AS4991 COGENT-4991-4994

AS4991 belongs to Cogent Communications, LLC, one of the largest IP transit carriers in the world. It is registered under the ARIN handle COGENT-4991-4994, a single record covering a small run of consecutive AS numbers Cogent holds alongside its flagship [AS174](https://asn.ipinfo.app/AS174).

What it's used for

Cogent operates a global backbone selling wholesale IP transit, dedicated internet access, and Ethernet transport, largely to carriers, hosting providers, content networks, and businesses in multi-tenant office buildings. AS4991 is a secondary AS in that estate rather than the backbone itself: the ~16k addresses under it are customer and infrastructure assignments carried across the same network.

Notable

Cogent's commercial identity is built on volume and price. It has long been among the most widely connected networks by peer count, which is why its routes appear near the top of transit-path rankings and why Cogent shows up repeatedly in the industry's peering disputes with other large networks.

Large carriers rarely announce everything from one AS number. Acquisitions, legacy customer blocks, and regional builds accumulate spare ASNs, and consolidating them under one ARIN handle (as COGENT-4991-4994 does) is a common way to keep the registry tidy.

Interesting

The address space and AS numbers Cogent holds today are in part inherited: the company grew heavily through acquisition of earlier internet businesses, so its registry footprint is older than the Cogent brand itself.