JP4668224B2 - Route selection control device and communication system - Google Patents

Description

  The present invention relates to a route selection control device and a communication system.

In recent years, ALL-IP (Internet Protocol) network technology has been studied, and a method called IMS (IP Multimedia Subsystem) or MMD (Multi Media Domain) (hereinafter referred to as “IMS / MMD”) is used as the core network technology. Use is under consideration. In a communication network using IMS / MMD, a user notifies the core network of a communication partner, the type of application to be used, a communication band, and the like using SIP (Session Initiation Protocol) and SDP (Session Description Protocol). In addition, in IMS / MMD, the use of MPLS (Multi Protocol Label Switching) as a routing technique for the core network is being studied. In a communication network using MPLS (MPLS network), a virtual path (LSP: Label Switch Path) can be set as a communication path from one base to another base on a physical line. When setting LSP, MPLS-TE (Traffic Engeneering) can be used. MPLS-TE is a technology that monitors core network traffic using MPLS and performs path control according to the traffic. The MPLS-TE can specify the communication band of the LSP when setting the LSP. Then, it is possible to set LSPs from one base to another base so that the communication bandwidth allocated to each LSP is satisfied on the physical line.
RFC3261: "SIP: Session Initiation Protocol" RFC3312: “Integration of Resource Management and Session Initiation Protocol” RFC2327: “SDP: Session Description Protocol” RFC3031: “Multiprotocol Label Switching Architecture” RFC3209: “RSVP-TE: Extensions to RSVP for LSP Tunnels” 3GPP2 X.S0013: "All-IP Core Network Multimedia Domain"

However, the conventional techniques have the following problems.
There is a demand to realize QoS (Quality of Service) for traffic to be prioritized on a virtual path like ATM (Aynchronous Transfer Mode) for traffic flowing through an LSP by MPLS-TE. However, existing routers cannot set and operate QoS such as queuing on an LSP that is a virtual path set by MPLS-TE. Queuing QoS can be set only for physical interfaces. On the other hand, when an LSP is set, the LSP communication band can be specified, and the LSP path can be set so as to satisfy the communication band in the entire network. However, even if traffic that exceeds the communication bandwidth specified on the LSP flows, the traffic cannot be controlled on the LSP, and the traffic flows as it is, which guarantees the QoS of the traffic that you want to prioritize on the LSP. There is a problem that it becomes impossible.

  In addition, when it is desired to preferentially control a specific traffic among the traffic from the user, a QoS rule is described in the physical interface of each router separately from the MPLS LSP. In this case, the communication band value of the LSP calculated at the design stage cannot be used effectively, and QoS in LSP units cannot be realized.

  Also, in the future, when the function to implement QoS on the LSP can be implemented in the router, in a large-scale network, the number of LSPs that go through one router will generally be several tens. Therefore, managing the QoS that runs on each LSP is a daunting task. For this reason, in an actual commercial network, it is difficult to preferentially control a specific traffic on the LSP among the traffic from the user only by the function of the router.

  Also, in the network using IMS / MMD, the user notifies the session information to the core network by SIP, but how to handle the session information in the backbone network is not defined, and QoS is effectively used in the backbone network. Can not work.

  The present invention has been made in view of such circumstances, and its object is to provide a path selection control device and a communication system that can contribute to guaranteeing QoS of traffic that is desired to be prioritized on an LSP in an MPLS network. It is to provide.

  In order to solve the above problem, a route selection control device according to the present invention is a route selection control device for an MPLS network in which a bandwidth guaranteed LSP and a bandwidth non-guaranteed LSP are set between communication bases. When the communication bandwidth requested by the user terminal and the LSP database that holds the information on the communication bandwidth allocated to the guaranteed LSP and the information on the total traffic volume flowing on the bandwidth guaranteed LSP and the predetermined priority traffic conditions are met The traffic of the communication session is distributed to available bandwidth guaranteed LSPs, while the amount of traffic of the communication session can be used when the communication session does not meet a predetermined priority traffic condition. When the total value added to the traffic volume does not exceed the communication band assigned to the bandwidth guaranteed LSP, the communication session Route to the bandwidth guaranteed LSP that can be used, and when the total value exceeds the communication band assigned to the bandwidth guaranteed LSP, the traffic for the communication session is routed to the available bandwidth non-guaranteed LSP And a selection unit.

  A communication system according to the present invention includes a route selection control device according to claim 1, a SIP server that transmits information on a communication session requested by a user terminal to the route selection control device, and a route selection result of the route selection control device. According to the traffic output control means for controlling the traffic of the corresponding communication session to be output to either the bandwidth guaranteed LSP or the bandwidth non-guaranteed LSP, And a traffic transfer means for outputting to any of the LSPs.

  In the communication system according to the present invention, the traffic output control means is provided in a device on the communication network side.

  In the communication system according to the present invention, the traffic output control means is provided in a device on the user terminal side.

  ADVANTAGE OF THE INVENTION According to this invention, it can contribute to guaranteeing QoS of the traffic which wants to give priority on LSP in an MPLS network.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of a communication system according to an embodiment of the present invention. The communication system shown in FIG. 1 includes an SBPS (Session Bandwidth Path Selector) 1 serving as a path selection control device according to the present embodiment and an LSP database 2 accessed from the SBPS 1. The SBPS 1 is connected to the SIP server 3 via a communication line. The SIP server 3 is provided as one of the MMD nodes, has a P-CSCF (Proxy Call Session Control Function), and exchanges SIP messages with user terminals via a communication line. The MPLS network 10 includes a plurality of routers 11. The wireless network 20 is a wireless access network accessed from the user terminal 21. The wireless network 20 is connected to the MPLS network 10 via a PDSN (Packet Data Serving Node) 30.

First, the outline of the route selection control method according to the present embodiment will be described with reference to FIG.
In the MPLS network 10 shown in FIG. 1, a communication path is set with a full mesh from the router 11 at each base to the router 11 at another base. Bandwidth type LSP (hereinafter referred to as “Guarantee LSP”) that guarantees communication quality by specifying a communication band (communication speed) as the type of communication path, and a band that does not specify a communication band (zero-bandwidth) Non-guaranteed LSP (hereinafter referred to as “Non-guarantee LSP”) is used.

  In FIG. 2, two communication paths are set between POP (Presence Of Point) _A and B which are communication bases. One communication path is the Guarantee LSP 110, and a communication band is designated. The other communication path is Non-guarantee LSP 120, and no communication band is specified.

  In the present embodiment, it is assumed that user traffic is normally transmitted by the Guarantee LSP 110 in a network environment as shown in FIG. Then, the usage band is estimated from the SIP / SDP information issued by the user terminal, and when the total traffic volume exceeds the communication band of the Guarantee LSP 110, the low priority traffic is distributed to the non-guarantee LSP 120. High traffic (for example, emergency call) is always transmitted by the Guarantee LSP 110. This route selection control function is provided in the SBPS 1 shown in FIG. As a result, the QoS of the traffic to be prioritized on the LSP is guaranteed.

  Next, a route selection control operation according to the present embodiment in the communication system of FIG. 1 will be described in detail with reference to FIG. FIG. 3 is an operation flowchart of the SBPS 1 shown in FIG.

  First, the user terminal 21 transmits an INVITE message 200 to the SIP server 3 on the MMD network according to the SIP Precondition procedure. The SIP server 3 acquires session information such as a communication partner, a used bandwidth (bandwidth), an application, and a telephone number from the INVITE message 200 received from the user terminal 21, and notifies the session information to the SBPS 1 (S0).

  The SBPS 1 holds attribute information (hereinafter referred to as “priority traffic information”) of traffic to be preferentially controlled, which is defined in advance by a network administrator. The priority traffic information corresponds to items such as a telephone number notified by a SIP / SDP message and an application used.

  The LSP database 2 holds the value of the communication band assigned to the LSP connecting between the bases and the total traffic amount flowing on the LSP. The communication band of each LSP is determined by the network administrator. The traffic flowing on the LSP can be calculated by periodically acquiring a MIB (Management Information Base) value implemented in the router 11 by SNMP (Simple Network Management Protocol).

  The SBPS 1 determines whether the session information received from the SIP server 3, that is, the SIP / SDP information transmitted by the user terminal 21, corresponds to any item of the priority traffic information (S1).

  As a result of the determination in step S1, if the session information corresponds to any item of the priority traffic information, the SBPS 1 transmits an approval message to the SIP server 3 (S2). When the SIP server 3 receives an approval message having a meaning of permitting transfer to the Guarantee LSP from the SBPS 1, the SIP server 3 transmits an OK message (210) to the user terminal 21 according to the SIP Precondition procedure. Based on the OK message (210), the wireless network 20 of the user terminal 21 instructs the corresponding PDSN 30 to perform priority marking for the packet from the user terminal 21. The PDSN 30 (traffic output control means) adds a priority flag to the instructed packet. Information such as DSCP and Precedence included in the packet can be used for the priority flag. The network administrator defines in advance which value of DSCP or Precedence is the priority flag. A PE (Provider Edge) router 11 (traffic transfer means) in the MPLS network 10 distributes incoming packets to LSPs. The PE router 11 outputs the packet with the priority flag to the Guarantee LSP. As a result, when the user terminal 21 starts using the application and transmits a packet, the packet is transmitted with the Guarantee LSP with the priority flag added by the PDSN 30.

  On the other hand, as a result of the determination in step S1, if the session information does not correspond to any item of the priority traffic information, the SBPS 1 allocates the traffic from the user terminal 21 to the Guarantee LSP or the Non-guarantee LSP. Is determined (S3). In this LSP selection process, first, a Guarantee LSP corresponding to a transmission path of traffic from the user terminal 21 is detected based on the session information. Next, the current total traffic amount in the Guarantee LSP is acquired from the LSP database 2. Next, the total value obtained by adding the traffic volume (usage band) from the user terminal 21 to the total traffic volume is compared with the communication band of the Guarantee LSP in the LSP database 2. As a result of this comparison, when the total traffic amount does not exceed the communication bandwidth of the Guarantee LSP, traffic from the user terminal 21 is distributed to the Guarantee LSP. On the other hand, when the total amount of traffic exceeds the communication bandwidth of the Guarantee LSP, traffic from the user terminal 21 is distributed to the Non-guarantee LSP.

  As a result of step S3, when the traffic from the user terminal 21 is distributed to the Guarantee LSP, the SBPS 1 transmits an approval message to the SIP server 3 (S2).

  On the other hand, when allocating traffic from the user terminal 21 to the non-guarantee LSP, the SBPS 1 transmits a disapproval message to the SIP server 3 (S4). When the SIP server 3 receives a disapproval message indicating that transfer to the Guarantee LSP has not been permitted from the SBPS 1, a message notifying that the communication quality of the application cannot be guaranteed in the MPLS network according to the SIP Precondition procedure. (210) is transmitted to the user terminal 21. Based on the message (210), the radio network 20 of the user terminal 21 instructs the corresponding PDSN 30 to perform non-priority marking for the packet from the user terminal 21. The PDSN 30 adds a non-priority flag to the instructed packet. For the non-priority flag, information such as DSCP and Precedence included in the packet can be used. The network administrator defines in advance which value of DSCP or Precedence is the non-priority flag. The PE router 11 in the MPLS network 10 outputs a packet with a non-priority flag to the non-guarantee LSP. As a result, when the user terminal 21 starts using the application and transmits a packet, the packet is added with a non-priority flag by the PDSN 30 and transmitted by a non-guarantee LSP. Note that the SIP server 3 may not allow the user terminal 21 to use the application depending on the situation in the MPLS network.

  When the user terminal 21 notifies the SIP server 3 of the end of communication by a Bye message of the SIP procedure, the communication using the LSP ends.

  In the above-described embodiment, the PDSN 30 performs the priority / non-priority marking on the packet. However, other devices on the communication network side may perform the priority / non-priority marking on the packet. For example, the router 11 which is a device on the communication network side may perform priority / non-priority marking on the packet. Alternatively, the device on the user terminal side may perform priority / non-priority marking on a packet transmitted from the user terminal 21. For example, priority / non-priority marking may be performed on a packet transmitted by the user terminal 21 itself. Alternatively, as an external device of the user terminal 21, a device that performs priority / non-priority marking on a packet may be provided. In other words, “means for performing priority / non-priority marking on packets”, which is an embodiment of the traffic output control means, may be provided in either the communication network side device or the user terminal side device.

  According to the above-described embodiment, traffic from the user terminal 21 is distributed to the Guarantee LSP or the Non-guarantee LSP according to the total traffic amount of the Guarantee LSP. Thereby, QoS of the traffic transmitted by Guarantee LSP is guaranteed on LSP. Therefore, by distributing the traffic to be prioritized to the Guarantee LSP, it becomes possible to guarantee the QoS of the traffic to be prioritized on the LSP.

  In addition, according to the present embodiment, it is possible to guarantee QoS in units of LSPs by extending MMD nodes and SIP protocols without adding special functions to the router 11 of the MPLS network 10. Thereby, the quality of the predetermined priority traffic in the network can be guaranteed. Further, depending on the degree of congestion in the MPLS network, it is possible to prevent the backbone network from being congested by disabling the use of low priority applications at the time of application session establishment by the user terminal 21.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

1 is a block diagram showing an overall configuration of a communication system according to an embodiment of the present invention. It is a conceptual diagram for demonstrating the route selection control method which concerns on the same embodiment. It is an operation | movement flowchart of SBPS1 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... SBPS, 2 ... LSP database, 3 ... SIP server, 10 ... MPLS network, 11 ... Router, 20 ... Wireless network, 21 ... User terminal, 30 ... PDSN

Claims (4)

Bandwidth guaranteed LSP and non-guaranteed LSP are MPLS network route selection control devices set between communication bases,
An LSP database that holds information on the communication bandwidth allocated to the bandwidth guaranteed LSP and information on the total traffic volume flowing on the bandwidth guaranteed LSP,
When the communication session requested by the user terminal matches a predetermined priority traffic condition, the traffic of the communication session is distributed to an available bandwidth guaranteed LSP, while the communication session does not meet the predetermined priority traffic condition. If the total value of the bandwidth guaranteed LSP that can use the traffic volume of the communication session does not exceed the communication bandwidth allocated to the bandwidth guaranteed LSP, the traffic of the communication session can be used. A route selection unit that distributes traffic to a non-guaranteed bandwidth LSP that can be used when the total value exceeds the communication bandwidth allocated to the bandwidth guaranteed LSP;
A route selection control device comprising: A route selection control device according to claim 1;
A SIP server that transmits information on a communication session requested by the user terminal to the route selection control device;
Traffic output control means for controlling to output the traffic of the corresponding communication session to either a bandwidth guaranteed LSP or a bandwidth non-guaranteed LSP according to the route selection result of the route selection control device;
A traffic transfer means for outputting the controlled traffic to either a bandwidth-guaranteed LSP or a bandwidth non-guaranteed LSP;
A communication system comprising:   The communication system according to claim 2, wherein the traffic output control means is provided in a device on a communication network side.   The communication system according to claim 2, wherein the traffic output control unit is provided in a device on a user terminal side.

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