1. High Level Design :
High Level Design in short HLD is the general system design means it refers to the overall system design. It describes the overall description/architecture of the application. It includes the description of system architecture, data base design, brief description on systems, services, platforms and relationship among modules. It is also known as macro level/system design. It is created by solution architect. It converts the Business/client requirement into High Level Solution. It is created first means before Low Level Design.
2. Low Level Design :
Low Level Design in short LLD is like detailing HLD means it refers to component-level design process. It describes detailed description of each and every module means it includes actual logic for every system component and it goes deep into each modules specification. It is also known as micro level/detailed design. It is created by designers and developers. It converts the High Level Solution into Detailed solution. It is created second means after High Level Design.
Difference between High Level Design and Low Level Design :
| S.No. | HIGH LEVEL DESIGN | LOW LEVEL DESIGN |
|---|---|---|
| 01. | High Level Design is the general system design means it refers to the overall system design. | Low Level Design is like detailing HLD means it refers to component-level design process. |
| 02. | High Level Design in short called as HLD. | Low Level Design in short called as LLD. |
| 03. | It is also known as macro level/system design. | It is also known as micro level/detailed design. |
| 04. | It describes the overall description/architecture of the application. | It describes detailed description of each and every module. |
| 05. | High Level Design expresses the brief functionality of each module. | Low Level Design expresses details functional logic of the module. |
| 06. | It is created by solution architect. | It is created by designers and developers. |
| 07. | Here in High Level Design the participants are design team, review team, and client team. | Here in Low Level Design participants are design team, Operation Teams, and Implementers. |
| 08. | It is created first means before Low Level Design. | It is created second means after High Level Design. |
| 09. | In HLD the input criteria is Software Requirement Specification (SRS). | In LLD the input criteria is reviewed High Level Design (HLD). |
| 10. | High Level Solution converts the Business/client requirement into High Level Solution. | Low Level Design converts the High Level Solution into Detailed solution. |
| 11. | In HLD the output criteria is data base design, functional design and review record. | In LLD the output criteria is program specification and unit test plan. |
