Which is as it should be. Then somebody (not clear who) apparently took explicit steps to stop the traffic from taking these other paths.
Surprising. Severing a peering relationship is one thing, purposely filtering large swathes of the Internet over other all links is quite another. As I said, this is surprising behaviour, but not simple de-peering. And I'm sure that any Tier 1 has enough peering relationships with enough other Tier 1 networks that they can always buy temporary transit privileges over an existing link.
This is not surprising at all. One of the networks making arrangements to purchase transit immediately may help the customers of both networks in the short term, but the reality is that peering problem still exists and it immediately shows a weakness on one side. If they're willing to pay, they may agree to peering with settlements as well or just continue to buy transit. No transit free network is going to allow this to happen. It is in their best interest to make the de-peering as painful as possible to get a quicker resolution that satisfies both parties. Maybe not the greatest analogy, but think labor strikes and scabs (temporary workers willing to cross the picket line). If there were no repercussions to allowing scab workers to cross a picket line (lack of training leading to mistakes/accidents, pressure placed by the unions, negative publicity causing customers to boycott the company, etc), then unions wouldn't exist, or at least wouldn't have the strength needed to put the issue to rest as quickly as possible. When your customers (and the other networks customers) are complaining, the issue gets resolved much quicker. The Telia/Cogent depeering went longer than most, but it usually gets the job done.
-w
Randy