The document proposes a solution to enable context entity discovery in an Internet of Things (IoT) platform. It introduces a publish/subscribe approach using a rendezvous node as an initial publisher of a global Universal Context Identifier (UCI). Entities subscribe to this by default. Two new messages, joinUCI and DISCOVER, are added to the Distributed Context eXchange Protocol (DCXP) to allow entities to join and discover existing UCIs. Evaluation shows the extended DCXP achieves context entity discovery on par with the original protocol but can scale to larger networks.

1. Hasibur Rahman, PhLic
Enabling Distributed Context Entity Discovery for an
Internet-of-Things Platform
SAI Intelligent Systems Conference 2015
10-11 November 2015 | London UK

2. Introduction
• Everyday Things get connected
• Connected Things > human. Today, the ratio is 1.5:1
• Hundreds of billions by 2020
• Not limited to the scale of Connected Things only but also expands in its scope
• Leads to Internet of Everything (IoE)

3. Background
• The challenges surrounding IoT have so far focused on creating architectures, protocols
• In view of this, earlier researches have created MediaSense architecture which was implemented by
extending the Distributed Context eXchange Protocol (DCXP)
• MesiaSense allows to create context-aware applications with IoT and real-time sharing of Context
Information (CI)
• DCXP provides primitive messages to enable real-time communication between entities to share CI
• DCXP registers each entity as Universal Context Identifier (UCI) and other entity resolves the UCI to fetch
the corresponding CI

4. DCXP primitive messages
Message Description
REGISTER_UCI
This message is used to register a particular UCI that
holds context information in an entity
RESOLVE_UCI
This message needs to be invoked to fetch context
information associated with the UCI
GET
Once the UCI is resolved at an entity, this message is used
to get the context information
SUBSCRIBE
This enables an entity to subscribe to a particular context
information and entity only gets updated when there is a
new value
NOTIFY
Notifies the entity subscribes to a particular context
information with the latest information

5. CI sharing over MediaSense

6. What is the problem?
Conclusion
This mandates to look into new approach to enable context entity discovery
- Entities cannot be expected to have information
- May work for small-scale network
Entity needs to know the UCI prior to resolving

7. Solution
A Publish/Subscribe based solution
Rendezvous node as initial
publisher (a global UCI)
Each node by default subscribes to
the global UCI
Two new primitive messages have
been added to DCXP, i.e. joinUCI
and DISCOVER

8. Solution contd. (2)

9. Results
Message Description
joinUCI
This new functions now combines the old
REGISTER_UCI and GET primitive funcions, and
enables context entity to join and retrieve context
information at the same time
DISCOVER
This message needs to be invoked to discover
existing UCIs and to synchronize with newly joined
entities

10. Time for joinUCI
REGISTER_UCI +
GET joinUCI
sec 0.07 0.09

11. Time for DISCOVER
UCIs 100 200
ms 293 450

12. Conclusions
• Proposed algorithms that enable successful fast discovery of context
entity
• Introduced two new primitive functions namely joinUCI and
DISCOVER
• Result of the extended DCXP is on par with the existing DCXP
protocol
• Can be extended to any p2p-based platform

13. Future work
• Enable cross-platform communication
• Enable autonomic management
• Naming scheme for DCXP

14. Credits
EU for its funding for the FP7 MobiS project
Immersive Networking Research group

15. + 46 7 07 463 968
Contact Hasibur Rahman
hasibur.rahman021
hasibur.rahman29@gmail.com
@hasiburrahman29