AS9607 BBTOWER BroadBand Tower, Inc.

AS9607 (BBTOWER) is held by BroadBand Tower, Inc., a Japanese data-centre and cloud operator. The company runs carrier-neutral colocation facilities in central Tokyo and in Umeda, Osaka, and sells colocation, hosting, managed services and storage to media, gaming and telecoms customers.

What it's used for

The reverse DNS reads like a data-centre inventory rather than an ISP's subscriber pool. Sampled addresses resolve to names such as ethernet1-2.bbfw-01.colo03.bbtower.ne.jp, user.ge-0-0-43.aggr0502.colo05.bbtower.ad.jp and user.ge-0-0-0.medge0901.colo01.bbtower.ad.jp: firewall and aggregation-router interfaces tagged with the site they live in (colo01, colo03, colo05), with user. marking the customer-facing side of the port. Others fall back to the dotted-quad form 208x111x48x5.bbtower.ad.jp. The address footprint fits: 19 IPv4 prefixes for only 31,232 addresses, heavily fragmented into /21s, /22s, /23s and /24s, which is what colocation space looks like when it is carved up per tenant rather than handed out as access pools. The 28 observed BGP neighbours are consistent with a facility operator that peers at Japanese exchanges and buys multiple upstreams to give tenants carrier choice, without itself being a transit carrier.

Notable

• 208.111.48.0/21 is an ARIN-region block sitting inside an otherwise APNIC-region footprint, and it is announced with bbtower.ad.jp PTRs like the rest.
• The naming convention colo0N in the PTRs directly exposes which of the company's sites a given address is homed to.
• Three IPv6 blocks are announced, including 2001:370::/32 and 2404:c700::/32.