We have an h323 intercluster trunk between a 4.2(3) cluster - Belgium - and a 6.1 cluster - USA.
Since last week we suddenly experience calls failing between certain times. During the day, there is no problem... calls are setup ok, voice quality is ok.
Starting 17h30 no call can come through from the 6.1 to the 4.2(3) ... this lasts till 7u30 in the morning. Calls from the 4.2(3) towards the 6.1 keep working.
In the tracing we get the message ' h323hostcall > 59283 [RST] Seq=1 Win=0 Len=0 ' where for calls that do go though we get an [ACK] followed by callProceeding.
Does anyone have an idea what this could be ? I couldn't find any scheduled tasks ... no SQL jobs ... no timeschedules in CCM that start at 17h30 .
Maybe worth noting : We recently changes firewalls from CheckPoint to Cisco ASA about the same time this started.