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Enabling Routing Between Virtual Networks

 

In this section, you’ll enable routing between the blue and the green virtual networks so that servers in either network can reach each other. Contrail Command activates a logical router and uses centrally-routed bridging to place IRB interfaces on the spine devices. After Contrail Command configures the devices, network traffic from the blue and green networks travels over a VXLAN tunnel from the leaf devices to the spine devices. At the spine devices, the traffic is routed at Layer 3 to interconnect the blue and green networks.

Figure 1 provides a high-level illustration of the resulting network that enables ESX-VM01 (blue) to reach BMS2 and BMS4 (green) by way of the EVPN/VXLAN overlay.

Figure 1: New Fabric Network Topology
New Fabric Network
Topology

Configuring Routing Between Virtual Networks

This section sets up Contrail Networking and enables routing so that different VLAN subnets and VXLAN VNIs can reach each other. To use Contrail Command to configure routing between networks, do the following:

  1. Navigate to the Logical Routers screen at Overlay > Logical Routers, as shown in Figure 2.
    Figure 2: Contrail Command – Navigate to Logical Routers
    Contrail Command – Navigate to Logical
Routers
  2. Click Create, as shown in Figure 3.
    Figure 3: Contrail Command – Create Logical Routers
    Contrail Command – Create Logical
Routers
  3. Fill in the following fields to define the logical router, as shown in Table 1.

    Table 1: Logical Router Fields

    Field

    Explanation

    Values used in this example

    Name

    Name of your logical router

    logical-router-1

    Admin State

    Administrative state you want the logical router to have when activated

    Up

    Extend to Physical Router

    Add the devices that will provide routing services

    Note: For CRB, select the spine devices to provide routing.

    • qfx10K2-11

    • qfx10K2-12

    External Gateway

    Specify a gateway to reach networks external to the fabric

    None

    Connected networks

    Add the virtual networks (VLANs or VNIs) that you want to connect through the logical router

    • blue

    • green

    VxLAN Network Identifier

    VNI(s) to assign to the logical router

    Note: If you use the default value, Contrail Command automatically selects VNIs for you.

    Default value (1 - 167...)

    Figure 4 shows the values used in this example.

    Figure 4: Contrail Command – Define the Logical Router
    Contrail Command – Define the Logical
Router
  4. Click Create. The logical router is generated and activated, as shown in Figure 5.
    Figure 5: Contrail Command – Logical Routers Activated
    Contrail Command – Logical Routers
Activated
  5. Confirm the routing configuration was pushed to the fabric devices. The following configuration excerpts show the logical router-based configurations generated by Contrail Command:

    Leaf 4:

    Spine 2:

  6. Verify connectivity between the blue and green VLANs by issuing a ping command. If you can reach the blue network by sending a ping to the green network, routing services are working properly.

    The output below shows a successful ping from servers BMS2 and BMS4 to server ESX-VM01 and vice versa.

    BMS2:

    BMS4:

    ESX-VM01:

  7. Verify connectivity between the spine and leaf devices across the VXLAN tunnel.

    The output below shows a successful ping from Spine 1 to Leaf 2 and Leaf 4, and vice versa.

    Spine 1:

    Leaf 2:

    Leaf 4:

Enabling Routing Between Virtual Networks — Release History

Table 2 provides a history of all of the features in this section and their support within this reference design.

Table 2: Enabling Routing Between Virtual Networks in the Contrail Enterprise Multicloud—Release History

Release

Description

Stage 1

All features documented in this section are supported on all devices within the reference design running Junos OS Release 17.3R3-S3 or later, and Contrail 5.0.2 or later.