if ( !preg_match( '/^[0-9a-f]{12}$/i', $nodeId ) ) {
$nodeId = MWCryptRand::generateHex( 12, true );
$nodeId[1] = dechex( hexdec( $nodeId[1] ) | 0x1 ); // set multicast bit
if ( !preg_match( '/^[0-9a-f]{12}$/i', $nodeId ) ) {
$nodeId = MWCryptRand::generateHex( 12, true );
$nodeId[1] = dechex( hexdec( $nodeId[1] ) | 0x1 ); // set multicast bit