Patent ID: 8547848

Claim:
A method of controlling traffic flow through a service node located within a packet network, said traffic flow originating at a plurality of sending nodes, continuing downstream through a multiplicity of service nodes configured in a tree or other acyclic structure, and being destined for a receiving node, said service node comprising one of said multiplicity of service nodes, the method comprising: receiving at the service node a challenge from said receiving node or a downstream service node; at the service node, generating and caching a further challenge, and combining that further challenge with the received challenge to generate a modified challenge; at the service node, sending said modified challenge to a sending node or to an upstream service node; at the service node, receiving a request that originated at a sending node and that is destined for said receiving node; at the service node, validating a solution accompanying said request using the cached further challenge by verifying at the service node that the solution accompanying the request is valid based on one or more criteria; and at the service node, forwarding the request towards said receiving node only if the solution is valid, otherwise dropping the request.