[189860] in North American Network Operators' Group
Re: Traffic engineering and peering for CDNs
daemon@ATHENA.MIT.EDU (Wolff, Nick)
Wed Jun 8 11:42:16 2016
X-Original-To: nanog@nanog.org
From: "Wolff, Nick" <nwolff@oar.net>
To: Mark Tinka <mark.tinka@seacom.mu>, Tom Smyth
<tom.smyth@wirelessconnect.eu>, Mike Hammett <nanog@ics-il.net>
Date: Wed, 8 Jun 2016 15:40:44 +0000
In-Reply-To: <276869f3-d10a-8b44-795c-cb6673c7082f@seacom.mu>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 6/7/16, 2:46 AM, "NANOG on behalf of Mark Tinka"
<nanog-bounces@nanog.org on behalf of mark.tinka@seacom.mu> wrote:
>
>
>On 6/Jun/16 20:03, Tom Smyth wrote:
>
>> as far as im aware ... a friend of mine on INEX in Ireland said most
>>cdns
>> use source ip of the DNS requests to determine which network to direct
>>them
>> to ... so if you use you have your own resolver on an ip address in
>>your
>> network range cdns can accurately determine what network the request is
>> comming from and determine what ip address / what network that the cdn
>>has
>> nearest to your network...
>>
>> ff you use 3rd party dns servers for your clients... you may not get an
>> optimal ip answer for your dns queries from the CDNS involved
>
>Some CDN's use DNS (in addition to latency, congestion levels, busy
>state, e.t.c.).
>
>Others use Anycast routing, which I tend to prefer. The problem is the
>latter run a network while the former may typically not.
>
>Mark.
Also some companies make layer 7 decisions for their CDN=B9s in conjunction
with these other methods. Their applications makes a decision on what host
to send you to based on routing information, your source address, and
other accumulated data.
