Siena (Scalable Internet Event Notification Architectures) is a research project aimed at
  designing and constructing a generic scalable publish/subscribe event-notification service.
  The technical basis of Siena is an innovative type of network service called content-based networking.

Overview
The asynchrony, heterogeneity, and inherent loose coupling that characterize applications in a wide-area
 network promote event interaction as a natural design abstraction for a growing class of software systems.
  An emerging building block for such systems is an infrastructure called publish/subscribe event notification
  service.

Software systems of a significant dimension, especially those that are distributed over a computer network,
are often engineered by means of the integration of components. A promising approach to support component-based
software architectures is the so-called event-based style whereby the interaction of components is modeled with
events. Components emit events to inform other components of a change in their internal state or to request services
from other components. Upon detecting the occurrence of events, components react by executing some actions and possibly
 emitting other events. The glue that ties components together in an event-based architecture is an infrastructure that
  we call event service. The event service registers the interests of components and then dispatches event notifications
   accordingly. The advantage of using an event service instead of other "classical" integration mechanisms
   such as direct or remote invocation is that this method increases the degree of de-coupling among components
   thus eliminating static dependencies and improving interoperability.

We envision a ubiquitous event notification service accessible from every site on a wide-area network and suitable
for supporting highly distributed applications requiring component interactions ranging in granularity from fine to
 coarse. Conceptually, the service is implemented as a network of servers that provide access points to clients. Clients
  use the access points to advertise the information about events that they generate and to publish notifications
   containing that information. They also use the access points to subscribe for notifications of interest.
   The service uses the access points to then notify clients by delivering any notifications of interest. Clearly, an
    event notification service complements other general-purpose middleware services, such as point-to-point and multicast
    communication mechanisms, by offering a many-to-many communication and integration facility.

Given that the primary purpose of an event notification service is to support notification selection and delivery,
 the challenge we face in a wide-area setting is maximizing expressiveness in the selection mechanism without sacrificing
  scalability in the delivery mechanism. Expressiveness refers to the ability of the event notification service to provide
   a powerful data model with which to capture information about events, to express filters and patterns on notifications
    of interest, and to use that data model as the basis for optimizing notification delivery. In terms of scalability,
     we are referring not simply to the number of event generators, the number of event notifications, and the number
     of notification recipients, but also to the need to discard many of the assumptions made for local-area networks,
      such as low latency, abundant bandwidth, homogeneous platforms, continuous and reliable connectivity, and
      centralized control.


Intuitively, a simple event notification service that provides no selection mechanism can be reduced to a multicast
routing and transport mechanism for which there are numerous scalable implementations. However, once the service provides
 a selection mechanism, then the overall efficiency of the service and its routing of notifications are affected by the
 power of the language used to construct notifications and to express filters and patterns. As the power of the language
  increases, so does the complexity of the processing. Thus, in practice, scalability and expressiveness are two
   conflicting goals that must be traded off.

Siena is an event notification service that we have designed and implemented to maximize both expressiveness and
scalability. A prototype implementation of Siena is available.
People
Siena is primarily the work of Antonio Carzaniga and Alexander L. Wolf. D.S. Rosenblum also made significant
contributions to the initial design of Siena.

Others also contributed directly to the development of Siena. Among them are John Giacomoni, Mauro Caporuscio,
Matthew J. Rutherford, Cyrus P. Hall, Yanyan Wang, Giovanni Toffetti, and Amir Malekpour.
Documents
Articles are available in Portable Document Format (PDF) or PostScript® format and some of them are compressed
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Selected Papers

    Design and Evaluation of a Wide-Area Event Notification Service
    A. Carzaniga, D.S. Rosenblum, and A.L. Wolf
    ACM Transactions on Computer Systems, 19(3):332-383, August 2001.
    Abstract, BibTeX ref., PDF, DOI
    End-to-End Reliability for Best-Effort Content-Based Publish/Subscribe Networks
    A. Malekpour, A. Carzaniga, F. Pedone, and G. Toffetti Carughi
    In Proceedings of the 5th ACM International Conference on Distributed Event-Based Systems (DEBS 2011). New York, New York, July 2011.
    Abstract, BibTeX ref., PDF, DOI
    A Routing Scheme for Content-Based Networking
    A. Carzaniga, M.J. Rutherford, and A.L. Wolf
    Proceedings of IEEE INFOCOM 2004. Hong Kong, China. March 2004.
    Abstract, BibTeX ref., PDF, DOI
    Forwarding in a Content-Based Network
    A. Carzaniga and A.L. Wolf
    Proceedings of ACM SIGCOMM 2003. p. 163-174. Karlsruhe, Germany. August 2003.
    Abstract, BibTeX ref., PDF, DOI
    Design and Evaluation of a Support Service for Mobile, Wireless Publish/Subscribe Applications
    M. Caporuscio, A. Carzaniga, and A.L. Wolf
    IEEE Transactions on Software Engineering, 29(12):1059-1071, December 2003.
    Abstract, BibTeX ref., PDF, DOI
    Content-based Networking: A New Communication Infrastructure
    A. Carzaniga and A.L. Wolf
    In NSF Workshop on an Infrastructure for Mobile and Wireless Systems. Lecture Notes in Computer Science n. 2538 p. 59-68. Springer-Verlag. Scottsdale, Arizona. October 2001.
    Abstract, BibTeX ref., PDF
    Achieving Expressiveness and Scalability in an Internet-Scale Event Notification Service
    A. Carzaniga, D.S. Rosenblum, and A.L. Wolf
    Nineteenth ACM Symposium on Principles of Distributed Computing (PODC2000). Portland, Oregon, July 2000.
    Abstract, BibTeX ref., PDF, DOI
    Content-Based Addressing and Routing: A General Model and its Application
    A. Carzaniga, D.S. Rosenblum, and A.L. Wolf
    Technical Report CU-CS-902-00, Department of Computer Science, University of Colorado, January 2000.
    Abstract, BibTeX ref., PDF
    Architectures for an Event Notification Service Scalable to Wide-area Networks
    A. Carzaniga
    PhD Thesis. Politecnico di Milano. December, 1998.
    Abstract, BibTeX ref., PDF
    A Design Framework for Internet-Scale Event Observation and Notification
    D.S. Rosenblum and A.L. Wolf
    6th European Software Engineering Conference. Lecture Notes in Computer Science 1301, Springer, Berlin, 1997.

Acknowledgments
This work was supported in part by the Air Force Materiel Command, Rome Laboratory, and the Defense Advanced
Research Projects Agency under Contract Numbers F30602-94-C-0253, F30602-97-2-0021, F30602-98-2-0163,
and F30602-99-C-0174; by the Air Force Office of Scientific Research, Air Force Materiel Command, USAF, u
nder grant number F49620-98-1-0061; and by the National Science Foundation under Grant Number CCR-9701973.
The content of the information does not necessarily reflect the position or the policy of the US Governmen
t and no official endorsement should be inferred.

We thank Dennis Heimbigner, Richard S. Hall, and André van der Hoek of the Software Engineering Research Laboratory,
University of Colorado at Boulder (circa 1997), and Giampaolo Cugola, Elisabetta Di Nitto, and Alfonso Fuggetta of
 Politecnico di Milano for their contributions to this work.
this page is maintained by Antonio Carzaniga and was updated on September 15, 2019