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200 lines
12 KiB
ReStructuredText
Layer 3 Networking in Neutron - via Layer 3 agent & OpenVSwitch
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===============================================================
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This page discusses the usage of Neutron with Layer 3 functionality enabled.
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Neutron logical network setup
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-----------------------------
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::
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vagrant@precise64:~/devstack$ neutron net-list
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+--------------------------------------+---------+--------------------------------------------------+
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| id | name | subnets |
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+--------------------------------------+---------+--------------------------------------------------+
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| 84b6b0cc-503d-448a-962f-43def05e85be | public | 3a56da7c-2f6e-41af-890a-b324d7bc374d |
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| a4b4518c-800d-4357-9193-57dbb42ac5ee | private | 1a2d26fb-b733-4ab3-992e-88554a87afa6 10.0.0.0/24 |
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+--------------------------------------+---------+--------------------------------------------------+
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vagrant@precise64:~/devstack$ neutron subnet-list
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+--------------------------------------+------+-------------+--------------------------------------------+
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| id | name | cidr | allocation_pools |
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+--------------------------------------+------+-------------+--------------------------------------------+
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| 1a2d26fb-b733-4ab3-992e-88554a87afa6 | | 10.0.0.0/24 | {"start": "10.0.0.2", "end": "10.0.0.254"} |
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+--------------------------------------+------+-------------+--------------------------------------------+
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vagrant@precise64:~/devstack$ neutron port-list
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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| id | name | mac_address | fixed_ips |
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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| 0ba8700e-da06-4318-8fe9-00676dd994b8 | | fa:16:3e:78:43:5b | {"subnet_id": "1a2d26fb-b733-4ab3-992e-88554a87afa6", "ip_address": "10.0.0.1"} |
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| b2044570-ad52-4f31-a2c3-5d767dc9a8a7 | | fa:16:3e:5b:cf:4c | {"subnet_id": "1a2d26fb-b733-4ab3-992e-88554a87afa6", "ip_address": "10.0.0.3"} |
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| bb60d1bb-0cab-41cb-9678-30d2b2fdb169 | | fa:16:3e:af:a9:bd | {"subnet_id": "1a2d26fb-b733-4ab3-992e-88554a87afa6", "ip_address": "10.0.0.2"} |
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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vagrant@precise64:~/devstack$ neutron subnet-show 1a2d26fb-b733-4ab3-992e-88554a87afa6
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+------------------+--------------------------------------------+
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| Field | Value |
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+------------------+--------------------------------------------+
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| allocation_pools | {"start": "10.0.0.2", "end": "10.0.0.254"} |
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| cidr | 10.0.0.0/24 |
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| dns_nameservers | |
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| enable_dhcp | True |
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| gateway_ip | 10.0.0.1 |
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| host_routes | |
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| id | 1a2d26fb-b733-4ab3-992e-88554a87afa6 |
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| ip_version | 4 |
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| name | |
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| network_id | a4b4518c-800d-4357-9193-57dbb42ac5ee |
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| tenant_id | 3368290ab10f417390acbb754160dbb2 |
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+------------------+--------------------------------------------+
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Neutron logical router setup
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----------------------------
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* http://docs.openstack.org/admin-guide-cloud/content/ch_networking.html#under_the_hood_openvswitch_scenario1_network
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::
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vagrant@precise64:~/devstack$ neutron router-list
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+--------------------------------------+---------+--------------------------------------------------------+
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| id | name | external_gateway_info |
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+--------------------------------------+---------+--------------------------------------------------------+
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| 569469c7-a2a5-4d32-9cdd-f0b18a13f45e | router1 | {"network_id": "84b6b0cc-503d-448a-962f-43def05e85be"} |
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+--------------------------------------+---------+--------------------------------------------------------+
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vagrant@precise64:~/devstack$ neutron router-show router1
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+-----------------------+--------------------------------------------------------+
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| Field | Value |
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+-----------------------+--------------------------------------------------------+
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| admin_state_up | True |
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| external_gateway_info | {"network_id": "84b6b0cc-503d-448a-962f-43def05e85be"} |
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| id | 569469c7-a2a5-4d32-9cdd-f0b18a13f45e |
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| name | router1 |
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| routes | |
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| status | ACTIVE |
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| tenant_id | 3368290ab10f417390acbb754160dbb2 |
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+-----------------------+--------------------------------------------------------+
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vagrant@precise64:~/devstack$ neutron router-port-list router1
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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| id | name | mac_address | fixed_ips |
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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| 0ba8700e-da06-4318-8fe9-00676dd994b8 | | fa:16:3e:78:43:5b | {"subnet_id": "1a2d26fb-b733-4ab3-992e-88554a87afa6", "ip_address": "10.0.0.1"} |
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+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------+
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Neutron Routers are realized in OpenVSwitch
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-------------------------------------------
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.. image:: images/under-the-hood-scenario-1-ovs-network.png
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"router1" in the Neutron logical network is realized through a port ("qr-0ba8700e-da") in OpenVSwitch - attached to "br-int"::
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vagrant@precise64:~/devstack$ sudo ovs-vsctl show
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b9b27fc3-5057-47e7-ba64-0b6afe70a398
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Bridge br-int
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Port "qr-0ba8700e-da"
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tag: 1
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Interface "qr-0ba8700e-da"
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type: internal
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Port br-int
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Interface br-int
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type: internal
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Port int-br-ex
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Interface int-br-ex
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Port "tapbb60d1bb-0c"
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tag: 1
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Interface "tapbb60d1bb-0c"
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type: internal
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Port "qvob2044570-ad"
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tag: 1
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Interface "qvob2044570-ad"
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Port "int-br-eth1"
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Interface "int-br-eth1"
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Bridge "br-eth1"
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Port "phy-br-eth1"
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Interface "phy-br-eth1"
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Port "br-eth1"
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Interface "br-eth1"
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type: internal
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Bridge br-ex
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Port phy-br-ex
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Interface phy-br-ex
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Port "qg-0143bce1-08"
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Interface "qg-0143bce1-08"
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type: internal
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Port br-ex
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Interface br-ex
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type: internal
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ovs_version: "1.4.0+build0"
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vagrant@precise64:~/devstack$ brctl show
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bridge name bridge id STP enabled interfaces
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br-eth1 0000.e2e7fc5ccb4d no
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br-ex 0000.82ee46beaf4d no phy-br-ex
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qg-39efb3f9-f0
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qg-77e0666b-cd
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br-int 0000.5e46cb509849 no int-br-ex
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qr-54c9cd83-43
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qvo199abeb2-63
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qvo1abbbb60-b8
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tap74b45335-cc
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qbr199abeb2-63 8000.ba06e5f8675c no qvb199abeb2-63
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tap199abeb2-63
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qbr1abbbb60-b8 8000.46a87ed4fb66 no qvb1abbbb60-b8
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tap1abbbb60-b8
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virbr0 8000.000000000000 yes
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Finding the router in ip/ipconfig
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---------------------------------
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* http://docs.openstack.org/admin-guide-cloud/content/ch_networking.html
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The neutron-l3-agent uses the Linux IP stack and iptables to perform L3 forwarding and NAT.
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In order to support multiple routers with potentially overlapping IP addresses, neutron-l3-agent
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defaults to using Linux network namespaces to provide isolated forwarding contexts. As a result,
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the IP addresses of routers will not be visible simply by running "ip addr list" or "ifconfig" on
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the node. Similarly, you will not be able to directly ping fixed IPs.
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To do either of these things, you must run the command within a particular router's network
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namespace. The namespace will have the name "qrouter-<UUID of the router>.
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.. image:: images/under-the-hood-scenario-1-ovs-netns.png
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For example::
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vagrant@precise64:~$ neutron router-list
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+--------------------------------------+---------+--------------------------------------------------------+
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| id | name | external_gateway_info |
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+--------------------------------------+---------+--------------------------------------------------------+
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| ad948c6e-afb6-422a-9a7b-0fc44cbb3910 | router1 | {"network_id": "e6634fef-03fa-482a-9fa7-e0304ce5c995"} |
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+--------------------------------------+---------+--------------------------------------------------------+
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vagrant@precise64:~/devstack$ sudo ip netns exec qrouter-ad948c6e-afb6-422a-9a7b-0fc44cbb3910 ip addr list
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18: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
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link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
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inet 127.0.0.1/8 scope host lo
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inet6 ::1/128 scope host
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valid_lft forever preferred_lft forever
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19: qr-54c9cd83-43: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
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link/ether fa:16:3e:dd:c1:8f brd ff:ff:ff:ff:ff:ff
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inet 10.0.0.1/24 brd 10.0.0.255 scope global qr-54c9cd83-43
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inet6 fe80::f816:3eff:fedd:c18f/64 scope link
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valid_lft forever preferred_lft forever
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20: qg-77e0666b-cd: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
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link/ether fa:16:3e:1f:d3:ec brd ff:ff:ff:ff:ff:ff
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inet 192.168.27.130/28 brd 192.168.27.143 scope global qg-77e0666b-cd
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inet6 fe80::f816:3eff:fe1f:d3ec/64 scope link
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valid_lft forever preferred_lft forever
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Provider Networking
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-------------------
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Neutron can also be configured to create `provider networks <http://docs.openstack.org/admin-guide-cloud/content/ch_networking.html#provider_terminology>`_
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Further Reading
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---------------
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* `Packet Pushers - Neutron Network Implementation on Linux <http://packetpushers.net/openstack-neutron-network-implementation-in-linux/>`_
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* `OpenStack Cloud Administrator Guide <http://docs.openstack.org/admin-guide-cloud/content/ch_networking.html>`_
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* `Neutron - Layer 3 API extension usage guide <http://docs.openstack.org/api/openstack-network/2.0/content/router_ext.html>`_
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* `Darragh O'Reilly - The Quantum L3 router and floating IPs <http://techbackground.blogspot.com/2013/05/the-quantum-l3-router-and-floating-ips.html>`_
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