def node_id_s
      node_bytes = [ @node_id >> 32, @node_id & 0xFFFF_FFFF].pack("NN")
      elements   = node_bytes.unpack("CCa6")
      node         = elements[-1].unpack('C*')
      elements[-1] = '%02x%02x%02x%02x%02x%02x' % node
      "%02x%02x-%s" % elements
    end
def node_id_s
      node_bytes = [ @node_id >> 32, @node_id & 0xFFFF_FFFF].pack("NN")
      elements   = node_bytes.unpack("CCa6")
      node         = elements[-1].unpack('C*')
      elements[-1] = '%02x%02x%02x%02x%02x%02x' % node
      "%02x%02x-%s" % elements
    end
Public: Return the hexidcimal UUID string representation of just the
 node_id. This is just the last 2 parts