Calls between telephones in separate sites, each with its own PBX, establish a P2P connection over a VPN.
Conditions
[General]
• Three
codecs
are used for peer-to-peer calls: G.722, G.711, and G.729A. The speech quality of the codecs
varies as follows: (High) G.722, G.711, G.729A (Low).
When the preferred codec of each party differs, the call will be established using the lower codec. For
example, if the caller prefers G.711 while the called party prefers G.729A, the call will be established using
G.729A.
• G.722 is only available for calls between KX-NT300 series IP-PTs, KX-NT500 series IP-PTs, and some
SIP extensions that support this codec during peer-to-peer communication.
• Through system programming, it is possible to assign the preferred codec to use for IP-PTs and KX-UT
series SIP phones.
• For non-KX-UT series SIP extensions, the priority of the codec that will be used can be specified via the
telephone itself.
• For non-peer-to-peer calls via the DSP card, calls cannot be made or received when all of the card’s
resources are being used.
• KX-UT series SIP phones and general SIP phones support P2P communication over SIP trunks.
Feature Guide 469
5.2.3 Peer-to-Peer (P2P) Connection