CDN Concepts/Terms (PW: ContentRocks)

CDN

- A Content Delivery Network (CDN) is a globally distributed network of web servers or Points of Presence (PoP) whose purpose is to provide faster content delivery. - The content is replicated and stored throughout the CDN so the user can access the data that is stored at a location that is geographically closest to the user. This is different (and more efficient) than the traditional method of storing content on just one, central server. - A client accesses a copy of the data near to the client, as opposed to all clients accessing the same central server, in order to avoid bottlenecks near that server.

Token Authentication

-CDN and Content owner agree on how to generate an encrypted token -Code on website creates a single use token that is sent with content request -The CDN creates it's own token and checks it against the one presented It's a means to ensure content is only delivered to authorized end-users

Who are other CDN players in the market that I will likely run into?

1) Akamai 2) Limelight 3) CDNetworks 3) Highwinds (Stackpath) 5) Fastly 6) Amazon 7)Verizon

Why would anyone need a CDN service versus using their own network? (3 reasons)

1) Because they do not have a network that could support ... the Amount of Content to deliver + the Geographies & Audience to delivered to. 2) The costs to invest in such a network themselves is far too high 3) They require other services that are normally not equipped to support, such as: Blocking deliveries to selected Geographies Securing access and delivery of the content Reporting on access, delivery, and usage of the content etc.

Having a website with a high loading speed results in:

1) Better User Experience 2) Having a better position in search engines 3) Higher conversion rates (the number of website visitors who turn to customers)

DNS Flow

1) End user requests content 2) User's browser asks the server where that content lives 3) That server will ask the Customer Domain server where it is 4) Customer Domain server will tell the requesting server that the content is CNAMED to the CDN 5) The server then asks the CDN where the content is, and shows it's IP address 6) Based on the IP, the CDN will evaluate where the closest cluster is, and tells the server the IP address where it is 7) That information is returned to the browser 8) The browser then directs the end user to that CDN Cluster 9) If the content is in cache, it is delivered to the end user directly 10) If it is not, the CDN will go to the origin server to get the content

Adaptive bitrate formats that we support today:

1) HLS 2) HDS 3) HSS 4) DASH

What are typical profiles of a customer requiring CDN services?

1) Media & Entertainment 2) Gaming Companies 3) Content Aggregators 4) Multi-Service Operator(MSO) and Internet Service Provider (ISP) 5) Enterprises

The servers typically involved in a CDN are:

1) Origin 2) Mid-Tier 3) Edge Servers

3 Types of Mid-Tier Servers:

1) Origin Shield 2) Adaptive Origin Server (AOS) 3) Dynamic Content Packager (DCP)

3 Types of Content

1) Static Content 2) Dynamic Content 3) Streaming Content

Security Functions (4)

1) Token-Authentication 2) Secured Delivery 3) Geographic IP Filtering 4) Referrer Blocking

Digital Rights Management (DRM)

A means to control access or availability of content to end-users after delivery, such as limiting the number of playbacks. This is becoming less and less of a requirement with other solutions in-place, such as those mentioned above.

Geographic IP Filtering

A means to ensure content is delivered to only specified geographic regions (city, state, country, etc.)

Secured Delivery

A means to ensure that a content file or stream cannot be breached and pirated during delivery. Typical technical solutions includes: - Securing a connection via Secured Socket Layer - Encrypting the bits delivered over the wire

Cache Miss

A request that goes through the cache but finds an empty cache and therefore has to be fetched from the origin

Cache Pass

A request which is labelled as uncacheable, meaning it will bypass the cache and go straight to the origin. This might be an item that is unique to each visitor or one that hasn't been cached

Cache Hit

A request which is successfully served from the cache

Cache Control Headers

A set of rules attached to an asset, which tell the CDN what to do with that asset.

Dynamic Content Packager

Allows for VOD assets to be incapsulated from Mpeg4 or H.264 into HTTP Adaptive formats out

CNAME

Canonical Name- A mapping in a DNS name server to point one hostname to another (www.yahoo.com > www.yahoo.com.c.footprint.net). The key to tricking the end user to go to the CDN instead of the host.

Companies and organizations that have large volumes of content to that needs to be delivered to large audiences globally will typically employ multiple CDN vendors as primary and secondary (backup) services.

Companies and organizations that have large volumes of content to that needs to be delivered to large audiences globally will typically employ multiple CDN vendors as primary and secondary (backup) services.

Who would use a CDN and why?

Companies or organizations with content that need to be distributed to audiences across a wide geographic expanse. "Delivery across a wide geographic expanse" is a very important key point because whether it's a small amount of content being delivered or a large amount.

Examples of Multi-Service Operator(MSO) and Internet Service Provider (ISP)

Companies such as AOL, Comcast, Cox Communications, AT&T, Google, etc. looking to leverage their online presence and expand on their current offerings.

Examples of Content Aggregators

Companies such as Apple (iTunes), Netflix, Hulu, Sony Vue, YouTube, etc. who collect content from other content producers.

Example of Gaming Companies

Companies such as Sony (Wii and PlayStation), Sega, EA Games, Bandai, Riot Games, Gameloft etc. who produce games.

DNS

Domain Name Service- DNS is an Internet-wide distributed application that translates hostnames into IP numbers when an Internet application requests it

CDN Differentiator

How well they help customers accommodate and work with competitive CDN's. This is something that Centurylink does better than its competitors.

Edge Cluster

Interconnected Edge servers. They communicate with one another to determine whether an asset should be peer-filled, served by another edge, or retrieved from the origin. Clusters are dynamic based on what each one of the racks/servers knows about the other rack.

Storage

Involves offering the ability to store large amounts of content (files) on the storage servers of the CDN, saving customers the expense of having to invest in storage devices. Additional services offered include high-availability and redundancy.

File Download

Involves the delivery of any digitized file to end-users - files such as Video, Audio, Graphics, Software, Documents, etc. The key points here are the file being downloaded... - Is saved to the local hard-drive of the platform being delivered to - Must be completely downloaded before it can be used / viewed / listened to / read, etc. - While large files can be accommodated, this is better suited to smaller files (documents, graphics, software) - Typically uses HTTP (HyperText Transfer Protocol) for deliveries

CDNetworks

Korean based CDN company recently (in 2006) establishing a presence in the U.S. market with moves to the European side as well.

Adaptive Origin Server (AOS)

Live media ingest, live media server, live origin is meant to receive pre-encoded HTTP adaptive formats or RTMP in with HTTP Adaptive formats out.

Referrer Blocking

Looks at the website you were on when you requested content and blocks unauthorized sites from using another site's links

Examples of Media and Entertainment Companies

Media production studios such as CNN, BBC, Sky, Disney, ABC, CBS, NBC, Viacom, Sony, etc... and Sports affiliates such as the NFL, MLB, NBA, NHL, WWE, NASCAR, etc... all of whom produce video and audio content.

Enterprises

Organizations looking to deliver large volumes of content to their global workforce and not wanting to impact their current network infrastructure. NOTE: Centurylink's CDN services are currently not prepared to provide content delivery for Enterprise behind their firewall. This is a completely different market segment all together with completely different technical and business requirements.

Origin Shield

Protects the customer origin from being over run by requests but also to reduce the cost the client may face with the provider used as that origin

Reporting

Providing customers access to (up-to-the-minute) real-time and historical reports on various network, delivery, and usage metrics. This typically includes access to an online Portal system.

Mid-Tier Servers

Servers that act as regional intermediaries between the Origins and Edges. Their job is to reduce the load to Origin servers by maintaining copies of content that are delivered to Edge servers.

Edge Servers (Cache nodes, cache servers):

Servers that are geographically and strategically located to deliver content directly to end-users.

Origin Server

Servers that contain the main or original copy of the content to be distributed

Bitrate Stack

Taking a single file and creating different compressions into 3-6 sections (TS Chunks) and held in a manifest file that keeps it all organized. Adaptively moves within bitrates in order to prevent stopping or stuttering.

Akamai

The largest and probably oldest CDN service holding a majority of the CDN market segment with a considerable network presence globally.

Limelight

The next well known CDN name in the market place. While their solution does not require a considerable network footprint globally, they do have a considerable global presence in the market.

Progressive Download

This has the same characteristics as a File Download where... - The file being downloaded is saved to the local hard-drive of the platform being delivered to - HTTP is typically the protocol used for deliveries - This betters accommodates large files such as long-tail videos (movies)

HTTP Adaptive Streaming

This is a form of delivery very different from File or Progressive downloads where dynamically generated chunks of a content are delivered and... - Adjust the quality based on the viewers local internet connection - Proprietary protocols and/or content formats are typically involved HLS, HDS, HSS, DASH - Physical files are always involved - Better accommodates the delivery of large files such as long-tail videos (movies) and long running live events. - Does not accommodate the delivery of smaller and non-media oriented files such as documents, software, and graphics.

Encoding

Typically associated with taking a feed from a live broadcast such as concerts, sporting events, news events, etc. and converting the live feed into digital signals that can be transmitted over the internet. Additional servers offered include "event recording" that involves recording the event to a file for later download.

Transcoding

Typically involves taking a video or audio file already pre-recorded in an internet transmittable format such as: HLS, HDS, HSS, DASH (HTTP Adaptive) 320 Kbps, 512 Kbps, 720Kbps, 1M+ Kbps, etc. ...then converting that format into other formats.

Dynamic Content

content generated on the fly by the web server using any of several common web programming languages such as php, ruby or java

Static Content

content that typically does not change very often and does not require generation. Images, CSS, and JavaScript, etc.

Content Provider

the entity delivering the content

Streaming Content

videos or audio files that are played via a web browser control.