'Get fcns database info from fabric.
This method will return the connected node port wwn list(local
and remote) for the given switch fabric'

def get_nameserver_info(self, fabric_vsan):

    cli_output = None
    nsinfo_list = []
    try:
        cmd = [zone_constant.FCNS_SHOW, fabric_vsan, '    |    no-more']
        cli_output = self._get_switch_info(cmd)
    except exception.FCSanLookupServiceException:
        with excutils.save_and_reraise_exception():
            LOG.error('Failed    collecting    show    fcns    database    for    fabric')
    if cli_output:
        nsinfo_list = self._parse_ns_output(cli_output)
    LOG.debug('Connector    returning    fcns    info-%s', nsinfo_list)
    return nsinfo_list
