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.
Interconnection
Peering at a glance
Internet exchanges
Recorded at 4 exchanges in 3 countries, largest first.
| Exchange | Location | Their address |
|---|---|---|
| NAPAfrica IX Johannesburg | Johannesburg, South Africa | 196.60.8.213 |
| NAPAfrica IX Cape Town | Cape Town, South Africa | 196.60.70.40 |
| IX.br (PTT.br) Belo Horizonte | Belo Horizonte, Brazil | 200.219.139.166 |
| UAE-IX | Dubai, United Arab Emirates | 185.1.8.41 |
Transit providers
51 upstream, 6,437 downstream and 6,449 adjacent networks observed; most-used upstreams first.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-10, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 4,697 prefixes · 27.37M addresses IPv6 306 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 5,003 |
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
- Allocation
- assigned
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.
Routing security
RPKI and IRR
- RPKI
- 9% valid · 188 valid, 1,912 with no ROA 4 RPKI-invalid
- ROAs
- 1,291 authorising AS3356
- ASPA
- no ASPA record
- IRR
- 9% registered · 191 of 2,104 announcements 49 other origin
- Route objects
- 721 naming AS3356
Reputation
Classification and threat
Transit Tier-1 or major backbone carrying other networks’ traffic.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 431 networks and 1,775 prefixes, as published 2026-10-11. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
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 |
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere