ZigBee is a low power short range wireless networking system. It is primarily used for smart metering and sensor network applications. Strengths: Low cost, low power. Limitations: Few commercially available general purpose components (most embedded in other products), Only suitable for local manual RSU programming using a localized device, Not a true remote backhaul, Requires development of secure system access system to prevent unwanted RSU tampering, May require external antenna. Lifetime 5-10 years