The other problems are due to jitter and packet loss.

• Jitter arises due to the non-uniform delay in the packets received at each end. If all the packets are received with the same delay, it is fine, otherwise, the variable delay causes unbearable gaps in the speech. One technique followed is to drop the packets, which are unduly delayed. The variable transmission delay is the cause of this problem.
• In voice over IP networks, the packets may not be received in sequence and also there should not be variable delay. For example, in ATM networks there will be ATM adaptation layer in which if the packets are not received with the same delay, some packets are dropped so that there will be no gap in the speech.