What if we could declare a new copy of my %frame each time we detect the start of a new frame record?

We wouldn't need to initialize %info = (). We wouldn't need to test if (%info). We could store \%frame instead of the clever but busy { %info }.

All it takes is loop labels:

# detect start of new data record
my $FRAME_BEGINNING = qr/^Frame /;

# store parsed Frame records
my @frame_list;


SKIP:
while (<DATA>) {
    next SKIP if !/$FRAME_BEGINNING/;

    FRAME:
    while (!eof) {
        my %frame;    
        DETAIL:
        while (<DATA>) {
            last DETAIL if /$FRAME_BEGINNING/;
            if (/^  *Source port: (\S+)\s+(\S+)/) {
                $frame{source_port} = $1; # also save $2?
            }
            if (/^  *Destination port: (\S+)\s+(\S+)/) {
                $frame{dest_port} = $1;
            }
            if (/^[\da-f]{4}\s+[\da-f\s]+/i) {
                push @{$frame{data}}, $_;  # save data lines
            }
        }
        push @frame_list, \%frame; 
    }
}
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