CN104717142B - Method for carrying out mobility management based on OpenFlow protocol - Google Patents

Abstract

The invention discloses a method for carrying out mobility management based on an OpenFlow protocol, which comprises the following steps: step 1), a Controller maintains a corresponding relation table recorded with a plurality of OpenFlow switches with AP functions and port numbers connected to each gateway; step 2) receiving identification information containing a mobile node MN and reported information of a first OpenFlow switch attached to the mobile node MN, wherein the identification information of the mobile node MN is an MAC address and/or an IP address of the mobile node, and the identification information is transmitted by the first OpenFlow switch with the AP function; and 3) checking the corresponding relation table according to the report information, and executing different routing behaviors based on the identification information of the mobile node MN and the query result of the report information of the first OpenFlow switch attached to the mobile node MN.

Description

A method for mobility management based on OpenFlow protocol

technical field

The invention discloses a method and device for mobility management based on OpenFlow protocol, belonging to the technical field of mobile communication.

Background technique

Mobile IP is designed to meet the needs of mobile nodes (MN, Mobile Node) to maintain their connectivity while moving. Mobile IP now has two versions, namely Mobile IPv4 and Mobile IPv6.

Software-defined networking (SDN, Software-defined networking) is a network virtualization (Networkvirtualization) technology. Using the OpenFlow protocol, the router's control plane (control plane) is separated from the data plane (data plane) and implemented in software. This architecture allows network administrators to re-plan the network with programs in a central control mode without changing hardware devices, providing a new method for controlling network traffic and a good platform for core network and application innovation .

OpenFlow technology was first proposed by Stanford University. It aims to solve various bottlenecks caused by the current network facing new services with innovative network interconnection concepts based on the existing TCP/IP technical conditions.

Its core idea is to transform the packet forwarding process originally completely controlled by the switch/router into an independent process completed by the OpenFlow switch (OpenFlow Switch) and the controller (Controller).

Behind the transformation is actually the change of control rights: the flow direction of data packets in traditional networks is artificially specified. Although switches and routers have control rights, they do not have the concept of data flow, and only exchange at the packet level; while in OpenFlow In the network, a unified control server replaces the routing and determines the transmission path of all data packets in the network.

The OpenFlow switch will maintain a local flow table (Flow Table) that is different from the forwarding table. If the packet to be forwarded has a corresponding entry in the flow table, it will be forwarded directly; if there is no entry in the flow table, the packet will be forwarded directly. It will be sent to the control server for confirmation of the transmission path, and then forwarded according to the delivery result.

Each flow entry of an OpenFlow switch has a priority field, which indicates the matching order of the flow entries. The priority value ranges from 0 to 65535. When the data packet matches the flow table, the flow table entry with the higher priority is matched first. All fields are wildcarded (all fields omitted) and a flow entry with a priority equal to 0 is called a table-miss flow entry.

In IPv4, a node's IP address uniquely identifies the node's access point in the network. Therefore, a node must be on the network represented by its IP address in order to accept messages sent to it; otherwise packets sent to this node are unreachable. In order to make the node maintain the continuity of communication while moving, there are currently two methods: changing the access point while changing its IP address; using host-based routing. Both of these approaches are usually not advisable. Therefore, the mechanism of Mobile IP is proposed to solve this problem.

Each node is uniquely identified by its home address regardless of its access point in the network. When leaving the home network, the mobile node is assigned a care-of address, which represents the current location of the mobile node in the network. The mobile node registers its care-of address with the home agent to inform it of its current location. The home agent sends the data packet sent to the mobile node to the care-of address of the mobile node through the tunnel. After reaching the other end of the tunnel, the data packet is forwarded to the mobile node.

Proxy Mobile IPv6 (PMIP, Proxy Mobile IP) is a network-based regional mobility management solution that does not require mobile nodes to participate in any signaling process related to IP mobility. A mobile entity in the network tracks the movement of the mobile node and initiates mobility signaling procedures and sets the necessary routing states. The core entities in PMIPv6 are LMA (LocalMobility Anchor) and MAG (Mobile Access Gateway).

The LMA is used to maintain the access state of the MN and the prefix of the home network of the MN, and is used to maintain the connection between the home address of the MN and the network. The MAG acts as an access router on the access link. The MN directly accesses the MAG in the process of moving, and the MAG performs mobility management on behalf of the MN after detecting the access or moving information of the MN, and sends a binding registration message to the LMA. The MAG detects the state of the MN, and sends and receives the binding message on behalf of the MN and establishes the binding state, which reduces the signaling interaction of the MN participating in the handover, saves the bandwidth of the wireless link, and reduces the complexity of signaling messages. processing delay.

Most of the traditional mobility management solutions are based on tunnel management mechanisms. In Mobile IP, a tunnel is established between the home agent and the foreign agent, so as to realize the service continuity of the terminal in the moving process; in the agent mobile IPv6, the LMA and the MAG communicate through the establishment of a bidirectional tunnel. This brings problems such as triangular routing and tunnel state maintenance.

The triangular routing problem means that the data packets sent to the mobile node MN must be forwarded by the home agent or MAG, which increases the workload of the mobile node MN's home agent or the router where the MAG is located, and at the same time makes the data packets from the source address to the destination address. The route is not the best path; the tunnel between communicating entities needs to maintain state information regularly and tear down when necessary.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for mobility management using the OpenFlow protocol, which, through the controller's perception of the topology of the entire network, issues a flow table to enable the MN to communicate with the opposite end; when the MN moves, The traditional tunnel management mechanism is abandoned and the existing flow table is deleted and the flow table is re-issued to maintain the continuity of communication between the MN and the peer.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is as follows:

A method for mobility management based on OpenFlow protocol, comprising:

Step 1) Controller maintains a correspondence table that records a plurality of OpenFlow switches with AP function and the port numbers that are connected to each gateway;

Step 2) Receive the identification information of the mobile node MN and the report information of the first OpenFlow switch to which the mobile node MN is attached and transmitted by the first OpenFlow switch with the AP function, where the identification information of the mobile node MN is the mobile node's MAC address and / or IP address;

Step 3) Check the correspondence table according to the report information, and perform different routing actions based on the identification information of the mobile node MN and the query result of the report information of the first OpenFlow switch attached to the mobile node MN.

Preferably, it further includes:

By defining a field in the Vendor message, the identification information of the mobile node MN is stored; the Vendor message is sent to the controller by the OpenFlow switch with AP function; or,

By defining a field in the Experimenter message, the identification information of the mobile node MN is stored; the Experimenter message is sent to the controller by the OpenFlow switch with the AP function.

Preferably, the step 3) specifically includes: checking the correspondence table according to the reported information, wherein, if there is no mobile MN information in the correspondence table;

Then record it and the attached first OpenFlow switch, and at the same time, the controller delivers the flow table corresponding to the mobile node to other OpenFlow switches of the gateway of the network where the mobile node is located, so that the mobile node can establish communication with the mobile node of the opposite end.

Preferably, in step 3), further comprise:

If there is no IP address of the mobile node in the reported information, assign an IP address to the mobile node MN according to the controller's own DHCP function, and allocate an IP address to the mobile node MN according to the IP address of the mobile node MN, the OpenFlow switch with AP function and the AP function The OpenFlow switch is connected to the corresponding relationship of the port numbers of each gateway, and a flow table to reach the mobile node MN is added to the gateway corresponding to the IP address of the mobile node MN.

Preferably, the controller records the network address segment corresponding to each gateway and the IP address and the number of IP addresses that can be allocated to the mobile node MN in each network address segment;

When judging that the mobile node MN does not have an IP address, the controller selects a network address segment with the largest number of assignable IP addresses, and selects an IP address from the IP addresses that can be assigned to the mobile node MN from the network address segment to assign to MN and write the DHCP OFFER data packet, and at the same time modify the IP address and the number of IP addresses that can be allocated to the mobile node MN in the network address segment;

The DHCP OFFER data packet is encapsulated in the Packet_out data packet and sent to the OpenFlow switch with AP function, and the OpenFlow switch with AP function then sends the DHCP OFFER data packet to the mobile node MN;

The mobile node MN sends a DHCP REQUEST packet to the OpenFlow switch with AP function, and the OpenFlow switch with AP function encapsulates the DHCP REQUEST packet in a Packet_in packet and sends it to the controller Controller, which encapsulates the DHCP ACK packet in Packet_out The data packet is sent to the OpenFlow switch with the AP function, and the OpenFlow switch with the AP function sends the DHCP ACK data packet to the mobile node MN; at this time, the mobile node MN obtains the IP address.

Preferably, in step 3), it specifically includes: checking the corresponding relationship table according to the reported information, wherein, if the corresponding relationship table already has the information of the mobile node;

In addition, if the attached OpenFlow switch is different from the newly reported one, the record is deleted, and the information of the mobile node and the newly reported OpenFlow switch is added to the correspondence table as a new record.

Preferably, it further includes:

The controller and the controllers of other domains jointly maintain a piece of identification information of the mobile node MN and a correspondence table of the attached OpenFlow switches with the AP function, and the network address segments managed by them are different;

The controller determines, according to the IP address of the mobile node, whether the mobile node is moving across domains or within an area.

Preferably, it further includes:

If it is detected that the mobile node MN is moving in the same area;

The controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, and simultaneously issues a new flow table corresponding to the mobile node to other OpenFlow switches of the gateway of the network where the mobile node is located, so that the mobile node Communication with the peer end is not interrupted.

Preferably, in step 3), further comprise:

If it is detected that the mobile node MN is moving across domains, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located;

According to the weighted value of the newly added network, an appropriate communication path is selected, and the next flow table for the mobile node MN is set for all OpenFlow switches on the path, so that the communication between the mobile node and the opposite end is not interrupted.

Preferably, the weighting factor of the newly added network selects the link state of each link and the load of each OpenFlow switch.

After the present invention adopts the above scheme, the traditional tunnel management mechanism is abandoned, the problem of triangular routing is well solved, and the extra overhead caused by the maintenance of the tunnel state is avoided at the same time; the use of SDN technology makes the management of the network more convenient and flexible, and its Mobility management can be effectively performed through the perception of the current location of the mobile node MN and the flexible control of the flow table in each OpenFlow switch in the network controlled by the controller.

Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description, claims, and drawings.

Description of drawings

The present invention will be described in detail below with reference to the accompanying drawings, so as to make the above advantages of the present invention more clear. in,

1 is a network topology diagram of an embodiment of the present invention;

FIG. 2 is a network topology diagram of another embodiment of the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so as to fully understand and implement the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects. It should be noted that, as long as there is no conflict, each embodiment of the present invention and each feature of each embodiment can be combined with each other, and the formed technical solutions all fall within the protection scope of the present invention.

Additionally, the steps shown in the flowcharts of the figures may be performed in a computer system, such as a set of computer-executable instructions, and, although shown in a logical order in the flowcharts, in some cases, may be executed differently The steps shown or described are performed in the order shown herein.

Specifically, in an embodiment of the present invention, based on the implementation of OpenFlow, through the controller's perception of the entire network topology, a flow table is issued to enable the MN to communicate with the peer; when the MN moves, the traditional tunnel management mechanism is abandoned and the The continuity of communication between the MN and the peer is maintained by deleting the existing flow table and re-delivering the flow table.

Specifically, the detailed scheme of the present invention is as follows:

Example 1:

A method for mobility management based on OpenFlow protocol, comprising:

Step 1) Controller maintains a correspondence table that records a plurality of OpenFlow switches with AP function and the port numbers that are connected to each gateway;

Step 2) Receive the identification information of the mobile node MN and the report information of the first OpenFlow switch to which the mobile node MN is attached and transmitted by the first OpenFlow switch with the AP function, where the identification information of the mobile node MN is the mobile node's MAC address and / or IP address;

Step 3) Check the correspondence table according to the report information, and perform different routing actions based on the identification information of the mobile node MN and the query result of the report information of the first OpenFlow switch attached to the mobile node MN.

Preferably, it further includes:

By defining a field in the Vendor message, the identification information of the mobile node MN is stored; the Vendor message is sent to the controller by the OpenFlow switch with AP function; or,

By defining a field in the Experimenter message, the identification information of the mobile node MN is stored; the Experimenter message is sent to the controller by the OpenFlow switch with the AP function.

Preferably, the step 3) specifically includes: checking the correspondence table according to the reported information, wherein, if there is no mobile MN information in the correspondence table;

Then record it and the attached first OpenFlow switch, and at the same time, the controller delivers the flow table corresponding to the mobile node to other OpenFlow switches of the gateway of the network where the mobile node is located, so that the mobile node can establish communication with the mobile node of the opposite end.

Preferably, in step 3), further comprise:

If there is no IP address of the mobile node in the reported information, assign an IP address to the mobile node MN according to the controller's own DHCP function, and allocate an IP address to the mobile node MN according to the IP address of the mobile node MN, the OpenFlow switch with AP function and the AP function The OpenFlow switch is connected to the corresponding relationship of the port numbers of each gateway, and a flow table to reach the mobile node MN is added to the gateway corresponding to the IP address of the mobile node MN.

Preferably, the controller records the network address segment corresponding to each gateway and the IP address and the number of IP addresses that can be allocated to the mobile node MN in each network address segment;

When judging that the mobile node MN does not have an IP address, the controller selects a network address segment with the largest number of assignable IP addresses, and selects an IP address from the IP addresses that can be assigned to the mobile node MN from the network address segment to assign to MN and write the DHCP OFFER data packet, and at the same time modify the IP address and the number of IP addresses that can be allocated to the mobile node MN in the network address segment;

The DHCP OFFER data packet is encapsulated in the Packet_out data packet and sent to the OpenFlow switch with AP function, and the OpenFlow switch with AP function then sends the DHCP OFFER data packet to the mobile node MN;

The mobile node MN sends a DHCP REQUEST packet to the OpenFlow switch with AP function, and the OpenFlow switch with AP function encapsulates the DHCP REQUEST packet in a Packet_in packet and sends it to the controller Controller, which encapsulates the DHCP ACK packet in Packet_out The data packet is sent to the OpenFlow switch with the AP function, and the OpenFlow switch with the AP function sends the DHCP ACK data packet to the mobile node MN; at this time, the mobile node MN obtains the IP address.

Preferably, in step 3), it specifically includes: checking the corresponding relationship table according to the reported information, wherein, if the corresponding relationship table already has the information of the mobile node;

In addition, if the attached OpenFlow switch is different from the newly reported one, the record is deleted, and the information of the mobile node and the newly reported OpenFlow switch is added to the correspondence table as a new record.

Preferably, it further includes:

The controller and the controllers of other domains jointly maintain a piece of identification information of the mobile node MN and a correspondence table of the attached OpenFlow switches with the AP function, and the network address segments managed by them are different;

The controller determines, according to the IP address of the mobile node, whether the mobile node is moving across domains or within an area.

Preferably, it further includes:

If it is detected that the mobile node MN is moving in the same area;

The controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, and simultaneously issues a new flow table corresponding to the mobile node to other OpenFlow switches of the gateway of the network where the mobile node is located, so that the mobile node Communication with the peer end is not interrupted.

Preferably, in step 3), further comprise:

If it is detected that the mobile node MN is moving across domains, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located;

According to the weighted value of the newly added network, an appropriate communication path is selected, and the next flow table for the mobile node MN is set for all OpenFlow switches on the path, so that the communication between the mobile node and the opposite end is not interrupted.

Preferably, the weighting factor of the newly added network selects the link state of each link and the load of each OpenFlow switch.

After the present invention adopts the above scheme, the traditional tunnel management mechanism is abandoned, the problem of triangular routing is well solved, and the extra overhead caused by the maintenance of the tunnel state is avoided at the same time; the use of SDN technology makes the management of the network more convenient and flexible, and its Mobility management can be effectively performed through the perception of the current location of the mobile node MN and the flexible control of the flow table in each OpenFlow switch in the network controlled by the controller.

Embodiment 2:

The OpenFlow protocol is one of the basic protocols of software-defined networking (SDN). The communication between the controller and the OpenFlow switch should follow the OpenFlow protocol.

And, in order to make the OpenFlow switch with the AP function report the information of the mobile node MN to the controller, in this embodiment of the present invention, a new message field is defined on the basis of the existing OpenFlow protocol message format:

Specifically, under the OpenFlow protocol version 1.0, in the Vendor message, a new field of 6 bytes 6 MN's MAC is defined to store the identification information of the mobile node MN; the Vendor message is sent to the controller by the OpenFlow switch with AP function Controller, Vendor message structure is as follows:

header vendor MN's MAC

Specifically, under the OpenFlow protocol version 1.3, in the Experimenter message, a new field of MN's MAC of 6 bytes is defined to store the identification information of the mobile node MN; the Experimenter message is sent by the OpenFlow switch with AP function to the controller Controller , the structure of the Experimenter message is as follows:

header experimenter exp_type MN's MAC

The network managed by one controller is referred to as a domain, and FIG. 1 and FIG. 2 correspond to the topologies of intra-domain mobility management and cross-domain mobility management respectively. That is to say, in the embodiment of the present invention, FIG. The topology shown in Figure 2 was studied.

When the mobile node MN moves within a domain, as shown in Figure 1, s1 is a non-OpenFlow switch and does not need to be connected to the controller; s2, s3, and s4 are traditional OpenFlow switches, which act as gateways and need to communicate with the controller. The Controller connects, but does not need to support the new OpenFlow protocol fields mentioned in the patent. The network address segments of s2, s3, and s4 are A, B, and C respectively;

s5, s6, and s7 are OpenFlow switches with AP function, which need to be connected with the controller and support the new OpenFlow protocol fields mentioned in the patent.

When the mobile node MN moves across domains, as shown in Figure 2, s1, s2, s3, s4, s1', s2', s3', and s4' are traditional OpenFlow switches, which need to be connected to the controller; s2 , s3, s4, s2', s3', s4' acts as a gateway and does not need to support the new OpenFlow protocol fields mentioned in the patent, the network address segments of s2, s3, s4, s2', s3', s4' A, B, C, A', B', C' respectively; s5, s6, s7, s5', s6', s7' are OpenFlow switches with AP function, which need to be connected to the controller and support New OpenFlow protocol fields mentioned in the patent.

The controller Controller has the function of a DHCP server and can assign an IP address to the accessing mobile node MN. The process is described as follows:

The controller Controller records the network address segment corresponding to each gateway and the IP address and the number of IP addresses that can be allocated to the mobile node MN in each network address segment;

When receiving an address request from the mobile node MN, the controller selects a network address segment with the largest number of assignable IP addresses, and selects an IP address to assign to the MN from the IP addresses that can be assigned to the mobile node MN in the network address segment. At the same time, modify the IP address and the number of IP addresses that can be allocated to the mobile node MN in the network address segment;

The mobile node MN sends a DHCP DISCOVER data packet to the OpenFlow switch with AP function, requesting an IP address, the OpenFlow switch with AP function encapsulates the DHCP DISCOVER data packet in a Packet_in data packet and sends it to the controller Controller, and the controller Controller selects an IP address , write the DHCP OFFER data packet, encapsulate the DHCP OFFER data packet in the Packet_out data packet and send it to the OpenFlow switch with AP function, and the OpenFlow switch with AP function then sends the DHCP OFFER data packet to the mobile node MN;

The mobile node MN sends a DHCP REQUEST packet to the OpenFlow switch with AP function, and the OpenFlow switch with AP function encapsulates the DHCP REQUEST packet in a Packet_in packet and sends it to the controller Controller, which encapsulates the DHCP ACK packet in Packet_out The data packet is sent to the OpenFlow switch with the AP function, and the OpenFlow switch with the AP function sends the DHCP ACK data packet to the mobile node MN; at this time, the mobile node MN obtains the IP address.

Before performing mobility management, some necessary initial configurations of the network are required.

In Figure 1, the non-OpenFlow switch s1 is configured with 4 pieces of routing information, so that the data packets sent to s2, s3, s4, and CN can be sent from the corresponding interfaces;

The traditional OpenFlow switch in the network establishes a connection with the controller. The controller sends two flow tables to the traditional OpenFlow switch. One flow table sends packets destined for the gateway address of the traditional OpenFlow switch to the LOCAL interface, and the other The flow table sends the data packets in the network corresponding to the gateway address of the traditional OpenFlow switch to s1;

The OpenFlow switch with AP function in the network establishes a connection with the controller. The controller sends three flow tables to the OpenFlow switch with AP function. Which one of the network s2, s3, and s4 are located in, and then send it out from the corresponding port.

In Figure 2, the traditional OpenFlow switches s1 and s1' are respectively configured with 7 initialization flow tables, so that the data packets sent to s2, s3, s4, s2', s3', s4', and CN can be sent from the corresponding interfaces.

s2, s3, s4, s2', s3', s4' establish connections with the controller Controller, and the controllers Controller1 and Controller2 respectively send two flow tables for s2, s3, s4 and s2', s3', s4', respectively. One sends the data packets destined to the gateway address of the traditional OpenFlow switch to the LOCAL interface, and the other flow table sends the data packets in the network corresponding to the gateway address of the traditional OpenFlow switch to s1 and s1'. The OpenFlow switch with AP function in the network establishes a connection with the controller. The controller sends three flow tables to the OpenFlow switch with AP function. The three flow tables determine the source address of the received data packet respectively. Check which of the networks where the source address belongs to s2, s3, and s4. In area 2, check which of the networks where the source address belongs to s2', s3', and s4', and then send it out from the corresponding port.

The priority of the flow table entry during initial configuration is set to 1 to avoid conflict with the flow table added in the mobility management. Each of s2, s3, s4, s2', s3', and s4' has a buffer area, which can buffer the communication data in the process of the mobile node MN moving and modifying the flow table, and send it after the movement is completed to maintain the communication data. continuity.

Embodiment three:

The intra-domain mobility management workflow is as follows:

When the OpenFlow switch with the AP function senses the attachment of the MN, it will actively report the identification information (MAC address, IP address, etc.) of the MN and the AP to which the MN is attached to the controller. If it is detected that the mobile node does not have an IP address, it needs to obtain an IP address through the DHCP function of the controller.

The controller records the correspondence between the OpenFlow switch with AP function and the port number of the OpenFlow switch with AP function connected to each gateway. After the controller assigns an IP address to the mobile node MN, according to the IP address of the mobile node MN The corresponding relationship between the address, the OpenFlow switch with AP function and the port number of the OpenFlow switch with AP function connected to each gateway, add a flow table to the mobile node MN in the gateway corresponding to the IP address of the mobile node MN.

The controller records the correspondence table between the MN in the network it controls and the OpenFlow switch with the AP function attached to the MN, and after receiving the report information of the OpenFlow switch with the AP function, the controller checks the correspondence table;

If there is no information about the MN in the correspondence table, it means that the MN is a host newly added to the network, then record it and the corresponding OpenFlow switch with the AP function. At the same time, the controller issues a flow table corresponding to the mobile node to the OpenFlow switch of the gateway of the network where the mobile node is located, so that the mobile node MN establishes communication with the mobile node CN of the opposite end.

If the information of the mobile node already exists in the correspondence table and the attached OpenFlow switch is different from the newly reported one, delete the record, and add the information of the mobile node and the newly reported OpenFlow switch as a new record to the correspondence table At the same time, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, and issues a new flow table corresponding to the mobile node to the OpenFlow switch of the gateway of the network where the mobile node is located. Make the communication between the mobile node and the peer end uninterrupted.

Embodiment 4:

The cross-domain mobility management workflow is as follows:

When the OpenFlow switch with the AP function senses the attachment of the MN, it will actively report the identification information (MAC address, IP address, etc.) of the MN and the AP to which the MN is attached to the controller. If it is detected that the mobile node does not have an IP address, it needs to obtain an IP address through the DHCP function of the controller.

The controller records the correspondence between the OpenFlow switch with AP function and the port number of the OpenFlow switch with AP function connected to each gateway. After the controller assigns an IP address to the mobile node MN, according to the IP address of the mobile node MN The corresponding relationship between the address, the OpenFlow switch with AP function and the port number of the OpenFlow switch with AP function connected to each gateway, add a flow table to the mobile node MN in the gateway corresponding to the IP address of the mobile node MN.

The controllers in the two domains jointly maintain a table of the identification information of the mobile node MN and the correspondence table of the attached OpenFlow switches with the AP function. After receiving the information reported by the OpenFlow switches with the AP function, the controllers check the correspondence surface;

If there is no information about the MN in the correspondence table, it means that the MN is a host newly added to the network, then record it and the corresponding OpenFlow switch with the AP function. At the same time, the controller issues a flow table corresponding to the mobile node to the OpenFlow switch of the gateway of the network where the mobile node is located, so that the mobile node can establish communication with the mobile node of the opposite end.

If the information of the mobile node already exists in the correspondence table and the attached OpenFlow switch is different from the newly reported one, delete the record, and add the information of the mobile node and the newly reported OpenFlow switch as a new record to the correspondence table middle.

The network address segments managed by controllers Controller1 and Controller2 are A, B, C and A', B', C' respectively. If it is detected that the mobile node MN is moving in the same area, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, and delivers the corresponding flow table to the OpenFlow switch of the gateway of the network where the mobile node is located. The new flow table of the mobile node, so that the communication between the mobile node and the opposite end is not interrupted; if it is detected that the mobile node MN is moving across domains, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, And according to the weighted value of the newly added network (such as the link status of each link, the load of each OpenFlow switch, etc.), select an appropriate communication path with the CN, and assign the next OpenFlow switch on the path to the mobile node. MN's flow table, so that the communication between the mobile node and the opposite end is not interrupted.

That is to say, the present invention records the correspondence table between the mobile node MN and the OpenFlow switch OVS AP with AP function in the controller, and the OpenFlow switch with the flow table of the mobile node MN in the network, and implements mobility management through the OpenFlow protocol.

It abandons the traditional tunnel management mechanism, solves the problem of triangular routing well, and avoids the extra overhead caused by tunnel state maintenance; and uses SDN technology to make network management more convenient and flexible.

It should be noted that, for the above-mentioned method embodiments, for the sake of simple description, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the described action sequence, Because in accordance with the present application, certain steps may be performed in other orders or concurrently. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the The technical solutions described in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A method for carrying out mobility management based on an OpenFlow protocol comprises the following steps:

step 1), a Controller maintains a corresponding relation table recorded with a plurality of OpenFlow switches with AP functions and port numbers connected to each gateway;

step 2) receiving identification information containing a mobile node MN and reported information of a first OpenFlow switch attached to the mobile node MN, wherein the identification information of the mobile node MN is an MAC address and/or an IP address of the mobile node, and the identification information is transmitted by the first OpenFlow switch with the AP function;

step 3) checking the corresponding relation table according to the report information, and executing different routing behaviors based on the identification information of the mobile node MN and the query result of the report information of the first OpenFlow switch attached to the mobile node MN;

the step 3) specifically comprises the following steps: checking the corresponding relation table according to the reported information, wherein if the corresponding relation table has no information of the mobile MN;

recording the mobile node and the attached first OpenFlow switch, and simultaneously issuing a flow table corresponding to the mobile node for other OpenFlow switches of a gateway of a network where the mobile node is located by the controller to enable the mobile node to establish communication with the mobile node of the opposite end;

in step 3), further comprising:

if the reported information does not contain the IP address of the mobile node, the IP address is distributed to the mobile node MN according to the self DHCP function of the controller, and a flow table reaching the mobile node MN is added in a gateway corresponding to the IP address of the mobile node MN according to the corresponding relation of the IP address of the mobile node MN, an OpenFlow switch with an AP function and the port number of each gateway connected with the OpenFlow switch with the AP function;

the Controller records the network address field corresponding to each gateway and the IP address and the number of the IP addresses which can be allocated to the mobile node MN in each network address field;

when the mobile node MN is judged to have no IP address, the Controller selects a network address segment with the maximum number of assignable IP addresses, selects an IP address from the IP addresses assignable to the mobile node MN in the network address segment, assigns the IP address to the MN and writes a DHCP OFFER data packet, and modifies the IP address and the number of the IP addresses assignable to the mobile node MN in the network address segment;

the method comprises the steps that a DHCP OFFER data Packet is packaged in a Packet _ out data Packet and sent to an OpenFlow switch with an AP function, and the OpenFlow switch with the AP function sends the DHCP OFFER data Packet to a mobile node MN;

the mobile node MN sends a DHCP REQUEST data Packet to the OpenFlow switch with the AP function, the OpenFlow switch with the AP function packages the DHCP REQUEST data Packet in a Packet _ in data Packet and sends the Packet _ in data Packet to a Controller, the Controller packages a DHCP ACK data Packet in a Packet _ out data Packet and sends the Packet _ out data Packet to the OpenFlow switch with the AP function, and the OpenFlow switch with the AP function sends the DHCP ACK data Packet to the mobile node MN; at this time, the mobile node MN acquires an IP address; further comprising:

defining a field in the Vendor message to store the identification information of the mobile node MN; the Vendormessage is sent to a Controller by an OpenFlow switch with an AP function; or,

defining a field in the Experimenter message to store the identification information of the mobile node MN; the Experimenter message is sent to a Controller by an OpenFlow switch with an AP function; in the step 3), the method specifically comprises the following steps: checking the corresponding relation table according to the reported information, wherein if the corresponding relation table has the information of the mobile node;

and the attached OpenFlow switch is different from the newly reported OpenFlow switch, the record is deleted, and the information of the mobile node and the newly reported OpenFlow switch is taken as a new record to be added into the corresponding relation table; in step 3), further comprising:

if the mobile node MN is detected to move in a cross-domain mode, the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located;

and selecting a proper communication path according to the weighted value of the newly added network, and providing a flow table for all OpenFlow switches on the path next to the mobile node MN, so that the communication between the mobile node and the opposite terminal is not interrupted.

2. The method for mobility management based on the OpenFlow protocol of claim 1, further comprising:

the Controller and controllers of other domains maintain a corresponding relation table of the identification information of the mobile node MN and the attached OpenFlow switch with the AP function together, and the network address sections managed by the Controller and the controllers of other domains are different;

and the Controller judges whether the mobile node moves in a cross-domain or a region according to the IP address of the mobile node.

3. The method for mobility management based on the OpenFlow protocol of claim 1, further comprising:

if the mobile node MN is detected to move in the same area;

the controller deletes the flow table corresponding to the mobile node in the OpenFlow switch of the gateway of the network where the mobile node is located, and simultaneously issues a new flow table corresponding to the mobile node for other OpenFlow switches of the gateway of the network where the mobile node is located, so that the communication between the mobile node and the opposite terminal is not interrupted.

4. The method for mobility management based on the OpenFlow protocol of claim 1, wherein the weighting factor of the newly added network selects a link state of each link and a load of each OpenFlow switch.

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