AS9757 CMBI-AS-KR CMB DONDAEMOON BROADCASTING

AS9757 (CMBI-AS-KR) is registered to CMB Dongdaemun Broadcasting, one of the regional cable system operators inside CMB, a South Korean cable MSO. CMB traces back to a wired music-broadcasting business and today runs cable television and cable broadband across parts of Seoul, Daejeon, South Chungcheong, Gwangju and Daegu. This AS is the Seoul (Dongdaemun-area) piece of that group.

What it's used for

The address space is cable-subscriber space: 60 IPv4 prefixes covering 32,768 addresses, no IPv6, and 2 observed BGP neighbours. The inventory is two /18 aggregates — 110.34.64.0/18 and 122.128.192.0/18, which account for the whole 32,768 addresses — sliced into a dense run of /21s, /22s and /24s. Contiguous space chopped into small equal-sized blocks is what a cable operator's access aggregation looks like: each block maps to a headend or service area rather than to a distinct customer organisation.

The two-neighbour count confirms the eyeball reading. A network holding 32,768 addresses could in principle be a small regional carrier, but a carrier peers; this one has two adjacencies, so it buys transit and originates only its own subscriber pools. No customer cone, no sign of transit or hosting.

Notable

• CMB is one of the last independent Korean cable MSOs. Most of its peers were absorbed by mobile carriers — HCN by KT, CJ HelloVision by LG Uplus, t-broad by SK Broadband.
• This is a single regional SO within CMB, not the group's whole national footprint.
• The two /18s are announced both whole and in pieces, so the prefix count overstates how much distinct space is involved.