Core Issue
The newer H323 versions 3 and 4, found in Cisco IOS 12.2(8)T and later, have some difficulty in communicating with some devices using some older H323 version stacks. In particular, NetMeeting connections may not complete with this version.Resolution
To correct this issue, disable the H245 tunnel, allowing additional TCP sessions rather than requiring use of the existing one. The two bold IOS commands below may correct this issue. These commands are hidden and will not be seen by normal parsing operations.
router(config)# voice service voip
router(conf-voi-serv)# h323
router(conf-serv-h323)# h245 caps mode restricted
router(conf-serv-h323)# h245 tunnel disable
For more information, refer to Third Party H323 Calls Fail with Cisco IOS Later than 12.2(8)T.
Problem Type
Call connection (Connection quality: One-way audio, no busy tone, dropped calls, etc.)Call Connection
Call connection establishmentCommon Software and Product Issues
Problems after an upgradeWhen Problem Occurs
While call is connectingEnd Where Problem is Heard or Device Type Involved
IP phoneSignaling Protocol
H323Voice Gateways
IOS gateways