Adding vPC (virtual port channel) support to the Cisco Nexus plugin

Scope: Adding Virtual Port Channel support to the Cisco Nexus plugin.

Use Cases: Quantum with the Cisco plugin.

Implementation Overview: Support will be added for multihomes hosts connected to more than one ToR switch. Configuration files will be slightly modified to specify all switch interfaces that a host is connected to and trunking configuration will be performed on all switches specified. The switches themselves are assumed to be connected manually with a vPC channel.

Data Model Changes: n.a

Configuration variables: A host can show up as connected to multiple switches.

API's: n/a

Plugin Interface: n/a

Required Plugin support: n/a

Dependencies: n/a

CLI Requirements: n/a

Horizon Requirements: n/a

Usage Example: n/a

Test Cases: n/a