COMMUNICATION NETWORK SYSTEM, PATH CALCULATION DEVICE, AND COMMUNICATION PATH ESTABLISHMENT CONTROL METHOD

• US 20100034205A1
• Filed: 06/10/2009
• Published: 02/11/2010
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Communication Technologies, Ltd. (Hitachi, Ltd.)
• Inventors: KUSAMA, Kazuhiro, MAEDA, Shuji
• Granted Patent: US 8,340,104 B2
• Time in Patent Office: Days
• US Class Current: 370/400
• CPC Class Codes: G06F 15/16 Combinations of two or more digital computers each having at least an arithmetic unit, a program unit and a register, e.g. for a simultaneous processing of several programs coordinating program control therefor G06F9/52; in regulating and control system G05B
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/03 by updating link state protocols
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/30 Routing of multiclass traffic
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04L 45/44 Distributed routing
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

In an MPLS or GMPLS network, links for hops of a communication path and adaptation to be implemented on the border of management domains or layers are automatically appropriately selected based on a service type or a requirement for maintenance. First, a unit that appends an identifier of a service to be provided and an attribute of the service to a communication path establishment control message, and requests path establishment is installed in a source node. Secondly, a unit that determines a requirement for maintenance of the communication path and adaptation on the basis of the service identifier and/or service attribute is installed in each node. Thirdly, maintenance attributes of network resources are compared with the requirement for maintenance in order to determine links and nodes through which the communication path passes. The determined links, nodes, and adaptation are designated as action parameters for a switching unit and/or interface unit.

Claims

1. A communication network system comprising a plurality of nodes and a first path calculation device, and transferring a control signal, which is used to establish a path among the plurality of nodes, so as to establish the path:

the first path calculation device includes a service definition table in which a service identifier, a service attribute, a requirement for maintenance, and adaptation are recorded in association with one another, and a link attribute table in which a link and a maintenance attribute of the link are recorded in association with each other;

the node includes a session management table in which a session identifier, a service identifier, a service attribute, an explicit route, and adaptation information are recorded in association with one another;

wherein;

a first node serving as an origin of the path transmits a path calculation request, which contains the service identifier and service attribute, to the first path calculation device;

the first path calculation device uses the service definition table to determine the requirement for maintenance, which links for hops of a communication path to be established should satisfy, on the basis of the received service identifier and service attribute;

the first path calculation device extracts a plurality of links, of which maintenance attributes satisfy the determined requirement for maintenance, from the link attribute table, and determines a candidate for a route of the communication path, which satisfies the requirement for maintenance in relation to each of the hops, in a network formed with the extracted plurality of links, and/or determines the adaptation, which is any of various connection facilities to be implemented at the end point of the path, by searching the service definition table on the basis of the service identifier and service attribute;

the first path calculation device produces a path calculation response, which contains the determined candidate for the route and/or adaptation information, and returns the path calculation response to the first node of the request source;

if the received path response contains the adaptation information, the first node records the adaptation information, which is contained in the received path calculation response, in the session management table in association with the service identifier, service attribute, and explicit route; and

the first node sets up an adaptation facility for the own node on the basis of the adaptation information contained in the path calculation response received from the first path calculation device, and transmits the path establishment request, which contains the service identifier, service attribute, and explicit route, to a second node terminating the subsequent hop.

2. The communication network system according to claim 1, further comprising a communication path establishment request system that issues a path establishment request, which contains a service identifier and a service attribute, to the first node, wherein:

when having received the path establishment request from the communication path establishment request system, the first node transmits a path calculation request, which contains the service identifier and service attribute, to the first path calculation device.

3. The communication network system according to claim 1, wherein the path calculation device inserts the determined adaptation information to the explicit route, and designates a network resource, which is an object in which the determined adaptation should be set up, according to part of the explicit route to which the adaptation information is inserted.

4. The communication network system according to claim 1, wherein a path establishment request is transferred among nodes connected to one another by links identified based on the explicit route, a query or a response is, if necessary, transferred to or from the first or second path calculation device, and session information and adaptation information are held in each node.

5. The communication network system according to claim 1, wherein the first node at an origin includes means that requests path establishment with the identifier of a service to be provided and the attribute thereof contained in a message serving as a path establishment request.

6. The communication network system according to claim 1, wherein a third node at a path end point obtains adaptation information contained in a path calculation response, sets up adaptation and cross-connection in an interface unit and switching unit respectively, and transfers a path establishment response message to a node terminating the previous hop.

7. The communication network system according to claim 1, wherein, when having received a path establishment response from a downstream node, each node designates an interface unit on the basis of adaptation information recorded in the session management table.

8. The communication network system according to claim 1, wherein:

when a link for any of hops forming a determined candidate for a route should be realized with a path defined in a server layer, the first path calculation device transmits a path calculation request, which contains the end point of the link as the end point of the path and contains the service identifier and service attribute, to a second path calculation device for the server layer; and

the second path calculation device uses, similarly to the first path calculation device, the service definition table to determine a requirement for maintenance which links for hops of a communication path to be established should satisfy, uses the link attribute table to determine a path that satisfies the requirement for maintenance in relation to each of the hops, and searches the service definition table on the basis of the service identifier and service attribute so as to determine adaptation information to be set at the end point of the path.

9. The communication network system according to claim 1, wherein the first path calculation device comprising:

means that determines a requirement for maintenance of a communication path and/or adaptation by assessing the identifier of a service contained in a received path establishment request and/or an attribute inherent to the service,

means that holds maintenance attributes of network resources including nodes and links among the nodes, and

means that compares the maintenance attributes of the network resources with the requirement for maintenance of the communication path so as to select links and nodes, which satisfy the requirement for maintenance, over an end-to-end interval for which path calculation has been requested, thus determines a route of the path, and returns the determined path route and adaptation to the request source.

10. The communication network system according to claim 1, wherein:

the first path calculation device further includes;

a contents-of-ticket management table in which the relationship of association between an adaptation ticket and adaptation is recorded,

means that assigns an adaptation ticket, which is a tag independent of the type of adaptation, to the adaptation information, and holds the relationship of association between the adaptation and adaptation ticket,

means that returns the adaptation ticket instead of the response representing adaptation, and

means that, when the path calculation request contains the adaptation ticket, returns the associated adaptation;

each node includes;

means that requests path establishment to an adjoining downstream node by inserting an explicit route to a path establishment request, the explicit route which is contained in a path calculation response received from the path calculation device and contains the adaptation ticket, and

means that interprets the explicit route, which is contained in the received path establishment request, from the beginning, that if the adaptation ticket appears, issues a path calculation request, which contains the adaptation ticket, to the first path calculation device identified with a path calculation device identifier contained as a ticket issuance source in the adaptation ticket; and

when having received the path calculation request that contains the adaptation ticket, the first path calculation device obtains the adaptation information, which is preserved at the time of issuance of the adaptation ticket, from the contents-of-ticket management table, and returns a path calculation response, which contains the adaptation information and explicit route, to the first node of the request source.

11. The communication network system according to claim 10, wherein the first path calculation device includes means that when assigning the adaptation ticket, designates the valid period of the adaptation ticket, and that, when the valid period is expired, invalidates the adaptation ticket.

12. The communication network system according to claim 1, wherein the first path calculation device includes means that requests a second path calculation device to determine a detailed route of a path and/or adaptation in relation to a portion of an interval for which path calculation has been requested, receives a response, and produces a response to a path calculation request, which the own path calculation device has received, by inserting the route and/or adaptation information, which are contained in the received response, to a part of the route of the path and adaptation information, which are determined by the own path calculation device, relating to the portion of the interval.

13. The communication network system according to claim 1, wherein an adaptation facility represented by the adaptation information includes one or more of an encapsulation function, a function of distributing a flow or integrating portions of a flow, and a function of selectively transferring a management alarm, which are applied to data to be transferred from the node.

14. The communication network system according to claim 1, wherein an adaptation facility represented by the adaptation information includes a QoS mapping function and/or a code conversion function, which are applied to data to be transferred from the node.

15. The communication network system according to claim 1, wherein the requirement for maintenance of the communication path and the maintenance attributes of the network resources each include information on a time zone during which a service should be provided, and/or information on the length of a time during which discontinuation of a service is permitted.

16. The communication network system according to claim 1, wherein the path establishment request or path establishment response is an MPLS or GMPLS RSVP extension message.

17. A path calculation device in a communication network system comprising a plurality of nodes and the path calculation device, and transferring a control signal, which is used to establish a path among the plurality of nodes, so as to establish the path:

the path calculation device includes a service definition table in which a service identifier, a service attribute, a requirement for maintenance, and adaptation are recorded in association with one another, and a link attribute table in which a link and a maintenance attribute of the link are recorded in association with each other;

wherein;

the path calculation device receives a path calculation request, which contains the service identifier and service attribute, from a first node serving as an origin of the path;

the path calculation device uses the service definition table to determine the requirement for maintenance, which links for hops of a communication path to be established should satisfy, on the basis of the received service identifier and service attribute;

the path calculation device extracts a plurality of links, of which maintenance attributes satisfy the determined requirement for maintenance, from the link attribute table, and determines a candidate for a route of the communication path, which satisfies the requirement for maintenance in relation to each of the hops, in a network formed with the extracted plurality of links, and/or determines the adaptation, which is any of various connection facilities to be implemented at the end point of the path, by searching the service definition table on the basis of the service identifier and service attribute;

the first path calculation device produces a path calculation response, which contains the determined candidate for the route and/or adaptation information, and returns the path calculation response to the first node of the request source.

18. The path calculation device according to claim 17, wherein the path calculation device returns an adaptation ticket instead of adaptation information, and/or returns adaptation information, which is associated with an adaptation ticket, in case the adaptation ticket is contained in a path calculation request.

19. A communication path establishment control method in a communication network system that includes a plurality of nodes and a first path calculation device, and transfers a control signal, which is used to establish a path among the plurality of nodes, so as to establish the path:

the first path calculation device including a service definition table in which a service identifier, a service attribute, a requirement for maintenance, and adaptation are recorded in association with one another, a link attribute table in which a link and a maintenance attribute of the link are recorded in association with each other, and a contents-of-ticket management table in which the relationship of association between an adaptation ticket and adaptation is recorded, and

the node including a session management table in which a session identifier, a service identifier, a service attribute, an explicit route, and adaptation information are recorded in association with one another,

the communication path establishment control method comprising the steps of;

transmitting a path calculation request, which contains the service identifier and service attribute, from a first node serving as an origin of a path to the first path calculation device;

referencing the service definition table by the first path calculation device on the basis of the received service identifier and service attribute so as to determine a requirement for maintenance which links for hops of a communication path to be established should satisfy;

extracting a plurality of links, of which maintenance attributes satisfy the determined requirement for maintenance, from the link attribute table by the first path calculation device, and determining a candidate for a route of the communication path, which satisfies the requirement for maintenance in relation to each of the hops, in a network formed with the extracted plurality of links;

searching the service definition table by the first path calculation device on the basis of the service identifier and service attribute so as to determine adaptation that is any of various connection facilities to be implemented at the end point of a path, issuing an adaptation ticket that is a tag which is independent of an adaptation type and assigned to the adaptation information, and that contains the path calculation device identifier of an issuance source and a ticket identifier, recording the adaptation information and ticket identifier in the contents-of-ticket management table;

producing a path calculation response by the first path calculation device, the path calculation response that contains identifiers of nodes existing along the route and the issued adaptation ticket as objects of an explicit route in the order appeared on the communication path to be established and that also contains the service identifier and service attribute, and returning the path calculation response to the first node of the request source;

interpreting the explicit route, which is contained in the path calculation response received by the first node, from the beginning, if the adaptation ticket appears, issuing a path calculation request, which contains the adaptation ticket, by the first node to the first path calculation device identified with the path calculation device identifier contained as a ticket issuance source in the adaptation ticket;

when having received the path calculation request containing the adaptation ticket, obtaining the adaptation information, which is held at the time of issuance of the adaptation ticket, from the contents-of-ticket management table by the first path calculation device, and returning a path calculation response, which contains the adaptation information and explicit route, to the first node of the request source;

recording the adaptation information, which is contained in the received path calculation response, in the session management table by the first node in association with the service identifier, service attribute, and explicit route;

setting up an adaptation facility for the own node on the basis of the adaptation information contained in the path calculation response which the first node has received from the first path calculation device; and

transmitting a path establishment request, which contains the service identifier, the service attribute, and the explicit route with the adaptation ticket, from the first node to a second node terminating the subsequent hop.