Mechanism for throttling untrusted interconnect agents

An apparatus includes an external device for causing messages to be transmitted with local traffic between internal blocks of a host system-on-chip (SoC) via a network on chip (NoC) in the host SoC, the transmitted messages including one or more memory requests directed to a memory of the host SoC, violating a traffic policy for a first time interval by transmitting a number of messages that exceeds a maximum threshold of for the first time interval, where the SoC monitors an amount of external traffic from an untrusted device transmitted over the NoC over a set of one or more time intervals including the first time interval, and in response to detection of the violation by the host SoC, reducing an amount of traffic transmitted via the NoC. The apparatus also includes an external processor link for transmitting the messages from the external device to the host SoC.