=Paper=
{{Paper
|id=None
|storemode=property
|title=Security Based Performance Issues in Agent-based Web Services Integrating Legacy Information Systems
|pdfUrl=https://ceur-ws.org/Vol-752/45-51ristovetal.pdf
|volume=Vol-752
|dblpUrl=https://dblp.org/rec/conf/asa/RistovT11
}}
==Security Based Performance Issues in Agent-based Web Services Integrating Legacy Information Systems==
https://ceur-ws.org/Vol-752/45-51ristovetal.pdf
PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS
ISBN 978-86-7031-188-6, pp. 45 - 51, 2011
Security Based Performance Issues in Agent-based Web
Services Integrating Legacy Information Systems
Sashko Ristov1, Aristotel Tentov2,
1
Ss. Cyril and Methodius University / Faculty of Natural Science and Mathematics -
Institute of Informatics, Gazi Baba BB,
1000 Skopje, Macedonia
sasko@ii.edu.mk
2
Ss. Cyril and Methodius University / Faculty of Electrical Engineering and Information
Technologies, Rugjer Boshkovik bb, PO Box 574,
1000 Skopje, Macedonia
toto@feit.ukim.edu.mk
Abstract. Many closed internal information systems (IS) must not concern
much about its security. But, nowadays, mostly due to globalization and
dynamic world, business demands integration of several legacy ISs into new
one. The new IS must improve its security compared to legacy ISs, because
they work in the heterogeneous environment, and need to be opened. Adding
security will decrease the new IS performance, but business wants to retain or
even improve it. In this paper, we simulate this issue and we create a baseline of
performance data that can be used to predict IS response time, for various
numbers of requests, request size and implementing security as a necessary
issue for new distributed IS.
Keywords: Software agents, wrapper, web services, legacy software,
performance, security
1 Introduction
Nowadays, there are many cases where companies’ ISs, often developed using
different technologies and on different platforms, need to communicate each other.
Even more, many companies buy or merge with others, which lead in merging two
independently developed ISs, probably with totally different structure. As a solution
concept, [15] offers three basic approaches, shown on Fig. 1. The first one,
introducing the transducer, accepts messages from the requester, translates them into
the program's native language and protocol, and passes to legacy IS. The second one,
introducing the wrapper, can “inject” code into legacy IS to allow it to communicate
with the requester. The third solution that is, rewriting is out of scope of this paper.
Many papers propose agent based web services as a solution for this issue, as a
platform independent and XML as most obvious format that meets this requirement.
In most of cases, legacies ISs are often isolated and closed to outside environment,
and do not concern much about security. However, the new IS must improve better
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PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS, 2011
security compared to legacy ISs, because legacy ISs are often on a different locations
and new IS will work in the heterogeneous environment, wide-opened to hackers.
Fig. 1. Three approaches to agentification, Transducer, Wrapper, Rewrite
In order to secure the new ISs, has to be achieved message confidentiality, data
integrity, authentication, authorization, non-repudiation, service availability, and web
service identification. For web services, XML Encryption [10] and XML Signature
[9] are considered as a de facto standard to provide a message security model. Their
implementation secures the new IS, but outcomes with the message overhead, as well
as requires complex cryptographic operations for each message or some parts of it.
Thus, it reduces the new IS performance. It is expected that the new IS will have more
users than legacy, which also impacts negative to its performance.
In this paper, we analyze the response time overhead of the signed and encrypted
messages through experimental approach, as well as the response time overhead of
increasing message size for the same message type. In Section 2, we show the results
of the experiments and analyze the dependency of the new IS response time for a
various number of requests. Next, in Section 3, we analyze the results of the
experiments in order to gain the response time ratio implementing signature and
encryption compared to legacy IS messages, and implementing encryption compared
to signed only messages.
1.1 Related Work
We find many articles discussing about agent-based web services. [1] presents an
agent-based web services evolution approach, which is well suited to building
software solutions for pervasive computing. [3] describes how web services will
become more agent-like and how the resultant agent-based web services will yield
unprecedented levels of software robustness. In [13] is presented an integration of
mobile agent and the web services technology and new security architecture for such
integration. In [14] the authors propose an agent-based Web services architecture and
apply to augment manufacturability to increase the efficiency of the distributed
collaboration. [4] presents some agent-based and context-oriented approach for Web
services composition. A gateway architecture for connecting software agents and Web
services in a transparent manner with fully automatic operation is shown in [5]. [6]
describes a possible solution for pro-active Web services selection and composition.
In [7] is introduced an architecture which seamlessly connects mobile agents with
web services in a transparent and fully automated manner by means of a specialized
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PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS, 2011
Web Service Engine. [8] shows how agent technology can be used to personalize web
services and to work together.
One of the most near article is [11], where authors define major features and
benefits of the agent-based approach to enhance a Legacy Information System. Also,
[12] discuss how to re-engineer legacy systems into agent-based Web services and
focuses on the fact that agent-based Web services are well suited to building software
solutions for distributed, open and dynamic web-based systems.
Only in [2], authors compare two transducer-based approaches to wrapping legacy
software, introducing that web services make less overhead of the messages
comparing software agents.
None of the related work analyzed the performance impact of the agent-based web
services, nor implementing different security-level mechanisms, using different
message size and concurrent requests.
This paper describes a series of experiments focused on understanding the
performance impact of message overhead, as well as increased number of requests, in
simulated wrapped legacy IS. We create a baseline of performance data that can be
used to predict new IS response time. That is, the number of concurrent requests can
be predicted, as well as the message sizes, because the new IS system information has
equally size to the legacy and the number of requesters can be predicted as a sum of
all users in the legacy systems.
1.2 Testing Environment
We create three test environments, (1) using unsecured messages, (2) signed messages
and (3) both signed and encrypted messages, on Windows platform. We simulate a
situation where two parameters (let’s say Street and City) in legacy IS are only one
parameter (let’s say Address) in the new IS. Thus, the wrapper receives and returns
equally sized messages. In each test case, we change the message size and the number
of concurrent requests, but in the range of normal workload.
2 Results and Analysis for Increasing Number of Requests
This section describes the results of the performed tests to measure the response time
dependency of the message size and a given number of requests, for the same
message type. On Fig. 2 is shown the response time in milliseconds (Y axis), for a
given number of requests in second and message type, for a different message size in
kilobytes (X axis).
2.1 Response Time Overhead for no Security
First, we perform a performance baseline, that is, we analyze the response time
without security for different payload of 1, 10 and 100 messages per second for
different message size. As shown on Fig. 2, the results are very strange. Namely, for
small sized messages, the system has better performance when loaded with 10 or 100
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PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS, 2011
messages per second, and for bigger messages (over 30K), the system performance is
as expected, that is, higher response time for a huge payload and bigger messages.
2.2 Response Time Overhead for Signed Messages
Next, when we implemented signature into messages, we analyze the response time
for different payload of 1, 10 and 100 messages per second. As shown on Fig. 2, the
results are a little strange. Namely, for small sized messages (smaller than 35K), the
system has better performance when loaded with 10, instead of loaded with 1. For a
100 messages per second, the system performance is as expected, that is, higher
response time for a huge payload and bigger messages.
2.3 Response Time Overhead for Signed and Encrypted Messages
Next, we implemented the encryption, besides signature, and payload the system with
1, 10 and 100 messages per second. As shown on Fig. 2, the results are similar as
signed only messages. Namely, for small sized messages (smaller than 25K), the
system has better performance when loaded with 10, instead of loaded with 1. For a
100 messages per second, the system performance is as expected.
Fig. 2. Response time in ms for a given number of requests in a second and message type,
depending of message size
3 Results and Analysis for Different Message Security Type
This section describes the results of the performed tests to measure the response time
overhead of the security implementation, for a given number of requests and various
message size. On Fig. 3 is shown the response time ratio (Y axis) of implementing
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PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS, 2011
signature and both signature and encryption to the unsigned messages, for a given
number of requests, and different message size in kilobytes (X axis).
Fig. 3. Response time overhead (ratio) for implementing security for a given number of
requests, depending of message size
3.1 Response Time Overhead Implementing Security
We analyze the response time overhead implementing signature to the different sized
messages, compared to the same unsigned message for different payload of 1, 10 and
100 messages per second. As shown on Fig. 3, adding signature increases the
response time ratio constantly, near linear, growing slowly when increasing message
size, but only for a small number of requests, because for a huge number (100), the
baseline payload (without security) has huge response time (shown on Fig. 2).
Implementing both signature and encryption creates similar overhead to the no
security messages.
3.2 Response Time Overhead Adding Encryption
At the end, we analyze the response time overhead adding encryption to the signature
for different sized messages, compared to the same signed only message for different
payload of 1, 10 and 100 messages per second. On Y axis on Fig. 4 is shown the
response time ratio, and X axis is original message size.
We can conclude that adding encryption to the signature increases the response
time ratio constantly, near linear, but only for a message size above 10K, growing
slowly when increasing message size. The reason that the ratio decreases at the range
of a huge messages and especially huge number of requests is because in that range,
the baseline, that is the signed messages only response time, is huge. With other
words, the IS has a low performance for that payload.
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PROCEEDINGS OF THE WORKSHOP ON APPLICATIONS OF SOFTWARE AGENTS, 2011
Fig. 4. Response time overhead (ratio) for adding encryption to the signature
4 Conclusion
In this paper we have done security based performance analysis and comparison
simulating a small part of new IS, which operates as a wrapper to the legacy IS. We
analyze the performance parameter “response time”, as well as its overhead
increasing “message size”, “number of messages”, and implementing different
security-level mechanisms.
We believe that these result can be considered as a baseline and with these
analysis, IT quality managers can predict response time for a new IS, knowing
number and size of concurrent messages, in order to retain the new system secured, as
the legacy.
5 Future Work
In this paper we analyzed the decreasing the performance to the new IS,
implementing security, increasing “message size”, “number of messages”, and
implementing different security-level mechanisms. But, for the business managers,
the most important issue is customer satisfaction, which is the most connected to the
performance issue, or response time.
Therefore, our future work will be oriented on necessary hardware improvements
to the new IS, to retain the same performance, such as the legacy system, for the same
payload, but with implemented signature and encryption. Also, the operating system
platform must be analyzed.
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