Add multi-segment network and trunk support for Cisco Nexus 1000v plugin

Multi-Segment Networks and Trunk support for Cisco Nexus 1000v

In a multi-segment network, multiple network segments of different types (VLAN/VXLAN) can be bridged to form a single broadcast domain. A VM port will be connected to only one segment (access port).
A trunk network will contain multiple network segments of the same type (VLAN/VXLAN). A VM port will have a bunch of segments enabled (trunk port).

How it works

In Cisco Nexus 1000v OpenStack plugin, a network profile is a container or a pool of segment id’s of a specific type. A network profile can be of type VLAN, VXLAN, MULTI-SEGMENT or TRUNK. Each network created in Neutron is associated with a network profile.
To create a multi-segment network, typically a user needs to create a network of type VLAN and another of type VXLAN. Then the user needs to create a multi-segment network and add the vlan and vxlan based networks to it. Cisco Nexus 1000v takes care of bridging the VLAN and VXLAN based networks and creating the broadcast domain.
To create a trunk network, a user needs to first create the networks he needs to trunk. Then the user needs to create a trunk network from a trunk-type network profile and add the networks created earlier to it.

Neutron Changes

There is no change to the core Neutron resources. All the changes necessary for multi-segment and trunk network support are done through attribute extensions on top of Cisco Nexus 1000v plugin.