Overlay Fabric Overview
The distributed overlay fabric is a group of AOS-CX Switches that are part of the BGP Border Gateway Protocol. BGP is a routing protocol for exchanging data and information between different host gateways or autonomous systems on the Internet. -EVPN VXLAN Virtual Extensible LAN creates virtual networks overlaid on a physical network. overlay. The overlay fabric is created by configuring VXLAN tunnels between Stub Stub is a device persona that supports both static VXLAN tunnels and EVPN VXLAN tunnels. and Edge Edge is a device persona that connects endpoints to the fabric. Switches. The ArubaOS 10 Gateways also participate in the overlay fabric, using static VXLAN tunnels to the Stub VTEP VXLAN Tunnel End Point is an entity that originates and/or terminates VXLAN tunnels.. Aruba Central allows you to configure the overlay fabric on top of a virtual network using AOS-CX Switches. You can assign a list of fabric personas such as Border VTEP, Route Reflectors, Edge VTEP, or Stub VTEP to the overlay fabric.
This section describes the different fabric personas and their functions in the Aruba Central BGP EVPN overlay fabric workflow.
- Border VTEP—Refers to a Gateway or an external facing device from the overlay fabric to the external network. Border VTEP participates in the Layer 3 VNI VXLAN Network Identifier refers to VXLAN network identifier or VXLAN segment ID. or VRF Virtual Routing and Forwarding. VRF is a technology that allows multiple instances of a routing table to co-exist within the same router. but does not have overlay VLANs Virtual Local Area Network. In computer networking, a single Layer 2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them through one or more routers; such a domain is referred to as a Virtual Local Area Network, Virtual LAN, or VLAN. or SVIs configured on this device.
- Route Reflector—Refers to a concept that is specific to iBGP that uses to optimize route propagation. Route reflector reduces the configuration required on all the devices and optimizes the way BGP sessions establishes. In a typical scenario, every edge device in the network peers with every other edge device. To avoid this, a route reflector is introduced where all the devices in the overlay fabric peer with the route reflector. Optimizing the configuration and route distribution. Core Switches are generally used as route reflectors in an overlay fabric.
- Edge VTEP—Refers to a traditional access Layer where the clients are onboarded. It is also the Layer 3 Gateway for all the clients that are associated with it. Edge VTEP typically has the SVI Switch Virtual Interface refers to a logical layer 3 interface on a switch. interface, and it is the entry point of all the wired clients onto the BGP EVPN overlay fabric.
- Stub VTEP—Supports static VXLAN and EVPN VXLAN. Stub VTEP is used to establish static VXLAN tunnel to the Gateway and EVPN-VXLAN Ethernet VPN-Virtual Extensible LAN uses Layer 2 connectivity between virtual machines and switches. towards the overlay fabric. Stub VTEP helps to carry role information between EVPN-VXLAN overlay fabric and devices like Gateway that only support Static VXLAN.
Optionally, you can create additional overlay networks, which are on the same VRF and Layer 3 VNI, if required. You can also configure the Gateway IP cluster for wireless Gateways.
For more information, see the topics listed below: