SIP (Session Initiation Protocol), based on RFC 3261
SIP RFC 3581
Backward compatible with entities running RFC 2543
SDP (Session Description Protocol) based on RFC 2327 and RFC 3551
Interworking with H.323, ISDN, SS7, and SIP
Q.1912.5 Support for SIP to ISUP Interworking
Authentication and Outbound Registration (IMG can register with other entities). An IMG does not support inbound registration, since it is not applicable for Media Gateways.
Call Release Data in the Radius CDR
Vocoder Data in the Radius CDR
An IMG acts as a User Agent (UA) and can inter-operate with SIP proxies. The IMG can act as a UAC (User Agent Client) or a UAS (User Agent Server).
3xx Redirection (e.g. 302 Moved Temporarily). Also see Supported 3xx Redirect Responses.
Transmission Control Protocol (TCP) Transport layer (single or multi-socket)
Early Media (supporting 180/183 Session Progress)
Reliable User Datagram Protocol (UDP) transport, with retransmissions
Supported Response Messages 1xx, 2xx, 3xx, 4xx, 5xx, 6xx
A SIP Profile allows you to easily assign a number of SIP features to a Physical IMG. You create a SIP Profile and then assign profiles to a gateway in the External Gateway pane.
Support of RFC 3666's Call Flows -- SIP to PSTN Dialing
Vocoder DATA in the CDR
Send a 180 Ringing after a 183 Session Progress (SIP SGP)
SIP HOLD/UNHOLD Propagation
SIP Reason Header (SIP to TDM and TDM to SIP)
Non-Standard Tags in From/To Header
Non-Standard Tags in R-URI
This feature allows the IMG to respond to the 3XX class of SIP messages returned from a redirect server.
The IMG can route SIP traffic to a remote entity based on the IP Address or the Host Name. The IMG supports having multiple DNS servers for redundancy and reliability purposes. See DNS Server and DNS Client panes.
Re-origination
This feature allows you to limit the number of INVITE re-transmission attempts (1-5 attempts). The number configured supersedes the standard # of re-transmissions specified in RFC3261 (which is based on timers T1 and T2. The default is Re-transmit All. You enable this feature in the SIP Profile.
The IMG can monitor the status of external SIP gateways by sending periodic SIP OPTIONS messages. If the gateway does not respond in a configured amount of time the IMG will mark the gateway as down and attempt to re-route the call to a different gateway. See SIP Busy Out.
DTMF out-of-band transfer using INFO and SUBSCRIBE/NOTIFY
Representing trunk groups in SIP Uniform Resource Identifiers (URIs)
SIP PRACK in 1xx messages
SIP Trunk Group Parameter (Route On dtg/otg)
SIP Call Processing Initiated Redirect on 302 message
Relay for Dual Tone Multi Frequency (DTMF) digits, including payload type negotiation (RFC 2833)
Note: If the remote side includes the fax maximum rate parameter in the SDP body of the INVITE message, the gateway returns the same rate in the response SDP.
G.729 AnnexB Selection
GSM Support for SIP
G.726 Support for SIP
Interworking with H.323, ISDN, and SS7
SS7 to SIP Calling Party Category (CPC)
SIP-T
Support of RFC 3666 Call Flows - SIP to PSTN Dialing