progala / max-parent-pfx-length

Computer maximum parent prefix length given child prefix lengths

max_parent_pfx_length

Compute largest parent prefix length given child prefix length(s).

Usage:

Import as a function

max_parent_pfx_len(pfx_lengths, ipv6=False)

:param pfx_lengths: iterable: prefix lengths :param ipv6: bool: set to False for IPv4 prefix lengths, True for IPv6 :return: int: computed largest prefix length

Example:

from max_parent_pfx_length import max_parent_pfx_len

max_parent_pfx_len([26,27,28,29])

max_parent_pfx_len([96,96,97,97], ipv6=True)

Use from the command line

• Provide one or more prefix lengths, separated by commas

$ max_parent_pfx_length prefix_lengths [-ipv6]

• Compute max prefix lengths for multiple lines of inputs stored in a file

$ cat ex_pfx_lengths_ipv4.txt | xargs -L 1 ./max_parent_pfx_length.py [-ipv6]

References

Blog post with the implementation details: https://ttl255.com/compute-largest-summary-prefix-length-with-python/