More detailsNeighboring subnets, expanded address, reverse DNS, and hextet breakdown
Neighboring /44 subnets
- Expanded address
- Compressed address
- Network (expanded)
- Last address (expanded)
- Prefix mask
- Total addresses (exact)
- Reverse DNS (PTR)
- Host bits / network bits
Hextet breakdown
Quick facts for IPv6 /44
- Prefix mask: ffff:ffff:fff0::
- Total addresses: 2⁸⁴
- Approx. count: 1.93 × 10²⁵
- /64 subnets: 2²⁰
IPv6 /44 reference guideBit split, overview, key facts, sizing tables, design notes, standards, and FAQ
Network / host bit split
- Network bits
- 44
- Host bits
- 84
- Prefix mask
- ffff:ffff:fff0::
- Total addresses
- 2⁸⁴
- Approx. count
- 1.93 × 10²⁵
- /64 subnets
- 2²⁰
- Addresses formula
- 2^84
- /64 relationship
- 2²⁰ × /64 subnets
Overview
A /44 provides 16 /48 site allocations (2⁸⁴ addresses). It is a convenient size for organizations that operate a handful of large sites, each of which can still subdivide its /48 into thousands of /64 LANs.
Common use cases
- Multi-site enterprises
- Organizations needing several /48s
Key facts
- A /44 fixes 44 network bits and leaves 84 host bits — 2⁸⁴ total addresses.
- In network design terms, /44 is typically a enterprise or multi-site allocation.
- You can subnet a /44 into 2²⁰ /64 LANs.
- At site scale, /44 equals 2⁴ /48 allocations.
Design guidance
A /44 suits organizations that have outgrown a single /48 but do not need a full /32 ISP allocation. Plan your addressing scheme before delegating: assign one /48 (or smaller) per major site, then subnet each site into /64 LANs. Document your nibble boundaries so future growth does not force renumbering.
Practical example
An ISP holding 2001:db8:abcd::/44 might announce the entire /44 to upstream providers as one BGP route, then delegate /48 blocks such as 2001:db8:0001::/48 and 2001:db8:0002::/48 to business customers. Each customer subnets their /48 into /64 LANs.
Related RFCs and standards
- RFC 4291IPv6 Addressing Architecture
Prefix sizing reference
Frequently asked questions
Common questions about IPv6 /44 blocks, prefix sizes, and use cases.