Backbone-News

Exactly 14 days after the “dispute” between Cogent and Telia started, it seems that both parties have finally reached an agreement.

Since 17:53 UTC today, there is again direct connectivity between both networks, and as a consequence customers on both networks can reach each others again.

Below is the view of the connectivity of one of the Cogent prefixes (38.0.0.0/8) as it was seen again today. (Click on the image for a larger version)

We did some test using the Cogent Looking Glass, and we can see that connectivity between both networks has been restored at multiple locations in the US and Europe.

Traceroute from Washington towards www.teliasonera.se:

 1 fa0-8.na01.b005944-0.dca01.atlas.cogentco.com (66.250.56.189) 4 msec 4 msec 0 msec
  2 gi3-9.3507.core01.dca01.atlas.cogentco.com (66.28.67.225) 4 msec 4 msec 4 msec
  3 te3-1.ccr02.dca01.atlas.cogentco.com (154.54.3.158) 4 msec 4 msec 0 msec
  4 vl3493.mpd01.dca02.atlas.cogentco.com (154.54.7.230) 4 msec
    te4-1.mpd01.dca02.atlas.cogentco.com (154.54.2.182) 0 msec 0 msec
  5 vl3494.mpd01.iad01.atlas.cogentco.com (154.54.5.42) 0 msec
    vl3497.mpd01.iad01.atlas.cogentco.com (154.54.5.66) 0 msec 4 msec
  6 ash-bb1-geth7-3-3-0.telia.net (213.248.88.41) 4 msec 4 msec 4 msec
  7 nyk-bb2-link.telia.net (80.91.250.18) 8 msec
    nyk-bb2-pos0-3-0.telia.net (213.248.80.137) 12 msec
    nyk-bb1-link.telia.net (213.248.83.21) 8 msec

Hop 6 is the first hop on the TeliaSonera network and the hostanme identifies this as Ashburn/US.

Traceroute from Los Angeles:

  1 gi10-0.224.core01.lax01.atlas.cogentco.com (66.250.4.5) 0 msec 4 msec 4 msec
  2 te3-1.mpd01.lax01.atlas.cogentco.com (154.54.2.102) 0 msec 0 msec 4 msec
  3 vl3492.mpd01.lax05.atlas.cogentco.com (154.54.3.10) 0 msec
    vl3493.mpd01.lax05.atlas.cogentco.com (154.54.6.230) 0 msec 0 msec
  4 gi0-0-0.core01.lax05.atlas.cogentco.com (154.54.6.185) 4 msec 4 msec 0 msec
  5 las-bb1-link.telia.net (213.248.72.177) 4 msec 4 msec 4 msec
  6 nyk-bb1-link.telia.net (80.91.254.18) 76 msec 72 msec 72 msec
  7 kbn-bb1-link.telia.net (80.91.249.25) 168 msec 172 msec 168 msec
  8 s-bb1-link.telia.net (213.248.65.141) 172 msec 176 msec 176 msec
  9 s-b4-link.telia.net (80.91.251.21) 176 msec 176 msec 176 msec

Hop 5 shows us the second interconnect in the US, located in LA.

Traceroute from Amsterdam:

 1 vl3.mpd01.ams03.atlas.cogentco.com (130.117.16.125) 0 msec 0 msec 4 msec
  2 gi2-0-0.core01.ams03.atlas.cogentco.com (130.117.0.33) 0 msec 0 msec 4 msec
  3 po1-0.core01.lon01.atlas.cogentco.com (130.117.1.225) 68 msec 220 msec 228 msec
  4 ldn-b4-link.telia.net (213.248.70.237) 8 msec 8 msec 12 msec
  5 ldn-bb1-link.telia.net (80.91.251.18) 8 msec
    ldn-bb1-link.telia.net (80.91.250.234) 8 msec 24 msec
  6 hbg-bb1-link.telia.net (80.91.250.220) 24 msec
    hbg-bb2-link.telia.net (80.91.254.218) 24 msec 24 msec

Hop 4 is the first router on the TeliaSonera network. This time located in London/UK.

Traceroute tests from the other Cogent routers in Europe all go through London, even from Stockholm, indicating that we London is the only interconnect between the two networks in Europe.

Over a week has now past since the disconnection between the Cogent and Telia networks happened. It is unprecedented that such a dispute goes on for such a long period, but interestingly enough, there doesn’t seem to be a lot of outcry happening.

Why is that? Are there really only very few networks out there who buy solely from one of the two and as such have alternate path to the affected networks?

Earl Zmijewski from Renesys posted an update on the Renesys Blog where he analyses further the situation. Interesting read.

As reported earlier, at the end of last week Cogent and Telia got disconnected from each other. The peering relationship between both networks has been terminated, and the fact that both Cogent and Telia customers can no longer reach each others shows that at least one of the two parties is preventing the normal flow of traffic through alternative paths (i.e. their upstream connections). Neither Cogent, nor Telia is a so-called Tier1 provider, and each one of them is buying Transit from at least one other network. As mentionned on the Renesys blog, this was actually the case during the first 12 hours after the peering connections got disconnected. During that period of time, traffic rerouted Verizon.

There is still no official comment from either side regarding this topic. Whenever Cogent had been de-peered in the past (Level3, OpenTransit,etc…) it didn’t take Cogent very long to release information blaming the other party. Well that isn’t the case this time.

Interestingly enough, the overall opinion out there seems to be that Cogent is the bad guy this time. This is mainly based upon the original post on Gigaom.

I was never really convinced that this is the case, since it doesn’t really make any sense for Cogent to de-peer Telia. If they would, it would clearly indicate a rather radical change of direction in Cogent’s peering policy, which was rather open over the past years (at least compared to other networks of the same size).

It is very interesting to see that Cogent only very recently extended their network footprint into the Nordics (Finland, Sweden, Norway), and as such straight into the heart of Telia-land! Until then, Cogent wasn’t a major competitor for Telia in these countries.

Now, we obviously don’t have any facts here, but it very suspicious that this peering dispute happens shortly after Cogent enters Telias home-market!

UPDATE: Gigaom has published further information, and although the source isn’t given, the article provides comments from Dave Schaeffer (Founder and CEO of Cogent):

Quote: Getting specific about Telia, Schaffer says that the Nordic carrier is in breach of a contract with his company. The bone of contention is quite arcane. Cogent says that Telia was obligated to install certain peer connections with Cogent at specific locations, but hasn’t done so because it wants to degrade the experience for Cogent customers.

Cogent says that Telia was obligated to install certain peer connections with Cogent at specific locations, but hasn’t done so because it wants to degrade the experience for Cogent customers.

“They are resentful of our expansion in these markets,” he says. Schaffer also says his company remains “willing and anxious for settlement-free peering” and that “Telia needs to meet their contractual obligations.”

Until last Friday, Cogent and TeliaSonera were in a bilateral peering relationship, meaning they exchanged traffic between their networks for free.

By what is known at the moment, it looks like Cogent is at the origin of the problem. They have decided to end the peering agreement no longer exchange traffic with TeliaSonera. The consequence is that people with Cogent only connectivity are no longer able to connect to sites on teh telia network, and vice-versa.

There is no official word yet from Cogent, but Telia has informed their customers and blames Cogent. Funny enough they basically recommend to their Transit customers to buy additional Upstream from a second ISP to get around the issue. Interesting approach.

It isn’t the first time that Cogent finds itself in a peering fight. In 2005 Level3 de-peered Cogent, the same year OpenTransit de-peered Cogent and I could continue to go on.

It shows unfortunately yet again one thing: Don’t rely on a single provider if you want reliable connectivity! get multihomed to at least to different Transit providers!

We will provide you with more updates on the current situation as soon as further details appear.

Further coverage:
GigaOm
Nanog