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The Secrets of De-Peering

Uta Meier-Hahn — 06 Aug 2017
There are many resources available to learn about Internet peering. But when it comes to de-peering, networkers are mostly left with their gut feeling.

The secrets of de-peering

There is no “Beginner’s Guide to De-Peering”, no “De-Peering 101”, no manual “How to De-Peer Respectfully in Five Easy Steps”. This absence of guidance exists for several reasons – the most obvious being that it appears counter-intuitive to busy oneself with de-peering and cutting down transmission capacity between networks when traffic levels on the Internet have kept going up and to the right since its inception.

And indeed, the network engineers I have spoken to for my PhD confirm that de-peering is not common. However, when it does happen, it is instructive to look at; the arguments networkers use to justify or assess de-peering offer a rare glimpse into the networking industry and the manufacturing of connectivity. Accepted conventions and areas of conflict become explicit. For instance, it may come as a surprise for some that not every de-peering indicates a dispute; and conversely, despite press coverage, not every “peering war” even implies de-peering.

Ordinary dictionaries do not (yet) include peering or de-peering, so let’s clarify the vocabulary. (Networkers may want to skip this paragraph.) Peering refers to a specific type of interconnection arrangement between network operators. On a technical level, to peer means to interconnect two Internet networks (Autonomous Systems in technical parlance) and exchange traffic that belongs to each other’s customers – be they end users or other networks. (So peering offers limited reachability, which is a key difference between peering and so-called transit. In transit, one network offers to transmit data to and from any endpoint on the Internet for another network for money.) Economically, the dominant understanding of peering was, for the longest time, that it did not involve the exchange of money between the parties who peered. More recently, though, so-called paid peering has surfaced as a variation. In this case, one network operator pays for her customers to reach the other network’s customers directly. To de-peer, then, means to terminate a peering relationship and disconnect the networks.

Where networkers agree about de-peering

While de-peering always leads to loss of Internet connectivity between networks, it does not always cause a conflict between the network operators involved. In fact, there is a widely accepted rationale for de-peering among network operators that prioritises functionality and efficiency. A network operator may legitimately shut down a peering session when his network receives malicious traffic (such as a DDoS attack) from its neighbours, when it is sent incorrect route announcements, when it disconnects from an Internet exchange point all together, when it merges with another network, or when it experiences congestion due to a peer not providing the throughput capacity that had been promised. Network operators widely agree that protecting a network’s functionality and performance has priority over any other criteria for assessing Internet interconnection. In the words of one interviewee: “Someone spamming my network is a damn good reason to de-peer. Is that a net neutrality issue? Of course not. It is an Internet peering issue”. Often times, networkers re-establish peerings after such issues have been resolved, sometimes automatically.

When de-peering becomes contentious

De-peering becomes a contentious issue only when rationales about connectivity clash. (For those interested: I am thinking along the lines of the concept of the “orders of worth” by French sociologists Thévenot and Boltanski.) These rationales include: 1) a domestic rationale, which emphasises personal relations, reputation and trust; 2) a market rationale in which the legitimate criterion for evaluation is the price and legitimate leadership equates to purchasing power; and 3) a civic rationale that bases decision-making about interconnection in collective interest and aims for solidarity and equality. All of these notions come to the fore in conflicts about de-peering. Let’s look at them one by one.

Personal relationships between networkers go way beyond peering (a topic for another article), but they surely accompany most peering relationships that are perceived as important by one of the parties. Some of these extend over long periods of time, and so de-peering can become emotional. One interviewee recalls a de-peering notice that “was a copy of the email I had sent him in my previous job, just with the names changed”. Similarly, others say, “de-peering is often quite a sensitive matter”, “it is sometimes taken personally”, “usually, the counterpart is upset” and, “this is not just about the hard facts of interconnecting; it is also about wounded pride”.

One networker even described how he chose to execute a number of de-peerings by withdrawing from an Internet exchange point all together – just to create the impression that the de-peering was impartial. He then took selected peers over to a private interconnection elsewhere.

It is important to note, though, that not one of the networkers I interviewed questioned that the principles of a market economy should apply to Internet interconnection, including the liberty to strive for profits, to peer freely only as long as there is mutual interest and to engage in competition. In fact, network operators commonly contain and solve conflicts within the market rationale without it even becoming public. For instance, they will clearly shut down a connection with a network that starts peering with their customer networks (thereby lowering their profits), or they will likely de-peer with a network that enters into direct competition.

However, several network operators are uncomfortable with an absolute market rationale, which, as a side effect, also puts pressure on what many think of as a community. The discomfort often becomes apparent in a specific situation: when a network seeks payment for a peering relationship that had previously been settlement free. Several interviewees have found themselves in such situations, on both sides. These cases are interesting, because they present a philosophical question of whether settlement-free peering even constitutes a market relation at all. Peering does not cost the parties anything beyond connecting their networks to an Internet exchange. But once a peering is gone, it is costly to replace. In this sense, peering is quite open to definition.

Now, depending on how it is communicated, asking for money for something that was free before can lead to a showdown between network operators. There are three ways for this situation to evolve. In the first, network operators see the conflict as a power play in the market. Then, a de-peering announcement will eventually lead to re-establishing the session under commercial conditions, whereby one of the parties becomes a seller and the other one becomes a buyer.

“When folk walk away, the other party kind of goes: ‘Well, you know, I could chase them. But if I chased them, I would be a customer.’ So if you and I are peering and you cut the wire, if it’s a true peering relationship, I would go: ‘Well, I don’t care.’ But if I really needed that peering, and you cut the wire, I’m a customer. Logically, I’m more reliant on you than you’re reliant on me. You demonstrated that by cutting the wire.”

As the news travels, the paid-peering course of events reinforces the legitimacy of a market convention for others.

The second option is for the network that was de-peered from to accept the loss of connectivity, thereby keeping the definition of roles open.

Changing the benchmark of legitimacy

The third option involves a challenge: The network that was de-peered from takes the position that it is not justifiable to apply a pure market mode of evaluation to the situation. It demands re-evaluation according to another rationale that it claims to be more legitimate. This is the civic rationale. We often see it when incumbent internet service providers are involved in a conflict in which they are accused of abuse of power.

The argument goes that it is not in the collective interest to let the market solve the conflict alone and that the incumbent must treat all interested peers equally and fairly. The civic rationale translates to a formalisation of rules and eventually to public intervention. In 2012, a Swiss Internet service provider was invited to change his settlement-free peering connection with the incumbent into a paid peering for traffic levels that exceeded a ratio of 1:2 (i.e., when it would send more traffic into the incumbent’s network). The operator took the conflict to the Federal Competition Commission, arguing among other things that ratio-based price discrimination is at odds with the recent evolution of the Internet towards caching content at the edges of the network. The case was intermittently suspended when the incumbent became the subject of a related preliminary anti-trust investigation with a third network, but it has just recently been resumed.

What this example shows, however, is that peering practices can only be challenged fundamentally by making conflicts known and taking them to a higher level in the public sphere. Publicity is what forces the parties to justify their actions and make them accessible to a broader evaluation. However, even the most insightful networkers warn against side effects of “well-meant” interconnection regulation. That is why calling upon the regulator more often remains a threat than something that is actually done.

Congestion is the new de-peering

With this in mind, two more recent developments may not come as a surprise:

  1. Peering policies are on the rise. Especially sought-after Internet service providers document the criteria that another network has to fulfil to qualify for peering. This serves them in two ways: vis à vis the regulator, the peering policies allow them to argue that they will treat every peering partner equal. And vis à vis potential peers, peering policies signal an impersonal decision process. They also signal an impersonal decision process for potential peers. In the meantime, every peering policy probably has a clause that allows the network to make business decisions (i.e., exceptions).
  2. Congestion is the new de-peering. Representatives from the largest networks were probably the first ones to realise that “de-peering between tier 1 networks is practically impossible”. It would create a fragmented Internet and a public uproar would be guaranteed. But even with other legacy peerings, “it is easier to let things live on forever than create a fuss about it or potentially have a fuss created about it, [so] we do not de-peer,” says one tier 1 network operator. Or, as another interviewee said provocatively:

“If I am a carrier, then it is better for me to not make any statement or decision that looks like an action...because if I make an action that looks like I am forcing an upgrade or forcing a network to pay, then that is potentially an area that particularly socially is kind of negative, and potentially from a regulatory viewpoint...So it is better for me to appear incompetent rather than actively seeking to extract a rent. So if I do not upgrade, if I have very little contact with a company, all I have to do is wait.”

Learning from bad experiences with regard to their reputation in the community, network operators who see the need to de-peer for commercial reasons may choose a softer tone to avoid open conflicts. This is actually in line with what most network operators want anyway when it comes to de-peering: personal communication, empathy, timely notice, and appropriate grace periods that allow those who have been de-peered from to transfer their traffic gracefully. What they also want is honesty and clarity – not de-peering in disguise. In light of both regulatory threats and the fact that it is the uncertainties where market opportunities reside, the latter may be wishful thinking for the time being.

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