The question is very simple that which CDN is the best? But the answer is not. There are different perspective for this question. eg
- Are you looking for Best CDN by performance?
- Are you looking for Best CDN by Price?
- Are you looking for Best CDN by your budget?
- Are you looking for Best CDN in terms of balance between performance and price?
- Are you looking for Best CDN in a particular region?
- Are you looking for Best CDN in a terms of features? and do you really need them?
I am going to explain different perspectives for this question. Many of you might be already aware for big CDN players in the market and most of you will agree that Akamai is the best CDN. But again, If Akamai is best the CDN, then why Facebook went ahead and created their own? Why Verizon left Akamai and acquired Edgecast? Why Apple is working on its own CDN and not depend on Akamai? Now, you should rephrase the question to the following, which will make more sense, Which CDN is best for me?
I will take data out of 3rd party reputed website Cedexis to bring some point to you. In case you dont know about Cedexis, you may consider it as a 3rd party independent unit. which runs various RUM based tests and publish data frequently about performance of various CDN and cloud service providers. It has also got a very good CDN load balancing product.
As per Cedexis report, In USA region, following is the CDN Response Time report:
Top of the chart is Cedexis, which uses other CDNs like Akamai or Limelight or Level3 or Edgecast, based on the the various factors. You might see that Akamai is appearing at 11th position with 39 msec response time, which is same as Cloudflare CDN. Tata CDN [Bitgravity] ranks at 17th place with 42 msec response time. Amazon’s Cloufront is at 19th place with a response time of 43 sec. Now, between rank#1 and rank#19, the difference is 10 msec. Out of the various players listed above, there is huge price difference among them and a very little difference in response time.
Since US network is already optimal, scope of improvement is less as compared to other region. Lets take example of India region where the network is not so good and you will see huge differences among the players.
Lets only discuss about individual CDN players here and exclude CDN load balancers [Multi CDN]. #1 is Akamai with 56 msec and Tata CDN [Bitgravity] at #2 with 67 msec. Amazon’s cloudflare is at #13 with 102 msec. Almost double the time as compared to Akamai or Tata CDN [Bitgravity]. So the difference is huge. Akamai is obviously at #1 and Tata CDN at #2 but just check the price difference between them and see if that is worth. Sometime it is not about price and you want the best CDN while sometime you want the best possible CDN with optimal performance.
You should also consider the CDN’s performance in Tier 2 cities, See if there are any hidden charges involved. Some CDN might charge you additional amount for professional services, internet traffic consumed between their own servers while other will just charge you flat priced per GB consumed for end user’s delivery. Always ask the following questions about the price before finalizing your CDN choice:
- Is there any additional charge for SSL certificate?
- Is there any charge for data transfer among CDN servers between cache hierarchies?
- Is there any charge involved for advanced changes done by professional services?
- Will CDN provider differentiate the way they will handle your problems vs some other big customer in the market?
- How much Cache hit ratio [offload] they can promise?
- How the CDN is going to handle outages caused by fiber cuts and natural disasters?
Lets discuss briefly about CDN Features. You might meet the sales guy of various CDN provider who will talk about endless features about the CDN he is trying to sell. Its always good to know them. But always ask the question, do you really need them? Suppose, a CDN has a feature to modify and compress content of yours at the edge. Check if you can implement it at the origin server. By evaluating such thing, you can always save a lot and avoid going for fancy CDN and stick to a CDN which fulfills all your needs at the best possible price.
I hope this post of mine helped you in some way to understand the CDN selection in a better way and you will wisely decide the best CDN for your needs. In case you have any questions, feel free to leave them in comment section and I will reply them asap.
