def parseURN (urn):
    """
    Parse a URN and returns the name and domain of the node.
    :param urn:  string
    :return:  a tuple (node,domain,port,link)
    """

    (x,y,z,domain,node,port,link) = tuple(urn.split(":"))
    if domain and "domain=" in domain:
        (x,domain) = domain.split('=')
    if node and "node=" in node:
        (x,node) = node.split('=')
    if port and "port=" in port:
        (x,port) = port.split('=')
    if link and "link=" in link:
        (x,link) = link.split('=')
    return(node,domain,port,link)