KR101621717B1 - Method, apparatus and computer program for virtualizing network resource of software defined data center - Google Patents

Abstract

The present invention relates to a method by which a server which implements a software switch inside a software defined data center (SDDC) environment forwards a frame. The method comprises the steps of: receiving, by a first software switch, a frame, transmitted from a first virtual machine to a second virtual machine, from the first virtual machine; when a second software switch connected to the second virtual machine is included in the same L2 network as the first software switch, adding an MAC header immediately before the frame; and, when the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch, sequentially adding a VXAN header, a UDP header, an IP header, and an MAC header before the frame.

Description

METHOD, APPARATUS AND COMPUTER PROGRAM FOR VIRTUALIZING NETWORK RESOURCE OF SOFTWARE DEFINED DATA CENTER FOR VIRTUALIZING NETWORK RESOURCES OF A SOFTWARE-DEFINED DATA CENTER

The present invention relates to a method for implementing network virtualization in a software defined data center (SDDC) environment. More particularly, the present invention relates to a method, apparatus and computer program for efficiently configuring tunneling of software switches in an SDDC environment.

Recently, 'software defined' technology is making new changes throughout the data center components. Software Defined Data Center (SDDC), a software-defined data center, is a concept that virtualizes servers, storage, and networking that make up a data center, thereby isolating hardware from computing resources and building a data center.

Software Defined Network (SDN), on the other hand, solves network problems that have been a problem with server virtualization in SDDC and provides structural flexibility. Software-defined network technology separates the complexity of the control plane from the data plane, processing the complex functions of the control plane with software, and the data plane is the control plane So that only a simple function of the instruction is performed. With these changes, software can develop new network functions without complex hardware constraints, while at the same time making various attempts that were not possible with previous network architectures.

The present invention aims at efficiently implementing network virtualization in an SDDC environment. In particular, it is an object of the present invention to provide a method for reducing network resources consumed in tunneling software switches.

A method for a server implementing a software switch in a Software Defined Data Center (SDDC) environment according to an embodiment of the invention for forwarding a frame includes: receiving a frame transmitted from a first virtual machine to a second virtual machine 1 software switch from the first virtual machine; If a second software switch connected to the second virtual machine is included in the same L2 network as the first software switch, adding a Mac header immediately before the frame; And adding the VXAN header, the UDP header, the Outer IP header, and the Outer Mac header before the frame if the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch The method comprising the steps of:

Further, a computer program stored in a medium for executing a process of forwarding a frame by a server implementing a software switch in a Software Defined Data Center (SDDC) environment according to an embodiment of the present invention may be provided in a first virtual machine 2) receiving a frame to be transferred to a virtual machine from a first virtual machine from a first software switch; If a second software switch connected to the second virtual machine is included in the same L2 network as the first software switch, adding a Mac header immediately before the frame; And adding the VXAN header, the UDP header, the Outer IP header, and the Outer Mac header before the frame if the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch Quot; function.

Meanwhile, a server implementing a software switch for forwarding a frame in a Software Defined Data Center (SDDC) environment according to an embodiment of the present invention includes a communication unit for connecting a physical network to the software switch; And a second software switch connected to the second virtual machine receives a frame transmitted from the first virtual machine to a second virtual machine from a first virtual machine, If the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch, a VXAN header before the frame is added, A UDP header, an Outer IP header, and an Outer Mac header.

According to the present invention, the size of the header for tunneling in the SDDC environment can be reduced by 72%, and there is an effect that the CPU overhead and the network overhead for processing frame forwarding can be drastically reduced.

1 is a diagram for explaining a software switch-based virtualization operation method in SDDC
2 is a diagram for explaining a VXLAN packet format used as a standard format for tunneling;
FIG. 3 is a view for explaining the L2-based light tunneling protocol (L2P) packet format of the present invention
4 is a diagram for explaining an example of forwarding a frame according to the present invention;
5 is a view for explaining a difference between the present invention and the prior art;

It is to be understood that the present invention is not limited to the description of the embodiments described below, and that various modifications may be made without departing from the technical scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the drawings, the same components are denoted by the same reference numerals. And in the accompanying drawings, some of the elements may be exaggerated, omitted or schematically illustrated. It is intended to clearly illustrate the gist of the present invention by omitting unnecessary explanations not related to the gist of the present invention. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram for explaining a software switch-based virtualization operation method in SDDC.

In general, network virtualization in SDDC is based on the configuration of an overlay network based on a software switch installed on a physical server, without concern for a physical network for connecting SDDC and a physical server for connecting the physical server do.

When SDDC is distributed among a plurality of physical servers, a plurality of virtual machines (VMs) and at least one software switch may be installed in each physical server. The software switch can serve as a virtual network hub that connects the VMs running on the installed server with the external physical network.

One physical server implementing the SDDC may include a communication unit and a control unit according to the present invention. 1, the communication unit 102 connects a physical network with another server, and the control unit includes a software switch 101 module serving as a network hub of a plurality of VMs 103 and 104 and VMs .

The procedure for forwarding packets at the server is as follows.

For example, when VM1 103 transmits an arbitrary packet to VM2 104, the traffic generated at 103 is transmitted to 101 via vNIC (virtual NIC) of VM1. 101 identifies the destination MAC address (L2 address) of the received traffic, and forwards the packet directly to the VM2 104 without additional encapsulation because it is the vNIC address in the same server.

However, if the VM 1 wishes to transmit a packet to a VM of another server, a tunneling procedure is required to encapsulate the packet. Through tunneling 101, the packet can be immediately forwarded to the software switch managing the incoming VM have. Tunneling means that a software switch encapsulates a packet. In a virtual network environment, tunneling allows the source software switch to forward the packet directly to the destination software switch regardless of the topology.

For example, when VM1 wants to transmit a packet to VM3 of another server, 101 can forward the packet by connecting a tunnel to a software switch that manages VM3.

Such tunneling can follow various protocols, but the VXLAN protocol is commonly used as a (de facto) standard.

The VXLAN protocol encapsulates the original network packets using the UDP protocol and supports tunneling to any IP network. Therefore, SDDC is not dependent on the physical network configuration of the physical server, but can freely implement the virtualized network as needed.

2 is a diagram illustrating a VXLAN packet format used as a standard format for tunneling.

In FIG. 2, the original frame of the VM is 201, and 202, 203, 204 and 205 are the headers to which software switches are added for tunneling. The VXLAN tunnel is a packet encapsulated by the software switch adding 202, 203, 204, and 205 header information to the original frame.

In the VXLAN packet format, 202 is allocated 8 bytes as a VXAN header, and 203 is allocated as 8 bytes as a UDP header for L4 information. In addition, 20 bytes are assigned as an IP header 204 for L3 information, and 205 bytes are assigned 14 bytes as MAC header for L2 information. That is, the size of the network header required for the VXLAN tunnel is 50 bytes in total.

However, considering that the original frame size is at most 1500 bytes in general, the 50 bytes of VXAN is very large as the header size. Furthermore, it may be inefficient to cover all L2, L3, and L4 headers without considering the number of tunneling cases. That is, according to the VXLAN packet format, there is an overhead to generate and process a total 50 byte header for VXLAN encapsulation in all tunneled packets

More specifically, according to the conventional VXLAN packet format, there arises a problem of resource consumption for transmitting a CPU overhead for generating a 50-byte network header and a frame added with 50 bytes in the original frame on the physical network.

Accordingly, the present invention proposes a light tunneling protocol that can solve the above-mentioned problem, that is, the problem that excessive resources are administered for tunneling while at the same time satisfying general purpose.

The present invention noted that most of the network traffic in SDDC moves within a server rack of the same server. Research shows that 80% of network traffic is forwarded only within the server rack. Typically, each Rack is configured with an L2 switch as the top of the rack (TOR) switch, and most of the traffic does not leave the L2 network.

Therefore, it is very inefficient to add all L2, L3, and L4 network headers to all packets to be tunneled according to the conventional VXAN format. This is because most tunneling can be performed without problems even if only the L2 header is used. Particularly, when the L2 header information is processed using the conventional Ethernet header format as it is, there is an effect that it can be interlocked with the legacy switch hardware without any problem.

The present invention proposes encapsulation to add only the L2 header, which is referred to as an L2P tunnel. L2 based Light Tunneling Protocol (L2P) packet format will be described below with reference to FIG. 3 attached hereto.

3 is a diagram for explaining the L2P Packet Format of the present invention.

As shown in FIG. 3, only the MAC header 302, 304, and 305 are added to the tunneled packet according to the present invention immediately before the original frame 301. In FIG. 3, 302, 304, and 305 are fields of the L2 header added for tunneling, and 303 is an option.

3, a destination address field 305, a source address field 304, and an Ethernet type / length field 304 are provided immediately in front of the original frame, Length field, 302).

More specifically, according to the present invention, 6 bytes of the destination address field 305 may include MAC address information of a network interface allocated to a software switch that manages a physical server operating a VM that is a destination of the packet.

According to the present invention, the starting address field 304 6 bytes may include MAC address information of the network interface assigned to the software switch that manages the VM which is the origin of the network packet.

According to the present invention, two bytes of type / length field 302 can be fixed to 0x8100 (Ethernet type) for interworking with a legacy switch. As a result, the header for the L2P tunneling of the present invention is only 14 bytes in total.

According to the present invention, 4 bytes of the VLAN tag field 303 may be optional. Specifically, if the physical network uses a VLAN (virtual LAN) and a VLAN is allocated for SDDC, the VLAN ID is written in 303, and if not, it is unnecessary to add 303. In the case of using the VLAN tag, the header for the L2P tunneling of the present invention increases from 14 bytes to 18 bytes.

A concrete example in which the software switch forwards the packet using the header information of FIG. 3 will be described below with reference to FIG. 4 attached hereto.

4 is a diagram for explaining an example of forwarding a frame according to the present invention.

The SDDC shown in FIG. 4 is implemented in a plurality of RACKs including RACK 1 and RACK 2, and the communication between 410 and 420 may be through the L3 network. Further, the RACK 1 includes the server 1 411, the server 2 412, and the server 3 413, and the communication between the servers 1, 2, and 3 may pass through the L2 network 416.

Likewise, RACK 2 includes server 4 414 and server 5 415, and communication between servers 4, 5 can be via L2 network 417. In FIG. 4, A, B, C, D and E are software switches implemented in the server, and 1, 2, 3, 4, 5, 6 and 7 are schematized VMs implemented in the server.

The case of forwarding a packet from VM 1 to VM 4 will be described as an example.

In this case, the software switch A receives the Ethernet frame from the VM 1, and the MAC address of all the software switches connected to the network with the mapping table, that is, the software switch, and the MAC address information of the Vnic of the VMs The mapping table is checked to confirm that the destination VM 4 is not present in the server 1 411 and the process of encapsulating the packet for tunneling can be performed.

According to an embodiment of the present invention, the mapping table may be a flow table composed of flow entries, and flow rules may be specified in each of the flow entries.

At this time, according to the conventional VXLAN protocol, the software switch A will send a packet encapsulated through the VXLAN tunnel to the software switch C, attaching a total of 50 bytes of header to the packet.

However, according to the present invention, since A and C are included in the same L2 network 416, the software switch A can forward packets encapsulated through the L2P tunnel to C by attaching only a total of 16 bytes of header to the corresponding packet .

On the other hand, when forwarding a packet from VM 2 to VM 5, the VXLAN tunnel may still be valid. According to the present invention, the software switch A that received the packet from the VM 2 checks the mapping table to confirm that the software switch that manages the VM 5 is D and that D is not included in its L2 network 416. In this case, A can forward the encapsulated packet to the software switch C through the conventional VXLAN tunnel instead of the L2P tunnel.

That is, according to the present invention, the software switch that receives the packet from the VM can forward the packet through the L2P tunnel when the destination of the packet is included in the same L2 network as the destination, or the VXLAN tunnel if not. Therefore, according to the present invention, packets can be forwarded in a general and efficient manner without additional overhead compared with the conventional standard.

On the other hand, mapping tables referenced by software switches can be created and updated in various ways.

For example, the mapping table can be created and managed using the Proactive method. This is a method of managing the mapping table by transmitting VM list information to a software switch in a central control system such as an SDN controller and transmitting updated list information whenever there is a change in a preset period or VM list .

As another example, the mapping table can be created and managed by applying the reactive method. This creates a mapping table in such a way that each software switch adds a corresponding VM to the VM list when each VM is created, and each software switch changes its own VM list every time there is a change in its VM list And all software switches are managed by broadcasting updated list information.

FIG. 5 is a view for clarifying the difference between the present invention and the prior art and the effect of the present invention in comparison with the prior art, by concretely explaining the two examples of FIG. 4 described above.

5 is a flow chart for forwarding a packet from VM1 to VM4 in FIG. 4 according to a conventional VXLAN protocol, and 502 is a flowchart for forwarding a packet from VM1 to VM4 according to the L2P protocol of the present invention. 5 is a flowchart for the case of forwarding a packet from VM1 to VM5 according to the L2P protocol of the present invention.

In step 510, when the software switch A receives the Ethernet frame destined for the VM 4 from the VM 1 in step 510, the software switch A checks the mapping table and confirms that the software switch for managing the VM 4 is C in step 511.

In step 512, software switch A encapsulates the packet by adding 50 bytes of header (i.e., outer Ethernet header, Outer IP header, UDP header, and VXLAN header) according to the VXALN protocol, and encapsulates the packet in step 513, encapsulated through the VXLAN tunnel Frame to the software switch C.

The software switch C that has received the frame can strip out the outer Ethernet header, the outer IP header, the UDP header and the VXLAN header in step 514 and forward the decapsulated Ethernet packet to the VM 4 in step 515.

On the other hand, according to the present invention, when the software switch A receives the Ethernet frame from the VM 1 to the VM 4 in step 520, the software switch A for checking the mapping table and managing the VM 4 in step 521 is C, Environment.

In step 522, the software switch A encapsulates the packet by adding only the 14-byte MAC header according to the L2P protocol of the present invention, and transmits the encapsulated frame through the L2P tunnel to the software switch C in step 523.

Software switch C may then strip the MAC header at step 524 and forward the decapsulated Ethernet packet to VM4 at step 525. [

According to the present invention, in step 530, the software switch A that receives the Ethernet frame from the VM 1 to the VM 5 as a destination checks the mapping table in step 531 and determines that the software switch for managing the VM 5 is D, It can be confirmed that it is not included in the environment.

In step 532, the software switch A encapsulates the packet by adding 50 bytes of header (i.e., outer Ethernet header, Outer IP header, UDP header, and VXLAN header) according to the VXALN protocol, and encapsulates the packet in step 533, encapsulated through the VXLAN tunnel Frame to software switch D, and at step 535 software switch D may forward the top encapsulated Ethernet packet to VM 5.

The embodiments of the present invention disclosed in the present specification and drawings are intended to be illustrative only and not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (6)

A method of forwarding a frame by a server implementing a software switch in a software defined data center (SDDC) environment,
Comprising: receiving a first software switch from the first virtual machine, the frame being transferred from a first virtual machine to a second virtual machine;
If a second software switch connected to the second virtual machine is included in the same L2 network as the first software switch, adding a Mac header immediately before the frame; And
Adding the VXAN header, the UDP header, the IP header, and the Mac header in order before the frame if the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch And transmitting the frame to the server. The method of claim 1, wherein the Mac header added immediately before the frame further comprises:
A Destination Address field including MAC address information of the second software switch, a Source Address field including MAC address information of the first software switch, and an Ethernet type ≪ / RTI > field). 3. The method of claim 2,
Further comprising a VLAN tag field including the VLAN ID information when a physical network connected to the server uses a VLAN and a VLAN ID is previously allocated to the software defined data center. / RTI > The method of claim 3,
After the step of receiving the frame by the first software switch,
Identifying a MAC address of a second software switch connected to the second virtual machine by referring to a mapping table of the software defined data center environment; And
Further comprising: determining whether the second software switch is included in the same L2 network as the first software switch. A computer program stored on a medium for causing a server implementing a software switch in a software defined data center (SDDC) environment to execute a process of forwarding a frame,
A function for a first software switch to receive a frame from a first virtual machine to a second virtual machine from the first virtual machine;
If a second software switch connected to the second virtual machine is included in the same L2 network as the first software switch, adding a Mac header immediately before the frame; And
If the second software switch connected to the second virtual machine is not included in the same L2 network as the first software switch, a function of adding a VXAN header, a UDP header, an IP header, and a Mac header before the frame is executed The computer program comprising: A server implementing a software switch for forwarding frames within a software defined data center (SDDC) environment,
A communication unit for connecting a physical network to the software switch; And
Wherein a first software switch receives a frame transmitted from a first virtual machine to a second virtual machine from the first virtual machine and a second software switch connected to the second virtual machine is connected to the same L2 network as the first software switch If the second software switch is not included in the same L2 network as the first software switch, adds a MAC header immediately before the frame, and if the VXAN header, UDP A header, an IP header, and a Mac header.

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