Level3 (3356/3549) changes routing policy

David Reader david.reader at zeninternet.co.uk
Thu Aug 2 12:41:29 UTC 2012

On Thu, 2 Aug 2012 10:33:38 +0200
Fredy Kuenzler <kuenzler at init7.net> wrote:

>  From my observation Level3 has recently changed their routing policy. It 
> seems that 3356 always prefers customer prefixes of 3549, regardless of the 
> AS path length. Example (seen from 3356):
> 3549_13030_[Customer1]_[Customer2]
> is preferred over
> 2914_[Customer1]_[Customer2]
> Considering that both 2914 and 3549 are peers of 3356, and 13030 is a 
> customer of 3549, 3356 seems to give higher local-pref on the longer 
> AS-path, likely to increase traffic and revenue of their sister network 3549.

Hi Fredy,

Level 3 owns both 3356 and 3549.
They're simply preferring to have their customers pay them, rather than
a 3rd party.

I don't think it's suprising at all that they're doing it. If, as you
think, it's only happened recently then what is suprising is that it
didn't happen sooner IMO.


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