Have you ever wondered how content on some websites and apps on the internet gets transmitted to users across the globe so seamlessly even while several thousand are requesting the same data? Have you thought about how some others crash incessantly under similar circumstances? What causes this difference in performance? Well, the difference permeates from how the content delivery happens and if a content delivery network (CDN) is used.
CDN or Content Delivery Network is the central component in the delivery of internet content across the geographically dispersed group of servers. It is the geographically dispersed group of edge servers that work together towards optimized content delivery across the globe in a speedy and efficient manner through a private global network by bypassing and working around the congestion of public networks or Internet service providers (ISP).
Before we get into how the CDN service works, let us first look at some important concepts related to content delivery service.
Point of Presence (PoP) refers to the interface or access points at which connection is made between two devices or networks and in the case of CDN, it is the group of servers present at different geographical locations.
Round Trip Time (RTT) is the time that it takes in milliseconds for the network request/signal pulse to travel from the source point to destination and back. It is a critical indicator of network health and performance.
Network Latency is the time it takes for the content to load or packet to be delivered on the requesting server from the endpoint sending server. It is different from RTT in that RTT is the time taken on both ends of the request plus the time taken to process the request.
Content caching is the process or mechanism that optimizes the way in which data or content is accessed and delivered from the closest servers, data centers and clouds to the requesting endpoint server. This helps in optimizing the time taken and improving overall speed and performance.
Caching Servers are those servers who store cached files on their multiple storage drives and high-performance RAM resources and instantaneously delivers content upon the receipt of the request so as to maximize website/application’s loading speed and performance and minimizing bandwidth usage.
Internet Exchange Points (IXPs) are the physical infrastructural setup and access points through which web traffic is routed by different network providers.
Hops are the changes in the network that happens during transmission of content from the server to the end-user.
Now, let us look at how exactly the CDN service works.
A CDN service provider will typically have several PoP, each with several caching servers, at strategic IXPs in several locations distributed across the globe. By having several PoP dispersed geographically, the CDN provider automatically enables you to have global or at least widespread presence. The CDN is always placed at close proximity to the edge of the network perimeter which also helps in securing content while also accelerating it.
Each PoP typically serves requests in the geographical areas it is placed it and users in its proximity. The caching servers as discussed will contain cached files. These edge caching servers help them in optimizing speed and connectivity even when several requests come in at the same time because the content is being transmitted through local servers. Just imagine how much faster and easier it will be to serve a request from Seoul user from a Seoul server rather than routing and transmitting content from the origin server at Seattle as network latency will be greatly reduced.
In the face of sky-rocketing internet usage across the globe and generation of voluminous content that can be accessed globally, it will be extremely difficult to handle requests thousands or even millions of requests together or spikes in traffic especially when they come from users spread out globally. When such spikes in web traffic take place, it makes the application vulnerable to attacks and cybersecurity threats along with the complete slow down of the server and higher latency and RTT. Using a CDN will help you to overcome such problems and seamlessly distribute content globally.
The best CDNs offer the following 4 important benefits:
Let us delve a little deeper into how CDN and network security work. All the requests go through the CDN which is at the periphery of the network. The request for cached content will be met through the nearest PoP. The request for un-cached content, however, needs to be routed to the origin server. With CDN, the request for un-cached content will pass through the network security infrastructure before being routed to the origin server. This way the requests that go to the origin server are all scanned thoroughly, and malicious requests are blocked out. Therefore, speed and security do not have to be compromised for one another.
While choosing a CDN, you will compare the services offered by several different content delivery network companies. Below are a few pointers to keep in mind while making a CDN comparison and choosing the right CDN.
Is it free?
At Indusface, we want you to experience the advantages of our CDN solution first-hand before you on board with us which is why we offer CDN free for 14-days after which you need to pay to use it. But if you are an existing AppTrana user, you can choose to activate the CDN service for your web applications at zero additional costs on your Premium and Advanced Plans as it is bundled with our web application security offerings.
Founder & Chief Marketing Officer, Indusface
Venky has played multiple roles within Indusface for the past 6 years. He was instrumental in building the product/service and technology team from scratch and grew it from ideation to getting initial customers with a proven/validated business model poised for scale. He has proven experience (10+ years) in the security industry and has held various mgmt/leadership roles in Product Development, Professional Services, and Sales during his time at Entrust Data card.