Mesh networking is a powerful way to route data over an RF network. Range is extended by allowing data to hop node to node and reliability and resiliency is increased by “self-healing,” or the ability to create alternate paths when one node fails or a connection is lost.
One popular mesh networking protocol is ZigBee®, which is specifically designed for low-data rate, low-power applications. Digi offers several products based on the ZigBee protocol. Additionally, Digi has developed a similar mesh protocol named DigiMesh®. Both ZigBee and DigiMesh offer unique advantages important to different applications. The following chart highlights these differences:
|Node types and their benefits||Multiple: Coordinators, Routers, End Devices. End devices can sometimes be less expensive because of reduced functionality.||Single: One homogeneous node type, with more flexibility to expand the network. DigiMesh simplifies network setup and reliability in
environments where routers may come and go due to interference or damage.
|Battery Deployed Networks||Coordinators and routers must be mains powered||All nodes are capable of battery operation and can sleep. No single point of failure associated with relying on a gateway or coordinator to
maintain time synchronization.
|Over-the-air firmware updates||Yes||Yes|
|Range||Most ZigBee devices have range of less than 2 miles (3.2 km) for each hop.||Available on XBee SX with range of up to 40+ miles for each hop.|
|Frame payload and throughput||Up to 80 bytes.||Up to 256 bytes, depending on product. Improves throughput for applications that send larger blocks of data.|
|Supported frequencies and RF data rates||Predominantly 2.4 GHz (250 kbps)||900 MHz (Up to 250 Kbps), 2.4 GHz (Up to 250 Kbps)|
|Security||128-bit AES encryption. Can lock down the network and prevent other nodes from joining.||Both 128 and 256-bit AES encryption. Can lock down the network and prevent other nodes from joining.|
|Interoperability||Potential for interoperability between vendors.||Digi proprietary|
|Interference tolerance||Direct-Sequence Spread Spectrum (DSSS).||900 MHz: Frequency-Hopping Spread Spectrum (FHSS). 2.4GHz: Direct-Sequence Spread Spectrum (DSSS).|
|Addressing||Two layers. MAC address (64 bit) and Network address (16 bit).||MAC address (64 bit) only.|
|Maintenance||More sniffers and diagnostic tools available on market.||Simpler addressing can help in diagnosing problems and setting up a network.|
For more information on DigiMesh and Digi XBee click here.