Understanding MOBIKE

MOBIKE is an extension to the IKEv2 protocol that provides mobility for VPN connections. Specifically, MOBIKE provides:

• The ability for a VPN client to change its reachable (Internet) address without having to reestablish its SAs with the VPN server.
• The ability for a VPN client and server to select pairs of reachable addresses when they each have access to more than one reachable address.

MOBIKE thus prevents disconnected VPN clients from having to perform IKEv2 renegotiation when Internet connectivity with the VPN server has been reestablished. Because IKEv2 negotiations typically require that between 4,000 and 8,000 bytes of traffic be exchanged, while MOBIKE negotiations only exchange about 500 bytes, MOBIKE enables interrupted VPN connections to be reestablished quickly, minimizing user impact.

Support for MOBIKE is new in Windows 7 and Windows Server 2008 R2 and is a key enabler of the new VPN Reconnect feature of these platforms. For more information on VPN Reconnect, see the next section.

More Info For more information concerning MOBIKE, see RFC 4555 at http://www.ietf.org/rfc/rfc4555.txt.