An in-depth review of service discovery protocols (SDPs) in multihop mobile ad hoc networks analyzes SDP building blocks and determines SDP suitability based on architecture, mobility, and network size. Mobile ad hoc networks (manets) include a variety of devices, such as cell phones, PDAs, laptops, and other relatively larger devices. These devices can move at high or low speeds or even remain stationary, entering and leaving the system when switched on or off. Such a variety of devices also offers a variety of services. A service is any tangible or intangible facility a device provides that can be useful for any other device. Services comprise those for software and hardware. A software service, for example, can be a simple file, such as an MP3 file, or a software implementation of an algorithm, such as converting one audio file format to another. A hardware service, for example, can be a printer that a mobile device can use wirelessly. To benefit from these services, a device must be able to both locate them in the network and invoke them. Service discovery protocols (SDPs) enable these capabilities.