mGRE (Multipoint Generic Routing Encapsulation)

Multipoint Generic Routing Encapsulation (mGRE) is a protocol feature available in Cisco's IOS XE operating system for its routers. It is not a standalone software product but a key component for building dynamic VPNs, particularly with DMVPN (Dynamic Multipoint VPN). mGRE enables a single tunnel interface to establish connections with multiple destination endpoints, simplifying configuration and management compared to creating numerous point-to-point tunnels. This is primarily used by network engineers and administrators to create scalable and secure site-to-site VPN networks. The feature supports both IPv4 and IPv6 transport. As a feature of Cisco's networking hardware, it does not have separate pricing, trials, or dedicated support options beyond standard Cisco support contracts.