BGP FlowSpec support on provider networks

I am trying to compile data on which providers are currently
supporting BGP Flowspec at their edge, if there are any at all. The
few providers I've reached out to have indicated they do not support
this and have no intention of supporting this any time in the near
future. I'm also curious why something so useful as to have the
ability to advertise flow specification information in NLRI and
distribute filtering information is taking so long to gain a foothold
in the industry...

nLayer has offered flowspec support to customers for many years now.

It's really quite simple to use and support too, if you happen to have a
largely Juniper based network that is. I'm not aware of any other router
vendor who currently supports it, but the loss is entirely theirs.

We do have a fair bit of Crisco in the network, with Juniper primarily
in the core and peering/transit edge, so we use a route-server to feed
the flowspec routes into the Juniper core. Customers set up an ebgp
multihop session with it, and can announce flowspec routes (or standard
blackhole via bgp communities) for anything in their register
prefix-list. It's also quite handy for distributing internal use packet
filters too.

As for why something so (insanely) useful is slow to be adopted... There
are a few reasons, but mostly:

1) A healthy dose of inter-vendor politics.

2) A silly religious belief that bgp shouldn't be used to carry firewall
information, and that some other protocol should be invented instead. I
think the counter-argument to that is the ability to do inter-provider
filtering is precisely why it should be done via bgp. and the success of
the current implementation proves how well it works.

3) Another large network who shall remain nameless once used a third
party flowspec speaking piece of software which shall also remain
nameless, and managed to blackhole their entire network for a noticeable
amount of time. As with anything combining the words "network wide
protocol" and "packet filter", a healthy amount of user discretion is