CDNs, or Content Delivery Networks, are the backbones of modern-day video streaming. Most streaming services depend on CDNs for their day-to-day operations and to ensure high QoS/QoE, and efficient global streaming while ensuring that their streaming costs are under control.
Before we dive into the rest of this article, if you are new to Content Delivery Networks, then take a few minutes to read these introductory tutorials –
- How does a CDN work?
- What is the Thundering Herd Problem in CDNs? What is Request Collapsing?
- How does a Multi-CDN work?
- What is the advantage of using a CDN for Live Streaming?
- What is Cache Hit, Cache Miss, and TTL (Time-To-Live) in CDNs?
In this article, we drive the point by listing nine reasons you should consider for using a CDN for your streaming service. If you have more points to add or have a contradictory viewpoint, we’d love to hear your thoughts in the comments section.
CDNs Increase Reliability in Video Streaming
- A CDN caches (stores) content across multiple servers in different locations (text, images, video, audio, etc.) and prevents a single point of failure.
- Thus, if one server (PoP) goes down, the content can still be served from another location.
- This distributed approach increases the availability and reliability of video streaming services.
Reliable Streaming across Multiple Geographies
- Increasingly, streaming services are going international and serving multiple geo-locations with their content.
- Example: If your origin server is in Japan and your users are in London, then if every playback request has to travel back to your origin server, it will result in huge delays and problems.
- In such situations, one should use a CDN service to cache content across multiple servers in different geo-locations and reduce the Round-Trip-Time for every request.
Scalable Video Streaming
- When you use a CDN, you can allow your service to scale effortlessly, providing reliable video delivery even during traffic spikes.
- This is important for service providers who have unpredictable traffic patterns or know their traffic will peak during certain events (like sports, breaking news, political events, etc.).
Reduction in Time to Start (Latency or Startup Delay)
- Time-to-Start / Startup-Delay / Latency tells you how much time has elapsed between the user pressing the play button and the first frame of the video being rendered on the screen. (PS: go here for a guide on choosing a QoE/QoS service).
- When content is cached on a CDN location close to the user, the time taken for the player to receive the video (segments, HLS playlist, or DASH manifest) is reduced, and the playback can begin quickly.
- In contrast, if a CDN is not used, the player must contact the origin server (probably in a different geographic location) for the manifests and segments, increasing the Round-Trip-Time.
- Even if the origin were in the exact geographic location, without a CDN, the origin would be at risk of suffering the Thundering Herd problem (overloaded with requests).
CDNs can protect against DDoS Attacks
- CDNs can help to protect against Distributed Denial of Service (DDoS) attacks by blocking malicious traffic before it reaches the origin server and overwhelms it.
- Additionally, most CDNs allow you to set up rules to deny requests from certain clients or sets of IP addresses (i.e., block or blacklist traffic).
CDNs Reduce the Cost of your Origin Server
- An origin server is where you host your content (i.e., the videos to be served). Typically, these servers have a high egress cost and are not recommended for video streaming.
- Using a CDN will reduce the usage of the origin server and lead to lower costs. Most video play requests will be served from the CDN’s cache and will not have to travel back to the origin server.
CDNs Reduce the Load on your Origin Server
- Origin servers have limited input-output capabilities, are not recommended for video streaming, and are poorly suited to handle thousands of connections per second.
- A CDN protects the origin from heavy loads and prevents issues like the Thundering Herd problem, for which CDNs use a solution called Request Collapsing.
Improved Experience from Reduced Latency & Buffering.
- By reducing the time it takes for content to load, a CDN can improve the overall user experience of a website. This is especially important for users accessing the website from a location far from the origin server.
- Overall, using a CDN can help improve a website’s performance, reliability, security, and cost-effectiveness, thus delivering an amazing user experience.
- Specifically, if you are a live-streaming company, you should read this article to understand how a CDN can improve live-streaming performance and reliability.
Streaming Analytics and Reporting:
- CDNs provide detailed analytics and reporting, giving publishers detailed insights into video performance, audience demographics, and more.
- You can get location, device, and consumption information from CDN logs, and if your CDN supports CMCD, you can extract a lot more information.
So, how do I get started with a CDN?
Commercial CDN providers cater to text, data, video, and audio streaming and delivery and provide various levels of service for different use cases, architectures, and budgets and enable you to improve your streaming service.
Don’t hesitate to contact us if you are looking for a bespoke solution or consulting service, and we’ll get in touch with you.
Krishna Rao Vijayanagar
I’m Dr. Krishna Rao Vijayanagar, founder of OTTVerse. I have a Ph.D. in Video Compression from the Illinois Institute of Technology, and I have worked on Video Compression (AVC, HEVC, MultiView Plus Depth), ABR streaming, and Video Analytics (QoE, Content & Audience, and Ad) for several years.
I hope to use my experience and love for video streaming to bring you information and insights into the OTT universe.
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