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Video – Level 3 versus Comcast peering dispute

By 3 December 2010 38 Comments

This is the follow up to my piece – Level 3 outbid Akamai on Netflix by reselling stolen bandwidth which explains things on a more high level.  Some people have criticized the assertions and claimed that Comcast is only a transit customer and that this is not a peering dispute because there never was a peering relationship in the first place.  After some detailed analysis, I’ve come up with the following video to explain why my original claims are correct.  The video goes into quite a bit of depth, but it really explains the details in a very visual and animated way.

This video gets to the bottom of the Comcast versus Level 3 Communications dispute by explaining how peering and Internet transit functions, and by examining the known facts surrounding this dispute.

Level 3 asserted that Comcast wanted to tax Netflix under the threat of blocking them which was therefore a “Net Neutrality” violation.  Comcast said they threatened no such thing and this was just a private peering dispute between Level 3 and Comcast, and no website companies or applications were singled out or threatened.

Note that video got slightly ahead of audio towards end because YouTube didn’t sync it right in their encoding.

Correction was made at 2:20 – Level 3 and Tata are the only transit providers for Comcast as of December 2010.

Nate Anderson reports that Comcast follow up letter confirms the assertions in this video.  Comcast “bent over backwards”.


UPDATE – Some people are still challenging the facts surrounding this issue, so I will include an analysis of Comcast’s letter to the FCC.

“Until Level 3 fomented this dispute, Comcast and Level 3 exchanged Internet traffic as part of a commercial interconnection agreement, under which Comcast paid Level 3 for interconnection facilities.”

“Commercial Interconnection agreement” where Comcast pays for interconnection facilities mean “transit”.  Comcast pays Level 3′s transit division for use of their Internet backbone (long haul fiber infrastructure) to reach other parts of the Internet.

Comcast goes on to talk about the peering agreement.

“Although the parties exchanged traffic at a ratio of about 2:1, with Comcast terminating more of Level 3’s traffic, this was well within the industry’s established bounds for “roughly balanced” traffic, and they exchanged their on-net traffic on a settlement-free basis.”

This 2:1 (and future 5:1) ratio specifically refers to “on-net” settlement-free traffic.  The 2:1 settlement free traffic is totally separate from the “commercial interconnection agreement” i.e., transit.

That debunks my critics claiming that you can’t have transit and peering simultaneously and independently because they clearly were being separated.  In fact, they’re even on different physical circuits.  The difference is that the on-net can be metered completely independently of off-net transit traffic.

Defining on-net versus off-net:

  • On-net refers to Comcast network <=> Level 3 network peering traffic which is to be free (neither company charges the other) if they’re “roughly” symmetric and fee-based if they’re too asymmetric.  This was free peering where Comcast was overlooking and forgiving a 2:1 imbalance of on-net traffic coming from Level 3.  Much of that imbalance was due to Level 3 CDN services even before the Level3-Netflix deal.
  • Off-net is the Comcast traffic coming from or to the Internet going through but not terminating in the Level 3 network.  This is where Comcast paid Level 3 for traffic going both directions to and from the Internet.  Level 3 is serving as the on-ramp to the Internet for Comcast.

Comcast goes on to say that even though they forgave a 2:1 on-net imbalance coming from Level 3, they’re not going to forgive the new 5:1 ratio caused by Level 3’s new CDN expansion to Netflix delivery.

Comcast goes on to say that Level 3 only notified Comcast of this massive expansion of on-net traffic shortly after they finalized their agreement with Netflix, and they wanted 30 new interconnection ports (These are likely 10 gigabit ports each for a total of 300 Gbps of additional peering capacity).  The big kicker was that Level 3 wants Comcast to do all this at no extra charge despite the fact that they were already being forgiven for a 2:1 imbalance, and they want to go up to a 5:1 imbalance and maintain a settlement-free peering agreement.

Comcast added 6 ports at no extra charge, but going to the 30 extra ports would put the peering ratio far out of balance.  Comcast then told Level 3 that they would continue to forgive the 2:1 imbalance in addition to the 6 recently added ports for free, but they told Level 3 that they had to pay for an additional 20 ports.

As an outside observer, that seems far more than fair since Comcast is well within its rights to charge Level 3 for any imbalance of on-net traffic.  Instead, they’re going to continue forgiving more than a 2:1 imbalance (with the added 6 ports) but they’ll charge for any additional imbalance after that.

Level 3 admitted in their press release that they’re going to pay Comcast for additional peering traffic but that they were very angry about Comcast’s “take it or leave it” approach.  In light of the fact that Comcast is forgiving so much imbalance and immediately added 6 more free ports, it seems that Comcast acted in good faith and that Level 3 is being very unreasonable and opportunistic in portraying this as a “net neutrality” violation.  What Level 3 is saying is that unless Comcast gives us another 24 free peering ports like we had asked, Comcast is violating net neutrality and they should be pressured by the government to give us what we want.  Under these circumstances, I’m surprised that Comcast has been so calm.

Update 2 – Comcast confirms my observations on peering dispute

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