Patent ID: 7917620

Claim:
An apparatus, comprising: a determiner, comprising one or more programmable hardware-based processing elements, configured to determine whether a message, comprising a session initiation protocol message, received at a first network has been through a security check by determining whether or not the message has been received with security at a first layer, the message comprising a second layer identity header; a forwarder, comprising the one or more programmable hardware-based processing elements, configured to forward the message within the first network regardless of the result of the determination; and a modifier, comprising the one or more programmable hardware-based processing elements, configured to modify the message so as to remove at least part of the second layer identity header to indicate that the message has not been through the security check applied at a secure Za interface between two security domains prior to being, received at the first network when the result of the determination is that the message has not been through the security check, wherein the second layer is a higher layer than the first layer; wherein the forwarder is further configured to forward the message without modification in response to the determination being that the message has been through the security check applied at the Za interface prior to being received at the first network.