An AS Number (Autonomous System Number) is a unique identifier for a network on the internet. It represents a network as an independent routing entity and is used to establish identity, policy, and trust between networks.
While AS Numbers are used in BGP, their role is broader and often underpins peering, interconnection, traffic engineering, and security. You can acquire an ASN through your regional internet registry such as RIPE NCC, AFRINIC, APNIC, LACNIC, or ARIN.
Connecting your ASN to Internet Exchanges such as LINX enhances performance, resilience and network control.
What is an AS Number?
An AS Number (ASN) Is a globally unique identifier assigned to an organisations network, called an Autonomous System (any network that controls its own routing decisions and publishes its own routing polices).
As well as defining your network, ASNs also allows other networks to recognise, establish relationships, and make decisions about exchanging traffic with you.
Why do you need an AS Number?
An AS Number is essential for any organisation that wants to operate as a recognised, independent network on the internet. They provide greater control over how traffic is routed, and enable you to work with multiple provides, whilst participated in the global interconnection ecosystem.
They allow organisations to benefit from:
- Establish network independence: allowing your network to be identified as its own entity
- Connect and peer at an Internet Exchange: your ASN allows your network to be identified and to form interconnection relationships with other networks
- Improve resilience: by controlling traffic flows, helping to maintain redundancy
How to get an AS Number?
AS Numbers are issued by Regional Internet Registries (RIRs), depending on where your organisation is based:
- RIPE NCC (Europe)
- AFRINIC (Africa)
- APNIC (Asia Pacific)
Do you need an AS Number to connect at LINX?
To connect and peer at LINX, members must have their own AS Number. This allows LINX and other members to:
- Identify your network
- Establish peering relationships
- Apply routing and traffic policies
- Exchange traffic efficiently and securely.
Whether you’re an ISP, cloud provider, content platform, or enterprise, an AS Number is the foundation of interconnection.
Frequently asked questions
What does AS stand for?
AS stands for Autonomous System.
Is an AS Number the same as an IP address?
No. An AS Number identifies a network, while IP addresses identify devices or services within that network.
Can enterprises have AS Numbers?
Yes. Many enterprises operate AS Numbers to support multi-provider connectivity, peering, and resilient architectures.
Can I peer without an AS Number?
No. Peering at an Internet Exchange like LINX requires a unique AS Number.
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