Download Use Case Description

CmpE 232 – Component-Based and
Reuse-Oriented SW Engineering
Practice Problem (4)
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This problem statement was developed by
Group name : NIDS Team
Team members: Asha Girija, Deepa Rao, Prathibha Gowda
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Part 1: Component-Based Software Development
Answer the following questions:
(1) Document all of the Use Cases in Your Problem:
(a) Identify two of the use cases
(b) Identify Actors and their roles
(c) Identify corresponding classes
(d) Describe the Use Case
Repeat the process for at least two of the use cases.
Use the following Use Case Template to document your Use Cases
All the fields must be filled for each use case.
1. Use Case Id.
2. Use Case Title
3. Actors & Corresponding Roles
4. Classes
5. Corresponding Attributes
6. Corresponding Interfaces (services or operations)
7. Use Case Description – Feel free to use pre- and post-conditions where
appropriate.
8. Alternatives
(2) Create CRC cards for the existing classes.
(CRC stands for Class Responsibility and Collaborations)
(3) Prepare traditional models for this problem showing at least 10 relationships among
the object classes in this problem, including associations, aggregations, and
generalizations. Show multiplicities in your diagrams. You must name attributes and
operations for each class. Use association and role names when needed.
(4) Create Sequence diagrams. Sequence diagrams will be used to "realize" Use Cases.
All Use cases should be described through sequence diagrams. The sequence diagrams
can describe the same Use Cases that a flow of events was created for in the Use Case
portion of the assignment.
(5) Create Components diagrams for as many components in your project as you wish, and
show all the interfaces, usage dependencies, ports, and connectors. Document the component
diagrams. Address implementation issues that are related to these component diagrams if any.
Please submit your answer electronically as MS word documents before the next
lecture. – Feel free to submit all diagrams in Rational Rose or Visio formats
Part 2: Stable Pattern-Based Software Development
(1) Use Cases. Update #1. Document all use case templates with software stability in mind.
Use the following template to document your use cases.
1. Use Case Id.
2. Use Case Title
3. Actors & Corresponding Roles
4. Classes
1. Corresponding Attributes
2. Corresponding Interfaces
3. Class Classification: EBTs, BOs, IOs
4. Use Case Description
6. Alternatives
(2) Create or/and update all the CRC cards for all the (EBTs, BOs, Roles) in your
stability model of your team project (CRC stands for Class Responsibility and
Collaborations).
(3) Class diagram (Stability Model). Create a new Class diagram of your team problem
based on the EBTs, BOs, and IOs – Describe your stability model. Class descriptions
should include all attributes and methods for the class. All class relationships
(associations, aggregations, dependencies, and specializations) should be included in the
class diagram. association classes, interface classes, constraints, interfaces, tagged values
and/or stereotypes, and notes must be included in the class diagram.
(4) Sequence diagrams. Create Sequence diagrams with stability in mind that will be
used to "realize" Use Cases. All Use cases should be described through sequence
diagrams. The sequence diagrams can describe the same Use Cases that a flow of events
was created for in the Use Case portion of the assignment.
(5) Create Components (or Stable Patterns) diagrams based on Software Stability for as
many components (Patterns) in your project as you wish, and show all the interfaces, usage
dependencies, ports, and connectors. Document the component (stable pattern) diagrams.
Address implementation issues that are related to these component diagrams if any.
Please submit your answer electronically as MS word documents before the next
lecture. – Feel free to submit all diagrams in Rational Rose or Visio formats
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Network Intrusion Detection System
Abstract
The system detects any intrusion in the network by constantly monitoring the network
traffic. Network intrusion is a method in which a person exploits the software features
and bugs to gain unauthorized access to the system. In the extreme case, he/she may
access well-known ports and services to infect the system with viruses and worms
bringing down the network performance. Various sensors, like operating system sensors
and network sensors, are installed at strategic locations through out the enterprise
network to monitor network performance.
Domain
In our system IDS is installed on the server side, which serves local hosts and users over
internet as shown in figure.1. There are four actors in the system namely monitor, user,
network and system administrator. User sends request to the server over the internet or
LAN and IDS will analyze the packets received by the server. This IDS detects both
internal and external intrusions. If it detects any intrusion then it alerts system
administrator.
System
Administrator
Server
IDS
User App1
User App2
Router
Host1
Host2
Internet
Hostn
.
User Appn
System Description
Network Intrusion Detection system (NIDS) is a system which monitors network
intrusion. Intrusion may be detected by techniques like anomaly detection,
signature pattern matching etc. Anomaly detection is a method in which normal
network behavior is captured and any abnormality in the network is detected such
as a sudden increase in network traffic rate (number of IP packets per second).
Signature pattern matching is a method in which network data is compared with
the known attack techniques that are saved in a database. For example an IDS that
watches web servers might be programmed to look for string “phf” as an indicator
for a CGI program attack.
Intrusion is detected and system administrator is alerted about the kind of
intrusion when any one of the following events takes place:
1. If a foreign entity has been detected in a log entry.
2. If user tries to access information which is beyond his/her access.
3. Baseline for critical system resources is measured such as cpu utilization, file
entries, disk activity, user logins etc. Then the system can trigger when there
is a deviation from this baseline.
Use Cases
Actors:
1) User
User sends request to server and server responds by providing the
requested service.
2) Network
Network carries the IP packets from source to destination.
3) IDS
IDS takes the packets from the network, analyses the packets.
4) System Administrator
System Administrator is alerted by the IDS of any suspicious activity or
whenever intrusion is detected.
Use Case Description
1) IP Packets
Network gives the IP Packets to IDS which does further processing of these
packets.
2) Anomaly Detection
If IDS Detects any abnormality in the network traffic, then it triggers the alert
system
3) Signature recognition
IDS examines the traffic looking for well-known patterns of attack, which are
saved in pattern database and triggers the alert system, if a match is found.
4) Alert System
Whenever triggered by anomaly detection or signature recognition, it alerts
the system administrator.
Use Case Diagram
Network
IDS
IP Packets
Login
User
Anomaly detection
Alert
Admin
Pattern
Database
Signature Recognition