Verification of configuration information in BGP VPNs

A method of verifying configuration information in a virtual private network (VPN), the VPN using border gateway protocol (BGP), the method comprising:

• generating a first knowledge digest encoding first configuration information associated with a current set of information advertised for a provider edge device, the current set of information comprising at least one forwarding table entry associated with the provider edge device;
• generating a second knowledge digest encoding second configuration information associated with cumulative information advertised for the provider edge device over a period of time, wherein the cumulative information comprises at least one forwarding table entry additional to the current set of information;
• receiving a third knowledge digest encoding third configuration information;
• and comparing the first knowledge digest to the third knowledge digest to determine whether the configuration information encoded in the third knowledge digest is a subset of the configuration information encoded in the first knowledge digest.