VXLAN and BGP EVPN Configuration Guide for Dell EMC SmartFabric OS10 Release 10.5.2

VXLAN concepts

Network virtualization overlay (NVO)

An overlay network extends L2 connectivity between server virtual machines (VMs) in a tenant segment over an underlay L3 IP network. A tenant segment can be a group of hosts or servers that are spread across an underlay network.

• The NVO overlay network uses a separate L2 bridge domain (virtual network), which is independent of legacy VLAN forwarding.
• The NVO underlay network operates in the default VRF using the existing L3 infrastructure and routing protocols.

Virtual extensible LAN (VXLAN)

A type of network virtualization overlay that encapsulates a tenant payload into IP UDP packets for transport across the IP underlay network.

VXLAN network identifier (VNI)

A 24-bit ID number that identifies a tenant segment and transmits in a VXLAN-encapsulated packet.

VXLAN tunnel endpoint (VTEP)

A switch with connected end hosts that are assigned to virtual networks. The virtual networks map to VXLAN segments. Local and remote VTEPs perform encapsulation and de-capsulation of VXLAN headers for the traffic between end hosts. A VTEP is also known as a network virtualization edge (NVE) node.

Bridge domain

A L2 domain that receives packets from member interfaces and forwards or floods them to other member interfaces based on the destination MAC address of the packet. OS10 supports two types of bridge domains: simple VLAN and virtual network.

• Simple VLAN: A bridge domain a VLAN ID represents. Traffic on all member ports is assigned with the same VLAN ID.
• Virtual network: A bridge domain a virtual network ID (VNID) represents. A virtual network supports overlay encapsulation and maps with either a single VLAN ID in a switch-scoped VLAN or with multiple (Port,VLAN) pairs in a port-scoped VLAN.

Distributed routing

All VTEPs in a virtual network perform intersubnet routing and serve as L3 gateways in two possible modes:

• Asymmetric routing: All VTEPs can perform routing. Routing decisions are made only on ingress VTEPs. Egress VTEPs perform bridging.
• Symmetric routing: All VTEPs perform routing. Routing decisions are made on both ingress and egress VTEPs.

Virtual network

In OS10, each L2 flooding domain in the overlay network is represented as a virtual network.

Virtual network identifier (VNID)

A 16-bit ID number that identifies a virtual network in OS10.

Virtual-network interface

A router interface that connects a virtual network bridge to a tenant VRF routing instance.

Access port

A port on a VTEP switch that connects to an end host and is part of the overlay network.

Network port

A port on a VTEP switch that connects to the underlay network.

Switch-scoped VLAN

A VLAN that is mapped to a virtual network ID (VNID) in OS10. All member ports of the VLAN are automatically added to the virtual network.

• You can map only one VLAN ID to a virtual network.
• Ideally suited for existing tenant VLANs that stretch over an IP fabric using VXLAN.

Port-scoped VLAN

A Port,VLAN pair that maps to a virtual network ID (VNID) in OS10. Assign an individual member interface to a virtual network either with an associated tagged VLAN or as an untagged member. Using a port-scoped VLAN, you can configure:

• The same VLAN ID on different access interfaces to different virtual networks.
• Different VLAN IDs on different access interfaces to the same virtual network.