Interoperability:
Making devices talk to each other
CSE481M: Home Networking Capstone
April 13th, 2011
Devices on an island
Need a language in common if they want to talk to each other
More devices on an island
Standardized languages reduce the number of languages each
device needs to know
Designing a language (standard)
A big challenge: making it future proof
• New devices and functionality will emerge
How to design a future-proof language?
Define the basics that everyone understands
Implement extension dialects
• DLNA, Z-Wave, ZigBee, …
What is the Speakeasy approach?
Can there be one universal language?
Has not happened so far ….
Unlikely: different concerns and capabilities
Interpretation
Allows devices that speak different languages to talk
• Without requiring them to learn new languages
Another dimension of being future proof
Being able to talk to devices with new languages
Enabling interpretation in practice
Ship interpreters with the system
Acquire dynamically
• From the cloud (as in Windows)
• From the device (as in Speakeasy)
•
Successful model?
Bootstrapping problem
• Discovering devices
• Establishing some common basis
Systems perspective:
The ability to talk is not enough
Restricting communication
Simultaneous (conflicting) talking
Need equivalents of social rules
Implementing communication rules
Closed systems (monolithic)
• Easy to implement the first time
but difficult to extend
Extensible systems
• Need rule specification and
enforcement mechanisms
The ugly truths of designing standards
Technical fights
•
E.g., how many bytes for device type?
Non-technical fights
•
To give edge to your company
•
•
Example: Stories of Cisco filling IETF rooms
Just coz
•
Example: point vs. comma in ALGOL
=> Long drawn out process
•
•
Compromises can render the final product unusable
ZigBee  Z-Wave
The hard facts of adopting standards
Each company makes a selfish decision
•
Even if involved in the standardization process
Chicken-and-egg problem
•
Little first-mover advantage
Testing is hard
 Major teething issues
•
Most never take off