The effectiveness of data communication system depends on four fundamental characteristics:
1. Delivery: the system must deliver data to correct destination. Data must be received by the intended device or user.
2. Accuracy: The system must deliver the data accurately. Data that have been altered in transmission and left uncorrected are unusable.
3. Timeliness: the system must deliver data in a timely manner. Data delivered late are useless.
4. Jitter: jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of packets.