I have a vey simple VoIP network to implement: three sites connected by a Frame-Relay cloud with a VoIP VLAN in each site. I have to connect two IP Phones (7960) for each site and they must communicate among them, while there is no need to interface with analog telephone networks.
I woudl like to use SIP and, as far as I know, it is a peer-to-peer protocol, so I guess it does not need a centralized manager. I know about SIP proxy, but I guess it is not needed, though it may be used. However, tha IP phone configuration guide seems to state that you must configure a SIP proxy. Is this true? In this case, can it be implemented by a router with advanced security IOS?
Thanks a lot in advance,