IMG 1010 - Overview of H.323

The IMG supports Version 2 of ITU H.323, including:

Basic Support:

• H.225 Call Signaling Protocol (Q.931 embedded)

• Registration, Admission, and Status (RAS)

• Real-time Transport Protocol/Real-time Transport Control Protocol (RTP/RTCP)

• Out-of-band DTMF signaling via H.245 and RFC2833

• Cisco Interoperability

• Keep Alive Timer

• FastStart

Media:

• DTMF transmission supported via DTMF tones using G.711, or out via RFC 2833 or H.245 UII signals.

• IP Bearer Profiles

• T.38 Fax, Fax Bypass, Modem Bypass (see IMG 1010 - H.323 Fax-Modem Techniques)

• Codecs: G.711 (Uncompressed), G.723.1 (Compressed), G.729 (Compressed), G.726 (Dynamic and Static), iBLC

• Codec Negotiation Both incoming and outgoing calls including the ability to limit the codecs that are allowed

Interworking:

• Cause code mapping to SS7 ISUP

• Cause code mapping of H.225 release reasons to Q.931 cause codes using H.246 interworking specification

• H.245 Tunneling - H.245 data is sent with the H.225 message

• ISDN to H.323 UUI support

Routing:

• Simultaneous gateway and gatekeeper routed calls

• Gatekeeper Support: 1 active gatekeeper and six alternate, auto-discovery, aliases for E.164, URL, and email.

• Symmetric NAT Traversal