I run a small CDN oriented to audio/video
distribution in Central Europe region. You mentioned challenges that CDN
are facing. There are several of these:
1) Geographic load distribution
- in example, you have to have enough capacity in
each distribution area that is being potentionally served by your customers
2) Computing power
- you have to have in each POP adequate computing
power that allows you to use full bandwidth available in that POP
3) Network capacity in each POP
- self explaining
4) Content moving
- you have to optimise internal data flows between
5) User redirection
- You have to implement a scalable mechanisms that
redirects users to the closes POP. You can use application redirect (fast, but
not so much scalable), DNS redirect (scalable, but not so fast) or anycasting
(this needs cooperation with ISP).
6) Costs of the system
- Most CDNs are designed for peaking traffic, but
load is more dynamic that in traditional networks.
7) Play alone
There is almost no way for handover traffic to
other CDN. No standards, no kinf of interconnection agreement.
These points are only a rough overview, this
ecosystem is developping and challenges also depend on the starting conditions
and region where you are running you CDN.
----- Original Message -----
Sent: Monday, August 06, 2007 23:10
Subject: Content Delivery Networks
Can anyone give a breakdown of the different kinds of content
deliver networks? For example, we have Akamai, which appears to be a pure
Layer 3 network that is tailored to pushing relatively small files like web
pages and we have Lime Light Networks, which is a mix of Layer 1 and Layer 3,
that focuses on bigger files like video streams.
Any insights out
there? And what are the major challenges in making scalable content delivery
Roderick S. Beck
Director of EMEA Sales
1, Passage du Chantier, 75012 Paris
respect for authority is the greatest enemy of truth.'' Albert