WO2017152563A1

WO2017152563A1 - Sdn layer-2 forwarding method and system

Info

Publication number: WO2017152563A1
Application number: PCT/CN2016/090310
Authority: WO
Inventors: 曹静
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-03-10
Filing date: 2016-07-18
Publication date: 2017-09-14
Also published as: CN107181681B; CN107181681A

Abstract

Disclosed are an SDN layer-2 forwarding method and system. The method comprises: when performing address resolution protocol (APR) fast-reply on a source host, a controller sets a destination host media access control (MAC) address in an ARP reply sent to the source host as a proxy MAC address generated in advance; the source host and the destination host encapsulate an interaction data packet and send the interaction data packet to a switch by using the proxy MAC address as the destination host MAC address; the switch forwards, between the source host and the destination host according to a forwarding table sent by the controller, the interaction data packet in which the proxy MAC address is encapsulated, wherein the forwarding table is used for indicating a forwarding path for an Internal control message protocol (ICMP) layer-3 data packet in which the proxy MAC address is encapsulated.

Description

SDN layer 2 forwarding method and system

Technical field

The present application relates to, but is not limited to, the field of computer network technologies, and in particular, to an SDN Layer 2 forwarding method and system.

Background technique

Software Defined Network (SDN) is a hotspot technology in the field of communication. The SDN consists of a control plane controller (Controller, referred to as C) and a forwarding plane switch (Switch, referred to as SW or S). According to the definition of the current SDN technology, the controller and the switch switch issue control commands through the OPENFLOW (OF) protocol to guide the data flow forwarding on the switch. The controller also uses the Network Configuration Protocol (Netconfig). Parameter configuration on the switch SW. Among them, the OF protocol is a forwarding/control separation protocol proposed by Stanford University in the United States in 2008. The external control plane entity uses the OF protocol to control the forwarding plane device to implement various forwarding logics, and the main function of the forwarding plane device is based on the OF controller. The delivered flow table performs controlled forwarding. It can be implemented in software on the control plane to implement a variety of complex network applications, such as Virtual Data Center (VDC), Service Function Chain (SFC), Virtual Tenant Network (VTN). )Wait.

FIG. 1 is a schematic diagram of a scenario in which the SDN network is actually used in the related art, where an ER1 (External Route) and an ER2 are uncontrolled routers. CSW1 (Core Switch), CSW2 is a controlled OPENFLOW physical switch, TSW1 (Tor Switch, access switch), TSW2, TSW3...TSWN is a controlled domain N OPENFLOW physical switches, each TSW is connected to M The host/server, the dotted line connected to the controller and the controlled switch represents the control plane, and the solid line between the switches represents the data plane. In the current network, TSW is a large number of underlying switches, which can be hundreds or even thousands. There are a large number of hosts/servers under the TSW, which can reach as many as thousands. Hosts/servers connected to different TSWs can belong to the same network segment or belong to different network segments. The common point is that the host/server under the same TSW can communicate normally, and the host/server under different TSWs can also communicate normally. 2 is a two-layer pure two of the same network segment server when there is no MAC address of the destination host on the controller in the related art. Signaling flow chart of layer switching, communication between H1 host under switch TSW1 and H2 host under switch TSW2. There are two scenarios for communication between hosts. The first scenario is that there is no MAC address of the destination host on the controller. The basic steps are as follows:

In step 201, the H1 host sends an ARP request, and the ARP message is sent to the controller on the TSW1. The controller queries the ARP table to check whether there is a MAC address entry record of the ARP Request. If the controller does not find the MAC address matching the H2 host IP address. The controller broadcasts the ARP message, and the broadcast interface includes all the trunk ports of the WA (the port of the server).

Step 202: The controller receives the ARP request of the H1 host, discovers and learns the MAC address of the H1 host that sends the ARP request, and calculates the path of the Layer 2 forwarded packet by using the SPF algorithm of the controller. According to the path calculated by the SPF, the controller needs to send and receive the Layer 2 forwarding table of the MAC of the H1 host to all the switches on the SPF calculation path.

Step 203: The H2 host that responds to the ARP and the H1 host that initiates the ARP request are under different TSWs, and the H2 host corresponding to the IP responds to the ARP request. The controller receives the ARP reply from the H2 host, discovers and learns the MAC address of the H2 host, and calculates the path of the Layer 2 forwarded packet through the SPF algorithm of the controller.

Step 204: The controller sends a Layer 2 forwarding table corresponding to the MAC of the H2 host to all the switches on the path according to the path of the Layer 2 forwarding packet calculated by the SPF.

In step 205, the ARP response of the H2 host is forwarded by the controller to the H1 host through the TSW.

In step 206, the H1 host receives the ARP reply of the H2, and learns the MAC address of the H2 host, and then sends an ICMP (Internet Control Message Protocol) Layer 3 data packet.

Step 207: The ICMP Layer 3 data packet sent by the H1 host reaches TSW1, and the TSW1 forwards the message to the CSW1 according to the lookup Layer 2 forwarding table. The CSW1 sends the switch to the TSW2 to which the H2 host belongs, and the switch TSW2 sends the packet to the corresponding H2 host.

Step 208: After receiving the ICMP Layer 3 data packet of the H1, the H2 host replies an ICMP response message to the H1 host, and the ICMP response packet arrives at the TSW2 switch. The TSW2 switch forwards the packet to the CSW1 according to the lookup layer 2 forwarding table, and the CSW1 searches for the Layer 2 forwarding table. The ICMP response packet is sent to the switch TSW1 to which the H1 host belongs. The TSW1 searches the Layer 2 forwarding table to find the forwarding of the corresponding destination address. The table is sent to the corresponding H1 host.

Step 209: Similarly, the communication between other hosts is performed, and the Layer 2 forwarding of the packet is also performed through the foregoing steps.

FIG. 3 is a signaling flowchart of host communication on the same network segment under different TSWs when there is a destination host's MAC address on the controller in the related art, as shown in FIG. 3, another scenario is that the controller has an intended purpose. The basic steps of the host's MAC address and host communication on the same network segment under different TSWs are described as follows:

In step 301, the H1 host sends an ARP request, and the ARP message is sent to the controller on the TSW1. The controller queries the ARP table to check whether there is a MAC address entry record of the ARP Request. If so, the controller performs ARP pickup.

Step 302: The controller receives the ARP request of the H1 host, discovers and learns the MAC address of the H1 host that sends the ARP request, and calculates the path of the Layer 2 forwarded packet by using the SPF algorithm of the controller. According to the path calculated by the SPF, the controller needs to send and receive all the switches on the SPF calculation path to the Layer 2 forwarding table of the MAC of the H1 host.

In step 303, the controller sends an ARP to the host H1. The host H1 learns the MAC address of the H2 host, and can send an ICMP (Internet Control Message Protocol) Layer 3 data packet.

Step 304: The ICMP Layer 3 data packet sent by the H1 host reaches TSW1, and the TSW1 forwards the message to the CSW1 according to the lookup layer 2 forwarding table. The CSW1 sends the switch to the TSW2 to which the H2 host belongs, and the switch TSW2 sends the packet to the corresponding H2 host.

Step 305: After receiving the ICMP Layer 3 data packet of the H1, the H2 host returns an ICMP response message to the H1 host, and the ICMP response packet arrives at the TSW2 switch. The TSW2 switch forwards the packet to the CSW1 according to the lookup layer 2 forwarding table, and the CSW1 searches for the Layer 2 forwarding table. The ICMP response packet is sent to the switch TSW1 to which the H1 host belongs. The TSW1 searches the Layer 2 forwarding table to find the forwarding table corresponding to the destination address, and then sends the forwarding table to the corresponding H1 host.

In the same way, the other hosts communicate with each other, and the Layer 2 forwarding of the packets is also performed through the foregoing steps.

Layer 2 forwarding mode of the above-mentioned packets. In a large Layer 2 scenario, the controller needs to be all on the forwarding path. The forwarding device delivers the destination host flow table, which is represented by the forwarding table of the MAC addresses of all the hosts in all TSWs on each TSW. There are 120 TSWs in the network topology scenario of the above example, if there are 5000 hosts attached to each TSW switch. The MAC address forwarding of the host directly under a TSW is expressed to 5000 tables. The total number of MAC address forwarding tables on the TSW switch reaches 120*5000, which is 600,000 host MAC address forwarding tables. The high-order host IPMAC address forwarding table not only consumes the storage resources of the TSW, but also affects the performance of the look-up table and increases the cost of maintaining and managing a large number of host MAC address forwarding tables. The number of tables on the switch has skyrocketed. When the host goes offline or migrates, a large number of flow tables need to be updated, which is likely to cause overload of the controller, and does not reflect the advantages brought by network virtualization.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

In view of the problem of the network topology layer 2 forwarding high-order host MAC address forwarding table in the related art, the embodiment of the present invention provides an SDN layer 2 forwarding method and system.

An SDN Layer 2 forwarding method includes:

When the controller performs address resolution protocol APR pickup on the source host, the destination host media access control MAC address in the ARP reply sent to the source host is set to a pre-generated proxy MAC address.

The source host and the destination host encapsulate the interactive data packet with the proxy MAC address as the destination host MAC address and send it to the switch.

The switch forwards the exchange data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, where the forwarding table is used to indicate the forwarding path of the ICMP Layer 3 data packet encapsulated with the proxy MAC address. .

An SDN Layer 2 forwarding system includes: a controller, a source host, a destination host, and a switch.

The controller is configured to set the destination host MAC address in the ARP reply sent to the source host to the pre-generated proxy MAC address when performing address resolution protocol APR pickup to the source host.

The source host is configured to encapsulate the interactive data packet with the proxy MAC address as the destination host MAC address and send it to the switch.

The destination host is configured to encapsulate the interactive data packet with the proxy MAC address as the destination host MAC address and send it to the switch.

The switch is configured to forward the exchange data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, where the forwarding table is used to indicate the ICMP Layer 3 data packet encapsulated with the proxy MAC address. The forwarding path.

A computer readable storage medium storing computer executable instructions that, when executed by a processor, implement the software defined network SDN Layer 2 forwarding method.

The beneficial effects of the embodiments of the present invention are as follows:

By borrowing the proxy MAC address, the MAC address forwarding table of the switch can be prevented from increasing rapidly. At the same time, the storage space occupied by the switch forwarding table can be reduced, and the switch can find the size of the forwarding table and improve the performance of the switch to forward packets. Reduce the difficulty and workload of maintaining the forwarding table.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic diagram of a scenario in which the SDN network is actually used in the related art;

2 is a signaling flowchart of a pure Layer 2 switching of a Layer 2 layer of the same network segment server when there is no MAC address of the destination host on the controller in the related art;

3 is a signaling flowchart of host communication of the same network segment under different TSWs when there is a MAC address of a destination host on the controller in the related art;

4 is a flowchart of an SDN Layer 2 forwarding method according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a communication structure between hosts of the same network segment to which different switches belong according to an embodiment of the present invention; FIG.

6 is a flowchart of signaling interaction of Example 1 according to an embodiment of the present invention;

7 is a schematic diagram of a communication process between hosts to which a switch belongs according to an embodiment of the present invention;

8 is a flowchart of signaling interaction of Example 2 according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of an SDN Layer 2 forwarding system according to an embodiment of the present invention.

Embodiments of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In order to solve the problem that the number of tables is increased due to the forwarding table (which may also become the host routing flow table) of all forwarding devices that are sent by the controller to the forwarding path. Avoid the problem of a large number of forwarding table updates and controller overload when the host finds offline or migrates. The embodiment of the present invention provides an SDN Layer 2 forwarding method and system, including: the controller generates a unique proxy MAC address in the network topology; the controller fills in the proxy MAC address when performing ARP pickup for the host; The proxy MAC address generation forwarding table is used to guide data forwarding; the host encapsulates the data packet by using the MAC address; and the switch knows the forwarding of the data packet encapsulated by using the proxy MAC address according to the forwarding table. Method embodiment

According to an embodiment of the present invention, an SDN Layer 2 forwarding method is provided. FIG. 4 is a flowchart of an SDN Layer 2 forwarding method according to an embodiment of the present invention. As shown in FIG. 4, an SDN Layer 2 forwarding according to an embodiment of the present invention is provided. The method includes steps 401-403:

Step 401: When the controller performs address resolution protocol APR pickup on the source host, the destination host MAC address in the ARP reply sent to the source host is set to a pre-generated proxy MAC address.

Optionally, in the embodiment of the present invention, before the controller performs APR pickup on the source host, the controller needs to receive the ARP request sent by the source host to which the source host belongs, according to the destination host MAC address in the ARP request. Querying the locally saved ARP table, determining whether the destination host MAC address is recorded in the ARP table, and if it is determined that the destination host MAC address is recorded in the ARP table, performing APR pickup on the source host, if the ARP table is determined If the destination host MAC address is not recorded, the ARP request is broadcast.

When it is determined that the destination host MAC address is not recorded in the ARP table, after the controller broadcasts the ARP request, the forwarding table needs to be sent, and the processing is as follows:

The controller performs the SPF calculation and obtains the source host path according to the ARP request carrying the source host MAC address, and delivers the source host Layer 2 forwarding table of the source host to all the access switches on the source host path, and the source host path is The core switch sends a source host host routing table corresponding to the source host, where the source host Layer 2 forwarding table is used to indicate the transition of the interactive data packet according to the destination host MAC address. The source host host routing table is used to indicate the forwarding path of the interactive data packet according to the destination host IP address.

The controller receives the ARP response sent by the destination host, performs the SPF calculation according to the source host MAC address carried in the ARP response, and obtains the destination host path, and delivers the destination host host routing table of the destination host to the core switch on the destination host path, and The destination host Layer 2 forwarding table is delivered to all the access switches on the destination host path, where the destination host Layer 2 forwarding table is used to indicate the forwarding path of the interactive data packet according to the destination host MAC address, and the destination host host routing The table is used to indicate the forwarding path of the interactive data packet according to the destination host IP address.

Finally, the controller performs APR pickup on the source host according to the destination host MAC address carried in the ARP reply, and saves the destination host MAC address to the ARP table.

Step 402: The source host and the destination host encapsulate the interaction data packet with the proxy MAC address as the destination host MAC address, and send the data packet to the switch.

Optionally, in step 402, the source host encapsulates the interaction data packet by using the proxy MAC address as the destination host MAC address, and sends the data packet to the switch, including:

The source host receives the ARP reply sent by the controller and uses the proxy MAC address as the destination host MAC address.

The source host sends an interaction data packet to the destination host, where the destination host MAC address of the interaction data packet is the proxy MAC address.

Optionally, the method further includes: the destination host feeding back the interaction data packet to the source host, where the destination host MAC in the feedback interaction data packet is the proxy MAC address.

When the destination host feeds back the interactive data packet to the source host, the proxy MAC address is used as the destination host MAC address to encapsulate the interactive data packet and send it to the switch.

Step 403: The switch forwards the interaction data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, where the forwarding table is used to indicate the ICMP Layer 3 data packet encapsulated with the proxy MAC address. The forwarding path.

Optionally, the step 403, according to the forwarding table sent by the controller, forwarding the interaction data packet encapsulating the proxy MAC address between the source host and the destination host, including:

The source access switch receives the interaction data packet according to the source host layer 2 forwarding table and the proxy MAC address. The address forwards the interactive packet to the corresponding core switch.

The core switch determines the destination access switch to which the destination host belongs according to the destination host IP address and the source host host routing table in the interaction data packet, and modifies the source host MAC address of the interaction data packet to the proxy MAC address, and the destination host MAC address is modified to The real MAC address of the destination host, and the modified interactive data packet is sent to the destination access switch.

The destination access switch sends the interactive data packet to the destination host according to the destination host MAC address and the source host Layer 2 forwarding table.

The destination access switch receives the interaction data packet fed back by the destination host, where the destination host MAC in the feedback interaction data packet is a proxy MAC address.

The destination access switch sends the feedback interaction data packet to the corresponding core switch according to the proxy MAC address and the destination host Layer 2 forwarding table.

The core switch determines that the source host belongs to the source access switch according to the destination host IP and the destination host host routing table in the feedback interaction data packet, and modifies the source host MAC address of the feedback interaction data packet to the proxy MAC address, and the destination host MAC address. The address is modified to the real MAC address of the source host, and the modified interactive data packet is sent to the source access switch.

The source access switch sends the feedback interaction data packet to the source host according to the destination host MAC address and the destination host layer 2 forwarding table.

It should be noted that, in the embodiment of the present invention, the proxy MAC address includes: a globally unique proxy MAC address, or a dedicated proxy MAC address generated for the corresponding switch.

That is to say, in the embodiment of the present invention, in order to further exert the advantages brought by the proxy MAC application in the layer 2 forwarding, the controller may be designed to generate a proxy MAC address for each switch; the controller performs ARP pickup for the host. The proxy MAC address is filled in; the controller generates a forwarding table for the proxy MAC address to guide data forwarding; the host uses the MAC address to encapsulate the data packet; and the switch learns the forwarding of the data packet encapsulated by the proxy MAC address according to the forwarding table. The host sends an ARP request first. The ARP message is sent to the controller on the switch TSW. The controller performs ARP pickup, replies with an ARP Reply, and carries a Proxy MAC as a response. The Proxy MAC uses the encoding method associated with the switching device, that is, each switching device has a unique Proxy MAC. In the forwarding search process, the Proxy MAC packet is first grouped, and then the packet destination identifier is used to query the target exit. Such as Therefore, the controller only needs to deliver a Layer 2 forwarding table to the destination TSW for all the forwarding devices on the forwarding path.

The above technical solutions of the embodiments of the present invention are described in detail below with reference to examples.

Example 1

The host is in the same network segment host communication scenario as the different WAs. Before sending a Layer 3 packet, the host checks whether it has the MAC address of the destination IP address. If not, the host sends an ARP request first. The IP address requested by the ARP message is the IP address of the destination host and is sent to the controller on the TSW. The controller generates a globally unique Proxy MAC and sends an ARP to the requesting host. The controller learns the host IP address and MAC address of the requesting ARP, calculates the path according to the SPF, delivers the Layer 2 forwarding table to all the switches in the path, and delivers the host routing table to all the CSW controllers in the path. At the same time, the controller checks whether there is a MAC address entry record of the ARP Request. If there is no MAC address entry record of the ARP Request, the controller sends an ARP broadcast message, and the ARP request is broadcast on all TSW trunk ports. The host corresponding to the destination IP receives the ARP request to reply to the ARP reply. Similarly, the controller learns the host IP address and MAC address of the ARP, calculates the path according to the SPF algorithm in the controller, delivers the Layer 2 forwarding table to all the switches in the path, and delivers the host routing table to all the CSWs in the path. Controller.

If the TSW is a pure Layer 2, then in principle, the TSW does not replace the MAC address encapsulation of the data packet, so the CSW needs to receive the data packet whose destination MAC address is the Proxy MAC. If there is a default gateway function on the CSW: the function of stripping the MAC and re-encapsulating the MAC. After the packet comes out of the CSW, it is tagged with the MAC address of the target host, and the TSW sent to the destination host is pure Layer 2 forwarding.

According to the network topology structure, the Layer 3 gateway delivers the host route, and the TSW functions as a pure Layer 2 device without host routing. Considering that TSW is pure Layer 2 forwarding, host routes are not delivered to TSW. The benefits of this are as follows: the number of flow tables generated by the host route is small, and only the host routing table corresponding to the CSW is sent and received; the network topology "TSW is pure Layer 2"; the forwarding behavior on the TSW is simple, that is, only Layer 2 forwarding There is no three-tier behavior.

5 is a schematic diagram of a communication structure between hosts of the same network segment to which different switches belong to the embodiment of the present invention, and FIG. 6 is a flowchart of signaling interaction of the example 1 of the embodiment of the present invention, as shown in FIG. In the network topology shown, steps 601-612 are included:

In step 601, the H1 host sends an ARP request, and the ARP message is sent to the controller on the TSW1. The controller queries the ARP table to check whether there is an ARP Request MAC address entry record. If there is an ARP Request MAC address entry record, the controller performs ARP. If the controller does not find the MAC address matching the H2 host IP address, the controller broadcasts the ARP message, and the broadcast interface includes the trunk ports of all TSWs (ports connected to the server).

Step 602: The controller receives the ARP request of the H1 host, discovers and learns the MAC address of the H1 host that sends the ARP request, and calculates the path of the Layer 2 forwarding packet through the SPF. According to the path calculated by the SPF, the controller sends a Layer 2 forwarding table to all the switches on the SPF calculation path, and sends a host routing table to the CSW switch on the SPF calculation path.

In step 603, the H2 host that responds to the ARP and the H1 host that initiates the ARP request are under different TSWs, and the H2 host corresponding to the IP responds to the ARP request. The controller receives the ARP reply from the H2 host, discovers and learns the MAC address of the H2 host, and calculates the path of the Layer 2 packet forwarding through the SPF. The controller sends a Layer 2 forwarding table corresponding to the H2 host MAC address to all the switches on the path according to the path of the Layer 2 forwarding packet calculated by the SPF, and sends and routes the H2 host routing table to all the CSW switches in the path.

Step 604, the controller confirms that the H2 host belongs to the TSW2 switch, and the controller responds to the ARP pickup of the H1 host; wherein the MAC address of the destination IP in the ARP pickup is the only Proxy MAC in the network topology generated by the controller.

Step 605: The H1 host receives the ARP response of the controller forwarded by the TSW1 switch, and considers that the Proxy MAC in the response packet is the MAC address of the destination IP address. The H1 host encapsulation Proxy MAC to which the TSW1 switch belongs is the destination MAC address, and the IP address of H2 is used as the destination IP address to send ICMP Layer 3 data packets to the host H2 to which the TSW2 switch belongs.

Step 606: The ICMP Layer 3 data packet sent by the H1 host reaches TSW1, and the TSW1 forwards the packet to the CSW according to the lookup Layer 2 forwarding table.

Step 607: The CSW queries all host routing tables in the network according to the destination host IP, and confirms that the H2 host belongs to the TSW2 host. The CSW modifies the source MAC address of the ICMP packet to the proxy MAC address, and changes the destination MAC address to the physical MAC address of the host H2, and then the third layer. The packet is forwarded to the TSW2 switch.

Step 608: The TSW2 switch receives the ICMP packet, and checks that the destination MAC address is the physical MAC address of the directly connected host, and forwards the ICMP packet to the H2 host according to the Layer 2 forwarding table.

Step 609: After the H2 host receives the ICMP Layer 3 data packet of the H1, the H2 replies to the ICMP response message to the TSW2 switch. The destination IP address encapsulated by the ICMP response message is the H1 host IP, and the destination MAC address is the Proxy MAC.

Step 610: The ICMP response message arrives at TSW2, and the carried destination IP address is the IP address of H2, and the destination MAC address is a Proxy MAC. TSW2 queries the Layer 2 forwarding table and sends the response packet to the CSW.

In step 611, the CSW receives the ICMP response packet of the H2 host, and the Proxy MAC in the CSW identification packet is the proxy MAC address. CSW modifies the source MAC to Proxy MAC. The destination MAC is modified to H1MAC. The CSW queries the host routing table and forwards ICMP packets to TSW1.

Step 612: The TSW1 receives the ICMP packet and sends the packet to the H1 host according to the Layer 2 forwarding table. The communication between the hosts on the same network segment under different TSWs is completed.

For the same reason, the communication between other hosts is also performed through the above steps.

Example 2

In Example 1, the only proxy MAC in the Proxy MAC network topology. When the CSW queries the host routing table, it searches the host MAC address of the destination IP address in the host-wide routing table. The breadth of the query is the maximum range of queries in the host routing table. When the number of host routing tables increases dramatically, the scope and difficulty of the query increase in proportion. Considering the double-layer optimization of reducing the complexity and improving the performance, the example 2 proposes a Proxy MAC that uniquely identifies the switch according to different TSWs, and the Proxy MAC of the TSW to which the host is associated with the TSW. The host under the different TSW switches adopts the unique identifier Proxy MAC of the TSW to which the target host belongs. When the CSW receives the Layer 3 data packet, the host routing table can be queried according to the Proxy MAC packet corresponding to the TSW. Accurately narrow the scope of the query and improve the performance of the query. The Proxy MAC proposed in the embodiment of the present invention is used as an advantage of the SDN network layer 2 forwarding method and system.

The link detection and the TOPO formation of the switch between the switch and the switch are performed by LLDP (Link Layer Discovery Protocol). LLDP provides a standard link layer discovery mode, which can be used to organize the main device, management address, device identifier, and interface identifier of the local device into different TLVs (Type/Length/Value, type/long Degree/value), and is encapsulated in the LLDP PDU (Link Layer Discovery Protocol Data Unit) to be directly connected to the neighbor. In the network topology scenario of the embodiment of the present invention, the WA organizes the information such as the host address and the switch identifier that are managed by the user into TLVs and encapsulates them in the LLDP PDUs to the connected controllers. The controller collects all the TSWs managed in the network topology. Host address, switch flag and other information. A unique Proxy MAC is encoded for each TSW switch, and the path to the TSW switch is calculated by the controller SPF algorithm. The controller sends a forwarding table to the TSW switch for all the switches in the path.

In the network topology scenario of the embodiment of the present invention, the communication mechanism between the host to which the TSW1 switch belongs and the host of the same network segment to which the TSW2 switch belongs is as follows: the host to which the TSW1 switch belongs is the ICMP Layer 3 data packet of the host to which the TSW2 switch belongs, TSW1 The host to which the switch belongs will first query whether there is a MAC address of the destination IP address. If the host to which the TSW1 switch belongs does not find the corresponding MAC address, the host to which the TSW1 switch belongs will first send an ARP request with the destination IP address. If the destination IP of the source host 1.1.1.2 sends the Layer 3 packet is 1.1.1.3, then the content of the ARP request message: Who has 1.1.1.3? Tell 1.1.1.2. The ARP request is broadcast to the TSW1 switch, which is sent to the controller on the TSW1 switch. The controller retrieves the destination IP host to the TSW2 switch, and the controller immediately responds to the ARP pickup. The destination MAC carried by the ARP proxy is the Proxy MAC2 of the TSW2 that is generated by the controller according to the TSW2 switch to which the destination IP host belongs. The host to which the TSW1 switch belongs receives an ARP response and sends an ICMP Layer 3 packet whose destination MAC address is Proxy MAC2. The Layer 3 packet arrives at the TSW1 switch. The TSW1 forwards the packet to the CSW1. The CSW1 receives the packet and replaces the source MAC address of the Layer 3 packet with the Proxy MAC1 of the TSW1. The destination MAC address of the packet is changed to the MAC address of the destination host H2. The core switch of the CSW1 forwards the packet to the TSW2 according to the forwarding table. The TSW2 searches the Layer 2 forwarding table according to the destination host MAC address and forwards the packet to the host to which the TSW2 switch belongs.

The host to which TSW2 belongs receives a Layer 3 data packet request and responds to the Layer 3 data packet response. The source MAC address of the response packet is its own MAC, and the destination MAC address is the Proxy MAC1 of the TSW1 switch. The message is sent to the TSW2 switch. The TSW2 switch forwards the response packet to the Proxy CSW1 according to the forwarding table. The CSW1 receives the packet and changes the source MAC to the proxy MAC2. The CSW1 core switch queries the host routing table of the response packet according to the destination IP address, and discovers that the host of the destination IP belongs to the TSW1. The CSW1 changes the destination MAC address of the packet to the real MAC address of the host H1, and forwards the packet to the TSW1. switch. The TSW1 switch sends a response packet to the corresponding host according to the Layer 2 forwarding table. At this point, communication between hosts on the same network segment under different TSWs is completed.

7 is a schematic diagram of a communication flow between hosts to which a switch belongs according to an embodiment of the present invention, and FIG. 8 is a flow chart of signaling interaction of Example 2 of the embodiment of the present invention, as shown in FIG. In the scenario where the controller does not save the host MAC address in the network, the inter-host communication includes steps 801-812:

In step 801, the H1 host sends an ARP request, and the ARP message is sent to the controller on the TSW1. The controller queries the ARP table to check whether there is an ARP Request MAC address entry record. If there is an ARP Request MAC address entry record, the controller performs ARP. If the controller does not find the MAC address matching the H2 host IP address, the controller broadcasts the ARP message, and the broadcast interface includes the trunk ports of all TSWs (ports connected to the server).

Step 802: The controller receives the ARP request of the H1 host, discovers and learns the MAC address of the H1 host that sends the ARP request, and calculates the path of the Layer 2 packet forwarding through the SPF. According to the path calculated by the SPF algorithm, the controller sends a Layer 2 forwarding table to all the switches on the SPF calculation path, and sends a host routing table to the CSW switch on the SPF calculation path.

In step 803, the H2 host that responds to the ARP and the H1 host that initiates the ARP request are under different TSWs, and the H2 host corresponding to the IP responds to the ARP request. The controller receives the ARP reply from the H2 host, discovers and learns the MAC address of the H2 host, and calculates the path of the Layer 2 packet forwarding through the SPF. The controller sends a Layer 2 forwarding table corresponding to the H2 host MAC address to all the switches on the path according to the path of the Layer 2 forwarding packet calculated by the SPF, and sends and routes the H2 host routing table to all the CSW switches in the path.

Step 804, the controller confirms that the H2 host belongs to the TSW2 switch, and the controller responds to the ARP pickup of the H1 host; wherein the MAC address of the destination IP in the ARP pickup is a unique proxy in the network topology generated by the controller for the TSW2 switch. MAC2.

Step 805: The H1 host receives the ARP response of the controller forwarded by the TSW1 switch, and considers that the Proxy MAC2 in the response packet is the MAC address of the destination IP. The H1 host encapsulation Proxy MAC2 to which the TSW1 switch belongs is the destination MAC address, and the IP address of H2 is used as the destination IP address to send ICMP Layer 3 data packets to the host H2 to which the TSW2 switch belongs.

Step 806: The ICMP Layer 3 data packet sent by the H1 host reaches TSW1, and is forwarded to the CSW according to the lookup Layer 2 forwarding table.

Step 807: The CSW queries the host routing table according to the destination host IP, and confirms that the H2 host belongs to the TSW2 host. The CSW changes the source MAC address of the ICMP packet to the Proxy MAC1 of the TSW1, and changes the destination MAC address to the physical MAC address of the host H2, and then the Layer 3 data. The packet is forwarded to the TSW2 switch.

Step 808: The TSW2 switch receives the ICMP packet, checks that the destination MAC address is the physical MAC of the directly connected host, and forwards the ICMP to the H2 host.

Step 809: After the H2 host receives the ICMP Layer 3 data packet of the H1, the H2 replies an ICMP response message to the TSW2 switch. The destination IP address encapsulated by the ICMP response message is the H1 host IP, and the destination MAC address is the Proxy MAC1.

In step 810, the ICMP response message arrives at TSW2, and the carried destination IP address is the IP address of H2, and the destination MAC address is Proxy MAC1. TSW2 queries the Layer 2 forwarding table and sends the response packet to the CSW.

Step 811: The CSW receives the ICMP response packet of the H2 host, and the CW modifies the source MAC address to the Proxy MAC2, and the destination MAC address is changed to the H1MAC, and the ICMP packet is forwarded to the TSW1.

Step 812: The TSW1 receives the ICMP packet and sends the packet to the H1 host according to the Layer 2 forwarding table. The communication between the hosts on the same network segment under different TSWs is completed.

In summary, the technical solution of the embodiment of the present invention solves the performance problem of finding, deleting, adding, and updating a series of operations caused by the bursting of the switch flow table in the SDN network, and at the same time, reducing the convection of the exchange table. The pressure of the table's mass storage.

System embodiment

An SDN Layer 2 forwarding system is provided according to an embodiment of the present invention. FIG. 9 is a schematic structural diagram of an SDN Layer 2 forwarding system according to an embodiment of the present invention. As shown in FIG. 9, an SDN Layer 2 forwarding according to an embodiment of the present invention is provided. The system includes a controller 90, a source host 91, a destination host 92, and a switch 93. Each module of the embodiment of the present invention is described in detail below.

The controller 90 is configured to set the destination host MAC address in the ARP reply sent to the source host to the pre-generated proxy MAC address when performing address resolution protocol APR pickup to the source host. site.

The controller 90 is further configured to: before the APR pickup of the source host, receive the ARP request sent by the source host to which the source host belongs, and query the locally saved ARP table according to the destination host MAC address in the ARP request, and determine Whether the destination host MAC address is recorded in the ARP table. If it is determined that the destination host MAC address is recorded in the ARP table, the source host performs APR pickup. If it is determined that the destination host MAC is not recorded in the ARP table. The address broadcasts the ARP request.

Controller 90 is also configured to:

After the ARP request is broadcast, the source host MAC address is carried in the ARP request to perform the SPF calculation and the source host path is obtained, and the source host's Layer 2 forwarding table corresponding to the source host is delivered to all the access switches on the source host path, and The source host on the source host sends a source host host routing table to the source host. The source host Layer 2 forwarding table is used to indicate the forwarding path of the interactive packet according to the destination host MAC address. The source host host routing table is used to The destination host IP address indicates the forwarding path of the interactive data packet.

Receive the ARP reply sent by the destination host, perform SPF calculation according to the source host MAC address carried in the ARP reply, and obtain the destination host path, and deliver the destination host host routing table to the core switch on the destination host path to the destination host. All the access switches on the host path deliver the destination host Layer 2 forwarding table of the destination host. The destination host Layer 2 forwarding table is used to indicate the forwarding path of the interactive data packet according to the destination host MAC address. The destination host host routing table is used. The forwarding path of the interactive data packet is indicated according to the destination host IP address.

The APR pickup is performed on the source host according to the destination host MAC address carried in the ARP reply, and the destination host MAC address is saved in the ARP table.

The source host 91 is configured to encapsulate the interactive data packet with the proxy MAC address as the destination host MAC address and send it to the switch.

The source host 92 encapsulates the interaction data packet with the proxy MAC address as the destination host MAC address, and sends the data packet to the switch, including: receiving the ARP response sent by the controller 90, using the proxy MAC address as the destination host MAC address, and sending the proxy MAC address to the destination host. An interactive data packet, wherein the destination host MAC address of the interactive data packet is a proxy MAC address.

The destination host 92 is further configured to encapsulate the interaction data packet with the proxy MAC address as the destination host MAC address, and send it to the switch 96. The destination host 92 is configured to: feed back the interaction data packet to the source host, where the feedback interaction data packet The destination host MAC in the proxy MAC address.

The switch 93 is configured to forward the exchange data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller 90, wherein the forwarding table is used to indicate the ICMP layer 3 encapsulating the proxy MAC address. The forwarding path of the packet. The switch specifically includes: an access switch and a core switch.

The switch 93 includes: a source access switch, a core switch, and a destination access switch.

The switch 93 forwards the interaction data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, including:

The source access switch is configured to: receive the interaction data packet, and forward the interaction data packet to the corresponding core switch according to the source host layer 2 forwarding table and the proxy MAC address.

The core switch is configured to: determine the destination access switch to which the destination host belongs according to the destination host IP address and the source host host routing table in the interaction data packet, and modify the source host MAC address of the interaction data packet to the proxy MAC address, and the destination host MAC address. The address is modified to the real MAC address of the destination host, and the modified interactive data packet is sent to the destination access switch.

The destination access switch is configured to: send the interaction data packet to the destination host according to the destination host MAC address and the source host layer 2 forwarding table; receive the interaction data packet fed back by the destination host, where the destination host MAC in the feedback interaction data packet is received. The proxy MAC address is sent to the corresponding core switch according to the proxy MAC address and the destination host Layer 2 forwarding table.

The core switch is further configured to: according to the destination host IP and the destination host host routing table in the feedback interaction data packet, determine that the source host belongs to the source access switch, and modify the source host MAC address of the feedback interaction data packet to the proxy MAC address. The destination host MAC address is modified to the real MAC address of the source host, and the modified feedback interactive data packet is sent to the source access switch.

The source access switch is further configured to: send the feedback interaction data packet to the source host according to the destination host MAC address and the destination host layer 2 forwarding table.

In the embodiment of the present invention, the proxy MAC address includes: a globally unique proxy MAC address, or The unique proxy MAC address generated for the corresponding switch.

In summary, by borrowing the proxy MAC address, the host MAC address forwarding table on the switch can be prevented from skyrocketing. At the same time, the storage space occupied by the switch forwarding table can be reduced, the scale of the switch looking for the forwarding table can be reduced, and the switch table forwarding can be improved. The performance of the message reduces the difficulty and workload of maintaining the forwarding table.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the embodiments of the invention. Therefore, it is intended that the present invention cover the modifications and variations of the embodiments of the present invention.

The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other device. Each general purpose system can also be used with teaching based on the teachings herein. The structure required to construct such a system is apparent from the above description. Moreover, embodiments of the invention are not directed to any particular programming language. It will be appreciated that the teachings of the embodiments of the invention described herein may be implemented in a variety of programming languages, and that the description of the specific language is described above to disclose alternative embodiments of the invention.

In the description provided herein, numerous specific details are set forth. However, it can be appreciated that embodiments of the invention may be practiced without these details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of the description.

Similarly, in order to simplify the present disclosure and to assist in understanding one or more of the various embodiments of the present invention, in the above description of the embodiments of the present invention, each feature of the embodiments of the present invention is sometimes grouped together into a single Embodiments, figures, or descriptions thereof. However, the method disclosed is not to be interpreted as reflecting the intention that the claimed embodiments of the invention are claimed. Rather, as the following claims reflect, inventive aspects are less than all features of the single embodiments disclosed above. Therefore, the claims following the embodiments are hereby explicitly incorporated into the embodiments, and each of the claims is a separate embodiment of the embodiments of the invention.

Those skilled in the art will appreciate that the modules in the client in the embodiment can be adaptively changed and placed in one or more clients different from the embodiment. The modules in the embodiments can be combined into one module, and further they can be divided into a plurality of sub-modules or sub-units or sub-components. In addition to such features and/or at least some of the processes or units being mutually exclusive, any combination of the features disclosed in the specification, including the accompanying claims, the abstract and the drawings, and any methods so disclosed, or All processes or units of the client are combined. Each feature disclosed in this specification (including the accompanying claims, the abstract and the drawings) may be replaced by alternative features that provide the same, equivalent or similar purpose.

Moreover, those skilled in the art will appreciate that, although some embodiments described herein include certain features that are included in other embodiments and not in other features, combinations of features of the different embodiments are implied in the embodiments of the invention. Different embodiments are formed within the scope of the invention. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

Each component embodiment of an embodiment of the invention may be implemented in hardware, or in a software module running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) may be used in practice to implement some or all of the functionality of some or all of the components loaded with the ordered web address in accordance with an embodiment of the present invention. . Embodiments of the invention may also be implemented as a device or device program (e.g., a computer program and a computer program product) for performing some or all of the methods described herein. Such a program implementing an embodiment of the invention may be stored on a computer readable medium or may be in the form of one or more signals. Such signals may be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

It should be noted that the above-described embodiments are illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention, and those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as a limitation. The word "comprising" does not exclude the presence of the elements or steps that are not recited in the claims. The word "a" or "an" Embodiments of the invention may be implemented by means of hardware comprising a plurality of different elements and by means of suitably programmed calculations Machine to achieve. In the unit claims enumerating several means, several of these means can be embodied by the same hardware item. The use of the words first, second, and third does not indicate any order. These words can be interpreted as names.

Industrial applicability

Claims

A software-defined network SDN Layer 2 forwarding method includes:

When the controller performs address resolution protocol APR pickup on the source host, the destination host media access control MAC address in the ARP reply sent to the source host is set to a pre-generated proxy MAC address;

The source host and the destination host encapsulate the interaction data packet with the proxy MAC address as the destination host MAC address, and send the data packet to the switch;

The switch forwards the interaction data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, where the forwarding table is used to indicate that the proxy MAC is encapsulated. The forwarding path of the ICMP Layer 3 packet of the address.
The SDN Layer 2 forwarding method according to claim 1, further comprising: before the controller performs APR pickup to the source host, the controller receives, by the source access switch, the source host to which the source access switch belongs The ARP request is configured to query the locally saved ARP table according to the destination host MAC address in the ARP request, and determine whether the destination host MAC address is recorded in the ARP table, and if it is determined that the destination is recorded in the ARP table. The host MAC address is forwarded to the source host by APR. If it is determined that the destination host MAC address is not recorded in the ARP table, the ARP request is broadcast.
The SDN layer 2 forwarding method of claim 2, the method further comprising: after the controller broadcasts the ARP request, the controller performs SPF calculation and acquires a source according to the source host MAC address in the ARP request. The source path sends a source host L2 forwarding table of the source host to all the access switches on the source host path, and delivers the source host host routing table of the corresponding source host to the core switch on the source host path. The source host Layer 2 forwarding table is configured to indicate a forwarding path of the interaction data packet according to the destination host MAC address, where the source host host routing table is configured to indicate a forwarding path of the interaction data packet according to the destination host IP address;

The controller receives the ARP response sent by the destination host, performs SPF calculation according to the source host MAC address carried in the ARP response, and obtains the destination host path, and delivers the destination host host corresponding to the destination host to the core switch on the destination host path. Routing the routing table, and delivering the destination host Layer 2 forwarding table of the destination host to all the access switches on the destination host path, where The destination host Layer 2 forwarding table is configured to indicate a forwarding path of the interaction data packet according to the destination host MAC address, where the destination host host routing table is configured to indicate a forwarding path of the interaction data packet according to the destination host IP address;

The controller performs APR pickup on the source host according to the destination host MAC address carried in the ARP response, and saves the destination host MAC address in the ARP table.
The SDN Layer 2 forwarding method according to claim 3, wherein the source host encapsulates the interactive data packet by using the proxy MAC address as the destination host MAC address, and sends the data packet to the switch, including:

The source host receives an ARP response sent by the controller, and uses the proxy MAC address as a destination host MAC address;

The source host sends the interaction data packet to the destination host, where the destination host MAC address of the interaction data packet is the proxy MAC address;

The method further includes: the destination host feeding back an interaction data packet to the source host, where the destination host MAC in the feedback interaction data packet is the proxy MAC address.
The SDN Layer 2 forwarding method according to claim 4, wherein the switch forwards the interactive data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller, including :

Receiving, by the source access switch, the interaction data packet, and forwarding the interaction data packet to a corresponding core switch according to the source host layer 2 forwarding table and the proxy MAC address;

The core switch determines, according to the destination host IP address in the interaction data packet and the source host host routing table, the destination access switch to which the destination host belongs, and modifies the source host MAC address of the interaction data packet to The proxy MAC address, the destination host MAC address is modified to the real MAC address of the destination host, and the modified interactive data packet is sent to the destination access switch;

The destination access switch sends the interaction data packet to the destination host according to the destination host MAC address and the source host layer 2 forwarding table;

The destination access switch receives the interaction data packet fed back by the destination host, where the destination host MAC in the feedback interaction data packet is the proxy MAC address;

Transmitting, by the destination access switch, the feedback interaction data packet to the corresponding core switch according to the proxy MAC address and the destination host Layer 2 forwarding table;

The core switch determines that the source host belongs to the source access switch according to the destination host IP and the destination host host routing table in the feedback interaction data packet, and modifies the source host MAC address of the feedback interaction data packet. For the proxy MAC address, the destination host MAC address is modified to be the real MAC address of the source host, and the modified interactive data packet is sent to the source access switch;

The source access switch sends the feedback interaction data packet to the source host according to the destination host MAC address and the destination host layer 2 forwarding table.
The SDN Layer 2 forwarding method of claim 1, wherein the proxy MAC address comprises: a globally unique proxy MAC address, or a dedicated proxy MAC address generated for a corresponding switch.
A software-defined network SDN Layer 2 forwarding system includes: a controller, a source host, a destination host, and a switch;

The controller is configured to: when performing address resolution protocol APR pickup to the source host, set a destination host media access control MAC address in an ARP response sent to the source host to a pre-generated proxy MAC address;

The source host is configured to encapsulate the interaction data packet by using the proxy MAC address as a destination host MAC address, and send the data packet to the switch;

The destination host is configured to encapsulate the interaction data packet by using the proxy MAC address as a destination host MAC address, and send the data packet to the switch;

The switch is configured to forward, according to the forwarding table sent by the controller, an interaction data packet encapsulating the proxy MAC address between the source host and the destination host, where the forwarding table is used to indicate that the encapsulation is The forwarding path of the ICMP Layer 3 packet of the proxy MAC address.
The SDN Layer 2 forwarding system of claim 7, wherein the controller is further configured to: before the APR pickup of the source host, receive, by the source access switch, the ARP sent by the source host to which the source access switch belongs And requesting, according to the destination host MAC address in the ARP request, querying the locally saved ARP table, and determining whether the destination host MAC address is recorded in the ARP table, If it is determined that the destination host MAC address is recorded in the ARP table, performing APR pickup on the source host, and if it is determined that the destination host MAC address is not recorded in the ARP table, performing the ARP request broadcast.
The SDN Layer 2 forwarding system of claim 8, wherein the controller is further configured to:

After the ARP request is broadcast, the source host MAC address is carried in the ARP request to perform the SPF calculation, and the source host path is obtained, and the source host corresponding to the source host is delivered to all access switches on the source host path. The layer forwarding table sends a source host host routing table corresponding to the source host to the core switch on the source host path, where the source host Layer 2 forwarding table is used to indicate the forwarding of the interactive data packet according to the destination host MAC address. a path, the source host host routing table is configured to indicate a forwarding path of the interaction data packet according to the destination host IP address;

Receiving an ARP response sent by the destination host, performing SPF calculation according to the source host MAC address carried in the ARP response, and obtaining a destination host path, and delivering a destination host host routing table to the core switch on the destination host path. And sending, to all access switches on the destination host path, a destination host Layer 2 forwarding table of the destination host, where the destination host Layer 2 forwarding table is configured to indicate the forwarding of the interactive data packet according to the destination host MAC address. a path, the destination host host routing table is configured to indicate a forwarding path of the interaction data packet according to the destination host IP address;

And performing APR pickup on the source host according to the destination host MAC address carried in the ARP response, and saving the destination host MAC address in the ARP table.
The SDN Layer 2 forwarding system according to claim 9, wherein:

The source host encapsulates the interaction data packet by using the proxy MAC address as the destination host MAC address, and sends the data packet to the switch, including:

Receiving an ARP response sent by the controller, using the proxy MAC address as a destination host MAC address, and sending the interaction data packet to a destination host, where a destination host MAC address of the interaction data packet is the proxy MAC address ;

The destination host is further configured to: feed back an interaction data packet to the source host, where the destination host MAC in the feedback interaction data packet is the proxy MAC address.
The SDN Layer 2 forwarding system of claim 10, wherein the switch comprises: The source access switch, the core switch, and the destination access switch;

Transmitting, by the switch, the interaction data packet encapsulating the proxy MAC address between the source host and the destination host according to the forwarding table sent by the controller includes:

The source access switch is configured to: receive the interaction data packet, forward the interaction data packet to a corresponding core switch according to the source host layer 2 forwarding table and the proxy MAC address;

The core switch is configured to determine, according to the destination host IP address in the interaction data packet and the source host host routing table, a destination access switch to which the destination host belongs, and a source host MAC of the interaction data packet. The address is modified to the proxy MAC address, the destination host MAC address is modified to the real MAC address of the destination host, and the modified interactive data packet is sent to the destination access switch;

The destination access switch is configured to: send the interaction data packet to the destination host according to the destination host MAC address and the source host layer 2 forwarding table; and receive an interaction data packet fed back by the destination host, where The destination host MAC in the feedback interaction data packet is the proxy MAC address; the feedback interaction data packet is sent to the corresponding core switch according to the proxy MAC address and the destination host layer 2 forwarding table;

The core switch is further configured to: determine, according to the destination host IP and the destination host host routing table in the feedback interaction data packet, that the source host belongs to the source access switch, and the source of the feedback interaction data packet is to be fed back The host MAC address is modified to the proxy MAC address, the destination host MAC address is modified to be the real MAC address of the source host, and the modified interactive data packet is sent to the source access switch.

The source access switch is further configured to: send the feedback interaction data packet to the source host according to the destination host MAC address and the destination host layer 2 forwarding table.
The SDN Layer 2 forwarding system of claim 7 wherein said proxy MAC address comprises: a globally unique proxy MAC address or a dedicated proxy MAC address generated for a respective switch.
A computer readable storage medium storing computer executable instructions, the computer executable instructions being executed by a processor to implement the software defined network SDN layer 2 forwarding method of any one of claims 1 to 6.