Multimedia Access Platforms
Glen Freundlich
Avaya, Inc.
ggf@avaya.com
IP Telephony Gateways
Network A
Gateway
Network B
Gateway converts between 2 networks:
• signaling conversion
• media (bearer) conversion
• service conversion
Networks could be same types (firewall, NAT).
IP-ISDN Gateway
Signaling conversion
D channel
H.323, SIP
Gateway
B channel
RTP
Bearer conversion
Gateway consists of multiple functions which need not
co-exist in same physical box.
Gateway Decomposition
Signaling
Gateway
Gateway
Media
Gateway
Media
Gateway
Controller
H.248/Megaco
IETF/ITU Collaboration
• Work begun independently in 1998 in IETF, ITUT SG16, ETSI TIPHON
• ETSI TIPHON and MSF became suppliers of
requirements
• Agreement at management level in March 1999
– IETF Megaco WG and ITU-T SG16 Q14 develop
gateway control protocol as a joint project
– Megaco to own requirements document
– Q14 to own final protocol standard
Gateway Control Protocols
NCS/J.162
IPDC
MGCP
TGCP/J.171
MDCP
H.248/Megaco
SGCP
others
Future Collaboration?
• Additions to H.248 for a Version 2
• Package coordination
– reduce or eliminate overlap
– validate architecture
– check for completeness
• Interoperability/testing
• Interworking (e.g., to H.323, SIP, BICC)
• ???