1.1 This part of ISO 13400 specifies the requirements for diagnostic communication between external test equipment and vehicle electronic components using Internet Protocol (IP) as well as the transmission control protocol (TCP) and user datagram protocol (UDP). This includes the definition of vehicle gateway requirements (e.g. for integration into an existing computer network) and test equipment requirements (e.g. to detect and establish communication with a vehicle). 1.2 This part of ISO 13400 specifies features that can be used to detect a vehicle in a network and enable communication with the vehicle gateway as well as with its sub-components during the various vehicle states. These features are separated into two types: mandatory and optional. 1.3 This part of ISO 13400 specifies the following mandatory features: — vehicle network integration (IP address assignment); — vehicle announcement and vehicle discovery; — vehicle basic status information retrieval (e.g. diagnostic power mode); — connection establishment (e.g. concurrent communication attempts), connection maintenance and vehicle gateway control; — data routing to and from the vehicle's sub-components; — error handling (e.g. physical network disconnect). 1.4 This part of ISO 13400 specifies the following optional features: — DoIP entity status monitoring; — DoIP entity firewall capabilities.