AS7843 TWC-7843-BB

TWC-7843-BB is one of the Time Warner Cable autonomous systems inherited by Charter Communications after the 2016 merger. It is operated today as part of Charter's Spectrum network.

What it's used for

• Cable broadband service to homes. Despite the BB (backbone) suffix in the handle, the announced space is overwhelmingly subscriber addressing.
• Reverse DNS is the standard Charter residential template: addresses in 66.61.0.0/16, 69.134.0.0/17, 24.30.192.0/19, 65.28.192.0/19 and 76.85.224.0/19 resolve as syn-066-061-000-001.res.spectrum.com and similar. The res label is Charter's residential zone.
• Older Road Runner infrastructure names survive alongside it on the routers, in the form ae5-3201.irtnoh-mx41.natcky.rr.com.

Notable

• The handle is a kind trap. A network named -BB invites being filed as backbone or transit; the rDNS says otherwise. Roughly 300,000 addresses of res.spectrum.com subscriber space is an eyeball network, and traffic from it is home users.
• Charter runs many legacy Time Warner Cable and Bright House ASNs alongside its own. Address space is regional here (holdovers from Time Warner's franchise footprint), so a single geolocation for the whole AS is a poor fit.

Interesting

• The rr.com domain in the router names is Road Runner, the Time Warner Cable consumer broadband brand retired in favour of Spectrum. The reverse-DNS zones outlived the brand by a decade, which is why one AS answers to three company names at once.