Failover while SIP connection established

Hi All,

 

 

I have 2 F5 BIG-IP configured as active-standby with HA between 2 machines, which connected to the ViG and our servers. We then setup a SIP call (VIG sent invite to F5, then F5 pass the message to server) and tried to perform failover between 2 BIG-IP after the call is succesfully established. After failover, The SIP connection(video streaming) is maintained , but however it is very unstable and the call may be disconnect. The unstable state of the connection is due to server received many unexpected signals from ViG.

 

 

After capture trace of the whole path, the root cause is due to F5 did not pass the information from server to ViG after failover.

 

 

Here is a normal signal flow after the call is established. When we press any button on our phone, ViG will send the message directly to the server, and then server will reply acknowledge to ViG through F5.

 

 

Signal Flow:

 

VIG -> Server (Request)

 

Server -> F5 -> ViG (Acknowledge)

 

 

The current situation:

 

ViG sent Information request to server, and server tried to reply 200 ok to VIG throught F5, however F5 did not send out the signal, ViG therefore cannot receive the acknowledge signal and resend the message again until reply is received. So many unexpect signal is received from server. We have verified the server has sent out acknowledge message to F5. And the problem did not happen before failover.

 

 

I encountered similiar problem on single F5 before, the case happened when we press any button after idle for more than one minutes since the call is established. The problem is solved after increased the idle time in the udp profile, would this case related to the setting of udp profile again?