[routing-wg] Re: Traffic between Cambridge (UK) and TDC-hosted destination (AS3292, Denmark) tromboning via North America — possible GTT interconnect issue

Hi On Wed, 29 Jul 2026 at 19:07, Ben Cartwright-Cox via routing-wg <routing-wg@ripe.net> wrote:

I have poked someone who knows more about this, but it is my understanding that TDC has this odd policy where they only peer with some networks in the US, causing the exact "harpoon" routing you have observed

OTOH, 3292 *mostly* sells paid transit in DK-area. If you are a "potential" transit customer. They will not peer with you. (Exceptions can apply) US it outside 3292's core market. Consequently, the peering policy on the flip side is much more (selectively) open. Hence the UK <=> Cogent <=> US peering <=> TDC <=> DK traffic pattern. The "maid's tale" is over a decade old. This story goes back to the 2000s.