More detailsNeighboring subnets, expanded address, reverse DNS, and hextet breakdown
Neighboring /36 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 /36
- Prefix mask: ffff:ffff:f000::
- Total addresses: 2⁹²
- Approx. count: 4.95 × 10²⁷
- /64 subnets: 2²⁸
IPv6 /36 reference guideBit split, overview, key facts, sizing tables, design notes, standards, and FAQ
Network / host bit split
- Network bits
- 36
- Host bits
- 92
- Prefix mask
- ffff:ffff:f000::
- Total addresses
- 2⁹²
- Approx. count
- 4.95 × 10²⁷
- /64 subnets
- 2²⁸
- Addresses formula
- 2^92
- /64 relationship
- 2²⁸ × /64 subnets
Overview
A /36 is a regional-scale allocation, larger than a single ISP /32 but smaller than an RIR /12. It holds 2⁹² addresses — 16 /32 ISP blocks — and is sometimes assigned to national research networks or very large multi-ISP organizations.
Common use cases
- National research and education networks
- Very large multi-site organizations
- Regional address-space aggregation
Key facts
- A /36 fixes 36 network bits and leaves 92 host bits — 2⁹² total addresses.
- In network design terms, /36 is typically a enterprise or multi-site allocation.
- You can subnet a /36 into about 2²⁸ /64 LANs.
- At site scale, /36 equals 2¹² /48 allocations.
Design guidance
A /36 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::/36 might announce the entire /36 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 /36 blocks, prefix sizes, and use cases.