Autonomous system
AS3356 LEVEL3
Transit ARIN NSP
Summary
Lumen Technologies (Level 3)
transit tier-1 backbone
AS3356 is the former Level 3 Communications backbone, now operated by Lumen
Technologies. It is one of the largest Tier 1 networks on the internet.
What it's used for
- Global IP transit — carrying traffic between networks that pay Lumen for reachability, and settlement-free peering with other Tier 1s.
- Long-haul fiber and wholesale backbone services underpinning many other providers.
Notable
- As a Tier 1, AS3356 reaches the entire internet without buying transit from anyone; it appears in a huge fraction of internet routing paths.
- After Level 3 merged with CenturyLink (later rebranded Lumen), 3356 remained the dominant backbone ASN, absorbing much of the old CenturyLink footprint.
Interesting
- The Level 3 backbone traces its lineage to some of the earliest commercial long-haul IP networks built during the late-1990s fiber boom.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.
Address space
Summary
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 4,980 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS3356- Registry name
- LEVEL3
- Registrant
- Level 3 Parent, LLC
- Abuse contact
- abuse@level3.com
- Registered
- 2000-03-10
- Last changed
- 2018-02-20
- Status
- active
Declared
PeeringDB profile
- Name
- Lumen AS3356
- Also known as
- CenturyLink; Level3;
- Network type
- NSP
- Scope
- Global
- Traffic ratio
- Balanced
- Peering policy
- Restrictive
- Present at
- 3 exchanges
- Website
- http://www.lumen.com
PeeringDB records are maintained by the network operator and are not independently verified. Treat them as a statement of intent rather than of fact. For the observed and recorded view, see peering, which lists the exchanges Packet Clearing House has a port on file for.
Reputation
Classification and threat
Transit Tier-1 or major backbone carrying other networks’ traffic.
1 IC3 indicators addresses in this network appear in FBI IC3 cybersecurity advisories.
| Prefix | Advisory | Published |
|---|---|---|
4.1.9.9 | Improve Router Hygiene to Protect Against Russian State-Sponsored Targeting | 2026-07-13 |
Threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere