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Protocol-aware network traffic recorder and simulator

IP.com Disclosure Number: IPCOM000177409D
Original Publication Date: 2008-Dec-12
Included in the Prior Art Database: 2008-Dec-12
Document File: 8 page(s) / 133K

Publishing Venue



This article describes a tool which can be used to simulate network attached devices from a management application for regression testing purposes. The simulator is inserted between a management application and the managed device, i.e. server, storage subsystem, SAN switch, etc. When a management action is initiated from the management application (i.e. interrogation of the configuration of the managed device or a specific configuration change command), the simulator stores all requests and responses in a database. Once the management action is complete, the record mode is stopped and the tool can now be used to replace and simulate the managed device. Of course the tool can only respond to the requests which have been stored in the DB, so only the same type of requests can be answered properly by the tool. However, the requests don't have to be received in the same order as they were sent during record mode, because the tool is protocol aware and can correlate the right response to the request. With this technique it is also possible to inject errors or delays which is also very useful for regression testing.

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Protocol-aware network traffic recorder and simulator

Background and Problem Statement:

Fig.1 shows an application communicating with external systems.


When developing software which communicates with external components over network interfaces the test of the software depends on the availability, stability, reliability, and performance of the network and the external components. Fig.1 depicts an example of this. An application 102 gathers information about an IT environment 100 in order to populate a CCMDB 104 (Configuration and Change Management Database). The application 102 needs to retrieve configuration data from various external systems 106a - 106d using a TCP/IP connection 108.

The following issues exist with testing this application:

If the external systems are not available, the network dependent functions of the application cannot be tested.

If the performance over the network channel is poor, the execution time might grow up to a time that makes is impossible to test the network dependent functions of the application.

If the external systems' configuration changes, it is difficult to compare the gathered data against an expected set of values. The external systems can be shared with other users which increases the risk of frequent configuration changes.

An existing solution to this problem is to implement simulators which act like the external systems, but can be installed locally. As the simulators are software components only, they don't have to be shared with other users. The advantage of this solution is to decouple application from network as well as from external components, but the drawback is that such simulation software must be developed which requires usually a huge amount of resources. In addition there is a continuous effort required to keep the simulators up to date with the behavior of multiple system types and versions and changes associated with it. With each new version the simulator has to be adapted. Also experience has shown that the simulators never





Figure 1: Application communicating with devices in a network






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have the exact same behavior as the simulated systems. Thus a test using simulators is not sufficient as the behavior of the real systems is not tested and might cause issues.

Relevant documents: http://www.alphaworks.ibm.com/tech/smis

Solution - the protocol-aware network traffic recorder and simulator

The proposed solution leverages the man in the middle approach, depicted in Fig.2.






Figure 2: Communication going through the recorder-simulator module in record mode

A recorder-simulator module 202 is inserted between management application 102 and external systems 106a - 106d which acts as recorder and simulator so that the same network operation can be executed once against a real life sys...