H323 call failures when q931 multiplexing enabled
Posted: Wed Jul 17, 2013 6:35 am
Hi,
I have seen an issue at a customer site wherein h323 calls were failing when q931 multiplexing was enabled.
Customer has two sites A & B connected via h323 trunks.
When q931 multiplexing on:
site A -----------tcp(syn)---------------> site B
<---------tcp(syn/ack)-----------
----------tcp(ack)--------------->
---------h.225 setup------------>
<--------connect-----------------
----------h.225 setup----------> (not reaching site B)
----------h.225 setup---------->
----------h.225 setup---------->
----------h.225 setup----------> (re transmission)
As you can see, when q931 mux is ON, only the first setup is responded back with connect and call is successful.The subsequent h.225 setups are not seen in the sniffer logs captured at site B !!
Site A keeps re-transmitting h.225 setups and calls started to fail.
When q931 mux is OFF, no issues are seen.
The question is:
1) why does the tcp packet go through the packet network when q931 mux is OFF?
2) Does the router check the q931 mux parameter value before routing?
3) Are there any restrictions imposed by router when we reuse the same tcp sockets(q931 mux is ON)??
Thanks
Unni
I have seen an issue at a customer site wherein h323 calls were failing when q931 multiplexing was enabled.
Customer has two sites A & B connected via h323 trunks.
When q931 multiplexing on:
site A -----------tcp(syn)---------------> site B
<---------tcp(syn/ack)-----------
----------tcp(ack)--------------->
---------h.225 setup------------>
<--------connect-----------------
----------h.225 setup----------> (not reaching site B)
----------h.225 setup---------->
----------h.225 setup---------->
----------h.225 setup----------> (re transmission)
As you can see, when q931 mux is ON, only the first setup is responded back with connect and call is successful.The subsequent h.225 setups are not seen in the sniffer logs captured at site B !!
Site A keeps re-transmitting h.225 setups and calls started to fail.
When q931 mux is OFF, no issues are seen.
The question is:
1) why does the tcp packet go through the packet network when q931 mux is OFF?
2) Does the router check the q931 mux parameter value before routing?
3) Are there any restrictions imposed by router when we reuse the same tcp sockets(q931 mux is ON)??
Thanks
Unni