IPsec secured GRE tunnel demultiplexing problem statement

This document describes the IPsec secured GRE based VPN demultiplexing problem statement. When two or more IPsec SAs are used to protect GRE encapsulated VPN network between the same pair of edge router, the current GRE based VPN does not support the edge router to demultiplex data for different IPsec SA. GRE key provides one solution to demultiplex the VPNs secured by IPsec.