Overview

eSurfing Cloud CDN uses globally distributed POPs to accelerate content delivery. It distributes content from your origin server to the POPs closest to users. Therefore, each user obtains content from the nearest POP. This solves access delay issues due to cross-ISP access, cross-region access, or bandwidth or performance bottlenecks of servers, and helps reduce the response time and increase the access success rate. eSurfing Cloud CDN is suitable for accelerating scenarios such as website content delivery, file downloads, and video-on-demand (VOD) streaming.

eSurfing Cloud CDN has more than 1,800 POPs in the Chinese mainland, cooperating with multiple Internet service providers (ISPs) and covering major provinces and cities. It also has more than 500 POPs outside the Chinese mainland, including the major countries and regions in Asia, America, Europe, and Africa. eSurfing Cloud CDN supports a bandwidth capacity of up to 150 Tbit/s. For more information about the POP distribution, see POP Distribution.

Benefits

eSurfing Cloud CDN can help resolve the following types of issues in Internet-based workloads:

If users are far away from the origin server, high transmission latency and instability issues occur because the content must be transferred multiple times to reach the users.
If the network used by a user and the network used by the origin server are provided by different ISPs, the risk of link instability increases because requests need to be transferred across ISPs.
The origin server has limited bandwidth and limited capacity for processing concurrent requests. When the origin server receives requests from a large number of users, high response latency and low availability issues occur.
Your business develops rapidly, but your IT infrastructure cannot be scaled out to support the business in a short period of time. If you use eSurfing Cloud CDN, you can deploy CDN resources on demand and elastically scale resources, helping you reduce the IT costs of your website.

eSurfing Cloud CDN is easy to use. To connect to eSurfing Cloud CDN for the one-stop global CDN acceleration service, you only need to complete some simple configurations in the CDN console and modify the DNS record. You do not need to adjust your service structure or complete complex configurations. For information about how to activate eSurfing Cloud CDN, see Getting Started.

Architecture

eSurfing Cloud CDN consists of the following three key systems: global load balance system, distributed cache nodes, and operations support system. The following figure shows the architecture.

The functions of each system are described as follows:

Global load balancing system: the scheduling system. The global load balancing system supports scheduling methods such as DNS scheduling, HTTPDNS scheduling, and 302 scheduling. It allocates the optimal CDN POPs to users and automatically switches and recovers faulty POPs based on the monitoring data.
Distributed cache nodes: the eSurfing Cloud CDN POPs that are deployed across the world. They can distribute website content to all clients. The multi-level cache architecture helps increase content delivery efficiency, reduce the bandwidth required for back-to-origin routing, and improve user experience.
Operations support system: includes the monitoring system, configuration system, content management system, and logging system. The monitoring system monitors the network status and POP status. The configuration system delivers service configurations. The content management system delivers content purge tasks and content prefetching
tasks. The logging system collects and analyzes user access logs and outputs statistical analysis reports and billing data.

How It Works

Assume that your domain name esurfingcloud.com is added to eSurfing Cloud CDN for acceleration, and a user in HongKong sends an HTTP request from a mobile device or PC to access specific content on the website. The following figure shows the entire service process.

The service process is described as follows：

The user initiates a request to access http://esurfingcloud.com/a.html. The first step is that the client sends a request to the local DNS server for resolving the esurfingcloud.com domain name.
The local DNS server sends a DNS request to the authoritative DNS server of the domain name.
Because the domain name is added to eSurfing Cloud CDN and has been mapped to the top-level CNAME domain assigned by eSurfing Cloud, the authoritative DNS server returns the CNAME record like esurfingcloud.com.epluscdn.com.
The local DNS server sends a query request to the authoritative DNS server of eSurfing Cloud (epluscdn.com).
The authoritative DNS server of eSurfing Cloud returns the IP address of the CDN edge node closest to the user to the local DNS server based on the global load balancing technology.
The local DNS server returns the IP address to the client. The client then obtains the IP address of the target CDN edge node.
The client sends a content access request to the CDN edge node. If the content is cached on the CDN edge node, the edge node directly returns the cached content to the client. The session is then closed.
If the content is not cached on the CDN edge node, the edge node retrieves the content from an intermediate node and then caches the content.
If the intermediate node does not store the content, it retrieves the content from the origin server. Then, it caches the content and sends it to the CDN edge node.
The CDN edge node returns the content to the client. The session is then closed.

Application Scenarios

eSurfing Cloud CDN can be used to accelerate content delivery for websites, file downloads, and VOD streaming.

Scenarios	Website	File Download	VOD Streaming
Business type	Web portals Media websites E-commerce platforms Entertainment news websites	Game software download Mobile phone ROM update Application update File download from online storage	Movie and TV playback websites UGC short video platforms Internet TV services Online educational video websites

Billing

eSurfing Cloud CDN supports two billing modes: pay-as-you-go and resource package. For more information, see Billing Overview.

Pay-as-you-go (postpaid): You need to select a billing method based on your business requirements. You are charged for the number of resources that are used. This billing mode is suitable for scenarios in which resource usage fluctuates greatly and cannot be precisely estimated. In pay-as-you-go mode, the pay-by-traffic and pay-by-bandwidth billing methods are supported.
Resource package (prepaid): You need to purchase resource packages that meet your business requirements. During settlement, the billing system uses the resource packages to offset the resource usage fees. This billing mode is suitable for scenarios in which resource usage fluctuates slightly and the total resource usage can be estimated.

After you understand the billing modes, you can activate eSurfing Cloud CDN. For more information, see Product Subscription.

Differences Among CDN,Integrated CDN, and Application Accelerator

The following table describes the differences among CDN, Integrated CDN, and Application Accelerator in terms of acceleration protocols, accelerated content types, application scenarios, applicable industries, features, and billing.

Product	CDN	Integrated CDN	Application Accelerator
Protocols	HTTP and HTTPS	HTTP and HTTPS	TCP and UDP
Accelerated content types	Static content	Static content and dynamic content	Dynamic content
Application scenarios	1. Static content delivery: accelerates the delivery of static webpage content, such as images and texts. 2. Download: accelerates game downloads, application downloads, version updates, and large file downloads. 3. VOD streaming: accelerates VOD streaming for applications and platforms such as short video apps and video portal websites.	1. Websites with pure dynamic content: accelerates dynamic content delivery in latency-sensitive workloads such as financial payment systems and competitive games. 2. Websites with both static and dynamic content: accelerates websites and platforms that contain both static content and dynamic content in the public service sectors, e-commerce, and media industries. 3. Upload: accelerates the upload of news materials, audios and short videos, and large files. 4. WebSocket communication: accelerates scenarios such as instant messaging, online education, and quote pushing.	1. Office applications: accelerates commonly used office applications such as office automation (OA) systems, mail systems, audio and video conferencing systems, and SSL VPNs. 2. Business systems: accelerates systems that are commonly used in the manufacturing industry, such as enterprise resource planning (ERP) systems, customer relationship management (CRM) systems, and distributor management systems (DMS). 3. Financial systems: accelerates systems such as mobile banking, online banking, online trading, and quote pushing. 4. Game systems: accelerates gaming in scenarios such as logging on, game props trading, voice chats, and interactions upon instructions.
Applicable industries	1. Public service websites, enterprise websites, and e-commerce websites 2. Application downloads and game downloads 3. Video portals and online education	1. Public service sectors 2. Finance 3. E-commerce 4. Entertainment and news 5. Online games	1. Finance 2. Games 3. Manufacturing 4. Global office applications
Features	1. Accurate traffic scheduling. eSurfing Cloud CDN supports accurate scheduling and edge node deployment based on Extension Mechanisms for DNS (EDNS). It maintains and continuously updates an ISP-grade accurate IP address library that is refined to the region or city granularity. 2. Rich resource coverage. In the Chinese mainland, eSurfing Cloud CDN has more than 1,800 POPs, cooperating with multiple ISPs and covering major provinces and cities. Outside the Chinese mainland, it has more than 500 POPs deployed across the major countries and regions in Asia, America, Europe, and Africa. 3. Excellent acceleration performance. Intelligent efficient caching: eSurfing Cloud CDN uses a popularity-based cache replacement algorithm, which greatly increases the cache space usage. Efficient proprietary transport protocol: eSurfing Cloud CDN intelligently judges network conditions and optimizes the congestion avoidance algorithms, greatly increasing the transmission rate.	1. Real-time probing. POPs probe other POPs in real time as planned, and all POPs probe origin servers and report the probing results in real time. 2. Intelligent routing. The system uses a self-developed algorithm to intelligently select a route that includes the first POP and the intermediate POP based on the POP probing result. 3. Transmission optimization. The advanced core technologies and self-developed proprietary transport protocol help greatly increase the transmission rate.	1. Intelligent routing. IP Application Accelerator supports multiple routing methods, including quick routing and stable routing. It uses the self-developed optimal link algorithm to obtain the optimal route when sending back-to-origin requests to the origin server based on the POP probing result. 2. Compatibility with multiple protocols. IP Application Accelerator can accelerate content delivery over TCP and UDP. This helps greatly increase the access speed and stability of interfaces and various dynamic instructions in office applications, business systems, finance systems, and game systems. 3. Multi-port access. IP Application Accelerator can accelerate content delivery on multiple TCP and UDP ports at the same time. It supports scenarios in which the access port and back-to-origin port are different and scenarios in which different back-to-origin ports are used for different access ports.
Billing	Billing item: bandwidth or traffic. Billing mode: pay-as-you-go or resource package. 1. Pay-as-you-go: pay-by-bandwidth or pay-by-traffic (Chinese mainland or Global (excluding Chinese mainland)). 2. Resource package: traffic package (Chinese mainland or Global (excluding Chinese mainland)).	Billing item: Bandwidth/Traffic + Number of dynamic requests + Number of static HTTPS requests. Billing mode: pay-as-you-go or resource package. 1. Pay-as-you-go: (1). Bandwidth/Traffic (Chinese mainland) + Number of dynamic requests + Number of static HTTPS requests. (2). Bandwidth/Traffic (Global (excluding Chinese mainland)) + Number of dynamic requests + Number of static HTTPS requests. 2. Resource package: (1). Traffic package (Chinese mainland) + Dynamic request plan + Static HTTPS request plan. (2). Traffic plan (Global (excluding Chinese mainland)) + Dynamic request plan + Static HTTPS request plan.	Billing item: Channel fee + Port fee + Bandwidth fee. Billing mode: pay-as-you-go.

Management Methods

After you sign into your eSurfing Cloud account, you can use one of the following methods to manage your CDN resources:

Use the CDN console.

The CDN console provides interactive webpages for intuitive and visual operations. It is easy to use. For more information about how to use the CDN console, please refer to Go to Console.

Related Services

The following table describes the services related to CDN to help you comprehensively understand the CDN service system.

Related Service	Descriptions
Integrated CDN	Integrated Content Delivery Network (ICDN) provides the intelligent DNS resolution feature that allows users to access the nearest POPs. Edge nodes intelligently distinguish static content and dynamic content. They cache static content at multiple levels and obtain the static content from the nearest node. For dynamic content, ICDN uses multiple self-developed technologies, such as intelligent routing, protocol optimization, link optimization, and content optimization, to obtain the requested content from the origin server through the optimal link. This helps prevent high response latency issues caused by factors such as network congestion, link jitters, and traffic spikes, thus increasing the performance of the origin server and optimizing user experience. This service is suitable for scenarios such as the acceleration of websites with pure dynamic content and websites with dynamic and static content, upload acceleration, WebSocket communication acceleration, and IPv6 upgrades.
Application Accelerator	Leveraging core features such as intelligent scheduling and transmission optimization, IP Application Acceleration (IPA) optimizes the performance of TCP- or UDP-based applications, including enterprise office systems such as OA systems and mail systems, business systems such as ERP and DMS, and dynamic instructions and interfaces in finance systems and game systems. IPA helps prevent issues such as network jitters and congestions to greatly improve the access speed and stability of applications such as office systems, business systems, and production systems.

Related Service

Descriptions

Integrated CDN

Integrated Content Delivery Network (ICDN) provides the intelligent DNS resolution feature that allows users to access the nearest POPs. Edge nodes intelligently distinguish static content and dynamic content. They cache static content at multiple levels and obtain the static content from the nearest node. For dynamic content, ICDN uses multiple self-developed technologies, such as intelligent routing, protocol optimization, link optimization, and content optimization, to obtain the requested content from the origin server through the optimal link. This helps prevent high response latency issues caused by factors such as network congestion, link jitters, and traffic spikes, thus increasing the performance of the origin server and optimizing user experience. This service is suitable for scenarios such as the acceleration of websites with pure dynamic content and websites with dynamic and static content, upload acceleration, WebSocket communication acceleration, and IPv6 upgrades.

Application Accelerator

Leveraging core features such as intelligent scheduling and transmission optimization, IP Application Acceleration (IPA) optimizes the performance of TCP- or UDP-based applications, including enterprise office systems such as OA systems and mail systems, business systems such as ERP and DMS, and dynamic instructions and interfaces in finance systems and game systems. IPA helps prevent issues such as network jitters and congestions to greatly improve the access speed and stability of applications such as office systems, business systems, and production systems.

Content Delivery Network

eSurfing Cloud CDN Intro