1Bridging the gap between peer-to-peer and conventional SIP networks

which is still being standardised in the IETF, holds much promise for enabling many diverse forms of realtime multimedia communications in completely, or partially, decentralised environments. The final spec-ification will likely feature a distributed storage API for manipulating records belonging to the SIP overlay network, as well as a multi-protocol routing layer. Though great pains have been taken to add support for different types of peer-to-peer platforms in order to realise a truly protocol-agnostic architecture, signif-icantly less effort has been invested in resolving the issue of how these networks will interoperate, if at all, with conventional SIP networks. This paper describes the precise nature of the problem of interoperation among these different types of networks, and presents a solution which is based on dynamic updates in DNS. The solution is described within the context of the P2P SIP architecture called OverCord, and describes how this architecture was extended to support this type of interoperation.1 Index Terms — Internet telephony, peer to peer, over-lays, DHTs I