Issue with submitting an array php form

I have a form that displays some information from a database that puts everything in a table and you are able to edit all the tables. Is issue i am having is when i click submit it says it can't find the index data_id, says its undefined. Code is below.

Table:

<form id="form" class="form-horizontal" role="form" data-toggle="validator" method="post" name="edit_interface.php">
			
			<div class="form-group">
					<label class="control-label col-sm-3" for="type">Type:</label>
					<div class="col-sm-6">
					<input name="type" class="form-control" id="type" value="<?php echo $data_interface['interface_type']; ?>">
					</div>
			</div>
			<div class="form-group">
					<label class="control-label col-sm-3" for="ip_address">IP Address:</label>
					<div class="col-sm-6">
					<input name="ip_address" class="form-control" id="ip_address" value="<?php echo $data_interface['ip_address']; ?>">
					</div>
			</div>
</div>
</div>
</div>
			<div class="col-sm-12">	
<div class="panel panel-primary">
                        <div class="panel-heading">
                             ATS Sites
                        </div>
                        <div class="panel-body">
                            <div class="table-responsive">
                                <table class="table table-striped table-bordered table-hover" id="edit_interface">
								<?php
$query_interface_data = mysql_query("SELECT * FROM site_router_interface_info WHERE router_interface_id = '$interface_id'") or die (mysql_error());

echo "<thead>";
echo "<tr>";
echo "<th>";
echo "<b>Delete Interface:</b>";
echo "</th>";
echo "<th>";
echo "<b>ID:</b>";
echo "</th>";
echo "</th>";
echo "<th>";
echo "<b>Name:</b>";
echo "</th>";
echo "<th>";
echo "<b>Speed:</b>";
echo "</th>";
echo "<th>";
echo "<b>Vendor:</b>";
echo "</th>";
echo "<th>";
echo "<b>LEC ID:</b>";
echo "</th>";
echo "<th>";
echo "<b>DID:</b>";
echo "</th>";
echo "<th>";
echo "<b>Account ID:</b>";
echo "</th>";
echo "<th>";
echo "<b>Circuit ID:</b>";
echo "</th>";
echo "<th>";
echo "<b>Support Number:</b>";
echo "</th>";
echo "<th>";
echo "<b>Notes:</b>";
echo "</th>";
echo "</tr>";
echo "</thead>";
echo "<tbody>";

while ($info = mysql_fetch_assoc($query_interface_data))
{

$data_id = $info['id'];
$name = $info['name'];
$speed = $info['speed'];
$vendor = $info['vendor'];
$lec = $info['lec'];
$did = $info['did'];
$account_id = $info['account_id'];
$support_number = $info['support_number'];
$circuit_id = $info['circuit_id'];
$notes = $info['notes'];

echo "<tr>";
?>
<td align='middle'>
<a href=remove_router_interface_data.php?id=<?php echo $id; ?>&interface_id=<?php echo $interface_id ?>&router_id=<?php echo $router_id ?>&data_id=<?php echo $data_id; ?> onclick="return confirm('Are you sure you want to Delete this Item?')"><img src='assets/img/decommission_asset.png' width='30' height='30' align='middle'/></a>
</td>
<td><input size="10" class="form-control" type="text" name="data_id[]" value="<?php echo $data_id ?>" readonly> 
</td>
<td><input size="10" class="form-control" type="text" name="name[]" value="<?php echo $name ?>"> 
</td>
<td><input size="15" class="form-control" type="text" name="speed[]" value="<?php echo $speed ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="vendor[]" value="<?php echo $vendor ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="lec[]" value="<?php echo $lec ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="did[]" value="<?php echo $did ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="account_id[]" value="<?php echo $account_id ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="circuit_id[]" value="<?php echo $circuit_id ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="support_number[]" value="<?php echo $support_number ?>"> 
</td>
<td><input size="10" class="form-control" type="text" name="notes[]" value="<?php echo $notes ?>"> 
</td>
<?php
echo "</tr>";

}
?>

</tbody>
			</table>
                        </div>
                        </div>
						
                    </div>
					<button name='form' type="submit" class="btn btn-primary" id="submit"> Edit Interface</button>	
            </form>

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Here is the code when you click the button:

if($_SERVER['REQUEST_METHOD'] == "POST") {

$type = $_POST['type'];
$ip_address = $_POST['ip_address'];

mysql_query("UPDATE site_router_interface SET 
interface_type='".$type."',
ip_address='".$ip_address."'
WHERE id = '".$interface_id."'") or die (mysql_error()); 

for ($i=0; $i < count($_POST['data_id']); $i++){

$data_id = $_POST['data_id'][$i];
$name = $_POST['name'][$i];
$speed = $_POST['speed'][$i];
$vendor = $_POST['vendor'][$i];
$lec = $_POST['lec'][$i];
$did = $_POST['did'][$i];
$account_id = $_POST['account_id'][$i];
$support_number = $_POST['support_number'][$i];
$notes = $_POST['notes'][$i];


mysql_query("UPDATE site_router_interface_info SET 
name='".$name."',
speed='".$speed."',
vendor='".$vendor."',
lec='".$lec."',
did='".$did."',
account_id='".$account_id."',
support_number='".$support_number."',
notes='".$notes."'
WHERE id = '".$data_id."'") or die (mysql_error());

}
echo "Interface Saved";


/*
	$server = $_SERVER['HTTP_HOST'];
$current_folder = basename(dirname(__FILE__));

header( "Location: http://$server/$current_folder/router_information.php?id=$id&router_id=$router_id" ) ;
*/
}

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