Network management apparatus

In a network management apparatus which manages a network composed of network elements installing different communication technologies such as an ATM, an MPLS, and a Diff-Serv, a QoS guarantee path route candidate retriever retrieves a route enabling a predetermined QoS to be guaranteed or a route enabling the predetermined QoS to be guaranteed by being assigned with the flow identifier from among routes between a source and a destination network elements based on network configuration information, QoS guarantee capability information, the flow identifier assignment capability information, and a QoS guarantee path establishing portion performs a QoS guarantee setting and a flow identifier assignment setting to the network elements on the retrieved route.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a network management apparatus, and in particular to a network management apparatus which manages a network composed of network elements implementing or installing different communication technologies such as an ATM (Asynchronous Transfer Mode), an MPLS (Multi-Protocol Label Switching), and a Diff-Serv (Differentiated Services).

Such a network management apparatus, when a Quality of Service (hereinafter, abbreviated as QoS) is requested in the network, is required to select a network element to be guaranteed with the QoS and to perform a QoS guarantee setting in each selected network element.

2. Description of the Related Art

FIG. 18Ashows a general network composed of network elements respectively installing different communication technologies. In this network, edge nodes (network elements)20—1and20—4are connected through an ATM node20—2or a DiffServ node20—3. Between the edge nodes20—1and20—4, there are following three routes; (1) link30—1→ATM node20—2→link30—3, (2) link30—1→ATM node20—2→link30—4→DiffServ node20—3→link30—5, and (3) link30—2→DiffServ node20—3→link30—5.

In the absence of an empty band in the links30—2and30—3, the route (2) (shown by thick lines) through the edge nodes20—1and20—4connected in cascade is the only route.

FIG. 18Bshows a general network example in which the nodes (network elements)20—1and20—2, whose communication technologies such as a QoS guarantee and a flow identifier assignment capability are different from each other, are connected with the link30—1and the node20—3which is different from the node20—2is connected to the node20—2with the link30—2.

Cases 1–4 respectively show that the nodes20—1and20—3employ an IP-ONU (Optical Network Unit), a DiffServ router, an LSR (Label Switch Router), or a router, and the node20—2employs an OLT (Optical Line Terminal), a DiffServ core router, a core LSR, or an ATM switch.

Thus, a general network is composed of network elements which mount thereon various communication technologies.

Hereinafter, the QoS guarantee in such a network will be described.

In a prior art IP network, as in the Internet, the QoS guarantee of the communication could not be performed, so that a best-effort type communication has been performed.

Also, in an IntServ of the IETF (Internet Engineering Task Force), a resource at the time of a communication has been secured by using a signaling technology RSVP (Resource ReSerVation Protocol) for a band guarantee path establishment, so that the QoS has been guaranteed.

Also, in a DiffServ technology of the IETF, the QoS guarantee per DSCP (DiffServ Code Point) has been set in the network element for setting a band guarantee.

However, only the network element which mounts thereon a single QoS guarantee mechanism such as the IntServ or the DiffServ has been able to guarantee the QoS, which limits the QoS guarantee.

Also, in an MPLS of the IETF, a mechanism of autonomously establishing a path has been prescribed so that an edge router assigns an identifier to an IP flow and a core router transfers an IP packet according to the identifier. However, a mechanism of exchanging information on the QoS guarantee setting has not been prescribed.

Also, while the QoS setting is possible in case the path is explicitly established manually or the like, the retrieval of a route and the preparation of QoS guarantee setting contents are required to be performed manually.

In such a prior art network management apparatus, there have been problems that the calculation of a QoS guarantee route and the preparation of the QoS guarantee setting contents can not be automatized, requiring much process time for the QoS control by end to end in the network composed of a plurality of sub-networks whose communication technologies such as a QoS guarantee and a flow identifier assignment capability are different from each other.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provide a network management apparatus which manages a network composed of network elements which mount thereon communication technologies whose patterns such as a QoS guarantee and a flow identifier are different, which retrieves a QoS guarantee route passing through a plurality of network elements or sub-networks at a high speed, and which guarantees a QoS of the network element on the route.

In order to achieve above-mentioned object, a network management apparatus of the present invention according to claim1comprises: a storage for storing network configuration information indicating a connection state of a plurality of network elements, QoS guarantee capability information indicating a QoS guarantee capability of the network elements, and flow identifier assignment capability information indicating a flow identifier assignable by the network elements; a QoS guarantee path route candidate retriever for retrieving a route enabling a predetermined QoS to be guaranteed or a route enabling the predetermined QoS to be guaranteed by being newly assigned with the flow identifier from among routes between a source and a destination network elements based on the network configuration information, the QoS guarantee capability information, and the flow identifier assignment capability information, and for preparing QoS guarantee setting information and predetermined flow identifier assignment setting information provided to the network elements on the retrieved route; and a QoS guarantee path establishing portion for performing the QoS guarantee setting and the flow identifier assignment setting to the network elements.

FIG. 1shows a principle of a network management apparatus10according to the present invention. Network elements20—1–20—N (hereinafter, occasionally represented by a reference numeral20) connected to the network management apparatus10are general network elements which mount thereon various communication technologies.

A QoS guarantee path route candidate retriever16retrieves, based on network configuration information indicating a connection state of the network elements20, QoS guarantee capability information indicating a QoS guarantee capability of the network elements20, and flow identifier assignment capability information indicating a flow identifier assignable by the network elements20which are all stored in a storage18, a route enabling a predetermined QoS to be guaranteed from routes between a predetermined source network element20and a destination network element20as well as a route enabling the predetermined QoS to be guaranteed by being assigned with the flow identifier, and prepares setting information for guaranteeing the QoS and for assigning the flow identifier to the network elements20on the route.

Namely, the QoS guarantee path route candidate retriever16retrieves not only the route enabling the predetermined QoS to be guaranteed but also the route enabling the QoS to be guaranteed by the route available between the network elements20at the preceding and the subsequent stages by setting the flow identifiers of the network element20at the preceding or the subsequent stage on the route, and prepares the setting information.

A QoS guarantee path establishing portion17performs a QoS guarantee setting and a flow identifier assignment setting to the network elements20.

Thus, even in the network composed of the network elements20which mount thereon communication technologies whose patterns of the QoS guarantee, the flow identifier, and the like are different from each other, it becomes possible to retrieve the QoS guarantee route at a high speed and to establish the QoS guarantee route of the network element20on the route.

It is to be noted that an operator terminal70shown inFIG. 1serves to provide a QoS guarantee request prepared by a customer and an operator to the network management apparatus10. A QoS guarantee request accepting analyzer15serves to analyze the QoS guarantee request to be provided to the QoS guarantee path route candidate retriever16, which will be described later.

Also, in the present invention according to claim2, the storage may further include network element setting information of the network elements composed of the QoS guarantee setting information and the predetermined flow identifier assignment setting information prepared by the QoS guarantee path route candidate retriever; and the QoS guarantee path establishing portion may perform, based on the network element setting information, the QoS guarantee setting and the flow identifier assignment setting of the network elements.

Namely, the storage18stores the QoS guarantee setting information and the flow identifier assignment setting information for setting the network elements on the route detected by the QoS guarantee path route candidate retriever16as network element setting information14.

The QoS guarantee path establishing portion17may perform the QoS guarantee setting and the flow identifier assignment setting of the network element20based on the network element setting information14.

Also, in the present invention according to claim3, the QoS guarantee path establishing portion may store a flow identifier value determined by the network element to which either the QoS guarantee setting or the flow identifier assignment setting has been performed, and may make the flow identifier value an identifier value set in other network elements.

Namely, when the QoS guarantee path establishing portion performs the QoS guarantee setting and the flow identifier setting to the network elements in the presence of the network element20which determines a flow identifier value, the network management apparatus10can not predetermine the flow identifier value of the related network element20.

Therefore, the flow identifier value determined by the network element20is stored and made a flow identifier value of the related network element.

Thus, it becomes possible to select the network element which autonomously determines the flow identifier value as an element on the QoS guarantee route.

Also, in the present invention according to claim4, upon failing to establish a QoS guarantee path of a network resource securing type, the QoS guarantee path establishing portion may establish a next QoS guarantee path retrieved by the QoS guarantee path route candidate retriever.

Namely, when the QoS guarantee path can not be established by the failure of securing a network resource, the QoS guarantee path establishing portion establishes a next QoS guarantee path retrieved by the QoS guarantee path route candidate retriever16.

Thus, the QoS guarantee path establishing portion17can secure the QoS guarantee path of the network resource securing type from a plurality of QoS guarantee routes.

Also, in the present invention according to claim5, in presence of a plurality of routes enabling the predetermined QoS to be guaranteed, the QoS guarantee path establishing portion may select a single route from among the routes according to a preliminarily designated selection method.

Namely, in the presence of a plurality of routes enabling the predetermined QoS to be guaranteed, the QoS guarantee path establishing portion17selects a single route according to a preliminarily designated selection method, e.g. a selection method preliminarily designated by a network provider.

Thus, the condition of designating the QoS guarantee path can be further set.

Also, in the present invention according to claim6, the QoS guarantee capability information may further indicate a QoS guarantee capability of a sub-network composed of a plurality of network elements.

Namely, QoS guarantee capability information12can store QoS guarantee capability information of a sub-network. For example, the QoS guarantee capability information12stores the QoS guarantee capability indicating the QoS guarantee capability of the sub-network composed of a plurality of network elements mutually connected and having the same QoS guarantee capability.

The QoS guarantee path route candidate retriever16retrieves the QoS guarantee route based on the QoS guarantee capability information of the sub-network.

Thus, the QoS guarantee path route candidate retriever16can retrieve the QoS guarantee route at a higher speed.

Also, in the present invention according to claim7, the QoS guarantee capability information may further indicate a QoS guarantee capability of a sub-network composed of a plurality of network elements whose treatable flow identifiers are coincident with each other.

Namely, the QoS guarantee capability information of the sub-network indicates the QoS guarantee capability of a sub-network composed of a plurality of network elements whose treatable flow identifiers are coincident with each other. Thus, the QoS guarantee path route candidate retriever16can retrieve the QoS guarantee route at a higher speed.

Also, in the present invention according to claim8, the sub-network may comprise a network of other carriers. Thus, it becomes possible to retrieve the QoS guarantee route including the network of other carriers.

Also, in the present invention according to claim9, the QoS guarantee path route candidate retriever may retrieve, as a route enabling the predetermined QoS to be guaranteed by being assigned with the flow identifier, a route having no network element which deletes the flow identifier between a network element assigning the flow identifier and a network element guaranteeing a QoS based on the flow identifier.

Namely, the QoS guarantee path route candidate retriever16checks that there is no network element20which deletes the flow identifier between the preceding and the subsequent stages of the network elements20even if the network element20which guarantees the QoS based on the flow identifier is not directly connected to the subsequent stage of the network element20which assigns the flow identifier, thereby retrieving the QoS guarantee route.

Thus, the network element20can determine the route based on the flow identifier assigned by the preceding network element20.

Also, in the present invention according to claim10, the QoS guarantee path route candidate retriever may specify, as a route enabling the predetermined QoS to be guaranteed by being assigned with the flow identifier, a network element which deletes the flow identifier per classification of a flow identifier, and may retrieve a route to a network element having a capability to assign the deleted flow identifier.

Namely, the QoS guarantee path route candidate retriever16specifies the network element20which deletes the flow identifier per classification of a flow identifier, and retrieves the network element having a capability to assign the flow identifier deleted at the network element20on the route at the subsequent stage of the network20.

Based on this retrieving result, the QoS guarantee path establishing portion17sets assigning the deleted flow identifier to the network element20on the route at the subsequent stage.

Thus, it becomes possible to establish the route including the network element20whose flow identifier is deleted as the QoS guarantee route.

Furthermore, in the present invention according to claim11, the QoS guarantee path establishing portion may establish one or more paths having a preliminarily guaranteed QoS to a network element, and may store QoS guarantee setting information and flow identifiers of the paths, thereby selecting a route enabling the QoS to be guaranteed, based on the QoS guarantee setting information, from among the paths when the predetermined QoS guarantee is requested, and setting another network element so that the flow identifier of the path is used.

Namely, the QoS guarantee path establishing portion17establishes paths having preliminarily guaranteed QoS's, and then stores the QoS guarantee setting information and the flow identifier of the paths.

When receiving an establishing request of the predetermined QoS guarantee path, the QoS guarantee path establishing portion17selects and establishes a path which satisfies the requested QoS from among the paths established based on the QoS guarantee setting information so that the flow identifier may be used in another network element20.

Thus, it becomes possible to retrieve the route enabling the QoS to be guaranteed at a high speed.

DESCRIPTION OF THE EMBODIMENTS

An embodiment (1) of the network management apparatus10according to the present invention will be described with a network shown inFIG. 2being made a management object. InFIG. 2, a management object network is a network between customer networks50—1and50—2, and is composed of routers20—1–20—3and an ATM switch20—4which are network elements. These network elements20are connected to the network management apparatus10.

On links30—1and30—6which respectively connect the management object network and the customer networks50—1and50—2, Service Access Points (hereinafter abbreviated as SAP's)40—1and40—2are set.

As for the route connecting these SAP's40—1and40—2, there are a route which passes through the router20—1, a link30—2, the router20—2, a link30—4, and the router20—3, and a route which passes through a link30—3, the ATM switch20—4, and a link30—5instead of the link30—2, the router20—2, and the link30—4.

As shown inFIG. 1, the network management apparatus10stores the network configuration information11, the QoS guarantee capability information12, the flow identifier assignment capability information13, and the network element setting information14in the storage18. The examples of the information11–14corresponding to the management object network shown inFIG. 2are respectively shown inFIGS. 3A–3D.

The network configuration information11ofFIG. 3Ashows a configuration of the management object network, which is composed of an identifier (hereinafter abbreviated as ID) of the network element, the SAP, and the ID of the link connected to the network element20corresponding to the network element ID. In case the network element20is the router20—1inFIG. 2for example, the SAP is the SAP40—1, and the link ID's are the links30—1–30—3′ ID.

The SAP's and the link ID's of the routers20—2,20—3, and the ATM switch20—4are the same as the case of the router20—1. However, the SAP's of the router20—2and the ATM switch20—4are represented by “none” since they are not connected to the links30—1and30—6on which the SAP's40—1and40—2are respectively set.

The QoS guarantee capability information12ofFIG. 3Bshows a QoS guarantee capability of the network elements, which is composed of the network element ID and the QoS guarantee capability. The QoS guarantee capability is represented by the combination of <identifier pattern C1—pattern, quality pattern Q1—pattern>.

In case the QoS guarantee capability information of the network element20is e.g. <destination IP address, fixed band guarantee>, <destination IP address, minimum band guarantee>, and <DSCP, fixed band guarantee>, it is indicated that the network element20has a capability of identifying a flow by the destination IP address and of guaranteeing the fixed band or the minimum band, and a capability of identifying the flow by the DSCP and of guaranteeing the fixed band.

The routers20—1and20—3shown inFIG. 2have a capability of identifying the flow by the identifier pattern C1—pattern=“destination IP address” and of guaranteeing the fixed band, and have a capability of identifying the flow by the identifier pattern C1—pattern=“DSCP” and of guaranteeing a priority control.

Similarly, the router20—2has a capability of identifying the flow by the identifier pattern C1—pattern=“DSCP” and of guaranteeing the priority control, and the ATM switch20—4has a capability of identifying the flow by the identifier pattern C1—pattern=“VPI/VCI” and of guaranteeing the fixed band.

Accordingly, as shown inFIG. 2, since the routers20—1,20—3, and the ATM switch20—4can guarantee the band, they are represented as “with band guarantee”, while since the router20—2is represented as “without band guarantee” because it can not guarantee the band.

The flow identifier assignment capability information13ofFIG. 3Cshows a capability of assigning the flow identifier of the network elements20, which is composed of the network element ID and a flow identifier assignment capability represented by <flow identifier, other flow identifiers>. This <flow identifier, other flow identifiers> indicates the combination of recognizable and assignable flow identifiers.

The flow identifier assignment capability is represented by e.g. (1) <destination IP address, VPI/VCI>, (2) <destination IP address, DSCP>, and the like.

(1) <destination IP address, VPI/VCI> indicates that the network element20has a capability of identifying the flow by the destination IP address and of newly assigning VPI/VCI (Virtual Path Identifier/Virtual Channel Identifier) to the flow.

(2) <destination IP address, DSCP> indicates that the network element20has a capability of identifying the flow by the destination IP address and of newly assigning DSCP to the flow.

For example, the routers20—1and20—3shown inFIG. 2can identify the flow by “the destination IP address” and assign the other flow identifier “VPI/VCI” to the flow. Neither the router20—2nor the ATM switch20—4has a capability of assigning another identifier.

The network element setting information14ofFIG. 3Dindicates setting information to be set in the network elements on the route, which is composed of QoS guarantee setting information and flow identifier assignment setting information. The QoS guarantee setting information is composed of an entrance link ID, an exit link ID, flow identifier information, and QoS information.

The flow identifier assignment setting information is composed of the entrance link ID, the exit link ID, the flow identifier information, and another flow identifier's information.

It is to be noted that some identifier values of the flow identifier information are “ANY” in the router20—1and the ATM switch20—4inFIG. 3D, which indicates that the network management system can not predetermine the flow identifier value since the network element autonomously determines the flow identifier value.

Upon establishing a path, the flow identifier value (=“ANY”) obtained as a result of the QoS guarantee setting to the ATM switch20—4will be set to another flow identifier value of the flow identifier assignment setting information in the router20—1.

Hereinafter, the operation will be described that the network management apparatus10retrieves and establishes the route enabling the requested QoS to be guaranteed on the management object network shown inFIG. 2based on a QoS guarantee request signal81of a customer inputted from the operator terminal70shown inFIG. 1.

The QoS guarantee request signal81is described as a quality discriminating request for a specific IP flow. Specifically, it is represented by the combination of the SAP, IP flow identifier information C1, and contents of service quality guarantee Q1. The IP flow identifier information C1 is represented by the combination of an identifier pattern C1—pattern and an identifier value C1—value, and the contents of service quality guarantee Q1 are represented by the combination of a quality pattern Q1—pattern and a quality value Q1—value.

As an example of the identifier pattern C1—pattern, the destination address, the DSCP, a protocol number, and the like can be cited. As an example of the quality pattern Q1—pattern, a fixed band guarantee, a minimum band guarantee, a delay guarantee, a delay fluctuation guarantee, and the like can be cited.

InFIG. 1, the operator terminal70requests, by the QoS guarantee request signal81, the network management apparatus10to transfer a flow of the destination address=“10.10.10.1” inputted from the SAP40—1to the SAP40—2with the contents of service quality guarantee (fixed band guarantee=“10 Mbps”). The QoS guarantee request signal81at this time as follows:

(2) Operation Procedure Example of QoS Guarantee Request Accepting Analyzer15

FIG. 4shows an operation procedure example of the QoS guarantee request accepting analyzer15. The accepting analyzer15analyzes the received QoS guarantee request, extracts components, and makes the SAP correspond to or associated with the link ID. The process operation of the accepting analyzer15will be described.

Step S10: The QoS guarantee request signal81is accepted from the operator terminal70.

Step S11: The SAP's40—1and40—2, the flow identifier information C1, and the contents of service quality guarantee Q1 are extracted from QoS guarantee request signal81.

Step S12: The identifier pattern C1—pattern and the identifier value C1—value are extracted from the flow identifier information C1 to be provided to the QoS guarantee path route candidate retriever16.

Step S13: The quality pattern Q1—pattern and the quality value Q1—value are extracted from the contents of service quality guarantee Q1 to be provided to the retriever16.

It is to be noted that the numerals within the parentheses indicate those of a specific network element20and a specific link30in the network corresponding toFIG. 2. Hereinafter, the same will apply to the followings.

It is to be noted that the retriever16is not always required to receive the above-mentioned information through the terminal70and the accepting analyzer15. The retriever16may directly receive the information from the terminal70in the form recognizable by itself, or may read the stored information.

(3) Schematic Operation Procedure Example of QoS Guarantee Path Route Candidate Retriever16

FIGS. 5–7respectively show operation procedures (Nos.1–3) of the QoS guarantee path route candidate retriever16. Steps S20–S25ofFIG. 5show the operation procedure for retrieving the route candidate of the QoS guarantee path by the retriever16. A subroutine called at step S22is shown at steps S30–S38inFIG. 6, which checks whether or not the QoS can be guaranteed in each network element.

Furthermore, a subroutine called at step S32is shown inFIG. 7, which checks whether the network element can identify the flow and guarantee the QoS by itself or with the aid of a flow identifier assignment capability of another network element.

Hereinafter, the schematic operation of the retriever16will be described referring toFIGS. 5–7.

InFIG. 5, the retriever16receives the above-mentioned information from the accepting analyzer15(at step S20), and retrieves a single route sequence S—NE from the network element NE—a (20—1) to the network element NE—z (20—3) based on the network configuration information11(at step S21). Then, the retriever16inquires of the subroutine shown inFIG. 6described later about the possibility of the sequence S—NE supporting the identifier pattern C1—pattern and the quality pattern Q1—pattern (at step S22).

In the presence of the supporting route at this time, the subroutine stores the QoS guarantee setting information (command) and the flow identifier assignment setting information (command) set in the network elements20on the route in the storage18as the network element setting information14.

When the response from the subroutine is “possible”, the retriever16ends the process (at step S23). When the response is “impossible”, whether or not there is any other route is determined. In case of “No” (indicating there is no route), the failure of the QoS guarantee is notified to the terminal70(at steps S23–S25), and in case of “Yes” (when there is another route), the process returns to step S21, so that the route supporting the identifier pattern C1—pattern and the quality pattern Q1—pattern is retrieved (at steps S23, S24, S21, and S22).

The schematic operation of the retriever16in the subroutine called at the above-mentioned step S22will now be described referring toFIG. 6.

The retriever16receives the identifier pattern C1—pattern, the quality pattern Q1—pattern, and the route sequence S—NE in the subroutine (at step S30), and inquires of the subroutine shown inFIG. 7described later about the possibility of a single network element NE—i on the sequence S—NE supporting the identifier pattern C1—pattern and the quality pattern Q1—pattern (at steps S31and S32).

When at least one network element20responds “impossible”, the retriever16returns the response “impossible” to step S23shown inFIG. 5to end the process (at steps S33and S38).

In case the response is “possible”, the retriever16stores the command of setting the quality pattern Q1—pattern for the network element NE—i as the QoS guarantee setting information of the network element setting information14(at steps S33and S35).

Also, in case the response is “possible with including NE—j, the identifier pattern C2—Pattern”, i.e. in case the network element NE—j preceding the network element NE—i on the route can support <C1—pattern, Q1—pattern> if another flow identifier is assigned, the retriever16stores the commands of assigning the other flow identifier pattern C2—pattern to the network element NE—j and of setting the quality pattern Q1—pattern respectively as the flow identifier assignment setting information and the QoS guarantee setting information of the network element setting information14(at steps S33–S35).

The above-mentioned steps S31–S35or steps S31–S33and S35are repeatedly executed to all of the network elements NE—a–NE—z on the route sequence S—NE (at step S36), and the response “possible” is returned to step S23shown inFIG. 5to end the process (at step S37).

Hereinafter, the subroutine called at step S32will be described referring toFIG. 7.

In the subroutine, the retriever16receives the route sequence S—NE, the network element NE—i, the identifier pattern C1—pattern, and the quality pattern Q1—pattern (at step S40). When the network element NE—i supports <identifier pattern C1—pattern, quality pattern Q1—pattern>, the response “possible (can support)” is returned to step S33shown inFIG. 6to end the process (at steps S41and S45).

In case of “impossible (can not support)”, and of the network element NE—j at the preceding stage of the network element NE—i on the route sequence S—NE supporting the flow identifier assignment capability <identifier pattern C1—pattern, other identifier pattern C2—pattern>, and of the network element NE—i supporting QoS guarantee capability <identifier pattern C2—pattern, quality pattern Q1—pattern>, the retriever16responds “possible with including NE—j, identifier pattern C2—pattern” to step S33(at steps S42and S43), and otherwise the response “impossible” is returned (at steps S42and S44).

(4) Specific Operation Example of QoS Guarantee Path Route Candidate Retriever16

FIG. 8shows a route which the retriever16has retrieved based on the information received from the QoS guarantee request accepting analyzer15ofFIG. 4, the QoS guarantee setting information (command), and the flow identifier assignment setting information (command) both set in the network element20on the route. The network element setting information14storing the QoS guarantee setting information and the flow identifier assignment setting information is shown inFIG. 3D.

Hereinafter, the operation when the retriever16determines the above-mentioned route and the network element setting information14will be described referring toFIGS. 9–14which show the flows ofFIGS. 5–7corresponding to specific names of network elements and information.

Step S20inFIG. 9: The retriever16receives the routers20—1,20—3, the links30—1,30—6, the C1—pattern (destination IP address), the C1—value (10.10.10.1), the Q1—pattern (fixed band guarantee), and the Q1—value (10 Mbps) from the accepting analyzer15.

Step S21: The retriever16retrieves a single route which passes through e.g. the ATM switch designated by the provider or the like from the routes from the router20—1to the router20—3referring to the network configuration information11(seeFIG. 3A) to obtain the route sequence S—NE {20—1,20—4,20—3} (see route shown by thick lines inFIG. 8).

It is to be noted that when the route passing through the ATM switch is not designated, the retriever16sometimes retrieves the route sequence S—NE {20—1,20—2,20—3}. This will be described later.

Step S30inFIG. 10: The inquiry about the possibility of the sequence S—NE supporting <C1—pattern, Q1—pattern> is received.

Step S31: A single network element20, e.g. the router20—1is selected among from the sequence S—NE.

Step S32: Possibility of the router20—1supporting <C1—pattern, Q1—pattern> is inquired.

Step S40inFIG. 11: Inquiry about the possibility of the router20—1on the sequence S—NE {20—1,20—4,20—3} supporting <C1—pattern (destination IP address), Q1—pattern (fixed band guarantee)> is received.

Step S41: Whether or not the router20—1supports <C1—pattern (destination IP address), Q1—pattern (fixed band guarantee)> is determined based on the QoS guarantee capability information12(seeFIG. 3B). Since router20—1has a capability of guaranteeing <destination IP address, fixed band guarantee>, the response is “YES”.

Step S45: The response “possible” is returned, and the process returns to step S32.

Steps S32and S33inFIG. 10: Since the response is “possible”, the process proceeds to step S35.

Step S35: The QoS guarantee setting information (command) for the router20—1<link30—1, link30—3, <destination address, 10.10.10.1>, <fixed band guarantee, 10 Mbps>> is stored in the QoS guarantee setting information of the network element setting information14. The storing result is indicated in the QoS guarantee setting information of the router20—1inFIG. 3D.

Step S36: Since all of the network elements20in the sequence S—NE [20—1,20—4,20—3] are not checked, the process returns to step S31.

Steps S31and S32inFIG. 12: The ATM switch20—4is selected from among the sequence S—NE, and possibility of the ATM switch20—4supporting <C1—pattern, Q1—pattern> is inquired.

Step S40inFIG. 13: The inquiry about the possibility of the ATM switch20—4of the sequence S—NE [20—1,20—4,20—3] supporting <C1—pattern (destination IP address), Q1—pattern (fixed band guarantee)> is received.

Step S41: Whether or not the ATM switch20—4supports <C1—pattern, Q1—pattern> is determined based on the QoS guarantee capability information12. Since the ATM switch20—4does not support <C1—pattern (destination IP address), Q1—pattern (fixed band guarantee)> according to the QoS guarantee capability information12shown inFIG. 3B, the response is “NO”.

Step S42: Since the ATM switch20—4guarantees the QoS guarantee capability <VPI/VCI, fixed band guarantee>, it is retrieved whether or not there is a network element, at the preceding stage of the ATM switch20—4, supporting the flow identifier assignment capability <C1—pattern (destination IP address), C2—pattern (VPI/VCI)>, in which the ATM switch20—4supports the QoS guarantee capability <C2—pattern (VPI/VCI), Q1—pattern (fixed band guarantee)>.

Namely, it is confirmed by referring to the QoS guarantee capability information12ofFIG. 3Bthat the ATM switch20—4has the QoS guarantee capability <VPI/VCI, fixed band guarantee>, so that the flow identifier assignment capability information13ofFIG. 3Cis retrieved to find the router20—1having the flow identifier assignment capability <destination IP address, VPI/VCI>. Therefore, “router20—1” is made NE—J and “VPI/VCI” is made C2—pattern, which answers “YES”.

Step S43: After the response “possible with including NE—j, C2—pattern” is provided, the process is ended, and returns to step S32inFIG. 12.

Steps S32and S33inFIG. 12: In response to the response “possible with including NE—j, C2—pattern”, the retriever16recognizes that the ATM switch20—4can not support <destination IP address, fixed band guarantee> but can guarantee a VPI/VCI based-fixed band if the flow identifier VPI/VCI based on the destination IP address is assigned by the router20—1.

Steps S33and S34: Therefore, the flow identifier assignment setting information command for the router20—1<link30—1, link30—3, <destination IP address, 10.10.10.1>, <VPI/VCI, ANY>>, and the QoS guarantee setting information (command) for the ATM switch20—4<link30—3, link30—5, <VPI/VCI, ANY>, <fixed band guarantee, 10 Mbps>> are stored in the network element setting information14(seeFIG. 3D).

Hereafter, the QoS guarantee setting information of the remaining router20—3in the sequence S—NE will be similarly determined as shown inFIG. 3D.

It is to be noted that when the route is not designated to path through the ATM switch20—4at step S21inFIG. 9, the retriever16may retrieve the sequence S—NE [20—1,20—2,20—3] as a single route. In this case, the retriever16finds, referring to the QoS guarantee capability information12shown inFIG. 3B, that the router20—2can not guarantee the fixed band, and does not select the route sequence S—NE [20—1,20—2,20—3].

Also, even if it is shown in the QoS guarantee capability information12that the router20—2can guarantee the fixed band, the retriever16finds, by referring to the flow identifier assignment capability information13, that the router20—1does not have the assignment capability of <destination IP address, DSCP>, and does not select the route sequence S—NE [20—1,20—2,20—3].

(5) Operation Example of QoS Guarantee Path Establishing Portion17

The QoS guarantee path establishing portion17(seeFIG. 1) performs the QoS guarantee setting and the flow identifier assignment setting of the network elements (router20—1, ATM switch20—4, and router20—3) on the retrieved route based on the network element setting information14stored by the retriever16(seeFIG. 8).

FIG. 14shows an operation when the QoS guarantee path establishing portion17fails in establishing the QoS guarantee path of a network resource securing type.

Steps S21–S25: The retriever16determines the QoS guarantee setting information and the flow identifier assignment setting information in the same way as steps S21–S25shown inFIG. 9.

Steps S26–S28: The establishing portion17performs the setting of the network elements20, so that the process is ended if securing resource is succeeded. If it is not the case and another path exists, the process returns to step S20to repeat the same operation.

Step S29: In the absence of other paths, the failure of the QoS guarantee is notified to the terminal70.

FIG. 15shows an embodiment (2) of the present invention, in which a plurality of network elements20having the same QoS guarantee capability are preliminarily aggregated as a single sub-network. The QoS guarantee capability information12of this sub-network is stored in the storage18, so that the QoS guarantee route is retrieved based on the QoS guarantee capability information12of the network elements and the sub-network when the QoS guarantee is accepted.

InFIG. 15, the routers20—5and20—6both without the band guarantee are aggregated as a single sub-network60—1without the band guarantee, so that the QoS guarantee capability information12of the sub-network60—1is stored in the storage18. The routers20—7and20—8both with the band guarantee are aggregated as a single sub-network60—2with the band guarantee, so that the QoS guarantee capability information12of the sub-network60—2is stored in the storage18.

Thus, it becomes possible to shorten a route retrieving time.

FIG. 16shows an embodiment (3) of the present invention, in which the network management apparatus10has means (not shown) for specifying a network element in which a flow identifier vanishes (is deleted), and assigns the vanished flow identifier.

FIG. 16shows a network where the routers20—5and20—6, and the ATM switch20—7having the band guarantee are inserted between the ATM switch20—4and router20—3shown inFIG. 8(router20—2is omitted).

If the flow identifier VPI/VCI vanishes in the routers20—5and20—6, the route between the ATM switches20—5and20—7is not established, so that the retriever16can not retrieve the route (shown by the thick lines) from the router20—1to the router20—3.

Therefore, the retriever16retrieves the routers20—5and20—6in which the flow identifier VPI/VCI on the route between the ATM switches20—4and20—5vanishes, confirms that the router20—6has a capability of assigning the flow identifier VPI/VCI, and then provides the assigning setting information of the flow identifier VPI/VCI to the router20—6.

Thus, the router between the ATM switches20—5and20—7is established in the same way as the above-mentioned router20—1and the ATM switch20—4, so that the route (shown by the thick lines) from the router20—1to the router20—3can be established.

FIG. 17shows an embodiment (4) of the present invention, in which the configuration of the management object network is the same as the network shown inFIG. 8.

In this embodiment (4), the establishing portion17preliminarily establishes the path to the ATM switch20—4, and stores the flow identifier VPI/VCI and the QoS guarantee setting information (both are not shown) of the path in the storage18.

When the retriever16accepts the QoS guarantee request and the retrieved route sequence S—NE includes the ATM switch20—4to which a layer2path is established, the flow identifier assignment setting is performed so that the other router20—1may use the flow identifier VPI/VCI.

Thus, it becomes possible to perform the route retrieval and the QoS guarantee setting at a higher speed.

As described above, a network management apparatus according to the present invention is arranged such that a QoS guarantee path route candidate retriever retrieves a route enabling a predetermined QoS to be guaranteed or a route enabling the predetermined QoS to be guaranteed by being newly assigned with the flow identifier from among routes between a source and a destination network elements based on network configuration information, QoS guarantee capability information, and flow identifier assignment capability information, and a QoS guarantee path establishing portion performs a QoS guarantee setting and a flow identifier assignment setting to the network elements on the retrieved route. Therefore, it becomes possible to retrieve a QoS guarantee route at a high speed even in a network composed of network elements whose pattern such as a QoS guarantee and a flow identifier is different from each other, and to perform the QoS guarantee route setting of the network element on the route.

Also, the QoS guarantee path establishing portion determines a flow identifier value autonomously determined by the network element to which the QoS guarantee setting or the flow identifier assignment setting has been performed as an identifier value set in other network elements. Therefore, it becomes possible to select the network element which determines the flow identifier value as a network element on the QoS guarantee route

Also, upon failing to establish a QoS guarantee path of a network resource securing type, the QoS guarantee path establishing portion establishes a next QoS guarantee path retrieved by the QoS guarantee path route candidate retriever, thereby enabling the QoS guarantee path of the network resource securing type to be secured from among a plurality of QoS guarantee routes.

Also, in the presence of a plurality of routes enabling the predetermined QoS to be guaranteed, the QoS guarantee path establishing portion selects a single route from among the routes according to a preliminarily designated selection method, thereby enabling a condition for designating the QoS guarantee route to be further set.

Also, the QoS guarantee capability information indicates a QoS guarantee capability of a sub-network composed of a plurality of network elements, and further a QoS guarantee capability of a sub-network composed of a plurality of network elements whose treatable flow identifiers are coincident with each other, thereby enabling the QoS guarantee route to be retrieved at a higher speed.

Also, as a route enabling the predetermined QoS to be guaranteed by being assigned with the flow identifier, a route without network element in which the flow identifier vanishes between a network element assigning the flow identifier and a network guaranteeing a QoS based on the flow identifier is retrieved, or a network element in which the flow identifier per classification of a flow identifier vanishes is specified, and a route to a network element having a capability to assign the vanished flow identifier is retrieved. Therefore, it becomes possible to determine the route based on the flow identifier assigned by the network element20at the preceding stage, or to establish the route including the network element20in which the flow identifier vanishes as the QoS guarantee route.

Furthermore, by establishing a layer2path having a preliminarily guaranteed QoS, it becomes possible to retrieve the route enabling the QoS to be guaranteed at a high speed.

Thus, according to the network management apparatus according to the present invention, a QoS guarantee process can be performed at a high speed. Also, this method is realized by an abstract information model independent of a technology. Therefore, even if a sub-network of new technology is added, an expansion can be easily performed.