CN1232135C - An end-to-end routing method of voice core network in wireless internet protocol - Google Patents

Abstract

The invention discloses an end-to-end routing method for a wireless Internet Protocol (IP) voice core network. The method includes: a calling user terminal initiates a call establishment request to a calling mobile switching center server (MSC Server), and the calling MSC Server Obtain the routing information containing the roaming number of the called mobile user terminal (UE) from the called home location register (HLR); the calling MSC Server initiates to the telephone number mapping uniform resource identifier (URI) mechanism server ( ENUM Server) to obtain the domain name of the called MSC Server; the calling MSC server queries the IP address of the called MSC Server corresponding to the domain name from the domain name interpretation system (DNS); the calling MSC Server sends the called MSC Server Initiate a call setup message, the called MSC Server receives the call setup message, and sends a call setup request to the called UE. The invention completes the end-to-end routing by introducing the ENUM mechanism, so that the wireless network changes from a traditional layered structure to a flat structure. This method simplifies the network structure and saves the network construction cost.

Description

An end-to-end routing method for wireless internet protocol voice core network

technical field

The invention relates to an end-to-end routing technology, in particular to an end-to-end routing method for a wireless internet protocol (IP) voice core network based on a telephone number mapping uniform resource identifier (URI) mechanism (ENUM).

Background technique

The wideband code division multiple access system (WCDMA) core network is mainly divided into a circuit domain (CS) and a packet domain (PS). The CS domain provides voice, fax and circuit data services, and the PS domain provides packet data services.

According to the development stage of WCDMA agreement, WCDMA is divided into R99, R4 and R5 three stages. According to the current WCDMA specification, R4's bearer-independent CS domain (BICSCN, Bearer Independent Circuit Switching Core Network) supports voice packet bearer, which is the final network form of the wireless core network CS domain. The R4 network is mainly composed of mobile switching center server (MSC Server), gateway mobile switching center server (GMSC Server), media gateway (MGW), home location register (HLR) and other entities. Among them, bearer independent call control (BICC, Bearer Independent Call Control) is adopted between MSC Servers, and multiple bearers of time division multiplexing mode (TDM)/asynchronous transfer mode (ATM)/IP are supported between MGWs. The protocol stacks carried by it are BICC/Type 3, Type 2, Type 1 Message Transfer Protocol (MTP3/MTP2/MTP1), BICC/MTP3B/SAAL/Type 5 ATM Adaptation Layer (AAL5)/ATM/Layer 1 (L1), BICC/Stream Control Transmission Protocol (SCTP)/IP/L2/L1 and other protocols, and these bearers are all connection-oriented.

In the CS domain of the wireless core network that uses BICC as call control signaling, when BICC signaling is carried on SCTP/IP, since SCTP is a connection-oriented protocol, the physical medium characteristics and data link protocol flow are different from the traditional No. 7 signal Order (SS7) links, so theoretically SCTP links can be established statically or dynamically. However, from the perspective of external functional characteristics, SCTP links are equivalent to simulating SS7 links to work, which means that statically configured SCTP links will be used in WCDMA R4 networks, that is, pre-configured routing information to carry wireless core network signaling. In addition, since the startup and shutdown process of the SCTP protocol is relatively complicated, the memory and processing power overhead of the signaling terminal is quite large during the link establishment or teardown process, so the SCTP link is not suitable for frequent and dynamic establishment or teardown.

When voice is carried by IP in the wireless core network, the schematic diagram of its network structure is shown in FIG. 1 . The networking structure of voice over IP in the wireless core network mainly includes: several MSC Servers and multiple long-distance mobile switching center servers (TMSC Servers). The core network routing adopts the traditional public land communication network (PLMN) method, and is determined through MSC Server/TMSC Server multi-level routing. The specific hierarchical division of TMSC Server can be determined according to the scale of the network, and the routing information containing IP addresses has been pre-configured in the system. Figure 1 shows a three-layer structure of IP-borne voice networking in the wireless core network. From top to bottom, the first layer is TMSC Server 1, the second layer is TMSC Server 2, and the third layer is MSC Server. If communication is to be realized between two MSC Servers, the originating MSC Server should connect segment by segment according to the pre-configured routing data. It may be directly connected to the destination MSC Server, or it may be connected segment by segment through one or several TMSC Servers, and then establish a connection with the destination MSC Server. What path it will pass through is pre-configured.

From the above process, it can be seen that this layered end-to-end network structure of control plane servers is not the simplest and most efficient IP core network, and cannot give full play to the greatest advantages of end-to-end routing of IP networks. At the same time, due to the complexity of the network, the network construction cost is relatively high.

Contents of the invention

In view of this, the present invention provides an end-to-end routing method for a wireless internet protocol voice core network, which changes the wireless network from a traditional layered structure to a flat structure, simplifies the network structure, and saves network construction costs.

An end-to-end routing method for a wireless internet protocol voice core network, which is realized in this way.

A. When the calling user terminal initiates a call setup request to the calling Mobile Switching Center Server (MSC Server), the calling MSC Server obtains the call information from the called Home Location Register (HLR) through the Mobile Application Part (MAP) signaling. Routing information of mobile user terminal (UE) roaming number;

B. The calling MSC Server initiates an inquiry to the telephone number mapping URI mechanism server (ENUM Server) according to the roaming number of the called UE, and obtains the domain name of the called MSC Server;

C. The calling MSC server queries the IP address of the called MSC Server corresponding to the domain name from the domain name interpretation system (DNS) according to the domain name of the called MSC Server;

D. After the calling MSC Server obtains the IP address of the called MSC Server, it sends a call setup message to the called MSC Server. After receiving the call setup message, the called MSC Server sends a call setup request to the called UE.

In the step A, the calling MSC Server obtains routing information from the HLR and further includes:

A1. The calling MSC Server sends a MAP signaling to the called home location register (HLR) to request routing information. After receiving the MAP signaling, the called HLR sends a roaming number request to the called MSC Server;

A2. After receiving the roaming number request, the called MSC Server queries and returns the roaming number of the called UE to the HLR. After the HLR obtains the roaming number of the called UE, it returns the routing information containing the roaming number to the calling MSC Server.

The call control signaling between the MSC Servers is the initial session protocol (SIP/SIP-T).

The call control signaling between the MSC Servers is bearer-independent call control signaling (BICC).

The bearer channel of the call control signaling between the MSC Servers is dynamically established.

Described MSC Server is a mobile switching center gateway server (GMSC Server).

Described MSC Server is Mobile Switching Center (MSC).

Described GMSC Server is a mobile switching center gateway (GMSC).

The present invention implements the end-to-end routing function by introducing the telephone number mapping URI mechanism (ENUM, Telephone Number URI mapping) in the circuit domain of the wireless core network carrying voice over IP, so that the wireless network changes from a traditional layered structure to a flat structure. This method not only greatly simplifies the network structure, but also saves the cost of network construction for operators because the routing function of TMSC Server is no longer needed.

Description of drawings

Fig. 1 is a schematic diagram of a traditional hierarchical routing network structure;

Fig. 2 is a schematic diagram of a planar networking structure of end-to-end routing in the present invention;

FIG. 3 is a signaling flowchart of ENUM-based end-to-end routing in the present invention.

Detailed ways

The core content of the present invention is in the IP voice core network of Global System for Mobile Communications (GSM) or WCDMA, introduces the ENUM mechanism to realize the end-to-end IP routing function between MSC Servers, and realizes the planar network framework at the control plane, thereby at the core Both the control and bearer planes in the network domain implement end-to-end IP.

ENUM is a mechanism for mapping E.164 international telephone numbers to corresponding URIs. The ENUM system is a hierarchical tree structure, and its distributed database is very similar to the domain name interpretation system (DNS) widely used on the Internet (Internet). By using the protocol stipulated in RFC2916 in the Internet Engineering Task Force (IETF), ENUM can first translate the E.164 number into a domain name, and then query the Internet DNS to obtain the corresponding IP address from the domain name.

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

In this embodiment, in the circuit domain of the wireless core network with voice over IP, the end-to-end routing function is completed by introducing the ENUM mechanism, so that the wireless network is transformed from a traditional layered structure to a flat structure.

As shown in Figure 2, the networking structure of the present embodiment mainly includes: more than one MSC Server and ENUM server (Server). Wherein, the solid line represents the call routing, and the dotted line represents the ENUM query. If communication between two MSC Servers is to be implemented, the calling MSC Server first searches for the routing information of the destination MSC Server, and then initiates a query to the ENUM Server according to the obtained routing information. Since ENUM Server is a distributed system, the query information may be forwarded by multiple ENUM Servers to the destination ENUMServer, and the destination ENUM Server will translate the roaming number into a domain name, and then query the domain name to obtain the corresponding IP address; The address establishes the connection with the destination MSC Server, and then the communication with the destination MSC Server can be realized.

Here, the call signaling between MSC Servers is not specified, it can be initial session protocol (SIP/SIP-T), bearer-independent call signaling (BICC) or other signaling that can dynamically establish bearer channels . Since the SIP/SIP-T application layer has an error correction and retransmission mechanism, it is generally carried on the User Datagram Protocol (UDP), while the BICC application layer does not have an error correction and retransmission mechanism, and is generally carried on the Stream Control Transmission Protocol (SCTP) or on Transmission Control Protocol (TCP). Because the dynamic establishment of signaling channels requires relatively large system overhead, therefore, preferably, this embodiment adopts SIP/SIP-T signaling.

Referring to Figure 3, the call flow for implementing end-to-end routing by applying the ENUM mechanism in the IP-borne wireless core network is as follows:

Step 301, the calling UE initiates a call setup request (Setup) to the calling MSC Server;

After step 302, calling MSC Server receives this request, gets routing information to called Home Location Register (HLR) by Mobile Application Part (MAP) signaling;

Step 303, after the called HLR receives the MAP signaling, send a roaming number request to the called MSC Server, to obtain the roaming number (MSRN) of the called UE;

Step 304, after receiving the roaming number request, the called MSC Server searches for the roaming number of the called UE, and returns the roaming number to the HLR;

Step 305, after the HLR obtains the roaming number of the called UE, it returns the routing information containing the MSRN to the calling MSC Server;

Step 306, the calling MSC Server initiates a query to the ENUMServer according to the called roaming number returned by the HLR, and because ENUM is a distributed system, it may be forwarded by multiple ENUM Servers;

Step 307, ENUM Server returns the record of the queried customer, if the roaming number MSRN of the called UE is 13900188209, the customer record returned is 13900188209@msc188.sz, where msc188.sz is the domain name of the called MSC Server;

Step 308, the calling MSC server returns the domain name in the record to DNS according to the IP address corresponding to the domain name inquired by the ENUM Server;

Step 309, the DNS returns the IP address corresponding to the domain name, that is, the IP address of the called MSC Server, to the calling MSC Server. Here, since DNS is a distributed system, it may be forwarded by multiple DNSs;

Step 310, after the calling MSC Server obtains the IP address of the called MSC Server, it initiates a call setup message to the IP address of the called MSC Server;

Step 311, the called MSC Server further initiates a call setup request to the called UE.

In the present invention, the called user terminal is a UE, and the calling user can be a user terminal in any other network, such as a call from a user of the Integrated Services Digital Network (ISDN) and the Public Switched Telephone Network (PSTN) to a mobile user. The call process is completely consistent with the UE-to-UE case. Because these network interfaces are GMSC Server, and the present invention does not relate to the routing mechanism in PSTN or ISDN scope, therefore, what embodies in this case is the communication between GMSC Server and MSC Server. According to the called MSRN returned by the called HLR, the GMSC Server obtains the domain name and corresponding IP address of the called MSC Server from the ENUM Server and DNS, and directly initiates call establishment to the IP address of the called MSC Server.

Although MSC Server and MGW belong to two logical functional entities, both can be realized on the same physical entity, such as: the MSC that supports IP voice is used as the physical entity that MSC Server and MGW realize, so the present invention is included in MSC or GMSC The situation of using ENUM to realize the end-to-end routing in the IP network.

Claims (7)

1, a kind of end-to-end routing method of wireless internet protocol voice core network, it is characterized in that, the method comprises the following steps: A. When the calling user terminal initiates a call setup request to the calling mobile switching center server MSC Server, the calling MSC Server obtains the roaming number of the called mobile user terminal UE from the called home location register HLR through the mobile application part MAP signaling routing information; B. The calling MSC Server initiates a query to the phone number mapping URI mechanism server ENUM Server according to the roaming number of the called UE, and obtains the domain name of the called MSC Server; C. The calling MSC server queries the IP address of the called MSC Server corresponding to the domain name from the domain name interpretation system DNS according to the domain name of the called MSC Server; D. After the calling MSC Server obtains the IP address of the called MSC Server, it sends a call setup message to the called MSC Server. After receiving the call setup message, the called MSC Server sends a call setup request to the called UE. 2. The method according to claim 1, characterized in that, the call control signaling between the MSC Servers is the initial session protocol SIP/SIP-T. 3. The method according to claim 1, characterized in that, the call control signaling between the MSC Servers is BICC, which has nothing to do with bearer. 4. The method according to claim 1, characterized in that, the bearer channel of the call control signaling between the MSC Servers is dynamically established. 5. The method according to claim 1, wherein the calling MSC Server is a GMSC Server of a Mobile Switching Center gateway server. 6. The method according to claim 1, wherein said MSC Server is a Mobile Switching Center (MSC). 7. The method according to claim 1, wherein the calling MSC Server is a mobile switching center gateway GMSC.

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