Anycast is a design in which a single destination IP address is shared by devices in multiple locations. It can be used to implement large-scale UDP services (example: DNS) or to build multi-site high-availability solutions without DNS-based load balancing.
Anycast is also commonly used in data center fabrics to implement redundant first-hop gateways, and with overlay virtual networks (example: VXLAN) to build scale-out gateway clusters or MLAG clusters.
What Is Anycast?
Want to use anycast in a public cloud? Become a Cloudflare user ;) or use AWS Global Accelerator (described in Amazon Web Services Networking webinar).
Anycast in Data Center Fabrics
- Optimal L3 Forwarding with VARP and Active/Active VRRP
- VRRP, Anycasts, Fabrics and Optimal Forwarding
- Arista EOS Virtual ARP (VARP) Behind the Scenes
- Duplicate ARP Replies with Anycast Gateways
- Combining MLAG Clusters with VXLAN Fabric
- Using EVPN/VXLAN with MLAG Clusters
For more information watch:
- Mixed Layer-2 + Layer-3 Fabrics in Leaf-and-Spine Fabric Architectures webinar
- Routing with EVPN in EVPN Technical Deep Dive
- Arista EOS part of Data Center Fabric Architectures webinar.
Network Designs Using Anycast
- Ingress Traffic Flow in Multi-Data Center Deployments
- Routing in Stretched VLAN Designs
- IRB Design Models Overview
- Routing at the Outer Edge of the Fabric
Anycast Use Cases
- Dynamic Routing with Virtual Appliances
- Virtual Appliance Routing – Network Engineer’s Survival Guide
- Where Would You Need DNS Anycast?
Testing IP Anycast in a Virtual Lab