Why 2-Byte ASNs Still Matter: Value, Transfer & Registry
As global networks grow, Autonomous System Numbers (ASNs) are very important for keeping routing stable, identity, and control on the internet. 4-byte ASNs are more common now because the older ranges are running out, but 2-byte ASNs (also known as 16-bit ASNs) are still very valuable. Network operators, ISPs, hosting companies, and large digital businesses all benefit from these shorter ASNs, which usually range from AS1 to AS65535. They have historical significance, technical advantages, and even long-term strategic value.
Businesses can decide if getting a 2-byte ASN is good for their long-term network presence by understanding why companies want them and how transferability and registry policies work.
What is an ASN with 2 bytes?
A 2-byte ASN is an old format ASN that uses 16 bits to encode. When ASNs were first introduced, this 2-byte space seemed like it would be enough for everyone around the world. Over time, the demand grew, which led to the introduction of 4-byte ASNs. This greatly increased the amount of space available.
But 2-byte ASNs are still recognized around the world, all routers support them, and most major internet exchanges and cloud networks accept them. Their shorter, simpler notation makes them easier to manage and better for branding or operational visibility.
What Makes 2-Byte ASNs Useful?
Even though 4-byte ASNs are available, 2-byte ASNs have some benefits:
1. Works with everything
All routing hardware, both old and new, can use 2-byte ASNs. Even though 4-byte ASNs are common, some older BGP implementations and legacy equipment still work better with 2-byte ASNs.
2. Easier to Identify
A short ASN, like AS1234, is easier to read, recognize, and remember than a longer 4-byte ASN, like AS50000. This helps big companies and service providers with branding and makes things easier to understand.
3. Value because of its history and rarity
Because there aren’t many unassigned 2-byte ASNs, they are often thought of as “premium” ASNs. Like early IPv4 ranges, scarcity makes things more desirable.
4. Simpler peering and interconnection
Internet exchanges sometimes trust well-known 2-byte ASNs more because they have been around for a long time in the global routing ecosystem.
Rules for transferring 2-Byte ASNs
A lot of businesses these days want to get a 2-byte ASN through transfer instead of direct allocation. This is because most registries don’t keep large pools of unassigned 2-byte ASNs anymore.
Transferability is based on the rules of the regional internet registry (RIR):
ARIN
- It is possible to move ASNs from one organization to another if there is a good reason.
- The person receiving the message must show that they can meet the technical requirements for BGP routing.
RIPE NCC
- Lets you transfer ASNs without having to keep paying for membership.
- Both sides need to check the registry information and paperwork.
LACNIC, APNIC, and AFRINIC
- You can make transfers, but you have to follow local rules.
- Most of the time, a technical reason is needed.
Transfers might come with extra costs for things like paperwork, updating the registry, and getting help from a broker.
IPv4Hub.net
IPv4Hub.net is a great place to get help building a reliable and secure network environment if your company plans to get an ASN or run its own routed infrastructure. The platform gives you clean IPv4 ranges that are ready to be routed, BGP documentation, and ensures that all IP blocks are ready for RPKI and ROA configurations. IPv4Hub.net also helps companies rent or buy IPv4 addresses, keep their registry up to date, and keep their IP reputation strong. IPv4Hub.net makes it easy, safe, and efficient to get high-quality IPv4 resources, whether you’re expanding your network footprint or setting up a new ASN.
Requirements for the registry and reasons for them
Before giving out or moving a 2-byte ASN, RIRs usually need:
- A real technical need for multi-homing
- Proof that BGP will be used in 30 days
- Legal and administrative checks on the organization making the request.
- Correct registry data for WHOIS records
The process of justification makes sure that ASNs, especially rare 2-byte ones, are used correctly and not wasted on networks that aren’t active.
How Much Does a 2-Byte ASN Cost?
The price is very different depending on where you live, how available it is, and how you get the ASN.
Direct Allocation of Registry
- ARIN: $550–$650 to start, plus renewal fees
- RIPE NCC: Members get it for free (annual fee of €1,400)
- APNIC/LACNIC/AFRINIC: Depends on the type of membership
Market for Transfers
Because 2-byte ASNs are hard to find, transferred ASNs may cost:
- $300 to $1,200, depending on how much demand there is
- Extra paperwork or fees for the broker
2-byte ASNs with number patterns that are easy to spot or “premium” may sell for even more.
Is it worth it to get a 2-byte ASN?
If your business has a 2-byte ASN, it can help you:
- Runs important infrastructure with several upstream providers
- Needs full routing independence
- Wants an ASN that is easy to remember for branding or operational clarity
- Handles big services like hosting, VPN, CDN, or SaaS platforms
A standard 4-byte ASN is usually enough for small businesses. A 2-byte ASN can be a useful long-term asset for networks that want better visibility, trust, compatibility, and operational flexibility.
2-byte ASNs are still important in the global routing ecosystem because they work with everything, are easy to use, are rare, and have a lot of operational value. Businesses can make smart choices about whether to get one by knowing how much it costs, how easy it is to transfer, and what the registry requirements are. A 2-byte ASN can make your internet infrastructure and long-term routing strategy much stronger when used with high-quality IPv4 resources from trusted sources like IPv4Hub.net.