JP2007036599A - Phone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phone system with which resources in a network can be utilized to the utmost extent while ensuring speech quality. <P>SOLUTION: A resource particularizing processing section 34a particularizes a consumption state of communication resources in an IP network. On the basis of a caller terminal IP address and a called terminal IP address notified by a SIP server 1, a communication path particularizing processing section 34b particularizes a communication path between the terminals. A path particularizing processing section 34c particularizes a path whose remaining resources are at minimum among paths included in communication paths particularized by the communication path particularizing processing section 34b. A judgement processing section 34d permits call connection to the SIP server 1 only when the speech quality can be ensured even if remaining resources of the path particularized by the path particularizing processing section 34c are consumed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a telephone system used for an extension telephone system or the like formed in a company. In particular, the present invention relates to a telephone system that performs voice communication between terminals using IP (Internet Protocol).

  Telephone services (hereinafter referred to as IP telephones) that transmit voice data in IP packets have been introduced in companies and general households (see, for example, Patent Document 1). Compared with a circuit-switched telephone service that requires expensive resources such as an exchange, a low-priced telephone service can be provided by using an IP network that can use communication resources at low cost. However, since the IP network is a best-effort type network, transmission quality deteriorates due to packet discard, delay variation (jitter), and the like. These problems can be compensated to some extent by the buffering function on the receiving side. However, when excessive deterioration occurs, there is a problem that sound is interrupted, noise and echoes are generated.

  Packet discards and fluctuations in the amount of delay are caused by various causes, and the main one is that the number of connected calls becomes excessive and exceeds network resources. IP telephones include SIP (Session Initiation Protocol) and H.264. Incoming and outgoing calls are controlled by a communication control protocol such as H.323, but if the number of call connections is increased without considering network resources, packet discard and delay amount fluctuations gradually occur and voice quality begins to deteriorate. In addition, the influence of data packets flowing in the same network is great, and if network resources are occupied by a large number of data packets, the voice quality is similarly deteriorated.

Since an IP network is usually formed by a plurality of routers having a hierarchical structure, end-to-end is connected by a plurality of network paths. However, the bandwidth of each path is not all the same. For example, in the case of a company spanning a plurality of areas, the bandwidth of a path connecting the offices is often narrow even though the network bandwidth in the same office is relatively wide. In such a case, even if many (for example, 10) simultaneous calls are possible between certain departments in the office, the number of connections across offices must be less than that (for example, 5 or less). In some cases, sufficient quality cannot be ensured. In order to cope with this, there is another problem that the network resources cannot be utilized to the maximum by the technique of simply limiting the number of calls to 5 or less. Furthermore, data packets other than voice are simultaneously flowing through the network, and communication quality cannot be improved by simply limiting the number of calls without considering the bandwidth occupied by these data packets.
JP 2001-285342 A

As described above, the existing IP telephone system has fatal problems such as deterioration in call quality due to the use of the IP network and difficulty in using communication resources to the maximum.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a telephone system capable of making maximum use of network resources while ensuring call quality.

  In order to achieve the above object, according to one aspect of the present invention, a plurality of telephone terminals that realize voice communication by exchanging packetized voice data via a packet communication network formed by a plurality of nodes; In a telephone system comprising a call connection processing means for performing call connection control for the plurality of telephone terminals, a transmission capacity database for individually managing transmission capacities of a plurality of paths forming the packet communication network is provided. The call connection processing means notifies the resource management server of the address information of the caller telephone terminal and the address information of the callee telephone terminal when a call request is generated. The resource management server inquires packet traffic for each of the plurality of nodes and specifies a resource consumption state of the packet communication network. Communication between the caller telephone terminal and the callee telephone terminal based on the resource identification means and the notified address information of the caller telephone terminal and the callee telephone terminal address information A path that specifies a path with a minimum remaining resource among paths included in the specified communication path based on the resource consumption state of the packet communication network and the transmission capacity database; When a call is connected in accordance with the call request according to the specifying means, the call connection processing means is allowed to connect the call only when the call quality can be secured even if the remaining resources of the specified path are consumed. There is provided a telephone system characterized by comprising determination means for performing the above.

  By taking such means, the resource management server grasps the consumption state of communication resources between the caller and callee telephone terminals before establishing the call connection. The call connection is permitted only when the call quality can be ensured even if the call connection is made. Therefore, it is possible to limit the number of connected devices in consideration of not only the number of calls but also the bandwidth of each path of the transmission path occupied by the call. As a result, it is possible to provide an IP telephone service that can use network resources to the maximum while ensuring call quality.

  According to the present invention, it is possible to provide a telephone system capable of making maximum use of network resources while ensuring call quality.

  FIG. 1 is a system diagram showing an embodiment of a telephone system according to the present invention. In FIG. 1, reference numeral 1 is an SIP (Session Initiation Protocol) server, 2 is a resource management server, 3a and 3b are wireless LAN (Local Area Network) access points, 4a, 4b and 4c are routers, and 5a and 5b are layer 2s. Switches 6a, 6b, 6c, 6d, 6e, and 6f are wireless IP telephones, 7a and 7b are data terminals, and 8a, 8b, 8c, and 8d are IP telephones. Among these, the routers 4 a to 4 c function as nodes forming the IP network, and in particular, the router 4 c is connected to the Internet network via the communication path 21. In FIG. 1, reference numerals 9 to 23 are attached to the respective paths constituting the IP network. The data terminals 7a and 7b mainly exchange data other than voice, such as e-mails, but a function as a telephone can be realized depending on the application software installed.

  The routers 4a and 4b are respectively installed in office premises located at a relatively long distance, and mediate information communication between offices via the router 4c. That is, the wireless LAN access point 3a and the layer 2 switch 5a below the router 4a are arranged in the same office premises, and accommodate the wireless IP telephones 6a, 6b, 6c, the data terminal 7a, and the IP telephones 8a, 8b. Similarly, the wireless LAN access point 3b and the layer 2 switch 5b below the router 4b are disposed in the same office premises and accommodate the wireless IP telephones 6d, 6e, 6f, the data terminal 7b, and the IP telephones 8c, 8d.

  An extension call within the same office and an outside line call between offices via the IP network are realized by call connection processing by the SIP server 1. That is, the SIP server 1 performs call connection control based on the IP address for the wireless IP telephones 6a to 6f, the data terminals 7a and 7b, and the IP telephones 8a, 8b, 8c, and 8d, thereby realizing mutual communication. In particular, when the SIP server 1 receives a call request specifying a destination terminal from these telephone terminals, the SIP server 1 inquires the resource management server 2 about whether or not call connection is possible, and connects the call only when the call is permitted. In response to this inquiry, the SIP server 1 notifies the resource management server 2 of the IP address of the calling terminal and the IP address of the called terminal.

The resource management server 2 includes a network configuration database DB for individually managing the transmission capacities of the paths 9 to 23 forming the IP network, and manages the remaining state of communication resources in the IP network based on this database. As shown in the following table, in the network configuration database DB, the transmission band and section information are recorded in association with each path. The transmission band may change depending on the network design, and the resource management server 2 sequentially grasps the band of each path by periodically inquiring each node. The section information is defined by nodes at both ends of the path.

  FIG. 2 is a functional block diagram showing the resource management server 2 of FIG. The resource management server 2 includes a monitor unit 31, an input / output unit 32, an interface unit 33, and a main control unit 34 in addition to the network configuration database DB. Among these, the monitor unit 31 displays various network management information, for example, and has a user interface function together with the input / output unit 32. The interface unit 33 is connected to the router 4a in FIG. 2 and has an interface function for exchanging various information with the IP network via the router 4a.

  By the way, the main control unit 34 includes a resource identification processing unit 34a, a communication path identification processing unit 34b, a path identification processing unit 34c, and a determination processing unit 34d as its software processing functions. The resource specification processing unit 34a inquires packet traffic to each node forming the IP network, for example, in a polling format, and specifies a consumption state of communication resources in the IP network. Based on the IP address of the calling terminal and the IP address of the called terminal notified from the SIP server 1, the communication path specifying processor 34b specifies the communication path between these terminals. The path identification processing unit 34c identifies the path with the smallest remaining resource among the paths included in the communication path identified by the communication path identification processing unit 34b. In this process, the path identification processing unit 34c refers to the resource consumption state of the IP network identified by the resource identification processing unit 34a and the contents of the network configuration database DB. The determination processing unit 34d permits the call connection to the SIP server 1 only when the call quality can be ensured even if the remaining resources of the path specified by the path specifying processing unit 34c are consumed. Next, the operation of the above configuration will be described.

  In FIG. 1, for example, it is assumed that a call request is made from the IP telephone 8a to the wireless IP telephone 6d as a call destination. This call request includes the IP addresses of the IP telephone 8a and the wireless IP telephone 6d, and this call request is first sent from the IP telephone 8a to the SIP server 1. Then, the SIP server 1 inquires of the resource management server 2 whether or not the call connection based on the call request is permitted. This inquiry also includes the IP addresses of the IP telephone 8a and the wireless IP telephone 6d.

  Upon receiving the inquiry, the resource management server 2 refers to the network configuration database DB and confirms that the paths existing in the communication path connecting the IP telephone 8a and the wireless IP telephone 6d are paths 12, 10, 19, 20, and 14. Check. At this time, the resource management server 2 inquires the routers 4a, 4b, and 4c about the packet traffic of each network path 12, 10, 19, 20, and 14 at the present time.

  When the inquiry response is obtained from each router 4a, 4b, 4c, the resource management server 2 compares the collected packet traffic with the resources of each path registered in the network configuration database DB, and connects the requested call. Also, it is determined whether or not the resource is exceeded. At that time, the resource of each path is compared with the amount of data currently flowing in each path (including voice data and data other than voice), and the difference, that is, the path with the smallest remaining resource is specified. Then, it is determined whether or not the call quality can be maintained even if new traffic flows through the specified path. The determination result is notified from the resource management server 2 to the SIP server 1. The SIP server 1 performs call connection processing between the IP telephone 8a and the wireless IP telephone 6d only when the result notified from the resource management server 2 indicates connection permission. If information indicating that connection is impossible is notified, the SIP server 1 does not perform call connection processing.

  In summary, in this embodiment, the resource management server 2 is provided in the telephone system using the IP network, and the bandwidth of each path in the IP network and the connection information of each path are databased (network configuration database DB). )to manage. The network configuration database DB may specify the node in which each IP telephone is accommodated. When a call request is generated from a certain IP telephone terminal to the SIP server 1, the SIP server 1 does not blindly connect the call, but inquires of the resource management server 2 about whether or not the call can be connected. At the time of this inquiry, the IP address of the SIP server 1 caller and callee is notified to the resource management server 2.

  In response to this inquiry, the resource management server 2 identifies the path included in the communication path connecting the call based on the notified IP address, and checks whether the network resource is within the limit for each path. To do. At this time, the resource of each path is compared with the amount of data currently flowing through each path, and it is determined whether the connection is possible by paying attention to the path with the smallest difference. At that time, based on the packet traffic managed in the routers 4a to 4c, the data amount at the time is grasped. The resource management server 2 notifies the SIP server 1 that the call connection is permitted when it is determined that the call quality can be maintained even when a call passing through the path with the smallest remaining resource is newly connected. If it is determined that the call quality cannot be maintained, the SIP server 1 is notified that the call connection is not permitted. The SIP server 1 performs connection processing only when call connection is permitted based on the notification from the resource management server 2.

  Since it did in this way, it can prevent that a telephone call is connected exceeding the resource of the IP network which forms a telephone system, As a result, it becomes possible to improve the voice quality of an IP telephone. In addition, because the amount of data that actually occupies each path is also considered, whether or not call connection is possible is determined, so there is also a problem that it is not possible to make maximum use of network resources simply by managing the limit of the number of calls. Can be solved. Therefore, it is possible to provide a telephone system that can make maximum use of network resources while ensuring call quality.

  The present invention is not limited to the above embodiment. For example, when the IP addresses of the wireless IP telephones 6a to 6f, the data terminals 7a and 7b, and the IP telephones 8a to 8d are managed by a DHCP (Dynamic Host Configuration Protocol) server, the IP of each IP telephone (and data terminal) A connection location on the network is registered in the resource management server 2 based on a MAC (Media Access Control) address. When the IP address is notified from the SIP server 1, the resource management server 2 obtains the MAC address information of the corresponding IP address from the DHCP server, and based on the MAC address, the call source and destination IP phones You will know the location on the network.

  Furthermore, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

1 is a system diagram showing an embodiment of a telephone system according to the present invention. The functional block diagram which shows the resource management server 2 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... SIP server, 2 ... Resource management server, 3a, 3b ... Wireless LAN access point, 4a, 4b, 4c ... Router, 5a, 5b ... Layer 2 switch, 6a, 6b, 6c, 6d, 6e, 6f ... Wireless IP Telephone, 7a, 7b ... data terminal, 8a, 8b, 8c, 8d ... IP telephone, 9-23 ... path, DB ... network configuration database, 31 ... monitor unit, 32 ... input / output unit, 33 ... interface unit, 34 ... Main control unit, 34a ... resource identification processing unit, 34b ... communication path identification processing unit, 34c ... path identification processing unit, 34d ... determination processing unit

Claims (1)

A plurality of telephone terminals that realize voice calls by exchanging packetized voice data through a packet communication network formed by a plurality of nodes, and call connection control is performed for the plurality of telephone terminals. In a telephone system comprising a call connection processing means,
A resource management server having a transmission capacity database for individually managing the transmission capacity of a plurality of paths forming the packet communication network;
The call connection processing means notifies the resource management server of address information of a caller telephone terminal and address information of a callee telephone terminal when a call request is generated,
The resource management server
Resource identifying means for querying packet traffic for each of the plurality of nodes and identifying a resource consumption state of the packet communication network;
Communication for specifying a communication path between the call source telephone terminal and the call destination telephone terminal based on the notified address information of the call source telephone terminal and the address information of the call destination telephone terminal Route identification means;
Path specifying means for specifying a path with the smallest remaining resource among paths included in the specified communication path based on a resource consumption state of the packet communication network and the transmission capacity database;
A determination unit that permits call connection to the call connection processing unit only when call quality can be ensured even if the remaining resources of the specified path are consumed when a call is connected in response to the call request; A telephone system comprising:

Images