Network Considerations for Common VXLAN Deployments

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VXLAN (Virtual Extensible LAN) is a network virtualization technology that allows the creation of logical Layer 2 networks over a Layer 3 infrastructure. VXLAN uses a 24-bit identifier called a VXLAN Network Identifier (VNI) to identify the virtual network. Here are the two network considerations for common VXLAN deployments:

A. Placement of VXLAN Tunnel Endpoints: The VXLAN Tunnel Endpoint (VTEP) is responsible for encapsulating and de-encapsulating Ethernet frames into and out of VXLAN packets. VTEPs are typically located at the edge of the data center network where they connect to the physical servers or switches. When deploying VXLAN, it is important to carefully consider the placement of VTEPs to ensure that the network topology is optimized for performance, scalability, and resilience.

B. MTU Size in the Transport Network: When VXLAN is used to extend Layer 2 networks over a Layer 3 infrastructure, it adds an additional header to the Ethernet frame. This can cause the size of the packet to exceed the Maximum Transmission Unit (MTU) size of the underlying network, leading to fragmentation, packet loss, and other performance issues. Therefore, it is important to carefully consider the MTU size in the transport network when deploying VXLAN.

C. Multicast Group Scaling: VXLAN uses multicast to forward broadcast, unknown unicast, and multicast traffic to the VTEPs participating in the same VXLAN segment. Therefore, multicast group scaling is an important consideration in VXLAN deployments, especially in large-scale data center environments. Multicast group scaling refers to the ability of the network to handle a large number of multicast groups without impacting performance or causing other issues.

D. Consistent VLAN-to-VN-Segment Mapping: In VXLAN, each VXLAN segment is identified by a unique VNI. It is important to ensure that the VLAN-to-VN-Segment mapping is consistent across the network to avoid any confusion or misconfiguration. This can help to prevent traffic from being misrouted or dropped.

E. Consistent VNI-to-Group Mapping: VNI-to-group mapping refers to the mapping between the VNI and the multicast group used for forwarding traffic within the VXLAN segment. It is important to ensure that this mapping is consistent across the network to ensure proper forwarding of traffic between VTEPs participating in the same VXLAN segment.

In summary, the two network considerations for common VXLAN deployments are the placement of VXLAN tunnel endpoints and the MTU size in the transport network. However, it is also important to consider multicast group scaling, consistent VLAN-to-VN-Segment mapping, and consistent VNI-to-group mapping when deploying VXLAN.