The vast majority of Iranian ISPs' international transit connectivity is through AS12880 DCI , which is a government run telecom authority. Google "AS12880 DCI Iran" for more info. DCI is also responsible for layer 2 transport and DWDM services for smaller downstream ISPs, on other international terrestrial fiber links, which are opaque to us NANOG list people from the perspective of global v4/v6 routing table/prefix announcement analysis.

On Mon, Nov 18, 2019 at 7:10 AM Sean Donelan <sean@donelan.com> wrote:

Its very practical for a country to cut 95%+ of its Internet connectivity.
Its not a complete cut-off, there is some limited connectivity. But for
most ordinary individuals, their communication channels are cut-off.

https://twitter.com/netblocks/status/1196366347938271232