FS VXLAN Solution: Effortless VM Migrations Across Data Centers

As networking technologies advance, cloud computing has become the main trend in modern enterprise IT infrastructure. The reasons for its popularity are high system efficiency, low management costs, and strong flexibility and scalability. Server virtualization, as a core technology of cloud computing, is increasingly gaining widespread adoption.

The widespread adoption of server virtualization technology significantly enhances the computing density of data centers. To facilitate flexible business operations, virtual machines (VMs) need to migrate freely within the network. This poses new challenges to traditional ‘layer 2 plus layer 3’ data center networks.

Challenges Faced by Traditional Data Center Networks

Limited Virtual Machine Scale

In traditional layer 2 networks, devices forward data packets by looking up MAC address tables. With server virtualization, the number of VMs has grown dramatically compared to physical machines. This has caused a significant increase in the number of MAC addresses for VM network interfaces. However, the MAC address table capacity of access layer 2 devices is relatively small and cannot keep up with the rapid growth of VM numbers.

Insufficient Network Isolation

VLAN is the current mainstream network isolation technology. It defines only 12 bits and allows for a maximum of 4096 VLANs. This means that VLANs cannot adequately isolate scenarios like public clouds or large-scale virtualized cloud computing services with tens of thousands or more tenants.

Migration Scope Constraints

VM migration has become a routine operation because of problems such as high server CPU usage and insufficient memory. VM migration refers to moving a virtual machine from one physical machine to another.

To ensure uninterrupted service during the migration, it's essential to maintain the virtual machine's IP address, MAC address, and other parameters unchanged. This means that VM migration occurs within a layer 2 network. However, traditional layer 2 networks limit VM migration to a smaller local area.

To achieve dynamic migration of virtual machines over a large range or even across regions, it is necessary to centralize all servers that may participate in virtual machine migration into the same layer 2 network domain. The emergence of VXLAN technology effectively solves these challenges.

What is VXLAN？

Virtual eXtensible Local Area Network (VXLAN) is one of the Network Virtualization over Layer 3 (NVO3) technologies defined by the Internet Engineering Task Force (IETF). VXLAN encapsulates a layer 2 Ethernet frame into a UDP packet and transmits the packet over a layer 3 network. It is an extension of Virtual Local Area Network (VLAN).

VXLAN is essentially a tunneling technology. It establishes a logical tunnel on the IP network between the source and destination network devices to encapsulate user-side packets and forward them through the tunnel. Servers are connected to different ports of network devices in the data center VXLAN network, which can be considered as a virtual layer 2 switch.

VXLAN has become the mainstream technology for building data center networks because it meets the needs of dynamic VM migration and multi-tenancy.

Key Advantages of VXLAN

Addressing Limited Virtual Machine Scale

VXLAN encapsulates the original virtual machine messages generated in the same subnet planned by the administrator into new UDP messages. It uses the IP and MAC addresses of the physical network as the outer headers, presenting the packet to other devices in the network solely as encapsulated parameters. As a result, this significantly reduces the requirements for MAC address specifications in large layer 2 networks.

Enhancing Network Isolation

VXLAN introduces a user identifier similar to VLAN ID, known as VXLAN Network Identifier (VNI), composed of 24 bits. It supports up to 16 million VXLAN segments, effectively addressing the issue of massive tenant isolation in cloud computing.

Expanding Migration Scope

VXLAN encapsulates original VM packets in VXLAN tunnels, enabling seamless transmission. This allows VMs at either end of the tunnel to operate without awareness of the underlying physical network architecture. Consequently, VMs sharing the same subnet IP addresses appear logically within the same layer 2 domain, even if physically separated across different layer 2 networks.

VXLAN functions above layer 3 networks, effectively creating a virtual large layer 2 network. Administrators can place VMs within this extensive layer 2 network as long as virtual machine routing is feasible, thereby overcoming limitations on VM migration scope.

Typical VXLAN Applications

Service providers and cloud providers are typical use cases for VXLAN. They manage a large number of tenants or customers, and for various legal, private, and ethical reasons, providers must separate the network traffic of one customer from another.

In enterprise environments, tenants could be user groups, departments, or another set of network segment users or devices created for internal security reasons. For example, IoT devices like data center environmental sensors are vulnerable to attacks. Therefore, isolating IoT network traffic from production network application traffic is a reasonable security practice.

FS VXLAN Network Solution

To achieve an elastic, agile, and scalable network, FS focuses on deploying a Spine-Leaf architecture with VXLAN technology. Based on this approach, FS integrated the advanced PicOS® and AmpCon™ management platform to help X subsidiary build a high-performance video streaming data center.

The customer needed to establish a video streaming data center but faced issues with VM migrations causing business interruptions. Therefore, they required the new network's virtual machines to support live migration capabilities, allowing seamless movement of running virtual machines from one server to another without disrupting operations or affecting user experience.

Based on the Spine-Leaf architecture, we used VXLAN tunnel technology to create a virtual layer 2 network across multiple layer 3 networks. This allowed virtual machines to migrate flexibly between different data centers, ensuring uninterrupted business operations during migration. Since VXLAN uses standard protocols, devices are perfectly compatible, simplifying the replacement process and reducing operation risks.

We established VXLAN connections between leaf switches, which do not consume server CPU resources, significantly enhancing network forwarding performance. Additionally, our local service team brought switching equipment to assist customers in performing VXLAN compatibility tests in their labs, verifying the feasibility of establishing VXLAN connections between spine switches and virtual servers. This professional support lays a solid foundation for future video streaming network expansion.

Overall, FS VXLAN Network Solution provides significant advantages across multiple critical areas for video service providers.

Conclusion

The high scalability and virtualization capabilities of VXLAN make it an ideal choice. It meets the needs of new network environments, such as cloud computing and virtualization. FS utilized VXLAN technology to build virtual layer 2 networks and establish virtual tunnels. This enabled video service providers to achieve real-time VM migrations across data centers. The goal is to achieve zero downtime and flexible resource allocation.

We can customize solutions according to customer needs and explain the advantages of architecture and product connections on-site. Ready to elevate your network experience? With cutting-edge R&D and Australian warehouses, we deliver tailored VXLAN solutions. Register for more information and experience our solution design services.