This document presents a QoS-enabled architecture for efficient web services. It introduces a QoS broker module between service clients and providers to minimize resource wastage and analyze QoS evaluation. The key components are web servers, web services, and QoS attributes like availability, accuracy, reliability, security, latency, and jitter. The QCWS architecture includes servers that provide functionality and QoS information, a QoS broker that handles negotiation and analysis, and clients that request services. The broker aims to optimize system performance while reducing instability through homogeneous and non-homogeneous resource allocation algorithms.

1. QoS Enabled Architecture For
Efficient Web Service
Presented by:
A.S.M.Mannaf Rahman.
Roll: 988185

2. Executive Summary
This project is concerned with quality attributes for
Web Services
Web Services are in great demand. They can be
described, published and located over the World Wide
Web.
 In this project, We will try to present a QoS-capable
Web service architecture, QCWS, by introducing a QoS
broker module between service clients and providers.

3. Objective
Through out the presented project, We have tried to
accomplish the following objectives:
To Analyze QoS Evaluation of Web Service.
To Minimize the Resource Wastage of Web Service.
To Get the Better Idea about the Recent Development
in the field of Web Base QoS.

4. Key Components
 Web Server
The term web server can refer to either
the hardware (the computer) or the
software(the computer application) that helps
to deliver web content that can be accessed
through the Internet.

5. Key Components
Web Service
Web Services can convert your applications into
Web-applications. It is published, found, and used
through the Web.
Web services are application components.
Web services communicate using open protocols
Web services can be discovered using UDDI

6. Key Components
QoS
• Availability
– Ready for immediate consumption
– Probability the system is up (related to reliability)
– Time-to-Repair is associated with availability: the
time it takes to repair the WS

7. Key Components
QoS
• Accuracy
– The error rate generated by the WS. The number of
errors that the service generates over a time
interval should be minimized
• Reliability
– The percentage of packets discarded by a router.

8. Key Components
QoS
• Security
• Latency
-The delay in data transmission from source to
destination.
• Jitter
-The variation in latency.

9. Related Works
• A lot of research activities have been done in
the area of how to realize the QoS support in
Web services.
• Focus on extending UDDI registry to support
QoS information (Ran, S., 2009; Shaikhali, et
al.,2009).
• UDDIe project (Shaikhali, et al., 2011)extends
the current UDDI registry by
adding“bluepages”.

10. QCWS
Three Entities of QCWS :
 Server
 QoS Broker
 Clients

11. QCWS Architecture

12. Server
• Provide Functionalities information to Broker.
• Provide QoS Information about its services

13. Server Contents
 QoS Information.
Qos Admission And Enforcement.
Web Services.

14. Service oriented Server
The first class not build with QoS supports,
referred as Legacy Server. Here Clients are
treated equally and scheduled using native
schedulers in the OS.
Other class of servers build with QoS support
and called QoS server. They have the ability to
assign different amount of system resources to
different clients according to their QoS
requirements.

15. QoS Broker
A QoS broker receives clients’ functional &
QoS requirement requests and identifies
qualified services for them.

16. QoS Broker Contents
QoS Information Manager.
QoS Negotiation Manager.
QoS Analyzer.

17. QoS Broker

18. Clients
As the end users of Web services, Clients send
their service request and QoS requirements to
a broker and ask the broker to select a server
for them.
Clients also collect the QoS result information
after each service call and send them to the
broker.

19. Function of QCWS
The QoS broker module collects the QoS
information about service providers (servers).
Makes service selection decisions for clients.
and
 Negotiates with some of the servers to meet
the QoS requirements.

20. Resource Allocation(HQ)
Set the allocation policy: (K: current number of
clients)
• · If K ≤ A1, the resources allocated to each
client = R/ A1;
• · If Ai ≤ K ≤ Ai+1(1 ≤ i < m), the resources
allocated to each client = R/Ai+1;
• · If K ≥ Am, allocated resource =R/K.

21. Homogeneous Resource Allocation
Algorithm HQ
There are several terms we define in this project:
· Total System Utility (Ug(t)): Summation of all active (currently
receiving services) clients’ utility at time t;
· Average System Utility (Uavg): The integral of the instantaneous
total system utility with respect to time divided by the time period
through which it is measured;
· Reconfiguration: Reconfiguration means resources are reallocated
among existing clients and the incoming client;
· Reconfiguration Rate: The total number of reconfigurations divided
by the time through which it is measured

22. Algorithm HQ
The system performance is measured by
Uavg and the QoS instability is measured by
the reconfiguration rate. The goal of the
resource allocation algorithm is to optimize the
system performance while reducing the QoS
instability.

23. Non-homogeneous Resource
Allocation RQ
The algorithm RQ has the following parameters:
· W: weight of the virtual client;
· Nr: number of clients to be reconfigured during
a reconfiguration;
· Uc(r): client’s utility function;
· Uvc(r): virtual client’s utility function;

24. Example for Resource allocation

25. Allocation RQ
The rules for selecting Nr clients for reconfiguration are:
• a. Choose clients that are receiving resources more than
their minimum resource requirements;
• b. Choose clients that have the biggest differences
between their minimum resource requirements and
currently assigned resources;
• c. If the result of reconfiguration will cause a client to
drop below the minimum service level it should
receive, remove it from Nr list.
• b. Repeat this step until an available allocation is found.

26. Conclusion
• All of the approaches proposed in this project
are aiming at improving QoS management of
Web services.
• We discussed about QoS evaluation.
• The remaining part introduces resource
allocation algorithm for better QoS capable web
services.

27. Thank You