They use separate service flows and layer 3 interfaces (usually) in DOCSIS networks but they often use the same DNS infrastructure which is why I piped up. Scott Helms On Mar 2, 2018 4:46 PM, "Michel 'ic' Luczak" <lists@benappy.com> wrote: The ones I know do so on private VLANs (or ATM circuits on DSL) so anyway unrelated to any client’s address space. Also, french triple play ISPs use RFC1918 space for IPTV but again isolated of any customer network so doesn’t really matter.

On 2 Mar 2018, at 22:18, K. Scott Helms <kscotthelms@gmail.com> wrote:

I won't comment on the sanity of doing so, but _many_ service providers use EMTAs, ATAs, and other voice devices over RFC1918 space back to their core.