RE: [kNT] akamai

["Nick Bryant" <nick@xxxxxxxxxxxxx>]

Ok here is what I know.

Akamai deploys banks of servers (usually about 9 I think) into as many
IP networks as they can. These, obviously, are there edge servers that
they distribute the content from.

Then to direct users to the servers they use an intelligent DNS system
and they use the domain akamai.net to achieve this. The edge server
names are usually in the following format a103.c.akamai.net. Akamai.net
is served up from the following DNS servers:


ZC.AKAMAITECH.net. 216.32.65.14
ZD.AKAMAITECH.net. 204.248.36.130
ZE.AKAMAITECH.net. 216.200.14.134
ZF.AKAMAITECH.net. 63.215.198.78
ZG.AKAMAITECH.net. 209.185.188.14
ZH.AKAMAITECH.net. 213.161.66.165
ZA.AKAMAITECH.net. 204.178.107.226
ZB.AKAMAITECH.net. 12.47.217.18

These are Akamai version of the root dns servers. They are strategically
positioned globally for resilience and there is no intelligence used at
this level.

The next level is the sub domain that will start with one of the
following letters:

c
d
e
g
k
l
p
x

The letters are actually irrelevant to the technology but are used for
admin purposes. For example I think playboy have the whole of the
p.akamai.net.. but don't quote me on that as im not a regular viewer of
their site... honest ;)

But when root servers dish up the NS records for the subdomain (e.g.
g.akamai.net) this is where the first, and probably most important, part
of intelligence is used. The root servers take the IP address of the
person that is trying to get to the content. This is then applied
against akamia's own database of information which is derived from the
routing registries (RR), information they get from the networks they
deploy servers in and no doubt some other sources. Also real time
network information is also applied to the decision process. 

After all this clever stuff is done it will direct the DNS process to
the nearest set of Akamai servers to the user. Which in my case would
be:

n0g.akamai.net.         30M IN A        62.41.114.7
n1g.akamai.net.         45M IN A        62.41.114.8
n6g.akamai.net.         30M IN A        198.31.3.20
n2g.akamai.net.         1H IN A         62.41.114.10
n3g.akamai.net.         30M IN A        62.41.114.41
n7g.akamai.net.         45M IN A        199.232.159.242
n4g.akamai.net.         45M IN A        62.41.114.42
n5g.akamai.net.         30M IN A        62.41.114.7
n8g.akamai.net.         45M IN A        62.41.114.8

Now all these IP's are actually close to where I made the original
request from.

The final part is the host resolution i.e the a102 part of
a102.g.akamai.net. This address is just one of the servers that's in the
local group opf machines that serve up the DNS records for the sub
domain. So in my case it is:

Name:    a102.g.akamai.net
Addresses:  62.41.114.11, 62.41.114.12

If you look at these addresses then look at the DNS answers for the
subdomain g.akamai.net you can see which groups it actually used.
62.41.114.X

Ok I know this has come out really badly as im never very good at
dumping my brain on paper so fire away with the questions.

In terms of deployment: if you look at the html on www.about.com you
will see that the reference to images etc is something like:
http://a1028.g.akamai.net/6/1028/968/8fcb3213ec0b6a/i.abz.com/hp/lego_wh
t.gif

Which uses the above rambled process to make my browser go get the image
from a local(ish) Akamai server.

Again this can be used with links to downloads etc and one of their
services actually allows the whole site to be servers from local servers
so the domain name of the customer is actually akamaized like
www.yahoo.com.

Hope this helps.

Nick

ALL INFORMATION STATED ABOVE IS MY PERSONAL OPINION GATHERED FROM PUBLIC
INFORMATION AND MY NOT BE 100% CORRECT.

> -----Original Message-----
> From: owner-k-networktrial@xxxxxxxxxxxxxxxxxxx [mailto:owner-k-
> networktrial@xxxxxxxxxxxxxxxxxxx] On Behalf Of Emanuele Parravicini
> Sent: 08 November 2001 11:34
> To: 'k-networktrial@xxxxxxxxxxxxxxxxxxx'
> Subject: RE: [kNT] akamai
> 
> Hi Nick,
> 
> I'm studying about CDNs, I read some IETF drafts, but I have some
confused
> ideas...
> I know that one way to implement Reaquest-Routing System is to use an
> 
> > "intelligent" DNS system
> 
> and I know that Akamai use this technique... but I don't understand
the
> exact process that guide a request from a client to one of the
surrogates.
> 
> Which role does the DNS play in the process?
> Is the static html page requested to the origin server or to one
> surrogate?
> How is a static html page converted in an "akamaized" one with
references
> to
> surrogates?
> 
> Can you use an example with fictitious hosts, names, and so on?
> Thanks a lot in advance.
> 
> Emanuele