As the RADIUS protocol is a connectionless protocol it is low-level in terms of its functionality and cannot support the more complex unmet needs of WLANs and ISPS today (Wirbel, 2004). Conversely, Diameter supports the Transmission Control Protocol (TCP) and the Stream Control Transmission Protocol (SCTP) have the functionality necessary to provide connection-oriented controls over flow control and arbitrating packets across the network. This is one the most significant limitations of the RADIUS protocol that is leading to widespread adoption of the Diameter protocol.

Limited server failure check in due to the RADIUS protocol being based on a NAS-based architecture, silent discarding of packets (Karyotis, Papavassiliou, 2007), and inefficient server-fail-over due to the NAS-based architecture all have lead to broader acceptance and adoption of the Diameter protocol. From a security standpoint, it's been proven that the RADIUS protocol's reliance on NAS as the basis of its structure also allows for...
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