AS10012 FUSION Rakuten Mobile, Inc.

FUSION is registered to Rakuten Mobile, Inc., but the handle and the reverse DNS both point at its origin: Fusion Communications Corporation, the fixed-line and IP-telephony carrier that pioneered Japan's 050 VoIP numbers. Rakuten bought Fusion in 2007, rebranded it Rakuten Communications, and folded it into Rakuten Mobile in 2019. The AS came along with the corporate furniture.

What it's used for

Legacy carrier and corporate-services infrastructure. The AS announces 4 IPv4 prefixes totalling 20,480 addresses and one IPv6 /32 — a small, static estate. The only sampled PTR is ae-1-0.bb1.otemachi.fcc.ad.jp: an aggregated-Ethernet interface on a backbone router in Otemachi, Tokyo's carrier-hotel district, still living under Fusion's original fcc.ad.jp domain. That is a network-element name, not a subscriber or a server.

Notable

Despite the holder's name, this is not the Rakuten mobile network. Rakuten Mobile's consumer 4G/5G traffic rides other ASes; this one shows 1 observed BGP neighbour, which is a single-homed leaf, not the multiply-connected core a national mobile operator runs. Treat AS10012 as enterprise-telephony and business-connectivity space inherited from Fusion, and do not geolocate it to handsets.

Interesting

The address blocks are old and adjacent to other 1990s Japanese carrier allocations (61.114.160.0/20 sits right beside AS10006's 61.114.176.0/20). A handle that outlives its holder is the norm rather than the exception, and FUSION is a clean example: the legal owner has changed twice, but the routing, the domain and the router names never did.