JP5794891B2 - Routing method for signaling message using flow switch device and network system - Google Patents

Description

  The present invention relates to a technique for controlling a routing of a signaling message between SIP (Session Initiation Protocol) servers in an IMS (IP Multimedia Subsystem) network.

  SIP is a call control protocol in IP (Internet Protocol), which negotiates an IP address, a port number, and encoding necessary for communication between terminals, and controls outgoing and incoming calls. In order to perform necessary network resource allocation and gate control using SIP, there is IMS as an IP subsystem network. IMS is a standardized service control method for providing multimedia applications (voice, video and data) in an IP network. This is a core technology that realizes the next generation mobile phone network or NGN (Next Generation Network). As a result, the fixed network and the mobile network are integrated, and all-IP communication is realized in which all terminals communicate on an IP basis.

  FIG. 1 is a system configuration diagram of an IMS in the prior art.

  According to the system of FIG. 1, the access network is connected to the IMS network. The two networks are connected via the gateway 1. The access network is, for example, a mobile phone network or a wireless / wired broadband access network. A terminal (UE (User Equipment)) 5 operated by a user can be connected to the IMS network via the gateway 1. When the access network is a mobile phone network, the terminal 5 is, for example, a mobile phone or a smartphone.

  The IMS network has a control network separately from the transport network. The control network includes a plurality of call session control functions (CSCF) 4 and an HSS (Home Subscriber Server). The plurality of terminals 5 corresponding to the SIP client establish a call session with the counterpart terminal by connecting to the CSCF 4 via the gateway 1.

  According to FIG. 1, P-CSCF (Proxy-CSCF) 41, S-CSCF (Serving-CSCF) 42, and HSS are represented as CSCFs.

  The terminal 5 transmits a SIP message toward the IMS network via the access network. The SIP message is transferred to one P-CSCF 41 via the gateway 1. The P-CSCF 41 extracts media information for each session, and instructs gate control and resource control for the gateway 1 when the session is established. The P-CSCF 41 is determined at the time of location registration from the terminal 5, and establishes a secure IPsec tunnel with the gateway 1 (or SIP compatible terminal).

  The P-CSCF 41 transfers the SIP message to one S-CSCF 42. The S-CSCF 42 is a central SIP server for call session control, and executes authentication processing and registration processing. The S-CSCF 42 has a domain of a home network managed by itself, and manages a SIP-URI (SIP-Uniform Resource Identifier) of a terminal within the domain. In addition, the S-CSCF 42 performs user authentication by communicating with the HSS.

  The session established in this way is associated with the status information of the network resources being used and the status information of security association (encryption key, encryption method, etc.) for securing a secure communication path. Thereafter, it is managed by these CSCFs (P / S / I-CSCF).

  Therefore, according to the existing IMS network, the terminal is fixedly managed with respect to the CSCF once registered. That is, the CSCF is not changed unless the terminal moves and belongs to another domain. Thus, it is difficult to change the CSCF after location registration.

  However, depending on the CSCF failure (or overload) in the IMS network and the usage status such as CSCF optimization and maintenance, there is a case where the CSCF intervening in the session during registration of the terminal is to be transferred to another CSCF. is there. At this time, it is necessary to transfer the session information from one CSCF to the other CSCF. In addition, it is necessary to ensure consistency by notifying all the CSCFs related to the session of the succession.

  On the other hand, there is a technique in which the CSCF is configured by hot standby server redundancy. This makes one-to-one redundancy as a backup of the CSCF. However, it is necessary to separately provide a standby CSCF having the same performance as that of the operating CSCF, which causes a problem in terms of introduction and operation costs.

  In addition, there is a technique that allows a migration source session for a first SIP server to be migrated to a migration destination session for a second SIP server from a gateway connected by the terminal without re-establishing IPsec with the terminal (see FIG. For example, refer nonpatent literature 1).

  According to the system of FIG. 1, an IMS configuration management device 6 and a session management device 7 are further arranged in the IMS network.

  The IMS configuration management device 6 monitors the availability of each CSCF based on the reachability of the IP packet and / or the count information of the SIP message. Thereby, the IMS configuration management device 6 determines that the session should be transferred to another CSCF when the load state of the CSCF increases to a predetermined threshold value or more, or when a failure / stop is detected. At this time, the IMS configuration management device 6 transmits a session transition instruction request to the session management device 7. The session migration instruction request includes at least the SIP-URI of the migration source CSCF and the SIP-URI of the migration destination CSCF for the session from the terminal.

  The session management device 7 constantly updates and accumulates session information between the terminal, gateway, and CSCF. The session information includes at least a SIP-URI, a key for establishing IPsec, and a SIP state transition parameter for each session.

  FIG. 1 shows a case where the session between the gateway 1 and the P-CSCF # 1 is transferred to the session between the gateway 1 and the P-CSCF # 2. At this time, the transfer destination P-CSCF # 2 needs to establish a session with the S-CSCF # 2. The transition of these sessions is controlled by a session transition message from the session management device 7. The session management device 7 may be an HSS (subscriber information server) that stores the SIP-URI of the CSCF being registered for each SIP-URI of the terminal.

  Here, the gateway 1 uses the IPsec (key A) established with the P-CSCF # 1 as it is without re-establishing the IPsec with respect to the P-CSCF # 2. On the other hand, the transfer destination P-CSCF # 2 operates assuming that IPsec (key A) is established with the gateway 1. Therefore, the gateway 1 does not execute a sequence for establishing a new IPsec with the migration destination P-CSCF # 2. According to this technique, it is possible to transfer a session transparently as seen from the terminal.

Takeshi Usui, Kenji Komorita, Yoshinori Kitakuma, Hidetoshi Yokota, "Proposal of Network Configuration for Improving Call Control Server Availability in IMS", 2010 IEICE General Conference, B-6-16 "OpenFlow Consortium", [online], [October 14, 2011 search], Internet <URL: http://www.openflowswitch.org>

  However, according to the technique described in Non-Patent Document 1, in order to appropriately transfer signaling, it is necessary to transfer the session information from one CSCF to the other CSCF and also the IP address thereof. Here, the other CSCF as the restoration destination needs to use the original IP address (one CSCF), and must hold a plurality of IP addresses. In addition, the same IP address exists simultaneously in a plurality of CSCFs. Furthermore, each gateway (session transfer node) needs to transfer to an appropriate destination MAC address for each SIP message. This is because a gateway tends to be a bottleneck in a network system that handles a large amount of SIP messages.

  Further, according to the technique described in Non-Patent Document 1, the gateway must set up a tunnel between the terminal and the P-CSCF and between the P-CSCF and the S-CSCF. Therefore, the overhead of the sequence for tunnel establishment is inevitable. Further, as the number of terminals connected to the IMS network increases, the amount of the route table that the gateway should hold increases, and the processing capability of the routing control of the signaling message also increases.

  Accordingly, the present invention provides a signaling message path control method and network system that does not move an IP address and does not establish a tunnel even in an IMS network to which a large number of terminals are connected. The purpose is to do.

According to the present invention, a plurality of SIP (Session Initiation Protocol) servers connected to an IP subsystem network, one or more flow switch devices that switch a flow of signaling messages between the SIP server and a terminal, and a terminal A signaling message routing method in a system having one or more gateways for relaying and forwarding signaling messages between the network and the flow switch device,
The gateway stores a label table in which one or more terminal URIs are associated with a label based on a combination of identifiers of one or more SIP servers in which registration information of the terminal URI (Uniform Resource Indicator) exists or is used. And
For the first step, when the gateway receives a signaling message from the terminal,
Obtaining the originating terminal URI and the terminating terminal URI in the signaling message;
Cache the source MAC address and destination MAC address in the signaling message;
Using the label table, search for a source label corresponding to the originating terminal URI and a destination label corresponding to the terminating terminal URI,
Rewrite the destination MAC address header to the source label, and rewrite the source MAC address header to the destination label.
Send the signaling message to the flow switch device,
For the second step, the flow switch device transfers the signaling message to the SIP server according to the label.

According to another embodiment of the route control method of the present invention,
Regarding the label table, the label is a combination of the identifier of one or more SIP servers where the registration information of the terminal URI is present or used, and further the identifier of the base where the SIP server is located. It is also preferable that identifiers other than the identifiers of one site are designated by wild cards.

According to another embodiment of the route control method of the present invention,
For the third step, the SIP server
For the signaling message received from the flow switch device, cache the source label of the destination MAC address header, and cache the destination label of the source MAC address header,
A signaling message to be transmitted to the next hop, with the IP address of the next hop included in the Route header of the signaling message as the destination IP address, is transmitted to the flow switch device.
For the fourth step, the flow switch device forwards the signaling message to a gateway or other flow switch device,
For the fifth step, the gateway
For the signaling message received from the flow switch device, the source MAC address header is rewritten to the source MAC address cached in the first step, and the destination MAC address header is cached in the first step. Rewrite to MAC address,
It is also preferable to send the signaling message to the terminal.

According to another embodiment of the route control method of the present invention,
The system further includes a flow control device for controlling the flow switch device,
For the first step, if the signaling message is a registration request message (REGISTER message),
Gateway is,
Obtain the calling terminal URI in the registration message,
Cache the destination MAC address in the registration message,
When the sender label corresponding to the calling terminal URI cannot be searched using the label table, the sender label corresponding to the calling terminal URI is selected,
In the label table, the calling terminal URI and the label are stored in association with each other,
Send the originating terminal URI and the selected source label to the flow control device,
Flow control device,
Update the flow table associating the sending terminal URI with the source label,
It is also preferable to send an update completion response message back to the gateway.

According to another embodiment of the route control method of the present invention,
The IP subsystem network is an IMS (IP Multimedia Subsystem) network,
As SIP servers, P-CSCF (Proxy-CSCF (Call Session Control Function)), S-CSCF (Serving-CSCF), I-CSCF (Interrogating-CSCF) and / or HSS (Home Subscriber)
Server) is located,
The flow switch device stores the IP address of each CSCF by the flow table,
For the second step,
The S-CSCF of the source IP address reverses the source label of the destination MAC address header and the destination label of the source MAC address header for the request message transmitted to the I-CSCF or S-CSCF of the destination IP address. Rewrite to replace or
The I-CSCF or S-CSCF of the source IP address reverses the destination label of the destination MAC address header and the source label of the source MAC address header for the response message transmitted to the S-CSCF of the destination IP address. It is also preferable to rewrite so that it is replaced.

According to another embodiment of the route control method of the present invention,
The flow switch device is OpenFlowSwitch (registered trademark),
The flow control device is OpenFlowController (registered trademark),
The gateway is also preferably a SIP parser that converts protocol headers.

According to the present invention, a plurality of SIP (Session Initiation Protocol) servers connected to an IP subsystem network, one or more flow switch devices that switch a flow of signaling messages between the SIP server and a terminal, and a terminal A network system having one or more gateways for relaying and forwarding signaling messages between the device and the flow switch device,
To route signaling messages after session transition,
The gateway
A label table in which one or more terminal URIs are associated with a label based on a combination of identifiers of one or more SIP servers in which registration information of the terminal URI (Uniform Resource Indicator) exists or is used;
An uplink message transfer means for transferring a signaling message received from the terminal to the flow switch device;
URI acquisition means for acquiring the originating terminal URI and the terminating terminal URI in the signaling message;
MAC address cache means for caching the source MAC address and destination MAC address in the signaling message;
Label search means for searching for a source label corresponding to the originating terminal URI and a destination label corresponding to the terminating terminal URI using the label table;
In addition to rewriting the destination MAC address header to the transmission source label, it has an uplink address rewriting means for rewriting the transmission source MAC address header to the destination label.

According to another embodiment of the network system of the present invention,
Regarding the label table, the label is a combination of the identifier of one or more SIP servers where the registration information of the terminal URI is present or used, and further the identifier of the base where the SIP server is located. It is also preferable that identifiers other than the identifiers of one site are designated by wild cards.

According to another embodiment of the network system of the present invention,
Based on the flow table, the flow switch device transfers the signaling message received from the gateway to either one of the SIP server or another flow switch device, and transmits the signaling message received from the SIP server to another SIP server, Transfer to any one of the other flow switch devices or gateways,
The gateway
A downlink message transfer means for transmitting a signaling message received from the flow switch device to the terminal;
For the signaling message, the source MAC address header is rewritten to the source MAC address in the MAC address cache means, and the destination MAC address header is rewritten to the destination MAC address in the MAC address cache means;
SIP server
For a signaling message received from the flow switch device, a label cache means for caching the source label of the destination MAC address header and caching the destination label of the source MAC address header;
It is also preferable to have a message transfer means for transferring a signaling message to be transmitted to the next hop with the IP address of the next hop included in the Route header of the signaling message as a destination IP address to the flow switch device.

According to another embodiment of the network system of the present invention,
The system further includes a flow control device for controlling the flow switch device,
If the signaling message is a registration request message (REGISTER message), the gateway
The URI acquisition means acquires the calling terminal URI in the registration message,
MAC address cache means caches the destination MAC address in the registration message,
When the source label corresponding to the calling terminal URI cannot be searched using the label table, the source label corresponding to the calling terminal URI is selected, and the calling terminal URI and the label are stored in the label table. A label request transmitting means for storing the associated terminal URI and the transmission source label to the flow control device;
Label response receiving means for receiving a label response message from the flow control device;
The flow control device
Flow table updating means for updating a flow table in which a sender terminal URI and a source label are associated;
It is also preferable to have label response reply means for replying the update completion response message to the gateway.

According to another embodiment of the network system of the present invention,
The IP subsystem network is an IMS network,
As a SIP server, at least P-CSCF, S-CSCF, I-CSCF and / or HSS are arranged,
The flow switch device stores the IP address of each CSCF by the flow table,
The flow switch device
For a request message transmitted from the S-CSCF of the source IP address to the I-CSCF or S-CSCF of the destination IP address, the source label of the destination MAC address header and the destination label of the source MAC address header are reversed. Rewrite to replace or
For a response message transmitted from the I-CSCF or S-CSCF of the source IP address to the S-CSCF of the destination IP address, the destination label of the destination MAC address header and the source label of the source MAC address header are reversed. It is also preferable to rewrite so that it is replaced.

According to another embodiment of the network system of the present invention,
The flow switch device is OpenFlowSwitch (registered trademark),
The flow control device is OpenFlowController (registered trademark),
The gateway is also preferably a SIP parser that converts protocol headers.

  According to the signaling message path control method and network system of the present invention, by using an existing OpenFlow switch device, it is not necessary to establish a tunnel without moving an IP address after a session transition of a SIP server. be able to. In addition, it is possible to control the route at high speed without installing special functions in the existing OpenFlow switch device.

  Here, when the terminal URI and the label are associated with the existing OpenFlow switch device on a one-to-one basis, the number of entries in the flow table is required for the number of terminal URIs. That is, if an existing OpenFlow switch device is simply installed in an IMS network to which a huge number of terminals are connected, the number of entries in the flow table exceeds the upper limit. According to the present invention, even when the existing OpenFlow switch device is provided in the IMS network, the amount of the route table to be held by the gateway and the OpenFlow switch device can be reduced as much as possible, and the routing control of the signaling message can be performed. Processing capacity can also be reduced.

It is a system configuration | structure figure of IMS in a prior art. It is a system configuration diagram of IMS in the present invention. It is explanatory drawing showing the flow table and label table regarding the base 1 in the 1st Embodiment of this invention. It is explanatory drawing showing the flow table and label table regarding the base 2 in the 1st Embodiment of this invention. It is explanatory drawing showing the flow table and label table regarding the base 1 in the 2nd Embodiment of this invention. It is explanatory drawing showing the flow table and label table regarding the base 2 in the 2nd Embodiment of this invention. It is a request | requirement sequence diagram of the transmission in this invention. FIG. 8 is a call request sequence diagram following FIG. 7. FIG. 9 is an outgoing response sequence diagram following FIG. 8. It is a sequence diagram of registration in the present invention. It is a function block diagram of the SIP parser in this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a system configuration diagram of the IMS according to the present invention.

  According to FIG. 2, a plurality of grouped SIP servers are connected to the IMS control network (IP subsystem network) for each site. In each SIP server group, a plurality of P-CSCFs, a plurality of S-CSCFs, an I-CSCF, and an HSS are arranged. These CSCFs are connected to the IMS transport network via the flow switch device 2 for each site.

Here, all CSCFs of the same type have the same IP address (virtual IP address). That is, according to FIG. 2, each CSCF has the following IP address.
[CSCF] [IP address]
P-CSCF: 10.10.1.1
S-CSCF: 10.20.2.1
I-CSCF: 10.30.3.1
HSS: 10.40.4.1
However, the actual IP address is different for each node, and the IMS configuration management device 6 identifies each CSCF using the actual IP address. The IMS configuration management device 6 instructs the routing control of the signaling message accompanying the restoration / relocation of the CSCF and the HSS.

  The flow switch device 2 is a switch that can identify header information up to layer 4 having a plurality of ports, and the ports are connected to the SIP parser 1 and each CSCF and HSS of the SIP server group. The flow switch device 2 routes the signaling message between the terminal 5 and each CSCF and HSS.

  For this route control, the flow switch device 2 holds a “flow table” in which “terminal URI (Uniform Resource Indicator)” and “label” are associated with each other. Then, the flow switch device 2 identifies the input packet as a “flow” for each user session based on the label, and outputs the packet to a predetermined port based on the flow. According to FIG. 2, the flow switch device 2 at the site 1 can not only control the path to each CSCF at the site 1 but also control the route to the flow switch device 2 at the site 2. By going through a plurality of flow switch devices 2, it is possible to control the path to CSCFs at various locations.

  The gateway 1 is disposed at a connection point between the IMS network and the access network, and relays and transfers a signaling message between the terminal 5 and the flow switch device 2. The gateway 1 is a “SIP parser” that can identify a SIP message as a flow. The SIP parser 1 holds a “label table” in which “terminal URI” is associated with “label” in the flow switch device.

  The IMS configuration management device 6 always receives and stores session information between terminals and CSCFs. In other words, the CSCF and the HSS constantly transmit terminal session information to the IMS configuration management apparatus 6. Then, the IMS configuration management device 6 controls the path so that the signaling message from the terminal is transmitted from one CSCF to the other CSCF after the session transition in response to the recovery / transfer of the session information. Also, the IMS configuration management device 6 always notifies the flow control device 3 of the route control information.

  The flow control device 3 generates and transmits a “flow table” of the flow switch device 2 in accordance with the path control information from the IMS configuration management device 6. It also generates and transmits a “label table” for the SIP parser 1.

  The flow switch device 2 and the flow control device 3 are existing devices based on the OpenFlow technology. The flow base switch (flow switch device) distributed and arranged and the controller (flow control device) arranged centrally are separated and connected by an open API (Application Programming Interface). According to the OpenFlow technology, the communication unit of the network is defined as “flow”, and it is possible to control the route and ensure quality in units of flow. This is an interface specification proposed by the “OpenFlow Consortium” established mainly by Stanford University in the United States (see Non-Patent Document 2, for example).

  According to the OpenFlow switch technology, a network node can be constructed in a programmable manner (free combination) of various processor resources (for example, CSCF). In particular, the network can be expanded in units of 10 Gbps (up to 64 users can be used simultaneously).

  In general, as route control in the CSCF, there are SIP message transfer control using an IP tunnel prepared for the same IP address existing on a plurality of CSCFs, and use control of a plurality of migrated IP addresses. Therefore, the inventors studied to control the transfer of the SIP message using an identifier other than the IP address using the network device side (switch) instead of the CSCF. At the same time, in order to avoid using different IP addresses, the same type of CSCF was also considered to use the same IP address. Therefore, according to the present invention, an OpenFlow switch device capable of referring to a higher layer packet header is used as a route control method independent of the IP address. In the OpenFlow switch device, a series of packets distinguished by combinations of header values are routed as “flows”. For this purpose, a flow is assigned to each minimum path that should control the path of the SIP message to the CSCF.

FIG. 3 is an explanatory diagram illustrating a flow table and a label table related to the site 1 according to the first embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a flow table and a label table related to the site 2 in the first embodiment of the present invention.

  The “label”, which is a feature of the present invention, is composed of a combination of one or more identifiers (IDs) of CSCF (and HSS) in which registration information (or session information) of the terminal URI exists. Therefore, a plurality of terminal URIs are associated with one label, and as a result, the number of entries in the label table and the flow table is reduced.

The SIP parser 1 holds a “label table” in which “URI of the terminal” and “label” are associated with each other. According to FIG. 3, the label corresponding to the terminal URI of terminal # 1 is determined as follows.
IMS node where registration information of terminal # 1 exists or is used:
P-CSCF1 (ID: P1), S-CSCF1 (ID: S1)
I-CSCF1 (ID: I1), HSS1 (ID: H1)
Label corresponding to terminal URI of terminal # 1:
"P1 S1 I1 H1"
The SIP parser 1 may generate the label table itself, or may receive the label table generated by the flow control device 3.

  The SIP parser 1 acquires the calling terminal URI and the receiving terminal URI from the received SIP message. Next, the SIP parser 1 searches for labels corresponding to these terminal URIs from the label table. Then, the retrieved label is included in the destination MAC address and the source MAC address of the SIP message, and the SIP message is transferred to the flow switch device 2.

  The flow switch device 2 holds a “flow table” in which output ports (operations) are associated with each other in accordance with a combination of a label and a destination IP address. According to this, even for the same label, the operation is different for each different destination IP address. The flow table is generated by the flow control device 3, and the flow switch device 2 receives the flow table. The flow switch device 2 routes the signaling message according to this flow table.

FIG. 5 is an explanatory diagram showing a flow table and a label table related to the site 1 in the second embodiment of the present invention.
FIG. 6 is an explanatory diagram showing a flow table and a label table related to the site 2 in the second embodiment of the present invention.

  According to FIG. 5, compared with FIG. 3, in addition to the identifier of one or more SIP servers where the registration information of the terminal URI exists or is used, the label indicates the identifier of the base where the SIP server is located. It is a further combination.

According to FIG. 5, the “label table” held by the SIP parser 1 is determined as follows as a label corresponding to the terminal URI of the terminal # 2.
IMS node where registration information of terminal # 1 exists or is used:
P-CSCF2 (ID: P2): Base 2 (Ploc2)
S-CSCF2 (ID: S2): Base 2 (Sloc2)
I-CSCF1 (ID: I1): Base 1 (Iloc1)
HSS1 (ID: H1): Base 1 (Hloc1)
Label corresponding to terminal URI of terminal # 2:
“Ploc2 Sloc2 Iloc1 Hloc1 P2 S2 I1 H1”

  Further, in the “flow table” held by the flow switch device 2, identifiers other than the identifier of at least one site are designated by wild cards. “Wild card” refers to a special character that means “arbitrary character” used when a file name or the like is designated, for example. In general, “*” means any character of any length, and “?” Means any one character. As a result, the number of entries in the flow table can be reduced.

According to FIG. 5, for example, the label “Ploc1 * * * P1 * * *” corresponds when at least “Ploc1” and “P1” match. In this case, if the destination IP address is “10.10.1.1” (P-CSCF), the signaling message is output to port 1.
According to FIG. 5, for example, the label “Ploc1 * * * P2 * * *” corresponds when at least “Ploc1” and “P2” match. In this case, if the destination IP address is “10.10.1.1” (P-CSCF), the signaling message is output to port 2.

  Note that the technique using wildcards in the flow tables based on FIGS. 5 and 6 requires that the flow switch device 2 is compatible with version 1.1 of OpenFlow Switch.

  FIG. 7 is a sequence diagram of transmission in the present invention.

  According to FIG. 7, after the session information of terminal # 2 managed by P-CSCF # 2 and S-CSCF # 2 is transferred to P-CSCF # 3 and S-CSCF # 3, the terminal # 1 This shows the case of routing a signaling message from UE to terminal # 2.

[First step]
(S10) The terminal # 1 transmits an outgoing message (INVITE message, signaling request message) to the SIP parser 1. The address header of this INVITE message is set as follows.
Source IP address: IP address of terminal # 1 Destination IP address: IP address of P-CSCF # 1

(S11) The SIP parser 1 analyzes the SIP data portion of the received signaling message and acquires the following information.
From header in INVITE message-> Acquisition of sending terminal URI
To header in INVITE message-> Acquisition of called terminal URI

(S12) Next, the SIP parser 1 caches the following information from the MAC address header.
Cache source MAC address in INVITE message
Cache destination MAC address in INVITE message

(S13) Next, the SIP parser 1 searches for the following labels using the label table.
Search for “source label” corresponding to “caller terminal URI” (terminal # 1)
[P1 S1 I1 H1]
Search for “destination label” corresponding to “terminal URI of terminal” (terminal # 2)
[P3 S3 I1 H1]
The “transmission source label” is a label that identifies the “transmission source terminal URI”, and similarly, the “destination label” is a label that identifies the “destination terminal URI”.

(S14) Next, the SIP parser 1 rewrites the MAC address for the INVITE message (signaling request message) as follows.
Destination MAC address header <-Source label
[P1 S1 I1 H1]
Source MAC address header <-Destination label
[P3 S3 I1 H1]
The MAC address header rewriting process is executed by the I / F module of the SIP parser.

(S15) Then, the SIP parser 1 transmits the INVITE message to the flow switch device 2A.

[Second step]
(S2) The flow switch device 2A selects an output port for the received INVITE message according to the flow table. The flow switch device 2A identifies “flow” from the “destination MAC address” and “destination IP address” in the received INVITE message, and identifies the port to which the INVITE message is to be output.
“Destination MAC address”: Label [P1 S1 I1 H1]
“Source MAC address”: label [P3 S3 I1 H1]
“Destination IP address”: IP address of P-CSCF # 1 According to FIG. 3, this INVITE message is output to port 1 to which P-CSCF # 1 is connected.

[Third step]
(S311) The P-CSCF # 1 caches the following information for the INVITE message received from the flow switch device 2A.
Cache the source label of the destination MAC address header Cache the destination label of the source MAC address header And P-CSCF # 1 obtains the destination IP address of the node that should be sent to the next hop from the Route header of the INVITE message To do. Here, the destination IP address of S-CSCF # 1 is acquired as the next hop.
“Destination MAC address”: Label [P1 S1 I1 H1]
“Source MAC address”: label [P3 S3 I1 H1]
“Destination IP address”: IP address of S-CSCF # 1 “Source IP address”: IP address of P-CSCF # 1 Note that the rewriting process of the IP address header is executed by a normal CSCF function.

(S312) Next, P-CSCF # 1 transmits an INVITE message to be transmitted to S-CSCF # 1 to flow switch apparatus 2A.

(S313) The flow switch apparatus 2A outputs the received INVITE message as it is to the port 3 to which the S-CSCF # 1 is connected according to the flow table.

(S314) S-CSCF # 1 caches the following information for the INVITE message received from the flow switch device 2A, as in S311 to S313.
Cache the source label of the destination MAC address header Cache the destination label of the source MAC address header And the S-CSCF # 1 is the destination of the I-CSCF # 1 to be transmitted to the next hop from the Route header of the INVITE message Obtain an IP address.

(S315) S-CSCF # 1 transmits the received INVITE message (signaling request message) from S-CSCF or I-CSCF based on the source IP address to I-CSCF or S-CSCF based on the destination IP address Determine whether or not. Here, it is a request message to be transferred from the S-CSCF # 1 to the I-CSCF, and this determination is “true”. In this case, the flow switch device 2A reverses the contents of the MAC address header as follows.
"Destination MAC address header"<-Destination label of source MAC address header
Label [P3 S3 I1 H1]
"Source MAC address header"<-Source label of destination MAC address header
Label [P1 S1 I1 H1]
“Destination IP address”: IP address of I-CSCF # 1 “Source IP address”: IP address of S-CSCF # 1

(S316) The S-CSCF # 1 transmits an INVITE message to the flow switch device 2A.

(S317) The flow switch apparatus 2A outputs the received INVITE message as it is to the port 5 to which the I-CSCF # 1 is connected according to the flow table.

(S318) When the I-CSCF # 1 does not hold the key information in the terminal, the I-CSCF # 1 inquires the HSS about the key information using the Diameter protocol. The Diameter protocol is a next-generation AAA (Authentication, Authorization and Accounting) standard protocol that replaces RADIUS (Remote Authentication Dial In User Service). The I-CSCF transmits a DiameterUR message to the HSS # 1 via the flow switch device 2 in order to acquire terminal authentication information and key information. Further, the HSS # 1 transmits a DiameterUA message to the I-CSCF # 1 via the flow switch device 2A based on the received DiameterUR message.

(S319) Next, the I-CSCF # 1 sets the header of the INVITE message to be transmitted to the S-CSCF # 3 as follows.
"Destination MAC address header"<-Label [P3 S3 I1 H1]
"Source MAC address header"<-label [P1 S1 I1 H1]
“Destination IP address”: IP address of S-CSCF # 3 “Source IP address”: IP address of I-CSCF # 1 And I-CSCF # 1 transmits the INVITE message to the flow switch device 2 .

(S4) The flow switch device 2A outputs the received INVITE message as it is to the port 7 to which the flow switch device 2B is connected according to the flow table.

  FIG. 8 is a call request sequence diagram continued from FIG.

(S321) The flow switch apparatus 2B outputs the received INVITE message as it is to the port 4 to which the S-CSCF # 3 is connected.

(S322) Next, S-CSCF # 3 caches the following information for the INVITE message received from the flow switch apparatus 2B, as in S311 to S313.
Cache the source label of the destination MAC address header Cache the destination label of the source MAC address header And the S-CSCF # 3 is the destination of the P-CSCF # 3 to be transmitted to the next hop from the Route header of the INVITE message Obtain an IP address.

S-CSCF # 3 sets the header of the INVITE message to be transmitted to P-CSCF # 3 as follows.
“Destination MAC address header”: Label [P3 S3 I1 H1]
“Source MAC address header”: label [P1 S1 I1 H1]
“Destination IP address”: IP address of P-CSCF # 3 “Source IP address”: IP address of S-CSCF # 3 Then, S-CSCF # 3 transmits the INVITE message to flow switch apparatus 2B. .

(S323) The flow switch apparatus 2B outputs the received INVITE message as it is to the port 2 to which the P-CSCF # 3 is connected.

(S324) Next, the P-CSCF # 3 caches the following information for the INVITE message received from the flow switch apparatus 2B, as in S311 to S313.
Cache the source label of the destination MAC address header Cache the destination label of the source MAC address header And P-CSCF # 3 is the destination IP address of terminal # 2 to be transmitted to the next hop from the Route header of the INVITE message To get.

P-CSCF # 3 transmits an INVITE message to be transmitted to terminal # 2 to flow switch apparatus 2B.
“Destination MAC address header”: Label [P3 S3 I1 H1]
“Source MAC address header”: label [P1 S1 I1 H1]
“Destination IP address”: IP address of called terminal # 2 “Source IP address”: IP address of P-CSCF # 3

[Fourth step]
(S4) The flow switch device 2B transfers the INVITE message to the SIP parser 1B according to the flow table.

[Fifth step]
(S5) The SIP parser 1 rewrites the MAC address of the INVITE message received from the flow switch device 2B as follows.
Source MAC address header
<-Source MAC address cached at registration Destination MAC address header
<-Destination MAC address cached at the time of registration Then, the SIP parser 1 transmits an INVITE message to the terminal # 2 on the receiving side.

  FIG. 9 is a response sequence diagram of outgoing call following FIG.

  Terminal # 2 transmits an outgoing response message (183 message, signaling response message) to the SIP parser 1. The 183 message reaches the originating terminal # 1 by the same sequence as in FIG. Here, as compared with FIG. 7, only the characteristic part will be described.

(S14) The SIP parser 1 rewrites the MAC address for the 183 message (signaling response message) as follows.
Destination MAC address header <-Source label
[P3 S3 I1 H1]
Source MAC address header <-Destination label
[P1 S1 I1 H1]
Then, the SIP parser 1 outputs the 183 message to the port to which the S-CSCF # 3 is connected, and transmits it to the flow switch device 2.

(S315) S-CSCF # 3 determines whether or not the received 183 message is transmitted from S-CSCF or I-CSCF based on the source IP address to I-CSCF or S-CSCF based on the destination IP address. judge. Here, it is a message to be transferred from S-CSCF # 3 to I-CSCF, and this determination is “true”. In this case, the flow switch apparatus 2 reversely changes the contents of the MAC address header as follows.
"Destination MAC address header"<-Destination label of source MAC address header
Label [P1 S1 I1 H1]
"Source MAC address header"<-Source label of destination MAC address header
Label [P3 S3 I1 H1]
“Destination IP address”: IP address of I-CSCF # 1 “Source IP address”: IP address of S-CSCF # 3

  FIG. 10 is a sequence diagram of registration in the present invention.

(S611) The IMS configuration management device 6 assigns the identifier of the base and the identifier of the SIP server (CSCF and HSS), and manages the identifier of the SIP server where the registration information exists and is used for each terminal URI. The IMS configuration information is notified to the flow control device 3.
(S612) The flow control device 3 generates a flow table for the flow switch device 2 and a label table for the SIP parser 1 based on the IMS configuration information (see FIGS. 3 and 5 described above).
(S613) The flow control device 3 transmits the flow table to the flow switch device 2 and transmits the label table to the SIP parser 1.

(S621) The terminal # 1 transmits a location registration message (REGISTER message) to the IMS network. The REGISTER message is received by the SIP parser 1.
(S622) The SIP parser 1 parses the REGISTER message, and acquires the URI (source terminal URI) of the transmission source terminal # 1 from the From header (similar to S11 in FIG. 7).
(S622) Further, the SIP parser 1 caches the destination MAC address in the REGISTER message (similar to S12 in FIG. 7).
(S623) Next, the SIP parser 1 determines whether or not a label for the originating terminal URI is registered in the label table. Here, in the case of the first REGISTER message from terminal # 1, the label corresponding to it is not yet registered. If a label for the originating terminal URI is registered in the label table, the process proceeds to S627.

(S624) When a label for the calling terminal URI is not registered in the label table, the SIP parser 1 selects a label associated with the calling terminal URI and updates the label table. Then, the SIP parser 1 transmits the originating terminal URI and the corresponding label to the flow control device 3.
(S625) The flow control device 3 updates the flow table in which the originating terminal URI and the label are associated with each other, and notifies the SIP parser 1 of an update completion response.
(S626) The SIP parser 1 rewrites the destination MAC address header to the source label for the REGISTER message (similar to S14 in FIG. 7).

(S627) Then, the SIP parser 1 transmits a REGISTER message to the flow switch device 2 (similar to S15 in FIG. 3).

  For subsequent sequences, P-CSCF # 1 sends a REGISTER message to the I-CSCF to resolve the S-CSCF. As a result, the terminal # 1 establishes a session with the P-CSCF # 1 via the SIP parser 1, and the location registration is completed by the P-CSCF # 1 and the S-CSCF # 1.

  FIG. 11 is a functional configuration diagram of the SIP parser in the present invention.

  11, the SIP parser 1 includes an AN (access network) side communication interface 101, an IMS side communication interface 102, an upstream message transfer unit 110, a label table 111, a URI acquisition unit 112, a MAC address cache. Unit 113, label search unit 114, label request transmission unit 115, label response reception unit 116, uplink address rewriting unit 117, downlink message transfer unit 120, and downlink address rewriting unit 127. These functional components other than the communication interface are realized by executing a program that causes a computer installed in a gateway (SIP parser) to function.

  The uplink message transfer unit 110 transfers the signaling message received from the terminal 5 to the flow switch device 2.

  The label table unit 111 stores a label table in which the URI of the terminal is associated with the label.

  The URI acquisition unit 112 acquires the calling terminal URI from the From header in the signaling message, and acquires the receiving terminal URI from the To header. The sending terminal URI and the receiving terminal URI are output to the label search unit 114.

  The MAC address cache unit 113 caches the transmission source MAC address and the destination MAC address in the signaling message.

  The label search unit 114 refers to the label table 111 and searches for a transmission source label corresponding to the caller terminal URI and also searches for a destination label corresponding to the callee terminal URI.

  If the signaling message is a registration request message (REGISTER message), the label request transmission unit 115 determines the source terminal URI when the label search unit 114 cannot search the source label corresponding to the source terminal URI. A label request message including the message is transmitted to the flow control device.

  The label response receiving unit 116 receives a label response message including a request label and a response label from the flow control device 3. Then, the originating terminal URI and the label are stored in the label table 111 in association with each other.

  When the signaling message is a request message, the uplink address rewriting unit 117 rewrites the destination MAC address header to the transmission source label and rewrites the transmission source MAC address header to the destination label.

  The downlink message transfer unit 120 transmits the signaling message received from the flow switch device 2 to the terminal 5.

  The downlink address rewriting unit 127 rewrites the source MAC address header with the source MAC address in the MAC address cache unit 113 and the destination MAC address header with the destination MAC address in the MAC address cache unit 113 for the signaling message. .

  The flow switch device 2 transfers the signaling message received from the SIP parser to any one SIP server or another flow switch device based on the flow table, and transmits the signaling message received from the SIP server to the other SIP server. , Forward to any one of the SIP parser or other flow switch devices.

  The SIP server (CSCF, HSS) 4 includes a label cache unit, a label rewriting unit, and a message transfer unit. As SIP servers, at least P-CSCF (Proxy-CSCF (Call Session Control Function)), S-CSCF (Serving-CSCF), I-CSCF (Interrogating-CSCF) and HSS (Home Subscriber Server) Is placed.

  The label cache unit caches the source label of the destination MAC address header and the destination label of the source MAC address header for the signaling message received from the flow switch device 2.

  The label rewriting unit uses the source MAC address header as the destination label for the signaling message to be transmitted to the next hop with the IP address of the next hop included in the Route header of the signaling message as the destination IP address. Use address header as source label. Then, the signaling message is transferred to the flow switch device 2.

  Note that the SIP server 4 uses the source label of the destination MAC address header for the signaling message transmitted from the S-CSCF or I-CSCF based on the source IP address to the I-CSCF or S-CSCF based on the destination IP address. And the destination label of the source MAC address header are rewritten so as to be reversed.

  The flow control device 3 controls the flow switch device 2. The flow control device 3 includes a label generation unit, a label response reply unit, and a flow table update unit. The label generation unit generates a request label and a response label corresponding to the caller terminal URI. The label response reply unit returns a label response message including the label to the gateway. The flow table update unit transmits a flow table including a request label and a response label to the flow switch device.

  As described above in detail, according to the signaling message path control method and network system of the present invention, by using the existing OpenFlow switch device, without moving the IP address after the SIP server session transition, Moreover, it is possible to eliminate the need to establish a tunnel. In addition, it is possible to control the route at high speed without installing special functions in the existing OpenFlow switch device.

  Here, when the terminal URI and the label are associated with the existing OpenFlow switch device on a one-to-one basis, the number of entries in the flow table is required for the number of terminal URIs. That is, if an existing OpenFlow switch device is simply installed in an IMS network to which a huge number of terminals are connected, the number of entries in the flow table exceeds the upper limit. According to the present invention, even when the existing OpenFlow switch device is provided in the IMS network, the amount of the route table to be held by the gateway and the OpenFlow switch device can be reduced as much as possible, and the routing control of the signaling message can be performed. Processing capacity can also be reduced.

  Note that since the second CSCF of the second base can be used as an alternative to the first CSCF of the first base in the control network, the SIP server ( The availability of CSCF) can also be increased.

  In the various embodiments of the present invention described above, various changes, modifications, and omissions in the scope of the technical idea and the viewpoint of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Gateway, SIP parser 101 AN side communication interface 102 IMS side communication interface 110 Upstream message transfer part 111 Label table 112 URI acquisition part 113 MAC address cache part 114 Label search part 115 Label request transmission part 116 Label response receiving part 117 Upstream address rewriting Unit 120 downlink message transfer unit 127 downlink address rewriting unit 2 flow switch device 3 flow control device 4 CSCF
41 P-CSCF
42 S-CSCF
43 I-CSCF
44 HSS
5 Terminal 6 IMS Configuration Management Device 7 Session Management Device

Claims (12)

A plurality of SIP (Session Initiation Protocol) servers connected to the IP subsystem network, one or more flow switch devices that switch a flow of signaling messages between the SIP server and the terminal, the terminal and the flow switch device A signaling message routing method in a system having one or more gateways relaying signaling messages to and from
The gateway stores a label table in which one or more terminal URIs are associated with a label based on a combination of identifiers of one or more SIP servers in which registration information of the terminal URI (Uniform Resource Indicator) exists or is used. And
For the first step, when the gateway receives a signaling message from the terminal,
Obtaining the originating terminal URI and the terminating terminal URI in the signaling message;
Cache the source MAC address and destination MAC address in the signaling message;
Using the label table, search for a source label corresponding to the originating terminal URI and a destination label corresponding to the terminating terminal URI,
Rewriting the destination MAC address header with the source label, and rewriting the source MAC address header with the destination label,
Sending the signaling message to the flow switch device;
In the second step, the flow switch device transfers the signaling message to the SIP server according to the label.   Regarding the label table, the label is a combination of one or more SIP server identifiers in which the registration information of the terminal URI exists or used, and an identifier of a base where the SIP server is located, The route control method according to claim 1, wherein identifiers other than the identifier of at least one site are designated by a wild card. For the third step, the SIP server
For the signaling message received from the flow switch device, cache the source label of the destination MAC address header, and cache the destination label of the source MAC address header;
A signaling message to be transmitted to the next hop, with the IP address of the next hop included in the Route header of the signaling message as a destination IP address, is transmitted to the flow switch device.
For the fourth step, the flow switch device forwards the signaling message to the gateway, another SI or another flow switch device,
For the fifth step, the gateway
For the signaling message received from the flow switch device, the source MAC address header is rewritten to the source MAC address cached in the first step, and the destination MAC address header is cached in the first step. Rewritten to the destination MAC address that was
The signaling message path control method according to claim 1 or 2, wherein the signaling message is transmitted to the terminal. The system further includes a flow control device for controlling the flow switch device,
For the first step, if the signaling message is a registration request message (REGISTER message),
Before Symbol gateway,
Obtain the calling terminal URI in the registration message,
Cache the destination MAC address in the registration message,
When the source label corresponding to the calling terminal URI cannot be retrieved using the label table, the source label corresponding to the calling terminal URI is selected,
In the label table, the calling terminal URI and the label are stored in association with each other,
Sending the originating terminal URI and the selected source label to the flow control device;
Before Symbol flow control device,
Update the flow table associating the originating terminal URI with the source label;
4. The signaling message path control method according to claim 3, wherein an update completion response message is returned to the gateway. The IP subsystem network is an IMS (IP Multimedia Subsystem) network,
As the SIP server, P-CSCF (Proxy-CSCF (Call Session Control Function)), S-CSCF (Serving-CSCF), I-CSCF (Interrogating-CSCF) and / or HSS (Home Subscriber) Server) is located,
The flow switch device stores the IP address of each CSCF by a flow table,
For the second step,
The S-CSCF of the source IP address reverses the source label of the destination MAC address header and the destination label of the source MAC address header for the request message transmitted to the I-CSCF or S-CSCF of the destination IP address. Rewrite to replace or
The I-CSCF or S-CSCF of the source IP address reverses the destination label of the destination MAC address header and the source label of the source MAC address header for the response message transmitted to the S-CSCF of the destination IP address. The signaling message path control method according to any one of claims 1 to 4, wherein rewriting is performed so as to replace with the signaling message. The flow switch device is OpenFlowSwitch (registered trademark),
The flow control device is OpenFlowController (registered trademark),
5. The signaling message routing method according to claim 4 , wherein the gateway is a SIP parser for converting a protocol header. A plurality of SIP (Session Initiation Protocol) servers connected to the IP subsystem network, one or more flow switch devices that switch a flow of signaling messages between the SIP server and the terminal, the terminal and the flow switch device A network system having one or more gateways for relaying signaling messages to and from
To route signaling messages after session transition,
The gateway is
A label table in which one or more terminal URIs are associated with a label based on a combination of identifiers of one or more SIP servers in which registration information of the terminal URI (Uniform Resource Indicator) exists or is used;
An uplink message transfer means for transferring a signaling message received from the terminal to the flow switch device;
URI acquisition means for acquiring the originating terminal URI and the terminating terminal URI in the signaling message;
MAC address cache means for caching the source MAC address and destination MAC address in the signaling message;
Label search means for searching for a source label corresponding to the calling terminal URI and a destination label corresponding to the receiving terminal URI using the label table;
A network system comprising: an uplink address rewriting means for rewriting a destination MAC address header to the source label and rewriting the source MAC address header to the destination label.   Regarding the label table, the label is a combination of one or more SIP server identifiers in which the registration information of the terminal URI exists or used, and an identifier of a base where the SIP server is located, 8. The network system according to claim 7, wherein identifiers other than the identifier of at least one site are designated by a wild card. The flow switch device transfers a signaling message received from the gateway to any one of a SIP server or another flow switch device based on a flow table, and transmits the signaling message received from the SIP server to another Forwarding to any one of SIP servers, other flow switch devices or gateways,
The gateway is
A downlink message transfer means for transmitting a signaling message received from the flow switch device to the terminal;
For the signaling message, the source MAC address header is rewritten to the source MAC address in the MAC address cache means, and the destination MAC address header is rewritten to the destination MAC address in the MAC address cache means. Means,
The SIP server
For the signaling message received from the flow switch device, label caching means for caching the source label of the destination MAC address header and caching the destination label of the source MAC address header;
And a message transfer unit configured to transfer a signaling message to be transmitted to the next hop to the flow switch device using the next hop IP address included in the Route header of the signaling message as a destination IP address. Item 9. The network system according to Item 7 or 8. Further comprising a flow control device for controlling the pre-Symbol flow switch device,
The gateway, when the signaling message is a registration request message (REGISTER message),
The URI acquisition means acquires the calling terminal URI in the registration message;
The MAC address cache means caches the destination MAC address in the registration message;
When a source label corresponding to the originating terminal URI cannot be retrieved using the label table, a source label corresponding to the originating terminal URI is selected, and the originating terminal is selected in the label table. A label request transmitting means for storing the URI and the label in association with each other, and transmitting the originating terminal URI and the transmission source label to the flow control device;
Label response receiving means for receiving a label response message from the flow control device;
The flow control device is
Flow table updating means for updating a flow table in which the originating terminal URI and the source label are associated with each other;
The network system according to claim 9, further comprising label response reply means for replying an update completion response message to the gateway. The IP subsystem network is an IMS network;
As the SIP server, at least P-CSCF, S-CSCF, I-CSCF and / or HSS are arranged,
The flow switch device stores the IP address of each CSCF by a flow table,
The flow switch device is:
For a request message transmitted from the S-CSCF of the source IP address to the I-CSCF or S-CSCF of the destination IP address, the source label of the destination MAC address header and the destination label of the source MAC address header are reversed. Rewrite to replace or
For a response message transmitted from the I-CSCF or S-CSCF of the source IP address to the S-CSCF of the destination IP address, the destination label of the destination MAC address header and the source label of the source MAC address header are reversed. The network system according to any one of claims 7 to 10, wherein the network system is rewritten so as to be replaced. The flow switch device is OpenFlowSwitch (registered trademark),
The flow control device is OpenFlowController (registered trademark),
The network system according to claim 10, wherein the gateway is a SIP parser that converts a protocol header.

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