User's Manual

Nortel Product Bulletin# P-2007-0235-Global – Rev 1
Technical Advisements
Minimum Hardware for SIP Firmware Release on the IP Phone 1120E and 1140E
The SIP Firmware Release 1.1 for IP Phone 1120E and 1140E is only supported on the
GA hardware release of the respective IP Phone model.
Security -
NAT Traversal & STUN protocol
The SIP Firmware Release for IP Phone 1120E and 1140E supports two methods for
NAT traversal of the signaling path:
• SIP_PING
• Simple Traversal of User Datagram Protocol through Network Address
Translators (STUN)
SIP PING is a Nortel protocol for NAT traversal for SIP signaling only.
The STUN protocol lets a client discover the presence and type of NATs between the
client and the public Internet. In addition, a client can discover the mapping between the
private IP address and port number and the public IP address and port number.
Typically, an Enterprise or a service provider operates a STUN server in the public
Internet or internet domain. A STUN server can be located using DNS SRV records
using the domain as the lookup. STUN typically uses the well-known port number 3478.
The NAT traversal method can be selected manually through the Device Settings menu
or configured through the device configuration file.
SIP Firmware Release 1.1 for IP Phone 1120E and 1140E also supports NAT traversal
for the Media path. However, STUN protocol cannot coexist with Application Layer
Gateway (ALG), Media Portals or RTP Proxy servers. If STUN is configured on the SIP
Firmware Release, ensure none of these devices are configured in the SIP proxy server.
Secure Real-Time Transport Protocol (SRTP) and Transport Layer Security (TLS)
SIP-based Secure RTP and TLS are a planned enhancement for a future SIP
Firmware release.
Nortel Product Bulletin# P-2007-0235-Global – Rev 1 Page 17 of 20