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Cloud IPv6 Range & Network Performance Analyzer
Understand IPv6 Subnetting and Ranges
Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. Unlike IPv4, which uses 32-bit addresses, IPv6 uses 128-bit addresses, allowing for a vastly larger address space.
This IPv6 Subnet Range Calculator allows network administrators and cloud architects to visualize and calculate the range of IP addresses available within a specific subnet block.
How IPv6 Addresses are Structured
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits. The groups are separated by colons (:). For example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334.
To simplify representation, leading zeros in a group can be omitted, and one sequence of consecutive zeros can be replaced with a double colon (::).
CIDR Notation: Just like IPv4, IPv6 uses Classless Inter-Domain Routing (CIDR) notation to define the subnet mask. The notation adds a slash followed by a decimal number at the end of the address (e.g., /64), indicating the number of bits used for the network prefix.
Calculating the Host Count
The number of available addresses in an IPv6 subnet is calculated based on the number of bits remaining for the Interface ID (Host portion). Since the total length is 128 bits, the formula is:
For example, a standard /64 subnet leaves 64 bits for hosts, resulting in:
This immense size is designed to allow for stateless address autoconfiguration (SLAAC) and to ensure we never run out of addresses again.
Common IPv6 Prefixes
- /128 - A single specific host address (similar to a /32 in IPv4).
- /64 - The standard size for a LAN or a single subnet. It is the smallest subnet size recommended for use where SLAAC is desired.
- /56 - Often assigned to small business sites or home networks by ISPs.
- /48 - The standard allocation for a larger enterprise site.
Use the calculator above to verify your subnet boundaries and ensure your cloud network architecture is correctly segmented.