Understanding VXLAN: A Guide to Virtual Extensible LAN Technology

In modern network architectures, especially within data centers, the need for scalable, secure, and efficient overlay networks has become paramount. VXLAN, or Virtual Extensible LAN, is a network virtualization technology designed to address this necessity by enabling the creation of large-scale overlay networks on top of existing Layer 3 infrastructure. This article delves into VXLAN and its role in building robust data center networks, with a highlighted recommendation for FS’ VXLAN solution.

What Is VXLAN?

Virtual Extensible LAN (VXLAN) is a network overlay technology that allows for the deployment of a virtual network on top of a physical network infrastructure. It enhances traditional VLANs by significantly increasing the number of available network segments. VXLAN encapsulates Ethernet frames within a User Datagram Protocol (UDP) packet for transport across the network, permitting Layer 2 links to stretch across Layer 3 boundaries. Each encapsulated packet includes a VXLAN header with a 24-bit VXLAN Network Identifier (VNI), which increases the scalability of network segments up to 16 million, a substantial leap from the 4096 VLANs limit.

VXLAN operates by creating a virtual network for virtual machines (VMs) across different networks, making VMs appear as if they are on the same LAN regardless of their underlying network topology. This process is often referred to as ‘tunneling’, and it is facilitated by VXLAN Tunnel Endpoints (VTEPs) that encapsulate and de-encapsulate the traffic. Furthermore, VXLAN is often used with virtualization technologies and in data centers, where it provides the means to span virtual networks across different physical networks and locations.

VXLAN

What Problem Does VXLAN Solve?

VXLAN primarily addresses several limitations associated with traditional VLANs (Virtual Local Area Networks) in modern networking environments, especially in large-scale data centers and cloud computing. Here’s how VXLAN tackles these constraints:

Network Segmentation and Scalability

Data centers typically run an extensive number of workloads, requiring clear network segmentation for management and security purposes. VXLAN ensures that an ample number of isolated segments can be configured, making network design and scaling more efficient.

Multi-Tenancy

In cloud environments, resources are shared across multiple tenants. VXLAN provides a way to keep each tenant’s data isolated by assigning unique VNIs to each tenant’s network.

VM Mobility

Virtualization in data centers demands that VMs can migrate seamlessly from one server to another. With VXLAN, the migration process is transparent as VMs maintain their network attributes regardless of their physical location in the data center.

What Problem Does VXLAN Solve
Overcoming VLAN Restrictions
The classical Ethernet VLANs are limited in number, which presents challenges in large-scale environments. VXLAN overcomes this by offering a much larger address space for network segmentation.


” Also Check – Understanding Virtual LAN (VLAN) Technology

How VXLAN Can Be Utilized to Build Data Center Networks

When building a data center network infrastructure, VXLAN comes as a suitable overlay technology that seamlessly integrates with existing Layer 3 architectures. By doing so, it provides several benefits:

Coexistence with Existing Infrastructure

VXLAN can overlay an existing network infrastructure, meaning it can be incrementally deployed without the need for major network reconfigurations or hardware upgrades.

Simplified Network Management

VXLAN simplifies network management by decoupling the overlay network (where VMs reside) from the physical underlay network, thus allowing for easier management and provisioning of network resources.

Enhanced Security

Segmentation of traffic through VNIs can enhance security by logically separating sensitive data and reducing the attack surface within the network.

Flexibility in Network Design

With VXLAN, architects gain flexibility in network design allowing server placement anywhere in the data center without being constrained by physical network configurations.

Improved Network Performance

VXLAN’s encapsulation process can benefit from hardware acceleration on platforms that support it, leading to high-performance networking suitable for demanding data center applications.

Integration with SDN and Network Virtualization

VXLAN is a key component in many SDN and network virtualization platforms. It is commonly integrated with virtualization management systems and SDN controllers, which manage VXLAN overlays, offering dynamic, programmable networking capability.

By using VXLAN, organizations can create an agile, scalable, and secure network infrastructure that is capable of meeting the ever-evolving demands of modern data centers.

FS Cloud Data Center VXLAN Network Solution

FS offers a comprehensive VXLAN solution, tailor-made for data center deployment.

Advanced Capabilities

Their solution is designed with advanced VXLAN features, including EVPN (Ethernet VPN) for better traffic management and optimal forwarding within the data center.

Scalability and Flexibility

FS has ensured that their VXLAN implementation is scalable, supporting large deployments with ease. Their technology is designed to be flexible to cater to various deployment scenarios.

Integration with FS’s Portfolio

The VXLAN solution integrates seamlessly with FS’s broader portfolio, (such as the N5860-48SC and N8560-48BC, also have strong performance on top of VXLAN support), providing a consistent operational experience across the board.

End-to-End Security

As security is paramount in the data center, FS’s solution emphasizes robust security features across the network fabric, complementing VXLAN’s inherent security advantages.

In conclusion, FS’ Cloud Data Center VXLAN Network Solution stands out by offering a scalable, secure, and management-friendly approach to network virtualization, which is crucial for today’s complex data center environments.

How to Configure DHCP for Multiple VLANs?

Almost every device connected to the Internet needs an IP address. Previously, the countless IP addresses are assigned manually, which costs a lot of time and energy. As DHCP emerges, IT specialists are not required any longer to spend countless hours providing IPs for every device connected to the network device. But what is DHCP? How does it work and how to configure DHCP for multiple VLANs?

What Is DHCP?

DHCP – Dynamic Host Configuration Protocol is a network management protocol used on TCP/IP network. There may be at least a DHCP server and many DHCP clients. The DHCP server allows the client to request the IP addresses and other network configurations from the Internet service provider. This process eliminates the need for administrators or users to assign IP address to network devices one by one. Using this protocol, the network administrators will just set up the DHCP server with all the additional network information, and it will do its work dynamically. Both network switch and router can be configured as a DHCP server.

How Does the DHCP Process Look Like?

For the DHCP client that hasn’t accessed the Internet before, it will undergo 4 phases to connect the DHCP server.

dhcp process

Fig 1. DHCP process

1.Discover

DHCP client after being activated will first send a broadcast message to try to look for DHCP servers. In this way, the client request IP address from the DHCP server.

2.Offer

When the DHCP server gets the message from the client, it looks in its pool to find an IP address it can lease out to the client. It then adds the MAC address information of the client and the IP address it will lease out to the ARP table. When this is done, the server sends this information to the client as a DHCPOFFER message.

3.Selection

DHCP client chooses IP address. There may be several DHCP servers sending DHCP-Offer packet, the client only receives the first DHCP-Offer then sends back DHCP-Request packet in broadcast mode to all DHCP servers to request more information on the IP address lease time and verification. The packet includes the contents of the IP address requested from the selected DHCP server.

4.Acknowledge

When the DHCP server receives a DHCP-Request packet from the DHCP client, it confirms the lease and creates a new ARP mapping with the IP address it assigned to the client and the client’s MAC address. And then send this message as a unicast to the client as a DHCPACK.

How to Configure DHCP for Multiple VLANs?

The theory cannot be well digested unless it is combined with the practice. In this section, how to configure DHCP for multiple VLANs is introduced for your reference. Take the following picture as an example.

DHCP configuration

Fig 2. DHCP Configuration for Multiple VLANs

PC1 and PC2 are connected to access port of VLAN switch 1 with VLAN ID 100 and 200.

The DHCP server was supposed to serve both the VLANs.

Command to enable multiple VLANs.

DHCP configuration 1

Command to enable DHCP.

DHCP configuration 2

Add both subnets.

DHCP configuration 3

Run DHCP server.

DHCP configuration 4

Now make PC1 and PC2 as DHCP client. Both should be able to get IP address from DHCP server in their respective VLAN.

Conclusion

How to configure DHCP for multiple VLANs? This issue has been illustrated in the above content. DHCP configuration is worthy of being learned by those who are engaged in fiber optic communication field. You just need to know “How”, and let FS provide you with the best network devices. Ethernet switch like gigabit Ethernet switch and 10gbe switch, and routers are available in FS.