SIP and IPS
You can enable IPS in security policies that also accept SIP sessions to protect the SIP traffic from SIP-based attacks. If you enable IPS in this way then by default the pinholes that the SIP ALG creates to allow RTP and RTCP to flow through the firewall will also have IPS enabled.
This inheritance of the IPS setting can cause performance problems if the RTP traffic volume is high since IPS checking may reduce performance in some cases. Also if you are using network processor (NP) interfaces to accelerate VoIP performance, when IPS is enabled for the pinhole traffic is diverted to the IPS and as a result is not accelerated by the network processors.
You can use the following CLI command to disable IPS for the RTP pinhole traffic.
config voip profile
set ips-rtp disable