 20 Current Number object to each SNMP agent 2 based on a request from the message request processing unit 12 (Step S201).

The SNMP Get Request/Set Request reception unit *050 0 211 in the SNMP protocol processing unit 21 within the SNMP agent 2 receives the Get Request transmitted from the SNMP manager 1 (Step S202).

Upon recognizing that the message received at 29 Step S202 is a Get Request (Step S203), the SNMP Get Request/Set Request reception unit 211 transfers the Get Request to the SNMP Get Response'generation unit 212.

The SNMP Get Response generation unit 212 searches the data relating to items to be managed in the item to be managed data storage unit 23 for an entry having an Object ID designated by the Get Request in question and obtains a Value (state value) corresponding to the relevant Object ID to generate a Get Response having the state value (Step S204). Then, the unit 212 transfers the Get Response to the SNMP Get Response transmission unit 213.

The SNMP Get Response transmission unit 213 transmits the Get Response (Get Response having the 15 state value of the Trap Current Number) to the SNMP manager 1 (Step S205).

The SNMP Get Response reception unit 112 in the SNMP protocol processing unit 11 within the SNMP manager 1 receives the Get Response in question transmitted from 20 the SNMP agent 2 (Step S206) and transfers the Get Response in question to the SNMP Get Response analysis unit 113.

The SNMP Get Response analysis unit 113 refers to the item to be managed data storage unit 14 to determine whether a Trap omission occurs or not. More specifically, the unit 113 compares a state vale of the Trap Current Number in the item to be managed data for the relevant 30 SNMP agent 2 (the SNMP agent 2 as a transmission source of the Get Response in question) at the item to be managed data storage unit 14 and a state value of the Trap Current Number in the Get Response in question to determine whether the values coincide with each other (Step S207).

When determining by the comparison at Step S207 that "the values fail to coincide with each other (Trap omission occurs)", the SNMP Get Response analysis unit 113 notifies the Trap retransmission request processing unit 13 to that effect (Step S208). When the determination is made at Step 207 that "the values coincide", none of the processing for Trap retransmission at Step S208 and the following Steps will 15 be conducted.

Upon recognizing by the notification at Step 208 that the SNMP manager 1 and the relevant SNMP agent 2 oeooo differ in the Trap Current Number, the Trap retransmission request processing unit 13 generates a Set Request in a manner as shown in the following a) to c) (Step S209) and transfers the Set Request to the SNMP eeeee S"Get Request/Set Request transmission unit 111 in the SNMP protocol processing unit 11.

a) To set, at the Trap Request Start No., a value obtained by adding 1 to a state value of the Trap Current Number held within the SNMP manager 1 (within the item to be managed data for the relevant SNMP agent 31 2 in the item to be managed data storage unit 14) (information designating a start number of a Trap group to be retransmitted).

b) To set, at the Trap Request End No., a state value of the Trap Current Number in the Get Response from which "disagreement in a state value" is detected at Step S207 (information designating the end number of a Trap group to be retransmitted).

c) To generate a Set Request having the information indicated in a) and b) being set.

The SNMP Get Request/Set Request transmission unit 111 transmits the Set Request in question to each SNMP agent 2 (Step 210).

The SNMP agent 2 having received the Set Request .i 15 addressed to itself retransmits a Trap group having the Trap Number designated by the Set Request (a group of Traps having Trap Numbers starting with the Trap Request Start No. and ending with the Trap Request End No.) to the SNMP manager i.

At this time, the SNMP Get Request/Set Request reception unit 211 in the SNMP protocol processing unit 21 within the SNMP agent 2 in question receives the Set Request transmitted from the SNMP manager 1 (Step S211).

Upon recognizing that the received message is a Set Request (Step S212), the SNMP Get Request/Set Request reception unit 211 transfers the Set Request to the Set Request analysis processing unit 22.

32 The Set Request analysis processing unit 22 takes out a start number and an end number of a Trap group to be retransmitted from the Set Request in question (Step S213).

After obtaining the start number and the end number, the Set Request analysis processing unit 22 instructs the SNMP Get Response generation unit 212 in the SNMP protocol processing unit 21 to generate a Get Response to the Set Request in question because the contents of the Set Request in question are analyzed (Step S214).

The SNMP Get Response generation unit 212 generates a Get Response to the Set Request in question (Step S215) and transfers the Get Response to the SNMP .i 15 Get Response transmission unit 213.

The SNMP Get Response transmission unit 213 transmits the Get Response generated at Step S215 to the SNMP manager 1 (Step S216).

On the other hand, when the start number and the 20 end number of the Trap group to be retransmitted are analyzed at Step S213, the Set Request analysis S"processing unit 22 requests the SNMP Trap generation unit 214 in the SNMP protocol processing unit 21 to generate a Trap group to be retransmitted (Step S217).

The SNMP Trap generation unit 214 extracts a relevant Trap Number (Trap Number corresponding to a Trap number between the start number and the end number 33 analyzed by the Set Request analysis processing unit 22) from the Trap retransmission log data storage unit 24 to generate a Trap group (Trap group to be retransmitted) having the relevant Trap Number (Step S218).

The SNMP Trap transmission unit 215 sequentially transmits each Trap group in question to be retransmitted to the SNMP manager 1 (Step S219).

The SNMP Trap reception unit 114 in the SNMP protocol processing unit 11 within the SNMP manager 1 receives each retransmitted Trap (Step S220) to notify the SNMP Trap analysis unit 115 of the Trap in question.

Based on the Trap Number designated by the Trap in question, the SNMP Trap analysis unit 115 updates a state value of a Trap Current Number in the item to be i 15 managed data for the relevant SNMP agent 2 (the SNMP agent 2 as a transmission source of the Trap in question) at the item to be managed data storage unit 14 (Step S221). In addition, the SNMP Trap analysis unit 115 accumulates a Trap group to be retransmitted in S 20 question in the Trap accumulation data storage unit The processing at Steps 214 to S216 and the 9000.: a processing at Steps S217 to S221 are conducted in parallel to each other.

oo o o Next, the above-described "operation related to 0 25 detection of a Trap omission and Trap retransmission based on a Get Response" will be described with respect to a specific example.

34 a) Detection of one Trap omission and Trap retransmission First, with reference to Fig. 8, description will be made of specific operation conducted when one Trap omission is detected and the Trap in question is retransmitted.

As illustrated in Fig. 7, the SNMP agent 2 ordinarily receives a Get Request (Get Request inquiring about a Trap Current Number) transmitted from the SNMP manager 1 (see Al in Fig. 8) and transmits a Get Response to the Get Request in question to the SNMP manager 1.

The SNMP manager 1 obtains a current state value ("100" in this example) of a Trap Current Number at the 15 relevant SNMP agent 2 by referring to the Trap Current Number in the Get Response (Ml).

Thereafter, at a time point where transmission and reception of a Trap (Trap having the Trap Current Number of "101") from/to the SNMP agent 2 in question to/from the SNMP manager 1 is safely completed (A2 and M2) and the subsequent Get Request/Get Response processing is conducted, it is confirmed that the Trap Current Number is the same in the SNMP manager 1 and the SNMP agent 2.

Assume here that the SNMP manager 1 fails to receive the Trap (Trap having the Trap Current Number of "102"; A4) transmitted from the SNMP agent 2 for some 35 reason or other.

In this case, the SNMP manager 1 recognizes based on the subsequent Get Request/Get Response processing and M4) that the SNMP manager 1 and the SNMP agent 2 in question differ in the Trap Current Number.

At this time, the SNMP manager 1 sets "102" which is the value obtained by adding 1 to the internally held Trap Current Number at the Trap Request Start No. and sets "102" which is the value of the Trap Current Number obtained from the Get Response received at M4 at the Trap Request End No. to transmit a Set Request having such a Trap Request Start No. and such a Trap Request End No. to the SNMP agent 2 in question (A6).

The SNMP agent 2 having received the Set Request 15 retransmits a Trap having the designated Trap Number "102" as the Trap Current Number (also transmits a Get Response to the Set Request in question).

Based on the Trap Current Number designated by the retransmitted Trap, the SNMP manager 1 updates a state value of its internal Trap Current Number b) Detection of a plurality of Trap omissions eooee and Trap retransmission ooooo Next, description will be made of specific operation conducted when a plurality of successive Trap omissions are detected and a relevant Trap group is retransmitted with reference to Fig. 9.

Operation executed in normal Get Request/Get 36 Response processing (see B1 and Ni, and B3 and N3 in Fig.

9) and in the processing conducted when the SNMP manager 1 normally receives a Trap (B2 and N2) is the same as that of the above-described a).

Assume here that the SNMP manager 1 fails to successively receive two Traps (a group of Traps having the Trap Current Numbers of "102" and "103"; B4 and transmitted from the SNMP agent 2 for some failure or other.

In this case, the SNMP manager 1 recognizes based on the subsequent Get Request/Get Response processing (B6 and N4) that the SNMP manager 1 and the SNMP agent 2 in question differ in the Trap Current Number similarly to a case where one Trap omission occurs (the above- 15 described case of a).

At this time, the SNMP manager 1 sets "102" which is the value obtained by adding 1 to the internally held *Oo4* o Trap Current Number at the Trap Request Start No. and sets "103" which is the value of the Trap Current Number obtained from the Get Response received at N4 at the Trap Request End No. to transmit a Set Request having a* 4e such a Trap Request Start No. and such a Trap Request End No. to the SNMP agent 2 in question (B7).

The SNMP agent 2 having received the Set Request sequentially retransmits a Trap group having "102" and "103" which are the designated Trap Numbers as the Trap Current Numbers (also transmits a Get Response to the 37 Set Request in question).

Based on the Trap Current Number designated by each retransmitted Trap, the SNMP manager 1 updates a state value of its internal Trap Current Number (N5 and N6).

Secondly, description will be made of operation related to detection (sensing) of a Trap omission and Trap retransmission based on reception of a Trap (see Fig. 3).

The SNMP Trap reception unit 114 in the SNMP protocol processing unit 11 within the SNMP manager 1 receives a Trap transmitted from the SNMP agent 2 (Step S301) and transfers the Trap to the SNMP Trap analysis unit 115.

15 The SNMP Trap analysis unit 115 refers to the item to be managed data storage unit 14 to determine whether a Trap omission occurs or not. More specifically, p.

the unit 115 compares a value obtained by adding 1 to a 0.00 state value of the Trap Current Number in the item to be *554 *0"6 20 managed data for the relevant SNMP agent 2 (the SNMP agent 2 as a transmission source of the Trap in i question) at the item to be managed data storage unit 14 and a state value of the Trap Current Number in the Trap

SSS*

S *o in question to determine whether the values coincide with each other (Step S302).

When determining by the comparison at Step S302 that "the values fail to coincide with each other (Trap 38 omission occurs)", the SNMP Trap analysis unit 115 notifies the Trap retransmission request processing unit 13 to that effect (Step S303). When the determination is made at Step 302 that "the values coincide", none of "processing for Trap retransmission" at Step S303 and the following Steps will be conducted.

Upon recognizing by the notification at Step 303 that the SNMP manager 1 and the relevant SNMP agent 2 differ in the Trap Current Number, the Trap retransmission request processing unit 13 generates a Set Request in a manner as shown in the following a) to c) (Step S304) and transfers the Set Request to the SNMP Get Request/Set Request transmission unit 111 in the SNMP protocol processing unit 11.

a) To set, at the Trap Request Start No., a value obtained by adding 1 to a state value of the Trap Current Number held within the SNMP manager 1 (within S"the item to be managed data for the relevant SNMP agent e 2 at the item to be managed data storage unit 14) 20 (information designating a start number of a Trap group to be retransmitted).

b) To set, at the Trap Request End No., a value obtained by subtracting 1 from a state value of the Trap *Current Number in the Trap from which "disagreement in a 25 recognized state value" is detected at Step S302 (information designating an end number of a Trap group to be retransmitted).

39 c) To generate a Set Request having the information indicated in a) and b) being set.

The SNMP Get Request/Set Request transmission unit 111 transmits the relevant Set Request to each SNMP agent 2 (Step 305).

The SNMP agent 2 having received the Set Request addressed to itself retransmits a Trap group having the Trap Number designated by the Set Request (a group of Traps having Trap Numbers starting with the Trap Request Start No. and ending with the Trap Request End No.) to the SNMP manager i.

Operation at the relevant SNMP agent 2 and the following operation at the SNMP manager 1 conducted in this case is the same as that of the above-described "case where a Trap omission is detected by a Get Response" (see Steps S211 to S221 in Fig. 2).

Next, description will be made of a specific example of the above-described "operation related to 9 detection of a Trap omission and Trap retransmission 20 based on reception of a Trap" 9o9e Detection of one Trap omission and Trap retransmission First, with reference to Fig. 10, description will be made of specific operation conducted when one 25 Trap omission is detected and the Trap in question is retransmitted.

As illustrated in Fig. 10, the SNMP manager 1 is 40 allowed to obtain a Trap Current Number not only from a Get Response (see Cl and P1, and C3 and P3 in Fig. but also from a Trap (Trap PDU) transmitted from the SNMP agent 2 (C2 and P2) to determine also at the reception of a Trap whether there exists a Trap omission.

Assume, for example, a case (P4) where when the SNMP manager 1 fails to receive a Trap transmitted from the SNMP agent 2 (Trap having the Trap Current Number of "102"; C4), the manager 1 receives a Trap subsequently transmitted from the SNMP agent 2 In this case, the SNMP manager 1 determines based on the reception of the Trap in question (P4) that the SNMP manager 1 and the SNMP agent 2 in question differ in recognition of a Trap Current Number. More specifically, the manager 1 recognizes that the value of the Trap Current Number in the Trap in question and a value obtained by adding 1 to the value of the Trap i Current Number obtained by the former Get Response (P3) differ from each other.

20 At this time, the SNMP manager 1 sets "102" which is a value obtained by adding 1 to the internally held Trap Current Number (Trap Current Number obtained at P3) at the Trap Request Start No. and sets "102" which is a value obtained by subtracting 1 from the Trap Current 25 Number obtained from the Trap received at P4 at the Trap Request End No. to transmit a Set Request having such a Trap Request Start No. and such a Trap Request End No.

-41 to the SNMP agent 2 in question (C6).

The SNMP agent 2 having received the Set Request retransmits a Trap having the designated Trap Number "102" as the Trap Current Number (also transmits a Get Response to the Set Request in question).

Based on the Trap Current Number designated by the retransmitted Trap, the SNMP manager 1 updates a state value of its internal Trap Current Number b) Detection of a plurality of Trap omissions and Trap retransmission Next, description will be made of specific operation conducted when a plurality of Trap omissions are detected and a Trap group in question is retransmitted with reference to Fig. 11.

Consideration will be here given to a case where ~the SNMP manager 1 fails to successively receive two Traps (a group of Traps having the Trap Current Numbers of "102" and "103"; see D4 and D5 in Fig. 11) So...o transmitted from the SNMP agent 2 for some failure or other.

In this case, the SNMP manager 1 obtains a Trap Current Number from a subsequent Trap (D6 and Q4) to determine, similarly to a case where one Trap omission is detected (in the above-described case of that the 25 SNMP manager 1 and the SNMP agent 2 in question differ in recognition of the Trap Current Number. In other words, the manager 1 recognizes that the value of the 42 Trap Current Number at the Trap in question and the value obtained by adding 1 to the value of the Trap Current Number obtained from the previous Get Response (Q3) differ from each other.

At this time, the SNMP manager 1 sets "102" which is the value obtained by adding 1 to the internally held Trap Current Number (Trap Current Number obtained at Q3) at the Trap Request Start No. and sets "103" which is the value obtained by subtracting 1 from the Trap Current Number obtained from the Trap received at Q4 at the Trap Request End No. to transmit a Set Request having such a Trap Request Start No. and such a Trap Request End No. to the SNMP agent 2 in question (D7).

The SNMP agent 2 having received the Set Request sequentially retransmits a Trap group having "102" and "103" which are the designated Trap Numbers as the Trap Current Numbers (also transmits a Get Response to the ee Set Request in question).

Based on the Trap Current Number designated by each retransmitted Trap, the SNMP manager 1 updates a state value of its internal Trap Current Number (Q5 and Q6).

Only "detecting a Trap omission by the reception of a Trap and retransmitting the relevant Trap" 25 described above as the second processing (that is, without the execution of "detection of a Trap omission and retransmission of the relevant Trap based on a Get 43 Response" described above as the first processing) forms the SNMP network management system of the present invention (this is also the case with a second embodiment which will be described later).

Second Embodiment Fig. 12 is a block diagram showing a structure of an SNMP network management system according to a second embodiment of the present invention.

With reference to Fig. 12, the SNMP network management system according to the second embodiment of the present invention differs from the SNMP network management system according to the first embodiment shown in Fig. 1 in that it includes a recording medium 100 which records an SNMP network management processing program for a manager and a recording medium 200 which ~records an SNMP network management processing program for an agent. The recording media 100 and 200 may be a magnetic disk, a semiconductor memory or the like.

oooo The SNMP network management processing program for a manager is read into the SNMP manager 1 from the recording medium 100 to control operation of the SNMP manager 1 having the item to be managed data storage unit 14 and the Trap accumulation data storage unit as the SNMP protocol processing unit 11 (the SNMP Get S 25 Request/Set Request transmission unit 111, the SNMP Get Response reception unit 112, the SNMP Get Response analysis unit 113, the SNMP Trap reception unit 114 and 44 the SNMP Trap analysis unit 115) and the message request processing unit 12 including the Trap retransmission request processing unit 13. Since operation of the SNMP protocol processing unit 11, the message request processing unit 12 and the Trap retransmission request processing unit 13 under the control of the SNMP network management processing program for a manager is completely the same as that of the SNMP protocol processing unit 11, the message request processing unit 12 and the Trap retransmission request processing unit 13 in the first embodiment, no detailed description will be made thereof.

The SNMP network management processing program for an agent is read into the SNMP agent 2 from the recording medium 200 to control operation of the SNMP agent 2 having the item to be managed data storage unit 23 and the Trap retransmission log data storage unit 24 as the SNMP protocol processing unit 21 (the SNMP Get :eeeee Request/Set Request reception unit 211, the SNMP Get Response generation unit 212, the SNMP Get Response transmission unit 213, the SNMP Trap generation unit 214 and the SNMP Trap transmission unit 215) and the Set oo Request analysis processing unit 22. Since operation of the SNMP protocol processing unit 21 and the Set Request ~25 analysis processing unit 22 under the control of the SNMP network management processing program for an agent is completely the same as that of the SNMP protocol 45 processing unit 21 and the Set Request analysis processing unit 22 in the first embodiment, no detailed description will be made thereof.

As described in the foregoing, embodiments of the present invention attain the following effects.

The first effect is that a Trap omission can be reliably determined and detected to prevent the Trap omission in question by the retransmission of the Trap.

The reason such an effect is produced is that assigning a number to a transmitted Trap and holding a value (state value) of the number in a Trap Current Number object enables detection of disagreement between a Trap Current Number recognized by an SNMP manager and a Trap Current Number recognized by an SNMP agent based on Get Request/Get Response processing and Trap transmission between the SNMP manager and the SNMP agent.

The second effect is that a plurality of Trap omissions can be appropriately coped with and such a e plurality of Traps can be retrasmitted.

eg.. 20 The reason such an effect is produced is that a Trap Request Start No. object and a Trap Request End No.

oo object are set as MIB objects to enable a Set Request to designate a start number and an end number of a plurality of Traps to be retransmitted.

Although the invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that 46 the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodies within a scope encompassed and equivalents thereof with respect to the feature set out in the appended claims.

°.o oo* *oo o ooo* oo *o *o

Claims (14)

1. 2. The SNMP network management system as set forth in claim 1, further comprising: an item to be managed data storage unit in the SNMP agent for storing data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP agent, a Trap retransmission log data storage unit in the SNMP agent for storing Trap retransmission log data preserved for retransmitting a Trap which has been 10 transmitted to the SNMP manager, and an item to be managed data storage unit in the SNMP manager for storing, with respect to each SNMP agent, data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP manager. 49
2. 3. The SNMP network management system as set forth in claim 1, wherein the SNMP protocol processing unit in the SNMP agent includes: an SNMP Get Request/Set Request reception unit for receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation unit responsive to a Get Request requesting a state value of a Trap Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission unit for t transmitting a Get Response generated by said SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation unit for generating a Trap group to be retransmitted which is specified by a 20 start number and an end number designated by an instruction from the Set Request analysis processing unit based on Trap retransmission log data, and an SNMP Trap transmission unit for transmitting a Trap generated by said SNMP Trap generation unit to the 25 SNMP manager. The SNMP network management system as set forth 50 in claim 1, wherein the SNMP protocol processing unit in the SNMP manager includes: an SNMP Get Request/Set Request transmission unit for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception unit for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis unit for, when a Get Response having a Trap Current Number from an SNMP agent is received by said SNMP Get Response reception unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", e S an SNMP Trap reception unit for receiving a Trap 20 transmitted from the SNMP agent, and an SNMP Trap analysis unit for, when a Trap from :ee an SNMP agent is received by said SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of 51 Trap omission". The SNMP network management system as set forth in claim i, wherein the SNMP protocol processing unit in the SNMP agent includes: an SNMP Get Request/Set Request reception unit for receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation unit responsive to a Get Request requesting a state value of a Trap Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a *I Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission unit for transmitting a Get Response generated by said SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation unit for generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing unit based on Trap retransmission log data, and an SNMP Trap transmission unit for transmitting a Trap generated by said SNMP Trap generation unit to the 52 SNMP manager, and the SNMP protocol processing unit in the SNMP manager includes: an SNMP Get Request/Set Request transmission unit for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception unit for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis unit for, when a Get Response having a Trap Current Number from an SNMP agent is received by said SNMP Get Response reception unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception unit for receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis unit for, when a Trap from an SNMP agent is received by said SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of 53 Trap omission".
3. 6. An SNMP network management system for conducting management of a network using an SNMP comprising: an SNMP protocol processing unit in an SNMP agent for receiving a Set Request from an SNMP manager and responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing unit in the SNMP agent for, when a Set Request received by said SNMP protocol processing unit in the SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing said SNMP protocol processing unit in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing unit in the SNMP manager for, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by 20 the Trap in question and a state value of a Trap Current eeeee Number in item to be managed data for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing unit in the SNMP manager for, when a Trap omission is detected by said SNMP protocol processing unit in the SNMP 54 manager, referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting said SNMP protocol processing unit in the SNMP manager to transmit the Set Request.
4. 7. The SNMP network management system as set forth in claim 6, further comprising: an item to be managed data storage unit in the SNMP agent for storing data relating to items to be managed which 5 holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP agent, a Trap retransmission log data storage unit in the SNMP agent for storing Trap retransmission log data preserved for retransmitting a Trap which has been 10 transmitted to the SNMP manager, and 9 an item to be managed data storage unit in the SNMP manager for storing, with respect to each SNMP agent, data relating to items to be managed which holds a state value of an item to be managed of an MIB object as internally preserved data of the SNMP manager.
5. 8. An SNMP network management method of conducting management of a network using an SNMP comprising: an SNMP protocol processing step of receiving a 55 0.. 0 0. 0 Get Request/Set Request from an SNMP manager and responding to the Get Request/Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing step of, when a Set Request received by said SNMP protocol processing step in an SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing said SNMP protocol processing step in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing step of, when receiving either a Trap or a Get Response having a Trap Current Number from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question/the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing step in the SNMP manager of, when a Trap omission is detected by said SNMP protocol processing step in the SNMP manager, referring to item to be managed data for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for 25 56 the Trap omission in question and requesting said SNMP protocol processing step in the SNMP manager to transmit the Set Request.
6. 9. The SNMP network management method as set forth in claim 8, wherein the SNMP protocol processing step in a program for the SNMP agent includes: an SNMP Get Request/Set Request reception step of receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation step of, in response to a Get Request requesting a state value of a Trap Current Number from the SNMP manager, generating a Get Response having the Trap Current Number and in response to a Set Request requesting Trap retransmission from the SNMP manager, generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission step of transmitting a Get Response generated by said SNMP Get Response generation step to the SNMP manager, ooooo an SNMP Trap generation step of generating a Trap 20 group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing step based on Trap retransmission log data, and 57 an SNMP Trap transmission step of transmitting a Trap generated by said SNMP Trap generation step to the SNMP manager. The SNMP network management method as set forth in claim 8, wherein the SNMP protocol processing step in a program for the SNMP manager includes: an SNMP Get Request/Set Request transmission step of transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception step for receiving a Get Response transmitted from the SNMP agent, 10 an SNMP Get Response analysis step of, when a Get Response having a Trap Current Number from an SNMP agent is received by said SNMP Get Response reception step, S.comparing a state value of the Trap Current Number :designated by the Get Response in question and a state S 15 value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within an item to be managed data storage unit in the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception step of receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis step of, when a Trap from an SNMP agent is received by said SNMP Trap reception 58 step, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission".
7. 11. The SNMP network management method as set forth in claim 8, wherein the SNMP protocol processing step in a program for the SNMP agent includes: 5 an SNMP Get Request/Set Request reception step of :0 receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation step of, in response to a Get Request requesting a state value of a *0 10 Trap Current Number from the SNMP manager, generating a Get Response having the Trap Current Number and in response to a Set Request requesting Trap retransmission **e from the SNMP manager, generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission step of transmitting a Get Response generated by said SNMP Get Response generation step to the SNMP manager, an SNMP Trap generation step of generating a Trap 59 group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing step based on Trap retransmission log data, and an SNMP Trap transmission step of transmitting a Trap generated by said SNMP Trap generation step to the SNMP manager, and the SNMP protocol processing step in a program for the SNMP manager includes: an SNMP Get Request/Set Request transmission step of transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception step of receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis step of, when a Get Response having a Trap Current Number from an SNMP agent is received by said SNMP Get Response reception step, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be 40 managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission", an SNMP Trap reception step of receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis step of, when a Trap from an SNMP agent is received by said SNMP Trap reception 60 step, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission".
8. 12. An SNMP network management method of conducting management of a network using an SNMP comprising: an SNMP protocol processing step in an SNMP agent of receiving a Set Request from an SNMP manager and e. 5 responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing step in the SNMP agent of, when a Set Request received by said SNMP protocol processing step in the SNMP agent relates to a 10 Trap retransmission request, analyzing the contents of 6*w S: the Set Request in question to obtain a start number and an end number of a Trap group to be retransmitted and instructing said SNMP protocol processing unit in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing step of, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in 61 question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing step of, when a Trap omission is detected by said SNMP protocol processing step in the SNMP manager, referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting said SNMP protocol processing unit in the SNMP manager to transmit the Set Request.
9. 13. A computer readable memory storing an SNMP network management program for controlling a computer to conduct management of a network using an SNMP, said SNMP network management program comprising computer program code for: S: an SNMP protocol processing function for receiving a Get Request/Set Request from an SNMP manager and responding to the Get Request/Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing function for, when a Set Request received by said SNMP protocol processing function in an SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and an end number of a 62 Trap group to be retransmitted and instructing said SNMP protocol processing function in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing function for, when receiving either a Trap or a Get Response having a Trap Current Number from the SNMP agent, detecting a Trap omission based on a comparison between a state value of the Trap Current Number designated by the Trap in question/the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing function in the SNMP manager for, when a Trap omission is detected by said SNMP protocol processing unit in the SNMP 30 manager, referring to data relating to items to be managed for the S* SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and 35 requesting said SNMP protocol processing function in the SNMP manager to transmit the Set Request.
10. 14. The computer readable memory storing an SNMP network management program as set forth in claim 13, wherein the SNMP protocol processing function 63 a a a in a program for the SNMP agent comprises the functions of: an SNMP Get Request/Set request reception function for receiving a Get Request/Set Request transmitted from the SNMP manager, an SNMP Get Response generation function responsive to a Get Request requesting a state value of a Trap Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission function for transmitting a Get Response generated by said SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation function for generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing unit based on Trap retransmission log data, and an SNMP Trap generation function for transmitting a Trap generated by said SNMP Trap generation unit to the. SNMP manager. The computer readable memory storing an SNMP network management program as set forth in claim 13, a a a. a a oo a a a 25 25 64 wherein the SNMP protocol processing function in a program for the SNMP manager comprises the functions of: an SNMP Get Request/Set request transmission function for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception function for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis function for, when a Get Response having a Trap Current Number from an SNMP i* agent is received by said SNMP Get Response reception unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the o 20 comparison, recognizing "generation of Trap omission", an SNMP Trap reception function for receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis function for, when a Trap from an SNMP agent is received by said SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained by adding 1 to a state value of a Trap Current Number in data relating to items to be managed for the SNMP agent in question within the SNMP manager and when the two values fail to 65 coincide in the comparison, recognizing "generation of Trap omission".
11. 16. The computer readable memory storing an SNMP network management program as set forth in claim 13, wherein the SNMP protocol processing function in a program for the SNMP agent comprises the functions of: an SNMP Get Request/Set request reception function for receiving a Get Request/Set Request transmitted from 0 00 00 °o the SNMP manager, 0* o 0 0 0 10 an SNMP Get Request generation function responsive o o o 0 0o o to a Get Request requesting a state value of a Trap o 0 00°o Current Number from the SNMP manager for generating a Get Response having the Trap Current Number and responsive to a Set Request requesting Trap retransmission from the SNMP manager for generating a Get Response responding to the effect that the retransmission request in question is received, an SNMP Get Response transmission function for transmitting a Get Response generated by said SNMP Get Response generation unit to the SNMP manager, an SNMP Trap generation function for generating a Trap group to be retransmitted which is specified by a start number and an end number designated by an instruction from the Set Request analysis processing 66 unit based on Trap retransmission log data, and an SNMP Trap transmission function for transmitting a Trap generated by said SNMP Trap generation unit to the SNMP manager, and the SNMP protocol processing function in a program for the SNMP manager comprises the functions of: an SNMP Get Request/Set request transmission function for transmitting an SNMP Get Request/Set Request to the SNMP agent, an SNMP Get Response reception function for receiving a Get Response transmitted from the SNMP agent, an SNMP Get Response analysis function for, when a Get Response having a Trap Current Number from an SNMP agent is received by said SNMP Get Response reception 40 unit, comparing a state value of the Trap Current Number designated by the Get Response in question and a state value of a Trap Current N~irer in data relating to items to be mmged data for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the 45 comparison, recognizing "generation of Trap omission", an SNMP Trap reception function for receiving a Trap transmitted from the SNMP agent, and an SNMP Trap analysis function for, when a Trap from an SNMP agent is received by said SNMP Trap reception unit, comparing a state value of the Trap Current Number designated by the Trap in question and a value obtained 67 by adding 1 to a state value of a Trap Current Number in item to be managed data for the SNMP agent in question within the SNMP manager and when the two values fail to coincide in the comparison, recognizing "generation of Trap omission".
12. 17. A computer readable memory storing an SNMP network management program for controlling a computer to conduct management of a network using an SNMP, said SNMP network management program comprising computer program code for: i an SNMP protocol processing function in an SNMP agent'nt for receiving a Set Request from an SNMP manager and responding to the Set Request in question by a Get Response to transmit a Trap to the SNMP manager, a Set Request analysis processing function in the SNMP agent for, when a Set Request received by said SNMP protocol processing function in the SNMP agent relates to a Trap retransmission request, analyzing the contents of the Set Request in question to obtain a start number and .*ee 15 an end number of a Trap group to be retransmitted and instructing said SNMP protocol processing function in the SNMP agent to retransmit the Trap group to be retransmitted in question based on the analysis results, an SNMP protocol processing function for, when receiving a Trap from the SNMP agent, detecting a Trap omission based on a comparison between a state value of -68- the Trap Current Number designated by the Trap in question and a state value of a Trap Current Number in item to be managed data for the SNMP agent in question within the SNMP manager, and a Trap retransmission request processing function for, when a Trap omission is detected by said SNMP protocol processing unit in the SNMP manager, referring to data relating to items to be managed for the SNMP agent in question within the SNMP manager to generate a Set Request designating a start number and an end number of a Trap group whose retransmission is to be requested for the Trap omission in question and requesting said SNMP protocol processing unit in the SNMP manager to transmit the Set 0o Request.
13. 18. An SNMP network management system substantially as described herein in relation to any one of the embodiments shown in the accompanying drawings. 5i 19. An SNMP network management method substantially as described herein in relation to any one of the embodiments shown in the accompanying drawings.
14. 20. A computer readable memory storing an SNMP network management program substantially as described herein in relation to any one of the embodiments shown in the 20 accompanying drawings. DATED this eighth Day of March, 2005 NEC Corporation Patent Attorneys for the Applicant 25 SPRUSON FERGUSON *oo SR.\LIBQ102465.doc mxl