IMS-ALG
IMS Application Level Gateway
In the 3GPP IMS (IP Multimedia Subsystem) architecture, the IM-ALG is a DPI (Deep Packet Inspection) device which ensures that addressing contained within SIP signalling is removed if required or altered in order to support NAT traversal. Additionally, the IM-ALG will also monitor SIP signalling in order to detect malicious attack. The IM-ALG is a functional entity of the IBCF (Interconnection Border Control Function).