> I don't feel I have an understanding of how peering would change under proposed net neutrality rules.

tl;dr: I don't think the neutrality end of the rules would change peering at all, and peering disputes are never grounded in the kinds of things that neutrality seeks to protect. Title II classification permits the FCC to arbitrate peering disputes, which is a desirable side effect for people who just want to watch Netflix without buffering, but doesn't make it a neutrality issue.

Longer version:

Netflix reached Comcast customers through a third-party transit provider named Cogent. Cogent and Comcast have their networks connected together, and Netflix's volume of traffic was such that the links from Cogent -> Comcast became saturated, resulting in congestion and traffic issues for Comcast customers trying to get their packets from Netflix to their Comcast line. Non-Netflix traffic on this same link degraded, as well - but Netflix was the lion's share of the traffic, and online video tends to be more visibly sensitive to congestion issues than most other forms of traffic, so Netflix became the poster child for the problem.

Cogent and Comcast had a settlement-free peering agreement, broadly meaning that they agreed to exchange traffic with one another without charging for it, and with each side reasonably contributing to maintaining its end of the link. I'm remembering the details vaguely, but IIRC, Comcast claimed that the agreement's settlement-free status depended on maintenance of a roughly equal exchange ratio - traffic in from Cogent to Comcast should be appropriately balanced with traffic out from Comcast over Cogent. Netflix in particular skewed the ratio hard such that traffic in massively outweighed traffic out.

Historically, settlement-free peering agreements included provisions (or at least an understanding) that each party would built out their half of link capacity necessary to handle the exchanged traffic. As demand goes up, each party is responsible for contributing to the link's overall capacity. Comcast's claim was that Cogent's traffic ratios were so out of whack that Cogent should pay for the link upgrade. Cogent refused to pay for the link upgrade, citing the settlement-free nature of the peering relationship. Since nothing got upgraded, the link remained saturated in the face of increasing demand, until Netflix got tired of Comcast and Cogent slap-fighting and peered directly with Comcast, so they could deliver their bits directly to Comcast's customers without having to go through a transit provider (they had previously had similar issues with Level3, another transit provider). As I understand it, Cogent has a reputation for abusing traffic balances to offer cut-rate transit - they have a long and storied history of fierce peering disputes with a large number of peers, which makes me somewhat sympathetic to Comcast's position in this case (ick!)

So, as I understand it, Comcast was "throttling Netflix traffic" in the same way that a straw throttles nitrogen flow when you blow air through it - that is, traffic (air) was congested and limited, but it wasn't limited because it was Netflix (nitrogen) traffic, it was limited because the link was saturated (the straw was full of air), and it didn't really matter if it was Netflix or email or porn or what - if it went over that link, it was subject to routing issues. It's my non-expert, non-legal opinion that Comcast wouldn't be in violation because the Open Internet Order applies to a company's management of its own network, not of the interconnection points between networks, and because link saturation is not "impair[ment] or degrad[ation of] lawful Internet traffic on the basis of content, applications, services, or non-harmful devices". As long as all packets are congested equally, it's still being treated neutrally!

It's my opinion that Comcast absolutely was using Netflix's traffic as a bargaining chip to try to force Cogent into paying for the upgrade. Whether that was justified or not is a lot more nuanced than "omg, Comcast is blocking my Netflix, they must be evil!", though. As pertains to the regulations, Title II classification does grant the FCC the authority to step into peering disputes and take action if it deems a company's actions in a peering dispute to not be "just and reasonable", and would have allowed the FCC to step in and slap one party into compliance, thereby fixing the issue. That isn't a neutrality issue, though, and I'm not all that sure that Comcast would have been the losing party in an FCC mediation of the dispute.