The Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP1. BackgroundThe Internet Protocol (IP) is rapidly becoming a more popular for interoperable End-to-End Smart Grid Networks. Therefore, it is important to understand the different uses of the IP suite in Internet networking technologies for existing and emerging Smart Grid applications.The Internet Protocol (IP) suite is defined as (i) a set of network and transport data message protocols, using IP packets, and (ii) a set of routing, IP address mapping and device management protocols. This IP suite enables end-to-end Smart Grid applications to communicate over a set of interconnected network segments (defined in Figure 3), using various networking technologies (MAC/PHY lower layer protocol). It also allows for end-to-end session and transaction-based security mechanisms.It has been identified that there are several options of an IP protocol suite, such as TCP, SCTP, DCCP, UDP [3] and other protocols that could be used in any particular combination for the purpose one intends. As proposed by [3], for an end-to-end Smart Grid interoperability purpose, the set of IP protocol suite defined for Smart Grid shall focus on end devices (hosts). The Smart Grid IP end devices/nodes are defined as any IP-enabled device used in an Smart Grid such as smart meters, sensors, relays, actuators, intelligent electronic devices (IEDs).DNP3 (Distributed Network Protocol). For the purpose of establishing an IP architecture in Smart Grid, we will make three assumptions about this diagram:1. The entire routing domains represents a single Autonomous System (AS). This is necessarily the routing domain for the electric utility serving this customer. The implication here is that the IP address assigned to the customers meter comes from the electric utility.2. The Customer network could use non-routable addressing space.3. It is accepted that there could be an additional IP network connection, provided by the customers ISP (and is thus a different AS number), that also connects somewhere in the Customer network.2. Smart Grid Architecture LayersDifferent Smart Grid architecture layers proposed today. The additional layers defining the Smart Grid Communications Architecture, particularly focused on an End-to-End Smart Grid IP Architecture are covered.The Smart Grid IP Architecture considers the IP suite as the underlying and converging protocol layer for end-to-end Smart Grid interoperability.