3Com VCX V7122 SIP VoIP Gateway User Manual
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Option to configure ISDN Transfer Capability (per Gateway).
Supported SIP Features
The VCX V7122 SIP VoIP main features are:
Reliable User Datagram Protocol (UDP) transport, with retransmissions.
T.38 real time Fax (using SIP).
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.
Works with Proxy or without Proxy, using an internal routing table.
Fallback to internal routing table if Proxy is not responding.
Supports up to four Proxy servers. If the primary Proxy fails, the VCX V7122
automatically switches to a redundant Proxy.
Supports Proxy server discovery using Domain Name Server (DNS) SRV records.
Proxy and Registrar Authentication (handling 401 and 407 responses) using Basic or
Digest methods.
Supported methods: INVITE, CANCEL, BYE, ACK, REGISTER, OPTIONS, INFO,
REFER, UPDATE, NOTIFY, PRACK and SUBSCRIBE.
Modifying connection parameters for an already established call (re-INVITE).
Working with a Redirect server and handling 3xx responses.
Early Media (supporting 183 Session Progress).
PRACK reliable provisional responses <RFC 3262>.
Call Hold and Transfer Supplementary services using REFER, Refer-To, Referred-By,
Replaces and NOTIFY messages.
Supports RFC 3327 – Adding “Path” to Supported header.
Supports RFC 3581 – Symmetric Response Routing.
Session Timer <draft-ietf-sip-session-timer-10.txt>.
RFC 2833 Relay for Dual Tone Multi Frequency (DTMF) digits, including payload type
negotiation.
DTMF out-of-band transfer using:
INFO method <draft-choudhuri-sip-info-digit-00.txt>
INFO method, compatible with Cisco gateways
NOTIFY method <draft-mahy-sipping-signaled-digits-01.txt>.DTMF out-of-band
transfer using INFO method (draft-choudhuri-sip-info-digit-00.txt)
Can negotiate coder from a list of given coders.
Supported coders:
G.711 A-law 64 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.711 µ-law 64 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.723.1 5.3, 6.3 kbps (30, 60, 90, 120, 150 msec)
G.726 32 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.729A 8 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.729B is supported if Silence Suppression is enabled.