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Cisco Bug: CSCub20591 - TCP connection times out on H323 Call (Firewall issue)

Last Modified

Dec 11, 2018

Products (1)

  • Cisco Telepresence Integrator C Series

Known Affected Releases


Description (partial)

video calls using Cisco TelePresence codec fail after some time (for example 30 minutes) when using H323
When placing H323 calls between Cisco TelePresence codecs, the call may drop if there is a firewall located between the codec and the device (VCS for example) that is handling the h225 signaling.  Cisco TelePresence codecs use H245 round-trip request and response sent every 30 seconds as a keepalive.

Not all firewalls will monitor the H245 session of a H323 and this can causes issues where calls will drop after some amount of time; for example 30 minutes.

Prior to TC6, there was no TCP keepalive used for the H225 session.  Starting with TC6, a 7200 second (120 minute) TCP timer was enabled which is not configurable.
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