Efficient network management system and method of managing the same between network management devices and management object devices

In a network management system, a data portion of an SNMP packet transmitted/received between an SNMP manager 10 (network management device) and an SNMP agent 20 (management object device) is compressed by a predetermined compression algorithm in a compression/decompression processing section 13, 22, when the SNMP packet is transmitted. The compressed SNMP packet is decompressed to be reproduced as the SNMP packet by the predetermined compression algorithm in the compression/decompression processing section 13, 22, when the compressed SNMP packet is received. Further, a compression indicating bit [1] is set on a predetermined bit position in the compressed SNMP packet in order to distinguish the SNMP packet from another SNMP packet transmitted/received between the SNMP manager 10 and an SNMP agent 120 (conventional management object device).

BACKGROUND OF THE INVENTION

The present invention relates to a network management system and a method of managing a network which is for use in a network using SNMP (Simple Network Management Protocol) between a network management device for managing the network and a management object device connected to the network management device through the network to be managed thereby, in particular to a network management system and a method of managing a network which are capable of reducing load caused by SNMP packets flown on the network between the network management device and the management object device.

SNMP is one of protocols that are used in a system for carrying out, through an Internet, operations of managing a condition of a device constituting the Internet, such as a router, or the like.

In the interim, Internet Protocol (IP) has two protocols as protocols of a transport layer in a packet transfer. Namely, the two protocols are UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). UDP is a connection-less type protocol for providing the function of IP to an upper layer substantially as it stands, compared with TCP that is a connection type protocol having a re-transmission function and a flow control function.

SNMP protocol for managing operations is originally operable upon the connection-less type UDP/IP in view of reducing load on the network. Under the situation, when managing data are transmitted by BER (Basic Encoding Rules) encoding method, an object identifier (ID) portion is added to each managing item. However, information is transferred inefficiently, since the object identifier (ID) portion comes up to ten and several bytes. As a result, as will later be described more in detail, load on the network becomes large in a conventional network management system, when many traps are generated from the management object device on the network between the management object device and the network management device. Further, load on the network also becomes large, when many “Get-request”, “Set-request”, and the like are issued from the network management device to the management object device on the network. Consequently, it is feared that the network is suppressed by the large load in the conventional network management system.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a network management system and a method of managing a network which are capable of reducing load caused by SNMP packets flown on the network between the network management device and the management object device.

According to an aspect of the present invention, there is provided a method of managing a network which is for use in a network using SNMP (Simple Network Management Protocol) between a network management device for managing the network and a management object device connected to the network management device through the network to be managed thereby, the method comprising the steps of: compressing a data portion of an SNMP packet transferred between the network management device and the management object device by a predetermined compression algorithm to transmit the SNMP packet including the compressed data portion; and decompressing the compressed data portion of the SNMP packet by the predetermined compression algorithm to carry out a predetermined processing on the SNMP packet.

The network management device may memorize a plurality of the management object devices to which the predetermined compression algorithm is applicable, respectively, in a table, the network management device compressing only the SNMP packet directed to the management object device to which the predetermined compression algorithm is applicable and which is memorized in the table to form a transfer packet to be transmitted.

A bit “1” may be set on a predetermined bit position of a packet tag showing a kind of a packet to be formed in a case that the data portion has been compressed by the predetermined compression algorithm, and wherein a bit “0” may be set on the predetermined bit position of the packet tag showing a kind of a packet to be formed in the other case.

According to another aspect of the present invention, there is also provided a network management system which is for use in a network using SNMP (Simple Network Management Protocol) between a network management device for managing the network and a management object device connected to the network management device through the network to be managed thereby, comprising: a packet which is transferred between the network management device and the management object device and which has a bit position for setting a compression indicating bit showing that the packet has been compressed by a predetermined compression algorithm; the network management device including: a table for memorizing whether or not the predetermined compression algorithm is applicable to the management object device; a compression/decompression processing section which investigates, by the table, whether or not the predetermined compression algorithm is applicable to the management object device as a transmission destination, when SNMP packet is transmitted from the network management device; the compression/decompression processing section compressing the packet with the compression indicating bit being set on the bit position, when the predetermined compression algorithm is applicable to the management object device as the transmission destination; the compression/decompression processing section decompressing the packet, when the compression indicating bit is set on the bit position of SNMP packet received from the management object device; and a communication processing section which adds a predetermined header to the SNMP packet to form a transfer packet; the transfer packet being transmitted to a transmission destination; the communication processing section extracting the SNMP packet from a received transfer packet; the communication processing section transmitting the extracted SNMP packet to the compression/decompression processing section, when the compression indicating bit is detected from the bit position of the extracted SNMP packet.

The management object device may include; a communication processing section which is connected to the network management device through the network and which adds a predetermined header to the SNMP packet generated in the management object device to form a transfer packet; the transfer packet being transmitted to a transmission destination through the network; the communication processing section extracting the SNMP packet from a transfer packet received through the network; the SNMP packet being transmitted to an internal of the management object device; and a compression/decompression processing section which compresses SNMP packet directed to the network management device with the compression indicating bit being set on the bit position; the compression/decompression processing section decompressing the SNMP packet, when the compression indicating bit is set on the bit position of SNMP packet received from the management object device.

The communication processing section may transmit the extracted SNMP packet to the compression/decompression processing section, in a case that the compression indicating bit is set on the bit position of the extracted SNMP packet, the communication processing section canceling the received packet in the other cases.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1 through 3, description is, at first, made about a conventional network management system and a conventional method of managing a network in order to facilitate an understanding of the present invention.FIG. 1is a schematic block diagram for showing an example of SNMP which is for use in a communication between an SNMP manager and an SNMP agent.FIG. 2is a schematic block diagram for showing an example of a conventional network management system.FIG. 3is a schematic view for showing a format of a transfer packet used in the conventional network management system illustrated inFIG. 2.

InFIG. 1, illustrated is an example of SNMP which is for use in a communication between an SNMP manager101and an SNMP agent102. The SNMP manager101is a network management device of an NMS (Network Management Station)1while the SNMP agent102is a protocol processing section of a management object device2. The management object device2further has an MIB (Management Information Base)103that is a managing condition determining section for previously determining a managing condition by a parameter. Accordingly, management of a condition of the management object device2is carried out by reading parameters of the MIB103. Besides, a trouble of a device is reported from the SNMP agent102to the NMS1by a mechanism called “SNMP trap”.

As illustrated inFIG. 2, such a conventional network management system, for example, comprises an SNMP manager (network management device)110and an SNMP agent (management object device)120connected to the SNMP manager (network management device)110through an Internet100as a network. Further, the SNMP manager (network management device)110comprises a packet processing section111and a communication processing section112. On the other hand, the SNMP agent (management object device)120comprises a communication processing section121and a packet processing section122.

Further, inFIG. 3, illustrated is an example of a transfer packet corresponding to “Get-request” packet, or the like transmitted from the SNMP manager110. A transfer packet electrically transmitted and received upon the Internet100between the communication processing sections112and121is composed of a predetermined header portion and a predetermined SNMP packet. A packet tag of eight bits “101xxxxx” for showing the kind of the SNMP packet is included in the predetermined SNMP packet. A packet tag of eight bits “10100000” is, for example, assigned to the “Get-request” packet. On the other hand, a packet tag of eight bits “10100100” is assigned to “Trap” packet in the above-described mechanism called (“SNMP trap”.

As mentioned in the preamble of the instant specification, SNMP protocol for managing operations is originally operable upon the connection-less type UDP/IP in view of reducing load on the network. Under the situation, when managing data are transmitted by BER (Basic Encoding Rules) encoding method, an object identifier (ID) portion is added to each managing item. However, information is transferred inefficiently, since the object identifier (ID) portion comes up to ten and several bytes. As a result, load on the network becomes large, when many traps are generated from the management object device on the network between the management object device and the network management device. Further, load on the network also becomes large, when many “Get-request”, “Set-request”, and the like are issued from the network management device to the management object device on the network. Consequently, it is feared that the network is suppressed by the large load.

Now, referring toFIGS. 4 through 10, description will proceed to a network management system and a method of managing a network according to a preferred embodiment of the present invention.FIG. 4is a schematic block diagram for showing a network management system according to the preferred embodiment of the present invention.

As illustrated inFIG. 4, the network management system according to the preferred embodiment of the present invention comprises an Internet100which is a network, an SNMP manager10which is a network management device, and a plurality of SNMP agents20,120each of which is a management object device. The SNMP manager10, the SNMP agents20and120are connected to each other by the Internet100. The network management system according to the preferred embodiment illustrated inFIG. 4has a structure similar to that of the conventional network management system illustrated inFIG. 2. Similar portions are designated by like reference numerals. Description about the similar portions is omitted accordingly.

The SNMP manager10comprises a management object table11, a packet processing section12, a compression/decompression (defrosting) processing section13, and a communication processing section14. Further, the SNMP agent20comprises a communication processing section21, a compression/decompression (defrosting) processing section22, and a packet processing section23. On the other hand, the SNMP agent120is the conventional management object device illustrated inFIG. 2. The SNMP manager10manages both the SNMP agent20and the SNMP agent120.

The management object table11is an area of compressed flags which are formed in a memory device (not shown) and which are corresponding to the SNMP agents20,120, respectively. The SNMP agent20has a predetermined compression algorithm as the above-mentioned compression/decompression (defrosting) processing section22. In the management object table11, for example, a bit “1” is previously set with respect to the numeral “20” of the object device number while a bit “0” is previously set with respect to the numeral “120” of the another object device number.

The packet processing section12reads the compressed flags corresponding to destinations, namely the SNMP agents20,120, respectively, from the management object table11, when the packet processing section12issues “Get-request” packet, and the like. As a result, the packet processing section12makes an SNMP packet directed to the SNMP agent20of the compressed flag “1” and then sends the SNMP packet to the compression/decompression (defrosting) processing section13.

Now, referring toFIG. 5, description proceeds to the SNMP packet.FIG. 5is a schematic view for showing a format of a transfer packet used in the network management system illustrated inFIG. 4. The SNMP packet illustrated inFIG. 5has a composition similar to that of the conventional SNMP packet described with reference toFIG. 3. With the composition being illustrated, a header portion including the kind of the SNMP packet cannot be changed from its predetermined format, because received data are directly interpreted to deal with the packet. On the contrary, data portion can be compressed. Therefore, a compression indicating bit for showing the SNMP packet having been compressed is added to a packet tag expressed by eight bits “101xxxxx” of the packet kind portion.

Namely, as illustrated inFIG. 5, the fifth bit of each packet tag is used for the compression indicating bit. Consequently, a packet tag “101xxxx” is assigned to each of non-compressed packets, for example, Get-request packet, Get-next-request packet, Get-response packet, Set-request packet, and Trap packet, for the conventional management object device. On the contrary, a packet tag “1011xxxx” is assigned to each of compressed packets, for example, Compressed Get-request packet, Compressed Get-next-request packet, Compressed Get-response packet, Compressed Set-request packet, and Compressed Trap packet, for the management object device of the present invention.

Accordingly, in the packet kind portion of an SNMP packet directed to the SNMP agent20for which the compressed flag is “1”, a packet tag “1011xxxx” is provided based on its packet kind. In other words, the compression indicating bit “1” is set on a position of the fifth bit of each packet tag. On the other hand, in the packet kind portion of an SNMP packet directed to the SNMP agent120for which the compressed flag is “0”, a packet tag “1010xxxx” is provided based on its packet kind. The SNMP packet directed thereto is then sent to the communication processing section14. Namely, in this case, the compression indicating bit “0” is set on a position of the fifth bit of the packet tag.

Besides, the packet processing section12similarly carries out a predetermined processing on any SNMP packet received from the compression/decompression (defrosting) processing section13or the communication processing section14, so that the packet processing section12provides the SNMP packet to internal management means (not shown).

The compression/decompression (defrosting) processing section13compresses predetermined object data among the SNMP packet received from the packet processing section12. The compression/decompression (defrosting) processing section13then sends the SNMP packet including the compressed object data to the communication processing section14. On the other hand, the compression/decompression (defrosting) processing section13decompresses (defrosts) a predetermined data portion of the SNMP packet received from the communication processing section14. The compression/decompression (defrosting) processing section13then sends the SNMP packet including the decompressed (defrosted) data portion to the packet processing section12.

The communication processing section14adds a predetermined header portion to the SNMP packet received from the packet processing section12or the compression/decompression (defrosting) processing section13to form a transfer packet. The communication processing section14then sends the transfer packet to the destinations, namely, the SNMP agents20,120through the Internet100. On the other hand, the communication processing section14receives the transfer packet from one of the SNMP agents20and120through the Internet100. When the communication processing section14receives the transfer packet from one of the SNMP agents20and120through the Internet100, the communication processing section14deletes the predetermined header portion from the SNMP (transfer) packet and reads the packet kind portion of the SNMP packet. The communication processing section14judges whether or not data have been compressed from the fifth bit of the packet tag in the packet kind portion of the SNMP packet. When data have not been compressed, the communication processing section14sends the SNMP packet to the packet processing section12. On the contrary, when data have been compressed, the communication processing section14sends the SNMP packet to the compression/decompression (defrosting) processing section13.

The communication processing section21of the SNMP agent20deletes a predetermined header portion from the transfer packet received from the SNMP manager10through the Internet100. The communication processing section21confirms the compression indicating bit “1” by the fifth bit portion of the packet kind portion of the SNMP packet. The communication processing section21then sends the SNMP packet to the compression/decompression (defrosting) processing section22. The communication processing section21never receive the fifth bit “0” by a record of the management object table11. Therefore, if the communication processing section21read the fifth bit “0”, the communication processing section21cancels the received SNMP packet to prevent the network from increase of load.

On the other hand, the communication processing section21adds a predetermined header portion to the SNMP packet received from the compression/decompression (defrosting) processing section22to form a transfer packet. The communication processing section21then sends the transfer packet to the SNMP manager10through the Internet100.

The compression/decompression (defrosting) processing section22decompresses (defrosts) a predetermined data portion of the SNMP packet received from the communication processing section21. The compression/decompression (defrosting) processing section22then sends the SNMP packet including the decompressed (defrosted) data portion to the packet processing section23. The compression/decompression (defrosting) processing section22compresses a predetermined data portion of the SNMP packet received from the packet processing section23. The compression/decompression (defrosting) processing section22then sends the SNMP packet including the compressed data portion to the communication processing section21.

The packet processing section23sends the SNMP packet received from the compression/decompression (defrosting) processing section22to internal control means (not shown) for controlling a managing condition within the management object device. In addition, the packet processing section23makes an SNMP packet by the data to be sent to the SNMP manager10. The packet processing section23set the compression indicating bit “1” on a position of the fifth bit of the packet tag in the packet kind portion of the SNMP packet. The packet processing section23then sends the SNMP packet including the compression indicating bit “1” in the packet tag to the compression/decompression (defrosting) processing section22.

FIG. 6is a schematic view for showing a format of another transfer packet (Trap packet) used in the network management system illustrated inFIG. 4. InFIG. 6, illustrated is a composition of “Trap” packet sent from the SNMP agents20,120. As illustrated inFIG. 6, the illustrated SNMP packet, namely “Trap” packet has a packet kind portion similarly to the other SNMP packets. Also in the illustrated SNMP packet, namely “Trap” packet, it is shown by the compression indicating bit of each packet tag of the packet kind portion whether or not data portion have been compressed.

Next, referring toFIG. 7with reference toFIGS. 4 and 5continued, description will proceed to packet transmission processes by the SNMP manager10that is a network management device.FIG. 7is a flow chart for showing the transmission processes in the SNMP manager10of the network management system according to the preferred embodiment of the present invention.

The SNMP manager10transmits the SNMP packets consisting of the kinds of packets, “Get-request”, “Get-next-request”, “Set-request” to the SNMP agent20, that is, a management object device by the format illustrated inFIG. 5.

The packet processing section12receives transmission data for managing the network (S1), and then makes an SNMP packet, dependent on the kind of packets (S2). At that time, the packet processing section12investigates a compressed flag area of the management object table11by the transmission destination, namely, management object device20(S3).

When the compressed flag “1” is detected from the corresponding area (Yes in S4), the packet processing section12sets the compression indicating bit “1” on a position of the fifth bit of the packet tag expressing the kind of packets (S4). The packet processing section12then sends the SNMP packet to the compression/decompression (defrosting) processing section13

The compression/decompression (defrosting) processing section13compresses data portion of the received SNMP packet by a predetermined compression algorithm (S5), and then send's the SNMP packet including the compressed data portion to the communication processing section14. The communication processing section14adds a predetermined header portion to the SNMP packet received from the compression/decompression (defrosting) processing section13to form a transfer packet. The communication processing section14then sends the transfer packet to the management object device of a transmission destination, namely, the SNMP agent20through the Internet100(S6).

On the other hand, in a case that a transmission destination is the management object device120, namely, the SNMP agent120, the compressed flag “0” is detected from the management object table11as the result of the investigation of the above step S3. Judgement in the above step S4therefore becomes “No”. The packet processing section12sets the compression indicating bit “0” on a position of the fifth bit of the packet tag expressing the kind of packets (S7). The packet processing section12then sends the SNMP packet directly to the communication processing section14. The communication processing section14carries out the above step S6.

Next, referring toFIG. 8with reference toFIGS. 4,5and7continued, description will proceed to packet reception processes following to the above step S6by the SNMP agent20that is a management object device.FIG. 8is a flow chart for showing the reception processes in the SNMP agent20of the network management system according to the preferred embodiment of the present invention. Packet reception processes following to the step S10by a management object device such as the SNMP agent120having no relation to the present invention (No in S10) is omitted.

If judgement is “Yes” in S10, in the SNMP agent20, the communication processing section21receives a transfer packet including the compressed data portion (S11). The communication processing section21deletes a predetermined header portion from the received transfer packet to take the SNMP packet out of the received transfer packet. The communication processing section21then investigates the fifth bit of the packet tag expressing the kind of packets (S12).

As a result, when the compression indicating bit “1” is set on the fifth bit of the packet tag (Yes in S13), the communication processing section21then sends the received SNMP packet to the compression/decompression (defrosting) processing section22. The compression/decompression (defrosting) processing section22decompresses (defrosts) the received SNMP packet (S14) to reproduce the data portion thereof. The compression/decompression (defrosting) processing section22then sends the SNMP packet including the reproduced or decompressed (defrosted) data portion to the packet processing section23. The packet processing section23carries out general processing on the decompressed (defrosted) SNMP packet, similarly to the conventional one (S15). The packet processing section23then sends the decompressed (defrosted) SNMP packet to internal control means (not shown).

If judgement is “No” in the above step S13, namely, the compression indicating bit “0” is set on the fifth bit of the packet tag, the communication processing section21cancels the received SNMP packet (S16), and finishes the packet reception processes.

Next, referring toFIG. 9with reference toFIGS. 4 and 5continued, description will proceed to packet transmission processes by the SNMP agent20that is a management object device of the present invention.FIG. 9is a flow chart for showing the transmission processes in the SNMP agent20of the network management system according to the preferred embodiment of the present invention.

The SNMP agent20transmits either the SNMP packet consisting of “Get-response” in the kind of packet illustrated inFIG. 5or the SNMP packet consisting of “Trap” in the kind of packet illustrated inFIG. 6to the SNMP manager10that is a network management device.

When the packet processing section23receives the transmission data, the packet processing section23makes an SNMP packet by a format dependent on the kind of packets (S21). At that time, the packet processing section23sets the compression indicating bit “1” on a position of the fifth bit of the packet tag expressing the kind of packets (S22). The packet processing section23then sends the SNMP packet to the compression/decompression (defrosting) processing section22. The compression/decompression (defrosting) processing section22compresses data portion of the received SNMP packet by a predetermined compression algorithm (S23), and then sends the SNMP packet including the compressed data portion to the communication processing section21. The communication processing section21adds a predetermined header portion to the SNMP packet received from the compression/decompression (defrosting) processing section22to form a transfer packet. The communication processing section21then sends the transfer packet to the SNMP manager10of the network management device through the Internet100(S24).

Next, referring toFIG. 10with reference toFIGS. 4 and 5continued, description will proceed to packet reception processes by the SNMP manager10that is a network management device of the present invention.FIG. 10is a flow chart for showing the reception processes in the SNMP manager10of the network management system according to the preferred embodiment of the present invention.

The communication processing section14receives the transfer packet through the Internet100(S31). The communication processing section14deletes a predetermined header portion from the received transfer packet to take the SNMP packet out of the received transfer packet. The communication processing section14then investigates the fifth bit of the packet tag expressing the kind of packets (S32).

As the result of the investigation, when the compression indicating bit “1” is detected on the fifth bit of the packet tag (Yes in S33), the communication processing section14then sends the received SNMP packet to the compression/decompression (defrosting) processing section13. The compression/decompression (defrosting) processing section13decompresses (defrosts) the received SNMP packet (S34) to reproduce the data portion thereof. The compression/decompression (defrosting) processing section13then sends the SNMP packet including the reproduced or decompressed (defrosted) data portion to the packet processing section12. The packet processing section12carries out general processing on the decompressed (defrosted) SNMP packet, similarly to the conventional one (S35).

On the other hand, judgement is “No” in the above step S33, namely, the compression indicating bit “0” is detected on the fifth bit of the packet tag, when a transmission source is the conventional SNMP agent120. In this case, the communication processing section14then sends the SNMP packet directly to the packet processing section12. The packet processing section12carries out general processing on the received SNMP packet (S36). The process of the step S36is similar to that of the above step S35. As described above, according to the present invention, it is possible to reduce the load on the network due to SNMP packets flown between the devices. This is because a data portion can be compressed by a predetermined compression algorithm in the SNMP packet transmitted and received between the SNMP manager of a network management device and the SNMP agent of a management object device.

While this invention has thus far been described in conjunction with the preferred embodiment thereof, it will now be readily possible for one skilled in the art to put this invention into effect in various other manners. For example, in the preferred embodiment mentioned above, the compression indicating bits are detected in the SNMP packet transmitted from the packet processing section and in the SNMP packet received by the communication processing section, respectively. However, the compression/decompression (defrosting) processing section can carry out the compression/decompression (defrosting) processing, no processing, and detection of the compression indicating bit, respectively. In this case, a conventional packet processing section and a conventional communication processing section can be used as it stands, respectively. Further, although the above-mentioned steps are serial operations, some operations can be processed in parallel. Moreover, the above-mentioned steps are not restricted to the described order. Namely, some of the above-mentioned steps can be carried out in another order.