The value of 291 seems awfully high. Most of the ip's that I work with have 0, 1, or 2, sometimes more. They refer to the number of prefixes, "/nn", for point-to-point networks. The + sign means that it has been signed with an extra 32-bit integer, again, for point-to-point broadcast purposes. It may make more sense if we look at the whole bundle of methods.

Sounds nonsensical

$ perl -MDDS -Mbignum -e " Dump 6123456789; "
$Math_BigInt1 = {
                  sign  => '+',
                  value => [
                             3456789,
                             612
                           ]
                };
bless( $Math_BigInt1, 'Math::BigInt' );
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Also, PerlMonks FAQ: Linking on PerlMonks: What shortcuts can I use for linking to other information?#All Links Within PerlMonks Should Be Relative