AS4911 CENTURYLINK-LEGACY-QWEST-SPA-MARION

CENTURYLINK-LEGACY-QWEST-SPA-MARION is one of the legacy Qwest autonomous systems now held by CenturyLink Communications, LLC, part of Lumen. The handle was rewritten during the CenturyLink/Qwest integration and preserves the Qwest lineage in its name.

What it's used for

• Carries a single large block of carrier address space announced behind Qwest's main backbone. Its only observed peer is [AS209](https://asn.ipinfo.app/AS209), the legacy Qwest backbone AS.
• Functions as a service-block AS rather than a backbone in its own right: it originates address space for carrier services and sits entirely inside the parent network.

Notable

• Distinguish this from the parent. AS4911 is a subordinate legacy Qwest AS, not the Qwest/CenturyLink backbone itself.
• Unlike most of its numeric neighbours, this ASN's ARIN registration dates to the mid-1990s, when Qwest-era carrier networks were being numbered. The number was not reissued to a modern holder.

Interesting

• The handle is an artifact of an acquisition chain: Qwest was absorbed by CenturyLink, which became Lumen, yet the ASN's name still carries the original operator's name and an internal service designation.