This Industry Viewpoint was contributed by David W Wang
The fundamental concept of a Content Delivery Network (CDN) is to make the content distribution or broadcast points of presence (POPs) closer to the end users who request for data or video content online. Such network closeness of content serving would reduce the Internet traffic latency, loss of packets, security risks, etc. and therefore boost the end users’ experiences in content consumption.
Via a globally distributed network of web servers, the CDN replicates content all over the POPs geographically so it exists in many places all at once and enables faster delivery and high availability to the end users. A client accesses a copy of the data from an “edge or front server” near to the client, as opposed to all clients accessing the same “central or origin server”, which avoids bottlenecks near that server.
Nowadays a CDN in most cases transports and delivers three primary types of content: Dynamic content: Web site or blog content that changes frequently and engages the reader, which can include animations, video or audio. Static content: content that has fixed sizes and typically does not change very often. Streaming content: videos or audio files that are played via a web browser control.
The first generation of CDN initiated around the end of last century and focused primarily on static and also some dynamic content delivery. The principle mechanism of the first gen CDN was very hardware server centric with the creation and the implementation of replicas, intelligent routing and edge servers. Akamai was the icon name of this stage.
The second generation of CDNs was mainly focused on Video-on-Demand applications, which is streaming video and audio content among users and news services. Think about Youtube and Netflix as good examples. The second gen CDNs also cleared a path for delivering content to mobile users. Technology wise, cloud computing and virtualization help to transform from high touch hardware to more cost effective, agile, and feature rich CDN deployment and models. Aside from Akamai, cloud players like Amazon, Google, CloudFlare , MaxCDN, etc. have been entering the CDN markets. Major telcos like Verizon, on the other hand, due to their advantage of owning major network capacity and elements like the last mile to the end users, are also eyeing bid on the CDN market growth.
What will the next generation CDN look like? Private network (i.e. MPLS) performance level content distribution over the public Internet (hence more cost effective) will be the goal of the next gen CDN. For instance, when watching IPTV today, although the picture quality can reach HD level, we often still experience latency and lag depending on factors like network conditions, peak hours, or WiFi strength. The next gen CDN should become intelligent and powerful enough to stabilize such situation and optimize customer experiences. It will do much more than just caching. Client self-management and quality of experience is expected to be in the focus of the new CDN offers.
Following the fundamental principle of CDN service which is to get closer to the end users with traffic optimization and robust security, we expect legacy CDN vendors like Akamai should still play well for the time being due to its large-scale footprint of front servers they have deployed globally; the major cloud CSPs should do well from their cloud service and data center availability all over the world; the major telcos will fare well too due to their control or traffic operation of last mile access composed of circuits, POPs and mostly importantly of all – wireless towers.
While the wireless towers no doubt make very close access points to end users, the mobile low throughput used to be the bottleneck for content delivery , but this is quickly changing as we speak. The incoming 5G mobile solution powered by fiber optic intensive backhaul and backbone will make a “black horse” for the next gen CDN solutions, with its bandwidth capacity expecting to reach gigabits per second level (considering today’s 4G LTE is only able to handle download speeds between 5 and 12 Mbps and upload speeds between 2 and 5 Mbps). Last September, by working with Nokia, Ericsson and Samsung, T-Mobile could show off speeds of 12 gigabits per second for its 5G network testing, which is more than three times as fast as the trials Verizon conducted back in February, 2016. All this will make high-quality, large size, and real time content delivery over the wireless access an amazing reality.
On the other hand, SD-WAN is quickly evolving and deploying globally to optimize the public Internet performance and serve as alternatives for the legacy MPLS network. From the CDN perspective, SD-WAN will enable better service management and client experiences in terms of application defined customization for both static and dynamic content, front end optimization, responsive server side, adaptive image compression, load balancing, content protection, origin management and security such as anti DDOS attacks.
With the high intelligence, scalability and cost effectiveness of the SD-WAN platform and super last mile throughput by the incoming 5G wireless solution, this combination may give birth to a brand new SD-5G hybrid WAN for the next gen CDN and disrupt some existing service models.
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