AS9689 SKB-FCABLE-AS SK Broadband Co Ltd

AS9689 (SKB-FCABLE-AS) is held by SK Broadband, Inc., one of South Korea's three major fixed-line broadband providers and a wholly owned subsidiary of SK Telecom. The company is the former Hanaro Telecom, which pioneered ADSL in Korea and was renamed after SK Telecom acquired it in 2008. The FCABLE handle points at the cable-broadband side of the estate rather than the operator's backbone.

What it's used for

This is consumer access space, and at scale: 164 IPv4 prefixes carrying 291,840 addresses, no IPv6, with only 2 observed BGP neighbours. That pairing is the whole story. Nearly 300,000 addresses would look like a mid-sized carrier on volume alone, but a carrier earns its volume by peering — hundreds of adjacencies, a customer cone beneath it. Two neighbours means this AS sells nothing downstream: it is a pool of subscriber addresses hanging off its parent's backbone.

The prefix list agrees. The inventory is built from large Korean access blocks — 124.254.128.0/17, 115.161.0.0/17, 223.131.0.0/17, 123.109.0.0/17, 112.212.0.0/17, 58.145.0.0/17 — then a long tail of /18s and /19s carved from those same ranges. Announcing a /17 alongside its own constituent /18s and /19s is how a broadband operator pins parts of an aggregate to regional aggregation points while keeping the covering route. That, plus the number of /17-scale blocks, is a residential network: pools handed to home lines, not server space.

Notable

• SK Broadband runs several ASNs; this is one part of the estate, not the whole operator.
• The two-neighbour figure is typical of a subsidiary eyeball AS whose transit is supplied in-group by its parent.