CN100459723C - The Method of Implementing Routing in Next Generation Network - Google Patents

Abstract

A method for implementing routing in the next generation network related to the field of communication technology. The routing function is completed by introducing the telephone number mapping (ENUM) mechanism. Through this hierarchical routing technology, the network is transformed from a flat structure to a layered structure, and the calling entity Obtain the domain name and the corresponding IP address of the called entity according to the called number to the telephone number mapping server (ENUM Server) and domain name system (DNS), and directly initiate a call setup message to the IP address, and the described entity includes a softswitch (SoftSwitch ), Session Initiation Protocol User Agent (SIP UA) or Session Initiation Protocol Proxy Server (SIP Proxy), etc. The present invention overcomes the disadvantages of the existing static configuration routing technology, and provides a simple and effective method for realizing routing selection in NGN, thereby making network maintenance and management convenient, easy to expand, and intercommunication between networks easier.

Description

The Method of Implementing Routing in Next Generation Network

technical field

The invention relates to the technical field of communication, in particular to a method for realizing routing in the next generation network.

Background technique

At present, the next generation network (NGN: Next Generation Network) is showing a growing trend. The number of NGN users and the number of soft switches (SoftSwitch) can be predicted to grow rapidly. Facing such a huge global network, the NGN network routing scheme In the process, it is necessary to solve such problems as how to perform fast and effective routing and positioning, how to reduce network maintenance costs, maintain mutual independence between networks, and how to ensure that a local expansion or change will not cause fluctuations in the entire network.

The existing NGN adopts flat static routing technology, that is, all routing entities adopt a flat structure, and only statically configure routing information. Figure 1 shows a schematic diagram of a flat static routing structure. When a call arrives, SoftSwitch first Determine whether the number belongs to the information of the local office, and if so, the internal module will directly process the call; otherwise, search the routing information, find the SoftSwitch to which the user belongs, and connect the call there. At present, due to the limited number of SoftSwitches, the peer SoftSwitch can be configured through a rough office code or area number. Obviously, with the continuous increase of the network scale, the existing static routing configuration scheme cannot meet the needs of future network development. .

The existing flat static routing technology is easy to implement, economical and convenient, but due to its own mechanism, it inevitably has the following disadvantages:

1) The configuration is complex and the maintenance is difficult. For example, during capacity expansion, user change, and number upgrade, all related SoftSwitch configurations need to be modified, which is a heavy workload and prone to errors.

2) In the existing NGN technology, different NGN operators may adopt completely different routing strategies within their networks, which brings difficulties to intercommunication.

Contents of the invention

The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing static configuration routing technology, and provide a simple and effective method for realizing routing selection in NGN, so that network maintenance and management are convenient, easy to expand, and interconnection between networks much easier.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: the method for implementing routing in this next-generation network includes the following steps:

A. The calling entity converts the called phone number into a domain name format, and initiates a query to the phone number mapping server ENUM Server;

B. ENUM Server returns the corresponding name authority pointer NAPTR record;

C. The calling entity obtains the IP address of the called entity according to the returned NAPTR record, and initiates a call setup message to the called entity according to the IP address.

If the returned NAPTR record does not contain an IP address, the calling entity searches the Domain Name System DNS for the corresponding IP address according to the domain name in the NAPTR record, and then the DNS returns the IP address to the calling entity.

The matching item of the regular expression in the NAPTR record or the keyword of the route identified by the enumservice subdomain of the Service domain indicates that the NAPTR record is used to provide routing information.

The matching items use office codes or area codes, or use custom symbols corresponding to office codes or area codes.

Said entity is SoftSwitch, SIP UA or SIP proxy server SIP Proxy.

The beneficial effects of the present invention are as follows: the present invention introduces the telephone number mapping (ENUM: Telephone Number Mapping) mechanism in the circuit domain of the core network carrying voice over IP to complete the routing function, and through this hierarchical routing technology, the network is changed from a flat structure to a component Layer structure, not only better solves the problem that the routing data of NGN large-scale flat routing is too large and complex, difficult to maintain and manage, and difficult to expand, but also ensures the security of the internal network structure of NGN, and the layer division can be compared with the existing operators. The administrative management structure is well matched, and at the same time, it is simple to implement and easy to expand, which can save operators the cost of network construction and make the intercommunication between public switched telephone network (PSTN) terminals and IP terminals easier.

The present invention can initiate ENUM query by SoftSwitch, Session Initiation Protocol User Agent (SIP UA) or Session Initiation Protocol Proxy Server (SIP Proxy), and use this technology of the present invention to realize routing by ENUM mechanism, once the user is in An operator registers its own data, and these Uniform Resource Identifiers (URIs) are defined by standard RFCs, so there is no problem of different strategies for interconnection.

The present invention utilizes the matching item of regular expression or the enumservice subfield of Service domain to mark routing information, so that it is distinguished from other applications of ENUM (such as calling, fax, mail, short message, etc.), so that the required information can be found quickly. The record is used for routing or calling. These two schemes for identifying routing information do not conflict and can also be used in combination. For example, enumservice is used to identify routing, regular expression matches are used to indicate the office code, and URI is used to indicate the terminal For security reasons, the regular expression matches may not use office codes or area codes, but use custom symbols (such as routing hops, etc.) to correspond to numbers.

To sum up, the present invention not only realizes the integration of different networks, making their interconnection and intercommunication easier, but also is simple to implement, can make full use of existing network resources, and is easy to build, maintain and manage the network.

Description of drawings

Fig. 1 is the schematic diagram of plane static route structure in existing NGN;

Fig. 2 is a schematic diagram of the hierarchical static routing network structure of the present invention;

Fig. 3 is the call flowchart from PSTN network to IP network based on ENUM routing;

Fig. 4 is the call flowchart from IP network to IP network based on ENUM routing;

Fig. 5 is the call flowchart from IP network to PSTN network based on ENUM routing;

FIG. 6 is a flowchart of a call from a PSTN network to a PSTN network based on ENUM routing.

Detailed ways

Below according to accompanying drawing and embodiment the present invention will be described in further detail:

The present invention completes the routing function by introducing the Telephone Number Mapping (ENUM: Telephone Number Mapping) mechanism in the circuit domain of the core network carrying voice over IP, and transforms the network from a flat structure into a layered structure through this hierarchical routing technology. The ENUM mechanism is a mechanism for mapping E.164 international telephone numbers to the corresponding Uniform Resource Identifier (URI: UniformResource Identifier). ENUM uses the protocol RFC2916 stipulated by the Internet Engineering Task Force (IETF), through which E. The .164 number is translated into a domain name, and then the Internet Domain Name System (DNS: Domain Name System) is queried to obtain the IP address of the network device from the domain name. As shown in Figure 2, the ENUM system is a hierarchical tree structure, and its distributed database is the same as the current The Domain Name System (DNS), widely used on the Internet, is similar.

Suppose that the calling number belongs to SoftSwitch 1 management, and the called number belongs to SoftSwitch 2 management, as shown in Figure 3, in the next generation network carried by IP, when the PSTN user initiates a call to the IP terminal to the gateway, the ENUM of the present invention is applied. The call flow of the mechanism to realize the routing function is as follows:

A1. The PSTN user initiates a call to the IP terminal to the gateway.

A2. The gateway is connected to SoftSwitch 1 through media gateway control protocol (MGCP) or protocol signaling such as H.248.

A3. SoftSwitch 1 compares the called number with the users managed by its own system, and finds that the user does not belong to the system, so according to the rules described in RFC2916, it converts the E.164 number into the domain name format, and initiates a query to the ENUM Server. Since ENUM is a distributed system, it may be queried by multi-level ENUM Server. For example: the called number is +8675526540808, SoftSwitch 1 converts the E.164 number into the domain name format according to the rules described in RFC2916: 8.0.8.0.4.5.6.2.5.5.7.6.8.e164.tld, where 86 is the Call the country code to which the number belongs. The specific rules are as follows:

1) Convert the number into a standard E.164 number format, such as: +86-755-26540808;

2) Remove all connectors except the leftmost "+", such as: +8675526540808;

3) Remove all non-numeric characters, such as: 8675526540808;

4) Add dots between each number character, such as: 8.6.7.5.5.2.6.5.4.0.8.0.8;

5) Reverse the order of the characters, such as: 8.0.8.0.4.5.6.2.5.5.7.6.8;

6) Add ".e164.tld" at the end of the string, where tld is the top-level domain, such as: 8.0.8.0.4.5.6.2.5.5.7.6.8.e164.tld.

The domain name formed by each E.164 number can correspond to multiple network resource records, called Uniform Resource Identifier (URI), which adopts the format defined by another IETF recommendation RFC 2915, called Name Authority Pointer (NAPTR: Naming Authority Pointer ).

A4. ENUM Server returns the corresponding NAPTR record, and there may be multiple NAPTR records returned, for example:

1) IN NAPTR 140 10 "u" "E2U+talk:sip" "!^867552654*$! Sip:8675526540808@huawei.com!"

2) IN NAPTR 140 10 "u" "E2U+talk:h323" "!^.*$!H323:user@huawei.com!"

The above NAPTR record contains several main domains as shown in the following table. The domain names, meanings and corresponding values in the first record in the above example are shown in the following table:

name meaning corresponds to the value in the example order priority 140 preference secondary priority 10 flag sign u (indicates that the query is a URI) service Query the protocols and services used E2U+talk:sip RegularExpression regular expression ! ^867552654*$! sip: 8675526540808@huawei.com! replacement Alternate domain Null

In the present invention, the matching item of the regular expression in the NAPTR record is used to indicate that the record is used to provide routing information, so as to be distinguished from other applications of ENUM (such as calling, fax, mail, short message, etc.), the matching Items can use office codes or area numbers. For security reasons, the matching items can also use custom symbols corresponding to office codes or area numbers (such as route hops, etc.). The format of the regular expression is:

! <regexp>! <string>!

It means that if the content of the expression matches the query number, the following character string should be used to replace the query number. For example, the matching item in the first NAPTR record above is the office code "867552654". If the numbers match, the query result is "Sip:8675526540808@huawei.com", where "huawei.com" is the domain name of the SoftSwitch to which the called party belongs.

You can also use the enumservice subdomain (routing:sip) in the Service domain (such as "E2U+routing:sip") to identify the routing keyword (routing) to indicate that the record is used to provide routing information, so you only need to judge The Service domain can quickly find the required records for routing or calling.

The above two solutions do not conflict, and can also be used in combination. For example, enumservice is used to identify routes, regular expression matches are used to indicate the office code, and URI is used to indicate terminal information.

A5. SoftSwitch 1 searches the DNS for the corresponding IP address based on the domain name huawei.com in the records returned by the ENUM Server.

A6. DNS returns the IP address corresponding to the domain name to SoftSwitch 1, that is, the IP address of SoftSwitch2. Since DNS is a distributed system, it may be queried through multi-level DNS.

A7. SoftSwitch 1 initiates a call setup message to the IP address of SoftSwitch 2. The inter-office call control signaling can use Session Initiation Protocol (SIP), H.323 or other signaling.

A8. SoftSwitch 2 connects the call to the IP user managed by itself.

In the above process, if the returned NAPTR record contains an IP address, SoftSwitch 1 does not need to query DNS, and SoftSwitch 1 directly initiates a call setup message to SoftSwitch2 based on the IP address.

The call flow between IP terminals and the call flow from IP to PSTN and between PSTN terminals is basically the same as the above situation. SoftSwitch 1 obtains the domain name and corresponding IP address of SoftSwitch 2 from ENUM Server and DNS according to the called number, and directly calls to the IP The address initiates a call setup message. If the returned NAPTR record contains an IP address, SoftSwitch 1 does not need to query DNS. SoftSwitch 1 sends a call setup message to SoftSwitch 2 directly based on the IP address. The call signaling between SoftSwitches is not specific. It is stipulated that it can be Session Initiation Protocol (SIP: Session Initiation Protocol), H.323 or other signaling, and the routing technology used in the present invention has nothing to do with the signaling protocol.

As shown in Figure 4, for the call between IP terminals, the call flow of applying the ENUM mechanism of the present invention to realize the routing function is as follows:

B1. The IP user initiates a call to another IP user to SoftSwitch 1.

B2. SoftSwitch 1 compares the called number with the users managed by its own system, and finds that the user does not belong to the system, so it converts the E.164 number into a domain name format according to the rules described in RFC2916, and initiates a query to the ENUM Server.

B3. ENUM Server returns the corresponding NAPTR record.

B4. SoftSwitch 1 queries the corresponding IP address in DNS according to the domain name in the record returned by ENUM Server.

B5. DNS returns the IP address corresponding to the domain name to SoftSwitch 1, that is, the IP address of SoftSwitch2.

B6. SoftSwitch 1 initiates a call setup message to the IP address of SoftSwitch 2.

B7. SoftSwitch 2 connects the call to the IP user managed by itself.

As shown in Figure 5, when an IP user initiates a call to a PSTN terminal, the call flow of applying the ENUM mechanism of the present invention to realize the routing function is as follows:

C1. The IP user initiates a call to the PSTN terminal from SoftSwitch 1.

C2, SoftSwitch 1 compares the called number with the users managed by its own system, and finds that the user does not belong to the system, so according to the rules described in RFC2916, it converts the E.164 number into a domain name format, and initiates a query to the ENUM Server.

C3. ENUM Server returns the corresponding NAPTR record.

C4. SoftSwitch 1 queries the corresponding IP address in DNS according to the domain name in the record returned by ENUM Server.

C5. DNS returns the IP address corresponding to the domain name to SoftSwitch 1, that is, the IP address of SoftSwitch2.

C6. SoftSwitch 1 sends a call setup message to the IP address of SoftSwitch 2.

C7, SoftSwitch 2 connects the call to the gateway (Gateway) through media gateway control protocol (MGCP) or protocol signaling such as H.248.

C8. The gateway (Gateway) connects the call to the PSTN user managed by itself.

As shown in Figure 6, for the call between PSTN terminals, the call process of applying the ENUM mechanism of the present invention to realize the routing function is as follows:

D1. The PSTN user initiates a call to another PSTN user to the gateway.

D2. The gateway is connected to SoftSwitch 1 through protocol signaling such as Media Gateway Control Protocol (MGCP) or H.248.

D3. SoftSwitch 1 compares the called number with the users managed by its own system, and finds that the user does not belong to the system, so according to the rules described in RFC2916, it converts the E.164 number into the domain name format, and initiates a query to the ENUM Server.

D4. ENUM Server returns the corresponding NAPTR record.

D5. SoftSwitch 1 queries the corresponding IP address in DNS according to the domain name in the record returned by ENUM Server.

D6. DNS returns the IP address corresponding to the domain name to SoftSwitch 1, that is, the IP address of SoftSwitch2.

D7. SoftSwitch 1 initiates a call setup message to the IP address of SoftSwitch 2.

D8. SoftSwitch 2 connects the call to the gateway (Gateway) through media gateway control protocol (MGCP) or protocol signaling such as H.248.

D9. The gateway (Gateway) connects the call to the PSTN user managed by itself.

It should be noted that calls between PSTN terminals are only applicable to long-distance calls, and there is no need to use ENUM for local calls.

The NGN network routing scheme of the present invention is not for single user service, is to control the user's SoftSwitch (SoftSwitch) service in this embodiment, that is to say, this scheme is only positioned at the SoftSwitch that serves for the user, cannot and should not be positioned at To the served user itself, use ENUM to find the routing information of the SoftSwitch that manages the called user, not the called terminal. The entity that initiates the ENUM inquiry can also be a Session Initiation Protocol User Agent (SIP UA) or a Session Initiation Protocol Proxy Server (SIPProxy) etc. except the SoftSwitch (SoftSwitch) in the present embodiment.

Using the technology of routing through the ENUM mechanism of the present invention, once the user registers his own data at a certain operator, these Uniform Resource Identifiers (URI) are defined by standard RFCs, so there is no difference in interconnection strategies The problem. The present invention not only better solves the problem that the routing data of NGN large network planar routing is too large and complex, difficult to maintain and manage, and difficult to expand, but also can ensure the safety of the internal network structure of NGN, and at the same time, it is simple to implement and easy to expand, and can be used for operation. Providers save network construction costs, and make the intercommunication between public switched telephone network (PSTN) terminals and IP terminals easier.

Claims (5)

1. A method for implementing routing in a next-generation network, comprising the following steps: A. The calling entity converts the called phone number into a domain name format, and initiates a query to the phone number mapping server ENUM Server; B. ENUM Server returns the corresponding name authority pointer NAPTR record; C. The calling entity obtains the IP address of the called entity according to the returned NAPTR record, and initiates a call setup message to the called entity according to the IP address. 2. The method for realizing routing in the next-generation network according to claim 1 is characterized in that: if the returned NAPTR record does not include an IP address, then the calling entity queries the corresponding domain name system DNS according to the domain name in the NAPTR record. IP address, and then the DNS returns the IP address to the calling entity. 3. The method for implementing routing in the next-generation network according to claim 1 or 2, characterized in that: use the matching item of the regular expression in the NAPTR record or the keyword of the enumservice subdomain identification route in the Service domain to represent The NAPTR record is used to provide routing information. 4. The method for realizing routing in the next generation network according to claim 3, characterized in that: the matching item uses an office code or an area number, or uses a self-defined symbol corresponding to the office code or area number. 5. the method for realizing routing in the next generation network according to claim 3, is characterized in that: described entity is SoftSwitch, Session Initiation Protocol User Agent SIP UA or Session Initiation Protocol Proxy Server SIP Proxy.

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