@walk = `$SNMPWALK -v 1 $HOST -c $COMMUNITY interfaces.ifTable.ifEntry.ifDescr`;

%interfaces = ();

my $count = 0;

foreach $interface (@walk)
{
 @ifDescr = split("=",$interface);
 if($ifDescr[0] =~ m/.(\d*)\s$/) { $ifNumber = $1; }

 $_ = $ifDescr[1];
 if($ifDescr[1] =~ m/STRING:/)		# Some SNMP Agents add field type identifier before
 { 					# value, so we omitting it.
  m/STRING:\s(\S*)/;
  $interfaces{$ifNumber} = $1;
 } else
   {
    m/\s(\S*)/;
    $interfaces{$ifNumber} = $1;
   }
 $count++;
}

print "Number of Interfaces found: $count\n\n";

if($WITH_RRD)
{
 $samples_4hrs = (60 * 4) / $CHECK_INTERVAL;
 $average_1day = 30 / $CHECK_INTERVAL;
 $average_1mon = $average_1day * 4;

 if ((30%$CHECK_INTERVAL) or ((60*4)%$CHECK_INTERVAL))
 {
  die "\nERROR: Value \$CHECK_INTERVAL is illegal. Enter another and try again.\n";
 }
}

# - Writing service definitions fo file.
open (CONFIG, ">>$OUTPUT_SERVICE_FILE");
print CONFIG "# - Service definitions for 'check_traffic' plugin\n\n";
foreach $ifNumber (keys %interfaces)
{

 $_ = `$SNMPGET -v 1 $HOST -c $COMMUNITY interfaces.ifTable.ifEntry.ifSpeed.$ifNumber`;
 m/\s(\d*)\s$/;
 $max_speed =  $1 / 8;
 if(!$max_speed)
 {
  print "Can't determine maximum speed for interface $interfaces{$ifNumber}.\n";
  print "Enter it manually [bps]: ";
  chop($max_speed = <STDIN>);
 }

 if($WITH_RRD)
 {
  $start_time = time;
  $db_file = $HOST."_".$interfaces{$ifNumber}.".rrd";
  `$RRDTOOL create $DB_PATH/$db_file --start $start_time DS:input:COUNTER:600:U:U DS:output:COUNTER:600:U:U RRA:AVERAGE:0.5:1:$samples_4hrs RRA:AVERAGE:0.5:$average_1day:48 RRA:AVERAGE:0.5:$average_1mon:372 RRA:MAX:0.5:1:48 RRA:MAX:0.5:$average_1day:48 RRA:MAX:0.5:$average_1mon:372`;
  create_rrd_cgi($HOSTNAME,$interfaces{$ifNumber},$db_file);
 }