The m-labs discussion list has had some traffic lately trying to figure out why NDT throughput changed abruptly.
Apparently Cogent (and others?) has started setting ToS bits on retail customer traffic, and leaving wholesale traffic as-is (see below).
Observed ToS settings include 0x00, 0x28, and 0x48:
Nice to see at least some network operators talking about what they're doing.
Justin
<blockquote>
Due to the severe level of congestion, the lack of movement in negotiating possible remedies and the extreme level of impact to small enterprise customers (retail customers), Cogent implemented a QoS structure that impacts interconnections during the time they are congested in February and March of 2014. Consistent with recommendations from BITAG (Broadband Internet Technical Advisory Group: http://www.bitag.org/documents/BITAG_-_Congestion_Management_Report.pdf), Cogent prioritized based on user type putting its retail customers in one group and wholesale in another. Retail customers were favored because they tend to use applications, such as VoIP, that are most sensitive to congestion. M-Labs is set up in Cogent’s system as a retail customer and their traffic was marked and handled exactly the same as all other retail customers. Additionally, all wholesale customers traffic was marked and handled the same way as other wholesale customers. This was a last resort effort to help manage the congestion and its impact to our customers. Hank Kilmer Cogent </blockquote>