Community Blog Content Delivery Network – Part 5: DCDN Usage

Content Delivery Network – Part 5: DCDN Usage

Part 5 of this 6-part series explains how DCDN utilizes protocol optimization to enable dynamic content delivery and a usage scenario related to DCDN.

By Shantanu Kaushik

In Part 4 of this series, we discussed Dynamic Route for Content Delivery Network (DCDN) and compared CDN and DCDN. We also discussed how exactly DCDN accelerates the delivery of dynamic content. Continuing from the smart routing technique, this article will discuss:

  • Protocol Optimization
  • Connection Optimization
  • Packet Parameter Optimization

Protocol Optimization

Alibaba Cloud DCDN enables protocol optimization of the Transmission Control Protocol (TCP). TCP is used for the information delivery between applications and services on a network. Alibaba Cloud DCDN optimizes multiple requests required by the TCP connection to work and avoid network congestion while dealing with large-scale enterprise content. Let’s discuss how Alibaba Cloud DCDN optimizes the delivery channel:

1.  Enabling a Faster TCP Start

TCP slow start is a TCP protocol algorithm that prevents network congestion by limiting the amount of data sent over the network. It starts with small congestion window sizes between the sender and receiver until the maximum capacity is reached or packet loss is detected.

Alibaba Cloud DCDN eliminates the TCP slow start through:

  • Monitoring the connection bandwidth between CDN nodes and the origin server
  • Collecting different metrics to understand the health status of the connection, server, and the CDN nodes
  • These collected metrics are shared between CDN nodes and the origin servers. This enables a synchronous feedback mechanism to make all the parties in the transactional channel aware of the network conditions and server health.
  • You can use small or large connection windows to transfer the content based on the health conditions of the server, the connection, or the CDN node.
  • Dynamic scheduling of content transmission size projects a more optimized content delivery scenario with dynamic content handling.

2.  Connection Optimization

You need to understand how your CDN interacts with the outside requests to enable connection optimization. A content delivery network is a gateway between your origin server and the outside world. Only certain connections connect directly to the origin server, and you can optimize them by scheduling transfer requests based on connection health and available bandwidth.

TCP protocol requires several handshakes to maintain a stable connection. We call it the Keep-Alive technique. It reuses existing TCP connections for multiple requests simultaneously, which optimizes the connection and accelerates content delivery.

3.  Packet Parameter Optimization

Alibaba Cloud DCDN enables parameter optimization to reduce the time between server-to-server connections to retrieve content. If a packet loss is detected, DCDN sets the packet parameter to retransmit the content quickly. Similarly, it increases the initial congestion window to enable the transmission of more packets. It does not wait for an acknowledgment and retransmits faster irrespective of packet loss.

Usage Scenarios

Let’s take a look at the usage scenarios of Alibaba Cloud DCDN.

Scenario 1 | Deploying an Application

In the first scenario, the developer wants to deploy a dynamic web application and use Alibaba Cloud DCDN with Container Service for Kubernetes (ACK).

The chart below shows the Alibaba Cloud ACK architecture:


In this scenario, the developer needs to provide the application and data to deploy it using Kubernetes clusters on Alibaba Cloud. Alibaba Cloud DCDN will sift through the content and automatically optimize the whole architecture to utilize the CDN for static content and DCDN to dynamically provide content on request as quickly and reliably as possible.

How does the developer achieve this?

  • The developer creates the application and creates an image for the container service.
  • The image is attached to the Kubernetes service (ACK) and deployed instantly.
  • The developer utilizes Alibaba Cloud RAM to assign user authorization and authentication.
  • The application is made public, and users start to access it.
  • When the content is required, it is dynamically accelerated using Alibaba Cloud DCDN and delivered to the user based on user requests.

Scenario 2 | Large-Scale Content Delivery

The chart below shows the architecture of this scenario:


Alibaba Cloud DCDN accelerates content delivery by utilizing optimal routes for static and dynamic content delivery from the origin servers. It allows you to specify a custom path for static content and detect dynamic content automatically.

In this scenario, Alibaba Cloud CDN has already cached the static content on the CDN nodes. Dynamic content is delivered using the acceleration scenario that involves the optimization practices above.

Alibaba Cloud DCDN is suitable for organizations that generate more dynamic content, such as e-commerce websites, financial applications, rapid blogging, or video streaming services. With DCDN, you can achieve a quick, reliable, available, and smooth experience regardless of external factors at the network or user end. Alibaba Cloud DCDN also supports elastic scaling that enables an optimized network experience in all locations without worrying about additional infrastructure.

Scenario Highlights

  • The user experience is enriched by low page load time, even with dynamic content rendering.
  • With DCDN, you need not worry about the page load latencies and content distribution failures, as DCDN optimized the network to counter any traffic surges and network congestion.
  • Alibaba Cloud DCDN further utilizes the Server Load Balancer to balance any traffic spikes.
  • With SCDN, the whole process is highly secure, so any unsecured protocol will not lead to attacks or data leakage. We will discuss secure content delivery practices in the next article.
  • Gaming applications require more availability as the concurrent user requests count is considerably high. Alibaba Cloud DCDN handles these requests in real-time and provides a seamless experience.

Wrapping Up

Alibaba Cloud DCDN provides unmatched acceleration for dynamic content but also helps static content. You can efficiently deploy your application or website using Alibaba Cloud DCDN without worrying about speed and stability.

Upcoming Articles

  1. Content Delivery Network – Part 6: Secure CDN
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