SAAS mode and ASP mode

Preface:
Cfans reproduced "who is suitable for ASP mode ERP" and "ASP mode overview" to give a more detailed introduction to ASP mode.
This article briefly describes the connection and difference between ASP and SaaS models.

Before reading this article, we strongly recommend that you read the two documents on SaaS officially published by Microsoft:
Architecture strategy to seize the long tail market
Multi-User Data Architecture
Two articlesArticleThe English version is here:
The English version is here:
Architecture strategies for catching the long tail
Multi-tenant Data Architecture

Author's blog:
Frederick Chong
Gianpaolo Carraro

Contact SaaS and ASP:
There is no doubt that the SAAs (software as a service) promoted by Microsoft has evolved from the ASP model. Although Microsoft has not mentioned ASP in the above documents, SaaS and ASP are closely related.
ASP and SAAs both focus on "software deployment as a hosting service and Internet access ". They share the following points:
Operation Mode:
Software ownership belongs to the supplier, and the supplier is responsible for infrastructure and software maintenance and upgrade.

Service method:
The customer rents the service of the supplier according to a certain payment cycle, and the cost may vary with the customer's usage. Suppliers regularly work with customers to sort out requirements so that the service can respond to customer changes.

Profit method:
Through the professional and economies of scale to reduce the cost of supplier software services, in order to achieve profitability. Additional profit methods include advertising and wireless value-added.
Only when a certain scale is reached can the hardware and professional service cost invested by the supplier be balanced with the operating income. After that, the supplier's sales cost will not be affected as the scale increases,
Profits start to grow.

Where is ASP different from Saas?
Traditional ASP only customizes different applications for each customer without putting all the customers together. In the SAAs model, an intermediate layer is added between the user and the application on the Web server. This intermediate layer is used to handle user customization, scalability, and multi-user efficiency issues. Technically speaking, the ASP mode is not complicated.
For the mature SaaS model used in the architecture strategy for long tail market

In this figure, we can clearly see the biggest difference between ASP and SaaS:
ASP is in the mature model level 1 region, and each customer runs a dedicated instance customized by the supplier for itself. Technically, each customer uses a database, a web site, or a virtual directory. Data Structures and applications in the databaseCodeAll modifications may be made based on the customer's needs.

The main feature of mature model level 2 is that the Code and data structure are the same, and the supplier has considered the scalability when designing the application, so for customers with different needs, flexible configuration can be used for response, but application data is still isolated. From a technical point of view, all customers use a set of installation packages with the same database structure. In this mode, suppliers face the following challenges:
1. How to Implement custom data storage during database design?
2. In the UI Layer Design, how can users customize the independent increase or decrease of UI and form fields?

The main feature of mature model level 3 is: using a set of applicationsProgramTo carry all customer instances. A database is also used to save data. UI and application data of all customers are isolated by authorization and security policies. In this mode, suppliers face the following challenges:
1. How to handle a large amount of concurrency and massive data during design?
2. How to ensure the stability of the application system?
3. How can we persuade customers to accept this data storage policy?

The most ideal mature model is Level 4. Using this model, the user accesses the Server Load balancer server group, and the others are the same as Level 3. In this mode, suppliers face the following major challenges:
1. How to balance the hardware input of the server group with the customer scale?
2. How to Reduce the initial investment and maintenance costs of the server group?

conclusion:
Saas-Based ASP adopts the concept of "software as a service", but SAAS is much more complicated than ASP. For suppliers who are interested in using SaaS for application development, they should first evaluate the degree to which target customers in the industry receive this model and evaluate their technical characteristics, in order to receive more rapid changes from software building, sales to deployment methods.