High Level Design is a general system design and includes the description of the system architecture and design. Data flow, flowchart, data structure are included in High level Design documents so that developers can understand how the system is expected to work with regards to the features and the design. It describes the relation between various components and function of the system. It defines the actual logic for each and every module of the system design architecture to understand the flow of the system with function and database design. As part of consultancy work or Architecture design, customer business requirements is converted into High Level Solution.

Components of High level Design :-

In order to describe a bird's eye view of the overall solution, High level Design should include two key components :-

1. Functionalities and properties attributes of components.

2. Interaction and relation between various components.

Purpose of High level Design :-

The purpose of this High level Design Documents is to add the necessary details description to represent a suitable model. This document is designed to help in operational requirements and can be used as a reference manual for how modules interact. HLD is a technical representation of functional requirements and flow of information across assets or components.

Scope of High Level Design :-

The High Level Design documentation presents the structure of the system as the application /database architecture, application flow and technology architecture. High level Design documentation may use some non technical terms unlike low level design which should be strictly technical jargon.

Characteristics of HLD :-

HLD presents all of the design aspects and defines them in form of a diagram. It describe the user interface being implemented and description of hardware and software interface. It describes the performance requirements and flow of user's daily process. HLD includes design features and the architecture of the project.

Requirements of /from High Level Design :-

HLD briefly describe about the platform /product /service /processes, flow of traffic that it depends on and include any important change that need to be made to them. HLD is the input for creating the LLD since the key communication items are displayed in HLD which are then concerted to detailed communication in LLD, showing connectivity and physical level. HLD requires contribution from a number of experts representing many distinct professional discipline like SME, Design Architecture. Every type of end user should be classified and identified in the HLD and each contributing design should give due consideration to the customer experience. Another important aspects is that HLD and LLD are source of reference in operations stages also after the project has been successfully implementes and now in BAU stage. Henxe design phase is of utmost importance.

Which phase HLD created?

After the requirements of project have been understood and an overview of overall solution /system components communication needs to be carved out this is where High level Design Is created. HLD will be the input for LLD or detailed design creation. The information available in HLD is the guiding principles which low level design needs to demonstrate in details. HLD is required during :-

Preliminary Design

In the preliminary stages the need is to size the project and to identify those parts of the project that might be risky or time consuming.

Design Overview

As the project processed the need is to provide an overview of how the various sub system and components of the system combines together in a frame.

Who is responsible for making HLD?

Solution architect are responsible for making the HLD They build HLD and then Subject Matter Expert or designer work to create LLD online to the guidelines of HLD. LLD will encompasses information related to understanding the traffic flow, creating network topology, IP Adress and naming convention of device in an Organization for smooth troubleshooting and to run operations.

Written by : Deepshikha Niyogi