Fix IPv6 default masks for SLAAC

IETF doesn't recommend use of IPv6 networks
with masks not "/64". Recommended subnetting is
3-1-4 - 48 for provider, 16 for subnetting and
64 for network. For example SLAAC will not
work if you use subnets different from /64.
Test with port update will not work until
bug 1364166 is fixed, added attribute to it.

Change-Id: I260c820dbde1f98b569e564c7b5e7e558e431c0d
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 29f80bd..dcc3c18 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -747,10 +747,10 @@
 
 # The cidr block to allocate tenant ipv6 subnets from (string
 # value)
-#tenant_network_v6_cidr=2003::/64
+#tenant_network_v6_cidr=2003::/48
 
 # The mask bits for tenant ipv6 subnets (integer value)
-#tenant_network_v6_mask_bits=96
+#tenant_network_v6_mask_bits=64
 
 # Whether tenant network connectivity should be evaluated
 # directly (boolean value)
diff --git a/tempest/api/network/test_ports.py b/tempest/api/network/test_ports.py
index f06d17c..e58461f 100644
--- a/tempest/api/network/test_ports.py
+++ b/tempest/api/network/test_ports.py
@@ -134,6 +134,7 @@
         for port in ports:
             self.assertEqual(sorted(fields), sorted(port.keys()))
 
+    @test.skip_because(bug="1364166")
     @test.attr(type='smoke')
     def test_update_port_with_second_ip(self):
         # Create a network with two subnets
diff --git a/tempest/config.py b/tempest/config.py
index af45ba5..39db9df 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -437,10 +437,10 @@
                default=28,
                help="The mask bits for tenant ipv4 subnets"),
     cfg.StrOpt('tenant_network_v6_cidr',
-               default="2003::/64",
+               default="2003::/48",
                help="The cidr block to allocate tenant ipv6 subnets from"),
     cfg.IntOpt('tenant_network_v6_mask_bits',
-               default=96,
+               default=64,
                help="The mask bits for tenant ipv6 subnets"),
     cfg.BoolOpt('tenant_networks_reachable',
                 default=False,