ML2 Mechanism Driver

Modular Layer 2 (ML2) Neutron plug-in allows OpenStack networking to simultaneously utilize multiple layer 2 networking technologies such as 802.1Q and VXLAN for virtual instances.

External networks are managed using Mechanism Drivers. The Mechanism Driver is responsible for taking the information established by the Type Driver and ensuring that it is properly applied given the specific networking mechanisms that are enabled. A single OpenStack installation can use multiple ML2 Mechanism Drivers.

Extreme ML2 Mechanism driver within Neutron initiates Neutron API calls for network management. OpenStack Service in EFA translates the Neutron network management calls to appropriate tenant API calls and provisions the fabric with appropriate L2 networking constructs.

The following figure shows an overview of the ML2 Mechanism Driver within Neutron.

Click to expand in new window
Overview of ML2 Mechanism Driver within Neutron

The following table shows an example mapping of the OpenStack Networks to the Tenant Service EPG constructs.

Table 1. ML2 tenant mapping
VM Neutron Network Tenant Service (EPG)
VM1 GREEN_NETWORK (VLAN30) UUID =74cbf489-f3d9-41c7-bbb2-6cb7df33da6d 74cbf489-f3d9-41c7-bbb2-6cb7df33da6d
  • Endpoint: eth 0/1 on Leaf-1
  • Endpoint: eth 0/1 on Leaf-4
  • CTAG 30
VM2 GREEN_NETWORK (VLAN30) UUID =74cbf489-f3d9-41c7-bbb2-6cb7df33da6d
Naming convention for EPG creation is <Neutron Network UUID>.

EPG provisioning on the fabric creates a L2 network on the fabric spanning VM1 and VM2 with necessary fabric mappings. This creates the necessary constructs to establish an end-to-end connectivity between DB1 and DB2.

The following table shows an example of the configuration on the leaf nodes.

Table 2. ML2 switch configuration
EPG Switch Configuration Comments
74cbf489-f3d9-41c7-bbb2-6cb7df33da6d (GREEN_NETWORK)
  • Endpoint: eth 0/1 on Leaf-1
  • EndPoint: eth 0/1 on Leaf-2
  • CTAG 30
vlan 30
description L2 Tenant vlan
!
evpn default
vlan add 30
!

VLAN 30 configured on Leaf-1 and Leaf-4

VLAN 30 added to evpn

Note: VLAN to VNI mapping is set to auto as part of fabric setup.
interface ethernet 0/1
switchport
switchport trunk allowed vlan add 30
no shutdown
!
Interface configurations on both the switches, Leaf-1 and Leaf-4.