In this verification, low-level design phase is considered. The abstraction level in this phase is low as compared to high-level design. In LLD, a detailed design of modules and data is prepared such that an operational software is ready. For this, SDD is preferred where all the modules and their interfaces are defined. Every operational detail of each module is prepared. The details of each module or unit are prepared in their separate SRS and SDD.

Testers also perform the following parallel activities in this phase:

1. The tester verifies the LLD. The details and logic of each module are verified such that the high-level and low-level abstractions are consistent.
2. The tester also prepares the Unit Test Plan which will be referred at the time of Unit Testing.

How to Verify Low Level Design

This is the last pre-coding phase where internal details of each design entity are described. For verification, the SRS and SDD of individual modules are referred. Some points to be considered are listed below:

• Verify the SRS of each module.
• Verify the SDD of each module.
• In LLD, data structures, interfaces, and algorithms are represented by design notations; verify the consistency of every item with their design notations.

Organizations can build a two-way traceability matrix between the SRS and design (both HLD and LLD) such that at the time of verification of design, each requirement mentioned in the SRS is verified. In other words, the traceability matrix provides a one-to-one mapping between the SRS and the SDD.