/31 subnet
A /31 prefix equals subnet mask 255.255.255.254 and wildcard 0.0.0.1. It holds 2 addresses, 2 of them usable by hosts.
/31
- Subnet mask
- 255.255.255.254
- Wildcard mask
- 0.0.0.1
- Binary mask
- 11111111.11111111.11111111.11111110
- Total addresses
- 2
- Usable hosts
- 2
- Example network
- 10.0.0.0/31
- Example range
- 10.0.0.0 – 10.0.0.1
- How many fit
- 8,388,608 × /31 in a /8, 32,768 × /31 in a /16, 128 × /31 in a /24
Under RFC 3021 both addresses of a /31 can be assigned on a point-to-point link. There is no network or broadcast address.