What is the difference between IoTivity vs AllJoyn  

AllJoyn provides the following components:

• App Code
• Service Frameworks Libraries
• Core Library
• Router

It also provides the Thin variant without the Router.

Protocols:

• IoTivity will be using multiple protocols, but for now it uses CoAP. IT also has a MQTT plugin.
• AllJoyn provides its own bus based on D-Bus Wire protocol. AllJoyn Gateway Agent will have connectors for REST, MQTT, XMPP and TR-069.

IoTivity currently supports:

• Android
• Arduino
• darwin/iOS
• Linux
• Tizen
• Windows
• Yocto

AllJoyn currently supports:

• Android
• Arduino
• iOS
• Linux
• OS X
• Windows