CDNs are a critical part of any streaming media service infrastructure, storing content on servers around the world and providing it to users in near real-time. However, as the load and complexity of delivering video increases, more and more streaming media providers are turning to integrating CDN architectures.
In a converged CDN architecture, you can simultaneously use multiple different CDN vendors to cache your video clips, and provide greater redundancy and performance advantages by leveraging the advantages of different providers and minimizing their weaknesses through intelligent load balancing algorithms.
This article will explore the working principles of a converged CDN architecture and the benefits of converged CDN.
1、 What is a CDN or content delivery network?
CDN (Content Delivery Network) uses servers worldwide to cache/store files such as images, videos, code libraries, and so on. When a user requests a media object from your website/service, the request is first forwarded to the CDN and then provided from there. If the CDN has not yet cached the object, the request will be forwarded to your source/Web server for completion. The closer your visitors are to one of the servers, the faster they can access your content.
2、 Why use a converged CDN?
Hosting content from different CDN vendors has many advantages – geographical redundancy, security, improved performance, and cost savings (converged CDNs can help reduce bandwidth costs by balancing load), and leveraging pricing differences between different CDN vendors for different situations, time periods, and more.
3、 What is Convergence CDN?
Convergence CDN is the integration of high-quality nodes from global mainstream CDN manufacturers through technical means based on traditional CDN to achieve intelligent scheduling and accelerated management services with full business processing capabilities.
Huosan Cloud Convergence CDN adopts a converged architecture, with greater bandwidth capacity reserves, more refined link control, and more intelligent scheduling management. It can meet the requirements of users for multiple types of content management and distribution, ensure the continuity of user services, and provide stable and fast network access quality.
Fusion CDN breaks the dilemma of limited nodes for a single CDN manufacturer, breaks through the limitations of geographical time and different operators, and uses intelligent scheduling strategies to comprehensively utilize the resources of various manufacturers to solve problems in actual scenarios, resulting in higher quality service effects, more stable quality, and relatively lower service costs.
4、 Integrating Different Ways of CDN Work
There are two main methods for determining which CDN to use: rule based static switching or rule based dynamic switching.
Although many of the Huosan Cloud’s CDN fusion peers advertise that they also provide CDN fusion, they actually use simple static switching. Static rule based switching is a simple form of CDN switching, where the rule engine uses simple instructions for programming, such as “If CDN-A fails, transfer traffic to CDN-B.”. This cannot accommodate much intelligence and requires close monitoring to ensure that conditions that are not subject to rules do not cause the system to collapse. This approach is actually just a simple formulation of plans A and B for your CDN, without truly possessing intelligent monitoring and scheduling capabilities.
Huosan Cloud Convergence CDN has a more accurate global IP library that is constantly evolving, with a scheduling accuracy rate of up to 99.99%; Scheduling from multiple dimensions such as availability, performance, and cost, and real-time feedback from big data on service quality, each end user obtains the best performance in different regions. In rule based dynamic switching, the decision to switch CDNs is based on information continuously collected from players, the CDN itself, and other business rules. Because these factors dynamically change during the day, decisions change adaptively.
In terms of specific switching mechanisms, the following methods are mainly used in combination:
The first is DNS based CDN switching
The logic behind DNS switching involves directing all content requests through a domain name that handles traffic allocation in real time and dynamically. Therefore, if all traffic from the domain needs to be redirected from CDN-A to CDN-B, DNS points to CDN-B.
The second is HTTP directed CDN switching
In this method, when the system wants to transfer traffic from one CDN to another, the load balancing server will return an HTTP 302 (found) response to the end user for each request made. This will notify the player that the content will not be accessed on the requested CDN and should use the alternate CDN indicated in the response header (the 302 status code indicates that the requested resource has been temporarily moved to the URL given in the location header).
Therefore, HTTP redirection can respond more quickly to changes in network and CDN conditions than time-consuming and not precise form of switching DNS exchanges.
5、 What logic is used in converged CDN load balancing?
When using converged CDNs, corresponding policies are very useful in load balancing and implementing certain important rules. So what factors are driving the integration of CDNs to achieve load balancing?
QoE (Quality of Experience)/QoS (Quality of Service) analysis is used to understand the performance and user experience of different devices, assets, and geographical locations, and summarize them at different levels for decision-making. If the delay or response time of a CDN increases, it can be used as a factor in switching traffic off the CDN.
CDN cost submission: The cost price per GB of delivery and submission based pricing are important factors in integrating CDN decisions. Providers can choose to transfer traffic from one CDN to another to satisfy submissions or leverage them.
6、 Converge the advantages of CDN for streaming media
Some practical benefits of merging CDNs are improving performance (reducing latency) by caching content across multiple CDN providers. This improves customer satisfaction when their videos are streamed satisfactorily with low latency and reduced buffering. By allowing users in one region to access content on another part of the world’s edge server, a broader geographical coverage is achieved.
On the other hand, integrating CDN strategies can help avoid vendor lockdown, enable budget allocation to multiple CDNs, and leverage peak/off peak pricing from multiple vendors. And a converged CDN has a higher security level than a single CDN, because if one of the traffic is attacked, you can switch all the traffic to the other CDN.
