A method and system for combined Peer-to-Peer (P2P) conferencing and central relay server-based conferencing using a telephony and conferencing protocol that includes Web Real-Time Communication (WebRTC) or Session Initiation Protocol (SIP), including receiving by a central relay server a request from a client device to participate in a conference call, comparing by the central relay server a received client device policy and a central relay server policy for selecting at least one of the P2P conferencing or the central relay server-based conferencing, and selecting at least one suggested connection mode for the client device based on a result of the comparing of the received client device policy and the central relay server policy, the combined P2P conferencing and central relay server-based conferencing including mixing server-based conferencing streams and P2P conferencing streams.