H.323 is one of the suite of protocols used for setup in VOIP Environment.
The Gatekeepercomponent isresponsible for Load Balancing and Address Resolution in H.323 suite.
It stands for Host.
Gatekeepers Gateways Multipoint Control Units Terminals
SIP
gatekeepers gateways multipoint control units terminals
H.323 gateway. network + page 561
b- handles call setup, call routing, and call termination
SIP has limited functionality, which makes it more flexible. SIP messages also use less processing resources.
SIP messages use fewer processing schemes AND SIP supports a wider range of voice and video codecs.
SIP, reference pg549-550 Network+ Guide to Networks, Fifth Edition, Tamara Dean.
The weaknesses of static (or stateless) packet filters and stateful packet filters are different in a few ways. Stateless packet filters frequently block SYN scans of networks, but .... Stateless packet filters. (cf. iptables connection tracking), cf. state vs. stateless discussion. confounded application layer protocols like FTP, H323 Because of the nature of connection tracking and state awareness, stateful packet filters are vulnerable to resource exhaustion and deliberate attempts to trip rate-limiting features.