ts for network internal protocols and also on the location management procedures [72]. The CT4 has a particularly long list of affected documents from Diameter to GTP, Proxy Mobile IPv6 (PMIPv6), numbering, addressing, packet radio service, organization of subscriber's data, Deploying IPv6 in 3GPP Networks and WLAN interworking to name a few. Finally, the CT6 is working on implications to smart card application aspects. IETF Standardization Work The main standardization organization for network and transport layer protocols, and the important organization for some application layer protocols, is the IETF http://www.ietf.org. The IoT devices that are not really constrained can easily utilize existing protocols, such as IPv4, IPv6, TCP, and HyperText Transfer Protocol (HTTP), defined by the IETF a long time ago. However, for a class of IoT devices, the existing protocols are too resource consuming. The constrained categories of devices can be, for example, those that perform industrial, structural, or agricultural monitoring or are used for home automation, healthcare, or vehicle telematics [59]. For those kinds constrained nodes IETF is defining new lightweight protocols. We list some of the most interesting standards or standard drafts below. Constrained Application Protocol (CoAP): The CoAP is a binary encoded protocol that allows HTTP style mechanisms and REpresentational State Transfer (REST)- mechanisms to work over UDP. The protocol is designed to be as lightweight to implement and transport as possible. The CoAP is actually a set of documents built over the core CoAP specification [73]. These include, for example, 'Observing Resources in CoAP' that allows a CoAP client to request a CoAP server to send data without continuous polling [74] and 'Constrained RESTful Environments (CoRE) Link Format' that defines how servers can describe their resources and attributes [75]. There are also several other CoAP related enhancements in the pipeline. At the time of writing, it seems that the CoAP is becoming the protoc