Cogent and Google no longer peered via IPv6

Marc Blanchet marc.blanchet at
Wed May 4 19:17:21 CEST 2011

Le 11-05-04 13:15, Frank Bulk a écrit :
> I misinterpreted our upstream networking guy's response -- we get 15169 via Sprint.  So that's consistent with your experience.
> Any way to find out when Google de-peered with Cogent?

my understanding is that they never peered.


>  I'm sure Renesys has that kind of data.
> Frank
> -----Original Message-----
> From: Tore Anderson [mailto:tore.anderson at]
> Sent: Wednesday, May 04, 2011 8:30 AM
> To: frnkblk at
> Cc: 'Martin Millnert'; 'Phil Benchoff'; ipv6-ops at
> Subject: Re: Cogent and Google no longer peered via IPv6
> * Frank Bulk
>> Yes, we're receiving 15169 from Cogent.
> Hi Frank,
> In Oslo we don't:
> tore at cr2>  show route aspath-regex 174.*15169.* table inet6.0 all
> inet6.0: 5570 destinations, 11272 routes (5569 active, 0 holddown, 1 hidden)
> tore at cr2>
> Traceroutes from all PoPs available at
> <>  to's
> IPv6 address all result in a !H error. Where do you take transit from
> them from?
> I opened a ticket with them about it and so far I've only gotten a
> boiler-plate answer that does not at all shed any light on the
> situation, considering that they used to carry those routes before.
> So either there's some kind of technical problem going on, or one
> network depeered the other. Considering that Cogent seems unable or
> unwilling to give a clear answer, I have my suspicions...
> * eu-support at
>> You have enquired with Cogent Support about missing routes in the
>> IPv6 routing table provided to you by Cogent as part of your Internet
>> service. We understand your concerns and would like to provide you
>> with additional information on the matter.
>> As you know, the Internet is made up of tens of thousands of networks
>> which must be interconnected, either by means of direct peering
>> between individual networks, or by connection to upstream transit
>> providers.  For IPv4 routes, the Internet follows these
>> interconnection rules and enables transit providers (such as Cogent)
>> to provide a full global IPv4 routing table to their customers. IPv6
>> interconnection, on the other hand, has not yet reached this level of
>> maturity.
>> Like other providers, Cogent is actively expanding its IPV6 routing
>> table.  This is not always easy due to the fact that certain networks
>> do not announce the IPV6 routes of their customers to their upstream
>> providers. Hence such IPv6 routes are not visible to the entire
>> Internet.  As a result, no network in the world can claim to provide
>> a full global routing table to its customers. Cogent remains
>> confident that IPv6 interconnection will gradually attain the same
>> level of maturity as IPV4. In the mean time, Cogent is continuously
>> working on improving global IPv6 connectivity by adding new IPv6
>> routes to its network on a daily basis and collaborating with the
>> Internet carriers' community to achieve ubiquitous IPv6 coverage
>> Cogent Support remains at your disposal for any subsequent questions
>> you may have.

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