Analysis and Improvements of Eventing Protocol for Universal Plug and Play Author: Yarema Mazuryk 1,

1
Analysis and Improvements of Eventing Protocol
for Universal Plug and PlayAuthor Yarema
Mazuryk 1, Co-author Johan Lukkien 1
1. Introduction

• 3. Proposed Solutions
• Modify GENA subscription mechanisms
• Decouple events from state variables
• Transmit event-specific data along with the
  notification
• Use UDP-based transport

UPnP is a growing interoperability standard,
which allows networked devices to cooperate in an
autonomous fashion by using functionality found
on the network.
4. Improved Eventing Protocol for UPnP
GENA

• Requirements to MDP
• GENA based protocol to minimize and localize
  changes in UPnP API

GENA
The key components in UPnP are devices, services,
and control points.
HTTP
MDP
SSDP advertise1
UPnP Device
TCP
TCP
SSDP search1
SSDP response2
UPnP Control Point
SOAP action request2

• Mechanisms for coupling request response pairs
  provided by the protocol
• Deals with faulty nature of UDP - resilient
  against duplicated and out-of-order messages (see
  figure)

SOAP response2
GENA subscription request2
GENA event notifcation2
1- multicast UDP messages 2- TCP messages
Example of the UPnP system
2. UPnP Evaluation
In this work we evaluated UPnP as a platform for
data-centric applications in terms of usability
and performance. To identify the weak points of
UPnP a simple file sharing service was
implemented.
MDP state machine
5. Performance Comparison
The figure compares event notification delivery
delay for traditional and improved UPnP
implementations.

• Usability evaluation
• UPnP is a control architecture, and therefore
  doesnt suit well for data-centric applications
• Only blocking actions calls are possible
• Action arguments are bound to service state
  variables
• Data types are limited to simple types
• Events can only be signals about changes of state
  variables
• Clients cannot subscribe to individual events

• Measurements conditions
• Clocks at the machines are synchronized
• Service exposes 4 events, which are generated
  with different frequencies

• 6. Conclusions
• UPnP is not suitable for the development of the
  data-centered services, which can be accessed by
  multiple clients simultaneously
• Decoupling events from service state variables
  and transferring event-specific data along with
  the event notification strengthen expressive
  power of UPnP
• Changing transport solution from TCP-based to
  UDP-based one significantly improves the
  performance of UPnP eventing mechanisms

• Performance evaluation
• TCP transport results in significant overhead for
  every event notification
• High mobility of devices may result in the
  situations when notifications have to be
  delivered to unavailable subscribers resulting
  in excessive TCP timeouts

About the Author Yarema Mazuryk received his
M.Sc. in Computer Science from the Department of
Computer Science and Engineering of National
Technical University in Lviv, Ukraine. In 2003
Yarema started as a researcher project within the
SAN group of Computer Science Department, TU/e.

• Affiliation
• 1) Eindhoven University of Technology
• Department of Mathematics and Computer Science
• HG 6.57, P.O. Box 513, NL-5600 MB, Eindhoven, The
  Netherlands