JPH10303894A - Network management system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the effect of a management information packet which accompanies the increase of management object nodes and increases on a network. SOLUTION: In this system, a network management device 20 performs multicast transfer of a request packet of management information which is transferred to nodes 11 to 17 that are objects to be managed. Each node stores multicast transfer routes 41 to 47 which are used by the request packet. When the nodes 11 to 17 transfer management information as a response packet to the device 20, they reversely track stored multicast transfer routes 51 to 57 and transfer it. In such cases, a relay point of multicast transfer reduces the effect on the network by limiting the transfer rate of a response packet that is sent from a management object node to the device 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network management system, and more particularly to a network including a management device for managing a network, and a plurality of nodes to be managed managed by the management device, and having a multicast transfer function of a transmission packet. Related to the management system.

[0002]

2. Description of the Related Art Conventionally, in this type of network management system, a management request packet is periodically transmitted to each node to be managed by a network management device, and nodes receiving the request packet independently manage the packet. A method of transmitting information or a method of transmitting management information to a network management device by the managed node itself is used.

[0003] In this example, an IP (Internet) is used for a node to be managed and a network management device that construct a network.
Protocol) found on IP networks with assigned addresses. These are UDP (User Data
gram Protocol) and SNMP (Simple Network Manag)
ement Protocol). Then, the network management device transmits a request for management information in a form of periodically performing polling, and the managed node receiving the request transmits the management information to the network management device, thereby transmitting the management information to the network management device. Exchanges. Alternatively, the managed node notifies the network management device of the management information in the form of a trap in the form of a trap.

[0004] Information transfer of management information requests and responses is based on I
A routing function for determining a transfer route of the P packet;
This is realized by a forwarding function that performs packet transfer based on the determined route. Therefore, the managed node can transfer the information in the same manner as normal user traffic without being limited by the information amount or the transfer route.

[0005]

The first problem of the prior art described above is that, as the number of nodes increases, the ratio of packets containing management information to the use of network resources (bandwidth, delay, etc.) increases. This raises the problem that there is a possibility of adverse effects such as discarding packets and increasing delay in communication of network users. The reason for this is that the network management device transmits management information request packets individually for the number of packets of the number of managed nodes, and furthermore, the network management device transmits management information independently of each other. The cause is considered to be an increase in the number of packets containing information and the occurrence of traffic having the burst property related to the polling period.

An object of the present invention is to provide a network management system capable of reducing the amount of management packets transferred from a network management device.

[0007]

According to the present invention, there is provided a network including a management device for managing a network, and a plurality of nodes to be managed managed by the management device, the network having a multicast transfer function of a transmission packet. A management system is provided, wherein the management information is transferred using a multicast transfer function when the management device requests management information from the node.

The operation of the present invention will be described. By utilizing the multicast transfer function of the network for the management information request packet transferred from the network management device, the amount of the packet can be reduced. Also, by mounting a so-called shaper function for controlling the transfer route in the packet relay node, it is possible to limit the transfer rate of packets transferred to the network management device.

[0009]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a network configuration to which the present invention is applied. The network management device 20 includes a plurality of nodes 11 to 17 connected to each other. All the nodes 11 to 17 and the network management device 20 are assigned with individual identification numbers a0 to a7, have a plurality of input / output ports p0 to p4, perform a packet-based communication, and perform multicast packet transfer. Has a function.

This packet transfer between adjacent nodes is converted into an optimum format according to the physical interface specifications of the node. For example, a plurality of means such as segmentation of a packet into an ATM cell, encapsulation into a frame of a frame relay, and encapsulation into an HDLC frame can be considered.

A packet used for transfer includes a destination identification number field in which an identification number of a node to which the packet is to be transferred is set, a source identification field in which an identification number of a node which has transmitted the packet is set, This is a configuration including a message field in which information to be set is set.

The present invention is a network management system in a network on the premise of having the above-described functions. First, in the present invention, one packet output from the network management device 20 is transmitted to the plurality of managed nodes 11 by using the multicast transfer function of the network.
~ 17. That is, transfer routes 41 to 47 as shown in FIG.

At this time, the network stores the transfer routes 41 to 47 used by the network management device 20 in the multicast transfer as a multicast transfer route in order to realize bidirectional communication using the route. Furthermore, the relay points 31 to 3 of the multicast transfer route
In No. 3, a shaper function for limiting the transfer rate is provided on the output side of the port p0 for inputting a packet from the network management device 20.

The network management device 20 transmits a request packet for management information to the managed node to all the managed nodes 11 to 17 using the multicast transfer routes 41 to 47.

The managed nodes 11 to 17 that have received the management information request packet transmit a response packet including the management information to the network management device 20. The response management information is management information common to the management target nodes or specific management information individually specified in advance in each node.

As shown in FIG. 1B, all response packets transmitted from the managed nodes 11 to 17 are transmitted to the network management device 20 based on the information on the multicast transfer route stored in the network. Are transferred along routes 51-57 which reversely follow the multicast transfer routes 41-47 used. Therefore, the network regards these response packets as all the same packets and performs processing.

[0018] However, the network management device enables identification of the node from which the received response packet was sent by inserting an identifier into the message field of the response packet.

This response packet limits the transfer rate of the management information to the network management device 20 by the shaper function at the relay points 31 to 33 of the network. Therefore, the response packet can be transferred to the network management device 20 without being affected by the rate of the response packet input to the relay points 31 to 33.

The multicast transfer includes a connectionless transfer method and a connection-oriented transfer method. For example, the connectionless transfer method uses an IGMP (Internet) using an IP packet having a class D IP address like an IP network.
A multicast group is formed by Group Management Protocol, and multicast transfer is performed hop-by-hop. On the other hand, connection-oriented transfer
As in an ATM network, multicast transfer is performed by establishing a point-to-multipoint end-to-end connection based on the identification number of a destination.

First, an example of an embodiment of the present invention in a connectionless network will be described. FIG.
Is a schematic block diagram of each node of the embodiment of the present invention,
For example, an example of the node 11 is shown. The node includes an interface unit 1 that interfaces with the ports P0 to P2, a control unit 2 that controls each unit, a route information table 3 for determining a packet transfer route, and a monitoring packet (for management information) transfer route. And an information table 4.

Each node that relays a packet has a route information table 3 for determining an output port of an input packet. By exchanging information for route information between adjacent nodes, the route information table 3 is exchanged. Has the function of dynamically forming Therefore, this routing information table enables multicast transfer.

First, all of the managed nodes 11 to 17
Belong to one multicast group, and a corresponding group identification number g0 is assigned. By exchanging route information between each node,
At each node, a route information table 3 for the destination node is constructed. In particular, FIGS. 3 to 9 show the state of the route information table 3 relating to the multicast transfer. 3 to 9 respectively show the contents of the tables 3 of the nodes 11 to 17 in a corresponding manner.

The method of creating each of these tables 3 will be described in detail. When nodes are connected to each other and communication becomes possible between adjacent nodes, by periodically exchanging route information between adjacent nodes, calculation is performed at each node using an algorithm of route information, and input is performed. The output port for the destination identification number of the packet thus determined is determined, and is generated and updated as a table.

In particular, regarding the multicast transfer of the present invention, the contents of the routing information table 3 for the multicast are automatically generated and updated by the node to be monitored participating in the multicast group.

The contents of the route information here depend on the algorithm of the route information for generating the route information table 3. Broadly speaking, this algorithm is called distance
It is roughly divided into -vector type and link-state type. distance-vec
In the tor type, a route information table is generated by obtaining information of a destination identification number and a cost (such as the number of hops) to the destination between adjacent nodes.

On the other hand, the link-state type generates a routing information table by transferring the link state (cost and identification number of an adjacent node) known to itself to all nodes and receiving the information. . At that time, in particular, in the case of multicast transfer, it is considered that the transfer route forms a loop or that the transfer route becomes a tree shape so that the routes do not overlap.

In FIG. 3 to FIG. 9, "local" means the node itself having this routing information table.
"-" Means that any identification number may be used.

To further explain, in the multicast transfer of connectionless communication, when a packet in which the multicast group identification number g0 is set in the destination identification number field is transmitted, these packets are transmitted to all multicast groups except the transmission node. Delivered to members. Therefore, for example, the packet whose destination is g0 transferred by the node 17 is delivered to the network management device 20 and the nodes 11 to 16.

The network management device 20 sets an identification number g0 corresponding to the multicast group in a destination identification number field in order to request each node for management information.
In the source identification number field, the identification number a0 of the management device is transmitted, and in the message field, a request packet in which a request message for management information is set is transmitted.

The first node 11 that has received the request packet determines from the value g0 of the destination identification number field of the request packet that the packet is a multicast packet addressed to the own node, and refers to the route information table. The ports p1 and p2 to be output are determined. And node 1
1 transfers a copy of the request packet to the nodes 12 and 13 using the ports p1 and p2.

At this time, with respect to the set of the value g0 of the destination identification number field and the value a0 of the transmission source identification number field of the packet, the node 11 determines the port number p0 of the packet input port and the output port number of the packet. Number p1,
p2 is recorded as one entry in the monitoring packet transfer route information table 4 shown in FIG. That is, the contents of the monitoring packet transfer route information table 4 correspond to a part of the contents of the record of the multicast transfer route in the above-mentioned network, and the contents of the record of this table of all the nodes correspond to the multicast transfer route of the entire network. Will correspond to the contents of the record. Note that FIG.
10, the contents of each table of all the leads 11 to 17 are collectively shown, but the contents of one row (one entry) of FIG.

If the node 11 is a relay node, a shaper function (to be described later) for limiting the transfer rate is provided on the output side of the input port p0 recorded in the multicast table.

If there is no port to be output, Null is recorded in the output port number column. In the table 4, when the information on the destination identification number g0 of the multicast group is deleted from the route information table 3, the entry on g0 is automatically deleted.

A request packet containing the same information is transferred to all the nodes 11 to 17 belonging to the multicast group while performing the same method.

The node 17 that has received the request packet from the network management device 20 and does not relay the request packet has a unique number in the message field of the multicast group that can identify that the network management device 20 is the node 17. (For example, identification number a7)
Is set in the message field, the identification number a0 of the network management device 20 is set in the destination identification number field, and the multicast group identification number g0 is set in the source identification number field. Create a response packet.

That is, all the managed nodes 11 to 17
The identification number field of the response packet from the client has the same value, and as a result, it is possible to handle the same type of packet in the network. Then, the node 17 transmits this packet from the input port p0 recorded in the monitoring packet transfer route information table 4, and transfers the packet to the node 15.

In a similar manner, node 14 becomes node 12
To node 16 to node 15, node 13 to node 1
1 respectively to transfer the response packets.

Next, the operation of the relay node for receiving a response packet from a downstream node (in this case, the node 16 and the node 17), taking the node 15 as an example, will be described.
The node 15 identifies whether or not the received packet is a response packet to the multicast transfer by referring to the monitoring packet transfer route information table (portion corresponding to the node 15) in FIG. If it is a response packet, this response packet is output from the port p0 registered in this table using the shaper function prepared at the time of registering an entry in this table.

When receiving a request packet from the network management device 20, the node 15 creates a response packet including a message to be transmitted by the node 15 in the same procedure as created by the node 17, and monitors the response packet. The packet is transferred to the port p0 registered in the packet transfer route information table. Then, like the other response packets, this response packet is output using the shaper function.

In the same manner as described above, the node 12 transfers the packet including the management information including the response message to the node 11 and the node 11 transfers the packet to the network management apparatus 20.

As described above, the response packet is transferred by following the reverse routes 51 to 57 of the route through which the request packet transmitted from the network management device 20 has passed, and the management information of all the nodes is combined into one type of packet. And arrives at the network management device 20.

Similarly, a packet containing management information transmitted by each node by itself is transferred to the network management device 20 by using the reverse routes 51 to 57 of the multicast transfer route.

On the other hand, when the network management device requests specific management information related to one node, the request packet is transferred to the node to be managed in the same manner as the transfer of a normal user packet. In other words, the route is determined hop-by-hop by the route information table 3 and delivered to the destination node. The response to this packet is also delivered to the network management device 20 by following the reverse routes 51 to 57 of the multicast transfer route in the same manner as described above.

The above is a description of a connectionless network. Next, an example of an embodiment of the present invention will be described with respect to a connection-oriented network.

In a connection-oriented network, all packets to be transferred are converted into a frame format corresponding to the transfer method, and are treated as exchange packets with a network identifier related to the connection. That is, the end-to-end communication is transferred using the network identifier instead of the identification number in the packet.

When a connection is established, an entry is created in the routing information table at the relay node in order to secure the transfer route. The path information table includes, as a set, a network identifier of a transfer packet for an input of a certain port, a port for outputting the transfer packet, and a value of the network identifier to be changed at the time of output.

First, all of the managed nodes 11 to 17
Belong to one multicast group, and the corresponding identification number g0 is assigned.

The network management device 20 establishes a point-to-multipoint bidirectional connection with all the nodes 11 to 17 to be managed using the multicast group identification number g0. At that time, as shown in FIG. 12, information on the multicast transfer routes 41 to 47 and the reverse routes 51 to 57 are recorded in the route information table. In FIG. 12, the route information table of each node is collectively shown.

Further, the relay nodes 11, 12, and 15 have
A shaper function is provided on the output side of the input port p0 recorded in the path information table. When the connection is established, the network management device 20 obtains a network identifier n1 for multicast transfer.

On the other hand, the managed nodes 11 to 17 also obtain the network identifiers n1 to n7 for transfer to the network management device 20, respectively. Further, a network identifier to be used for transfer of the management information packet between adjacent nodes can be obtained. This is shown in FIG.

The network management device 20 creates a request packet for requesting each node for management information, converts the request packet into a transfer packet including the network identifier n0, and transmits the packet. In the request packet, the identification number n0 corresponding to the multicast group is set in the destination identification number field, the source identification number field is set with the identification number a0 of the management device, and the message field is set with the management information request message. Set. This transfer packet is delivered to all the managed nodes 11 to 17 through routes 41 to 47 created by the set point-to-multipoint connection.

The node 17 which receives the request packet from the network management device 20 and does not need to relay the request packet
Indicates that the network management device 2
A unique number (for example, identification number a7) in a multicast group that can identify 0 as the node 17;
The management information including the response message is set in the message field, the destination identification number field contains the identification number a0 of the network management device 20, and the source identification number field contains the multicast group identification number g0.
To create response packets respectively. Then, the packet is converted into a transfer packet with a network identifier n7, and transferred to the network management device 20.

In a similar manner, node 14 becomes node 12
To node 16 to node 15, node 13 to node 1
1 respectively to transfer the response packets.

Next, the operation of a relay node such as the node 15 that receives a transfer packet from a downstream node (in this case, the nodes 16 and 17) will be described. The node 15 refers to the route information table based on the value of the network identifier of the transfer packet to determine whether the packet corresponds to the multicast transfer. If it corresponds to the multicast transfer, this transfer packet is registered in the route information table by using the shaper function prepared for the port p0 and the upstream node 1
Transfer to 2. At this time, the value of the network identifier of the transfer packet is changed to n5.

When the node 15 receives the transfer packet constituting the packet requested from the network management device 20, the node 15 creates the transfer packet in the same procedure as the node 17 creates. Transfer to the port p0 registered in the routing information table. The transfer packet is output using the prepared shaper function.

In the same manner as described above, the transfer packet including the response packet is transferred from the node 12 to the node 11 and from the node 11 to the network management device 20.

As described above, using the transfer packet, the response packet is transferred along the reverse routes 51 to 57 of the route through which the request packet transmitted from the network management device 20 passes, and the management information of all the nodes is transmitted. Arrives at the network management device 20 as one type of transfer packets.

Similarly, the management packet transmitted by each node by itself is also the reverse route 51 of the multicast transfer route.
It is possible to transfer the data to the network management device 20 by using.

On the other hand, when the network management device requests specific management information related to one node, the request packet is transferred to the node to be managed in the same manner as the transfer of a normal user packet. That is, a point-to-point connection is established between the network management device and the node requesting the management information, and the request packet is transferred using the connection. The response to the request packet is also delivered to the network management device 20 by following the reverse routes 51 to 57 of the multicast transfer route in the same manner as described above.

Next, the shaper function described above will be described. This shaper function is a packet transfer rate control function, and the existing technology can be applied as it is, but will be described below with reference to FIGS.

The shaper function is a function for limiting a transfer rate for a physical line, and is a technique used for priority control of packet transfer. In particular, the present invention is used to limit the transfer rate of packets transferred to the network management device 20, and aims to reduce the influence on other user packets.

The shaper function is implemented in the transmission side interface unit 1 (see FIG. 2) of each node. As shown in FIG. 13, a packet identification unit 31, a packet buffer 32, an interface conversion unit 33, a write address calculation unit 34,
It comprises a read timing generator 35, a shaping setting information provider 36, and a ring memory 37.

First, the shaping setting information providing unit 36 instructs the packet identifying unit 31 with respect to which information attribute of the input packet is to be identified. According to the present invention, in order to control the transfer rate of a packet to the network management apparatus, it is specified that the destination identification number and the source identification number of the packet be identified.

Further, the shaping setting information providing unit 36
Specifies the information for identifying the packet to be shaped and the limited rate information for the transfer to the write address calculator 34. In particular, in the present invention, when a route to a node to be monitored is registered from the network management device, information of a packet addressed to the network management device, that is, information in which a destination identification number a0 and a source identification number g0 are set is specified. . The transfer control rate is
A rate determined by the network administrator in advance is specified.

Next, in order to control the reading interval of the packet buffer 32, the write address calculation unit 34 uses the ring memory 37 to limit the transfer rate of the packet and schedules the transfer of the normal packet that is not so. Do. FIG. 14 shows the inside of the ring memory 37.

The ring memory 37 is composed of a plurality of slots, and an address for reading the packet buffer 32 is set in one slot. Each slot is sequentially numbered, and when reading a packet from the packet buffer 32, the read timing generation unit 35 accesses the slot in the order of the slot number according to the read pointer, extracts the read address, and The packet is read from the buffer 32.

The slot number to be accessed next to the largest slot number N is 1, and this operation is repeated, so that the memory arrangement is a ring image as shown in FIG.

The interval for accessing the slot is the minimum time interval at which the interface conversion unit 33 can make a packet read request from the packet buffer 32. The total number of slots (N) is m times the number obtained by dividing the maximum transfer rate (Rmax) of the interface converter 33 by the minimum set value (Rmin) of the transfer rate of the packet to be rate-limited. It is equal to the size of the buffer.

N = m · (Rmax / Rmin) The write address calculation unit 34
In step 7, a slot used by a packet whose transfer rate is restricted is assigned. The number of slots to be allocated (n) is calculated by dividing the packet limit rate (Rn) by the minimum limit rate setting value (Rmin) by the coefficient m in the above equation.
Multiplied by

N = m · (Rn / Rmin) Then, by arranging the slots in the ring memory at equal intervals, the scheduling of the transfer of the packet for limiting the transfer route is completed. Slots that have not been allocated are automatically scheduled as slots used for normal packet transfer.

Next, how a packet input to the shaper function unit is handled will be described. First, for a packet input at a node, a port to which the packet is to be output is determined from the destination identification number, and then the packet is transferred to the output port. At the output port, the packet is input to the packet identification unit 31. The packet identification unit 31 specifies that the contents to be identified are the destination identification number and the source identification number of the packet.
Notify 4.

The write address calculation unit 34 receiving this
Determines whether this packet is a packet for which the transfer rate restriction is specified. If this packet is a normal user packet, a write pointer is set to an empty slot closest to the read pointer among slots allocated to the normal packet. on the other hand,
If this packet is a packet whose transfer rate is limited, that is, a packet addressed to the network management device in the present invention (a packet whose destination identification number is a0 and whose source identification number is g0), the ring memory 37 The write pointer is set to a vacant slot closest to the read pointer among the slots allocated by the write operation.

If there is no empty slot, the packet is discarded. If there is an empty slot, the address of the packet buffer in which this packet is written is set to that slot of the ring memory, and this packet is written to the packet buffer at that address.

Next, upon receiving a packet buffer read request from the interface converter 33, the read timing generator 35 accesses a slot in the ring memory 37, acquires a packet buffer address from the slot, and Reads a packet from the packet buffer by address. If a valid address is not set in the accessed slot, the same operation is performed by accessing the next numbered slot.

As described above, the ring memory 37 is arranged,
The shaper function for limiting the transfer rate is realized by scheduling the transfer order of the packets.

[0077]

As described above, the first effect of the present invention is that the amount of management packets transferred from the network management device can be reduced. The reason is that the management packet transmitted from the network management device is transferred using the multicast transfer function of the network.

The second effect of the present invention is that it is easy to limit the transfer rate of packets transferred to the network management device. The reason is that packets from a plurality of nodes transferred to the network management device can be regarded as one type of packet, and a shaper function for controlling a transfer rate at a node that relays the packet is implemented; and This is because a plurality of nodes share the transfer rate to the network management device.

A third effect is that the method of the present invention can be used even when the network topology is changed. The reason is that the network changes the routing information table when a failure occurs because the table of the forwarding route information of the packet transmitted from the managed node can be related to the routing information table used for normal user communication in the network. If such a function is provided, the stored information of the multicast transfer route implemented in the present invention is also automatically changed.

[Brief description of the drawings]

FIG. 1 is a network configuration example showing an embodiment of the present invention, in which (A) shows a transfer rate of a management packet transmitted from a network management device, and (B) shows a transfer rate of a packet transmitted from a managed node. Indicates a transfer route.

FIG. 2 is a schematic block diagram of a node in FIG. 1;

FIG. 3 is a diagram showing contents of a route information table of a node 11 regarding multicast transfer in connectionless communication.

FIG. 4 is a diagram showing contents of a route information table of a node 12 regarding multicast transfer in connectionless communication.

FIG. 5 is a diagram showing contents of a route information table of a node 13 regarding multicast transfer in connectionless communication.

FIG. 6 is a diagram showing the contents of a route information table of the node 14 regarding multicast transfer in connectionless communication.

FIG. 7 is a diagram showing contents of a route information table of the node 15 regarding multicast transfer in connectionless communication.

FIG. 8 is a diagram showing the contents of a route information table of a node 16 regarding multicast transfer in connectionless communication.

FIG. 9 is a diagram showing contents of a route information table of the node 17 regarding multicast transfer in connectionless communication.

FIG. 10 is a diagram showing the contents of a monitoring packet transfer route information table of each node in connectionless communication.

FIG. 11 is a diagram illustrating a relationship between a multicast transfer route and a network identifier in connection-oriented communication.

FIG. 12 is a diagram showing the contents of a route information table related to multicast transfer in connection-oriented communication.

FIG. 13 is a block diagram illustrating a shaper function.

FIG. 14 is a diagram showing the operation of the ring memory 37 of FIG.

[Description of Signs] 1 Interface unit 2 Control unit 3 Route information table 4 Monitoring packet transfer route information table 11 to 17 Node 20 Network management device 31 to 33 Relay point 41 to 47 Multicast transfer route 51 to 57 Reverse route of multicast transfer route a0 to a9 identification number g0 multicast identification number n1 to n7 network identifier p0 to p4 port number of each node

Claims (4)

[Claims] 1. A management system in a network including a management device for managing a network, and a plurality of nodes to be managed managed by the management device, the network having a multicast transfer function of a transmission packet. A network management system, wherein the management information is transferred using a multicast transfer function when requesting the node for the management information. 2. Each of the nodes includes: a control unit that performs multicast transfer control of the management information request packet using multicast transfer information stored in a management information request packet from the management device; 2. A network management system according to claim 1, further comprising storage means for storing a transfer route for the network. 3. The control means, when returning management information to the management device in response to the management information request packet, performs the transfer by reversing a transfer route stored in the storage means. 3. The network management system according to claim 2, wherein: 4. The network management system according to claim 3, wherein each of the nodes further includes a limiter that limits a transfer rate of the packet of the management information when returning the packet.