Sammanfattning
There is an increasing use of distributed computer systems to provide services in both
traditional telephony as well as in the Internet. Two main technologies are Distributed
Object Computing (DOC) and Web based services.
One common DOC architecture investigated in this thesis is the Common Object
Request Broker Architecture (CORBA), specified by the Object Management Group.
CORBA applications consist of interacting software components called objects. Two
other DOC architectures investigated are the Telecommunications Information Net-
working Architecture (TINA) and a CORBA based Intelligent Network (IN/CORBA)
system. In a DOC environment, the objects of an application are distributed on mul-
tiple nodes. A middleware layer makes the distribution transparent to the application.
However, the distributed nature creates a number of potential performance problems.
Three problems in DOC systems are examined in this thesis: object distribution,
load balancing and overload protection. An object distribution describes how objects
are distributed in the network. The objective is to distribute the objects on the physical
nodes in such a way that intern-node communication overhead is as small as possible.
One way to solve the object distribution problem is to use linear programming. The
constraints for the problem are then given by both ease of management of the system
and performance concerns. Load balancing is used when there are multiple objects
that can be used at a particular time. The objective of load balancing is to distribute
the load e±ciently on the available nodes. This thesis investigates a number of de-
centralized load balancing mechanisms, including one based on the use of intelligent
agents. Finally, overload protection mechanisms for DOC systems are investigated.
While overload protection is well-researched for telecom networks, only little work has
been performed previously concerning DOC and overload protection.
Also, this thesis examines the use of overload protection in e-commerce web servers.
Two schemes are compared, one which handles admission to the e-commerce site on
request basis, and another which handles admission on session basis. The session based
mechanism is shown to be better in terms of user-experienced performance.
traditional telephony as well as in the Internet. Two main technologies are Distributed
Object Computing (DOC) and Web based services.
One common DOC architecture investigated in this thesis is the Common Object
Request Broker Architecture (CORBA), specified by the Object Management Group.
CORBA applications consist of interacting software components called objects. Two
other DOC architectures investigated are the Telecommunications Information Net-
working Architecture (TINA) and a CORBA based Intelligent Network (IN/CORBA)
system. In a DOC environment, the objects of an application are distributed on mul-
tiple nodes. A middleware layer makes the distribution transparent to the application.
However, the distributed nature creates a number of potential performance problems.
Three problems in DOC systems are examined in this thesis: object distribution,
load balancing and overload protection. An object distribution describes how objects
are distributed in the network. The objective is to distribute the objects on the physical
nodes in such a way that intern-node communication overhead is as small as possible.
One way to solve the object distribution problem is to use linear programming. The
constraints for the problem are then given by both ease of management of the system
and performance concerns. Load balancing is used when there are multiple objects
that can be used at a particular time. The objective of load balancing is to distribute
the load e±ciently on the available nodes. This thesis investigates a number of de-
centralized load balancing mechanisms, including one based on the use of intelligent
agents. Finally, overload protection mechanisms for DOC systems are investigated.
While overload protection is well-researched for telecom networks, only little work has
been performed previously concerning DOC and overload protection.
Also, this thesis examines the use of overload protection in e-commerce web servers.
Two schemes are compared, one which handles admission to the e-commerce site on
request basis, and another which handles admission on session basis. The session based
mechanism is shown to be better in terms of user-experienced performance.
| Originalspråk | engelska |
|---|---|
| Kvalifikation | Licentiat |
| Tilldelande institution |
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| Handledare |
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| Förlag | |
| Status | Published - 2002 |
Bibliografisk information
The information about affiliations in this record was updated in December 2015.The record was previously connected to the following departments: Department of Communication Systems (011020000)
Ämnesklassifikation (UKÄ)
- Kommunikationssystem