use strict;
use warnings;
use Data::Dumper;

my %key_hash;

local $/ = "\n\n"; 
while ( <DATA> ) {
  if ( /^KEY: ([^\n]+)/ ) {
    my $current_key = $1;

    while ( m/OID: ([^\n]+)\nNAME: ([^\n]+)|Error Status (.*)/g ) {
      if ( defined $3 ) {
        $key_hash{$current_key}{Error_Status} = $3;
      }
      else {
        push @{$key_hash{$current_key}{OID_NAME}}, [$1,$2];
      }
    }
  }
}

print Dumper \%key_hash;

##</code><code>##

__DATA__
KEY: request_1.3.6.1.2.1.2.2.1.12.27
OID: 1.3.6.1.2.1.2.2.1.11.27
NAME: ifInUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.15.27
NAME: ifInUnknownProtos.27
OID: 1.3.6.1.2.1.2.2.1.14.27
NAME: ifInErrors.27
OID: 1.3.6.1.2.1.2.2.1.13.27
NAME: ifInDiscards.27
OID: 1.3.6.1.2.1.2.2.1.18.27
NAME: ifOutNUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.17.27
NAME: ifOutUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.20.27
NAME: ifOutErrors.27
OID: 1.3.6.1.2.1.2.2.1.19.27
NAME: ifOutDiscards.27
OID: 1.3.6.1.2.1.2.2.1.10.27
NAME: ifInOctets.27
OID: 1.3.6.1.2.1.2.2.1.16.27
NAME: ifOutOctets.27
OID: 1.3.6.1.2.1.1.3.0
NAME: sysUpTime.0
OID: 1.3.6.1.2.1.2.2.1.5.27
NAME: ifSpeed.27
OID: 1.3.6.1.2.1.2.2.1.3.27
NAME: ifType.27
Error Status No error

KEY: response_1.3.6.1.2.1.2.2.1.12.27
OID: 1.3.6.1.2.1.2.2.1.11.27
NAME: ifInUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.15.27
NAME: ifInUnknownProtos.27
OID: 1.3.6.1.2.1.2.2.1.14.27
NAME: ifInErrors.27
OID: 1.3.6.1.2.1.2.2.1.13.27
NAME: ifInDiscards.27
OID: 1.3.6.1.2.1.2.2.1.18.27
NAME: ifOutNUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.17.27
NAME: ifOutUcastPkts.27
OID: 1.3.6.1.2.1.2.2.1.20.27
NAME: ifOutErrors.27
OID: 1.3.6.1.2.1.2.2.1.19.27
NAME: ifOutDiscards.27
OID: 1.3.6.1.2.1.2.2.1.10.27
NAME: ifInOctets.27
OID: 1.3.6.1.2.1.2.2.1.16.27
NAME: ifOutOctets.27
OID: 1.3.6.1.2.1.1.3.0
NAME: sysUpTime.0
OID: 1.3.6.1.2.1.2.2.1.5.27
NAME: ifSpeed.27
OID: 1.3.6.1.2.1.2.2.1.3.27
NAME: ifType.27
Error Status No error

##</code><code>##

$VAR1 = {
   'request_1.3.6.1.2.1.2.2.1.12.27' => {
        'OID_NAME' => [
             [
               '1.3.6.1.2.1.2.2.1.11.27',
               'ifInUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.15.27',
               'ifInUnknownProtos.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.14.27',
               'ifInErrors.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.13.27',
               'ifInDiscards.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.18.27',
               'ifOutNUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.17.27',
               'ifOutUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.20.27',
               'ifOutErrors.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.19.27',
               'ifOutDiscards.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.10.27',
               'ifInOctets.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.16.27',
               'ifOutOctets.27'
             ],
             [
               '1.3.6.1.2.1.1.3.0',
               'sysUpTime.0'
             ],
             [
               '1.3.6.1.2.1.2.2.1.5.27',
               'ifSpeed.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.3.27',
               'ifType.27'
             ]
           ],
        'Error_Status' => 'No error'
    },
   'response_1.3.6.1.2.1.2.2.1.12.27' => {
        'OID_NAME' => [
             [
               '1.3.6.1.2.1.2.2.1.11.27',
               'ifInUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.15.27',
               'ifInUnknownProtos.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.14.27',
               'ifInErrors.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.13.27',
               'ifInDiscards.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.18.27',
               'ifOutNUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.17.27',
               'ifOutUcastPkts.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.20.27',
               'ifOutErrors.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.19.27',
               'ifOutDiscards.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.10.27',
               'ifInOctets.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.16.27',
               'ifOutOctets.27'
             ],
             [
               '1.3.6.1.2.1.1.3.0',
               'sysUpTime.0'
             ],
             [
               '1.3.6.1.2.1.2.2.1.5.27',
               'ifSpeed.27'
             ],
             [
               '1.3.6.1.2.1.2.2.1.3.27',
               'ifType.27'
             ]
           ],
        'Error_Status' => 'No error'
   }
 };