# 3.6.5.API Traffic Management

* Traffic Management?
  * Provider必須確定可以滿足Consumer的需求, 同時必須確保data的完整性, 以下有三個原因為何要做Traffic Management
    * Response time consistency
    * Service Level Agreement (SLA)
    * Protecting the backend
* Response time consistency
  * 必須確保應用程式不會被某一個功能異常的APP所影響

    ![](/files/-M4M0YAOoGYRXnShNz4t)
* Service Level Agreement (SLA)
  * Ensure that SLA is met by the provider
  * Ensure that SLA on the consumer

    ```
    SLA {
      Number of calls: 10,000 Calls/ day
      Concurrency: 5 Calls/ second
      Response time: Under 1 second
    }
    ```
* Protecting the backend
  * This can be done by way of blocking or throttling the request on the edge of the enterprise network 
* Traffic management policies ![](/files/-M4M0YAQ__BpNcA-Rv2H)
  * Quota (限制單位時間的call數)
    * Defines maximum # of calls per unit time
    * Add quota for API: [apigee](https://apigee.com/api-management/#/homepage)
  * Rate limiting (限制瞬間的連線數)
    * Limits number of concurrent connections to API
    * API Rate limiting: [walmart](https://developer.walmartlabs.com/)

      ![](/files/-M4M0YASIUo6Tq_LgQdC)
  * Spike Arrest (限制Call/second的最大值)
    * Protect the API backend from server traffic spikes and denial of service attacks
    * Prevents calls beyond high water mark from reaching the backend
    * Add spike arrest: [apigee](https://apigee.com/api-management/#/homepage)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://jen-hsuan-hsieh.gitbook.io/asp-net/chapter3rest-api-design-development-and-management/35api-management/355api-traffic-management.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.