Abstract: Identity Federation enables Users to effectively manage their multiple Identities spread across different administrative domains. It leverages trust between the Identity Providers to allow Users to federate and share their Identity information to receive cross-domain Identity benefits. In this paper, we argue that with increasing number of VoIP providers as well as the ability for Users to host and self-manage their own VoIP Identities, an Identity Federation-based solution is required for VoIP as well. The paper analyzes differences for Identity Federation within VoIP scenarios, as compared to existing Web-based scenarios. We propose the VoIP Identity Federation Framework, enabling a User to establish Identity Federation as well as the assertion of any relevant Identity information from one VoIP context to another. The framework is designed using simple application-usage agnostic primitives viz. federate-out and federate-in, which can be applied within any VoIP Protocol scenario. One of the primary design goals has been to model these enablers as an independent protocol, so that they can be piggybacked on any of the existing VoIP protocol scenarios. As a result, Identity Federation benefits can be easily applied to any existing or future VoIP-based application usages. Another important aspect is to enable sufficient User control within the Identity Federation framework. We also present a set of exemplary yet novel use-cases enabled by the proposed framework.
