Hi,

Hi,

On Wed, Jul 29, 2026 at 06:04:19PM +0100, Peter Keller via routing-wg wrote:

*Context / timeline:*
The end-user's building-managed ISP changed their upstream international
connectivity provider. Prior to this change, routing to the affected
destination appeared to transit Colt directly into TDC in Europe with no
issues. Since the change, we have observed the latency problem described
below. We have not been able to confirm with certainty which provider the
ISP switched to, but the timing strongly correlates with the onset of the
issue.

Basically, this won't ever get fixed until the end user raises a ticket
with their provider, and if it doesn't get fixed in a reasonable timeframe,
raise a big stink and change ISP.

Yes, you are absolutely right, but:

* at the UK end, we have very little say in this because our main internet connection is provided by the building manager. We do have a backup connection which is not affected by this problem (so far), and obviously we are not going to relinquish it any time soon ;-)

* this was one of my first suggestions to my colleague at the Danish end, and he did investigate the possibility. However, it seems that all consumer ISPs in Denmark end up going via the same provider, so that is unlikely to solve the problem.

Depending on what other replies I get, I may try to take this back to the UK ISP, but their initial response was that it was out of their scope.

Regards,

Peter

There is a reason why some transits are cheap, and ISPs that do not
care for anything but "ooh cheap transit" need to hear from their customers
why this wasn't such a good idea.  They control their network, they need
to take responsibility for it.

(Do I sound like 20 years of talking to "wanna buy cheap transit?" has
worn out my patience with certain transit networks a bit?  maybe ;-) ).

Gert Doering
        -- NetMaster