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Cisco Virtual Topology System (VTS) 2.3 User Guide

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Book Title

Cisco Virtual Topology System (VTS) 2.3 User Guide

Chapter Title

Provisioning Overlay Networks

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Updated:
October 4, 2016

Chapter: Provisioning Overlay Networks

Provisioning Overlay Networks

This chapter has the following sections:

Provisioning Overlay Networks Using Cisco Virtual Topology System

Virtual Topology System enables overlay connectivity orchestrated through an SDN-based control plane. This ensures instant availability of computing and application workloads in the virtualized data center, and removes network provisioning challenges.

Cisco VTS uses VXLAN to overcome scale limits in the data center and to segment the network better. VXLAN is designed to provide the same Ethernet Layer 2 network services as VLAN does, but with greater extensibility and flexibility. The dependence on a Layer 3 underlay network allows VXLAN to take complete advantage of Layer 3 routing, equal-cost multipath (ECMP) routing, and link aggregation protocols. Virtual Topology System supports hardware and software VTEPs to segment the data center network.

Virtual Topology System supports both VXLAN overlays using the BGP EVPN control plane and VXLAN overlays using IP Multicast-based techniques.

Implementing VXLANs using MP-BGP EVPN based control plane to manage the VXLAN overlay provides a distributed network database, which enables federation and scaling. The BGP EVPN solution is the preferred option, and it can be flexibly implemented using the infrastructure policy constructs within the Virtual Topology System environment.

Virtual Topology System implements the highly scalable MP-BGP with the standards-based EVPN address family as the overlay control plane to:

  • Distribute attached host MAC and IP addresses and avoid the need for unknown unicast, and multicast traffic

  • Support multidestination traffic by either using the multicast capabilities of the underlay or using unicast ingress replication over a unicast network core (without multicast) for forwarding Layer 2 multicast and broadcast packets

  • Terminate Address Resolution Protocol (ARP) requests early

Control-plane separation is also maintained among the interconnected VXLAN networks. Capabilities such as route filtering and route reflection can be used to provide flexibility and scalability in deployment.

High-level Workflow for Establishing a VXLAN Overlay Network with Hardware and Software VTEPs using BGP EVPN

The following steps provide a high-level workflow for establishing a simple VXLAN overlay network with hardware and software VTEPs using a BGP EVPN control plane:

  • Prepare the physical environment to be managed by Cisco VTS to build virtual overlays. See the Prerequisites section in the Cisco VTS Installation Guide for details.

  • Discover the network topology in the data center. See the Managing Inventory chapter of the Cisco VTS User Guide for details.
  • Define Admin Domains. See Creating and Managing Admin Domains chapter of the Cisco VTS User Guide for details.

After you commit the changes to the network group, Virtual Topology System automatically pushes all the relevant configuration information to the respective leafs, Cisco IOS XRv route reflectors, and DCI gateways. At this point, the Admin Domain is ready to build overlay networks based on the intent defined by the service policy or through a Virtual Machine Manager (VMM) or orchestration environment.

For a detailed, illustrated example, see Cisco Virtual Topology System: Data Center Automation for Next-Generation Cloud Architectures White Paper.

Creating Overlays

As part of overlay provisioning, you may need to:

  • Create Tenant

  • Create Network

  • Create Subnet

  • Create Router

  • Create VM

This can be done using the VMM or Cisco VTS GUI.

Using OpenStack


Note

When you use a VMM such as OpenStack or VMware, the plugin will provide integration between the VMM and Cisco VTS. Once Tenant/ Network/ Subnets are created on the VMM, required overlay network(s) will automatically be created by Cisco VTS.

For information about performing these tasks via OpenStack Horizon dashboard, see OpenStack documentation.

Using VMware

For information about performing these tasks using VMWare, see the following sections:

Using Cisco VTS GUI

For information about creating Network and Router using Cisco VTS GUI, see the following sections:

Creating Network using VMware

To create a network:

    Step 1   Select one of the VDS switches you created, then select Manage tab.
    Step 2   Select the Cisco VTS Network tab and click Add (+) to add the network.
    Step 3   Select create Tenant and enter Network Name field.
    Step 4   Click Create to create the network.
    Step 5   Click the Refresh icon to display the created network.

    Creating Subnetwork using VMware

    Before you create the subnetwork, you need to create the network in which the subnetwork has to be created.

    To create subnetworks:

      Step 1   Select one of the VDS switches you had created, then click the Manage tab.
      Step 2   Select Cisco VTS Network tab, and click the network name in which the subnetwork has to be created.
      Step 3   Enter the subnet name, the network range in CIDR format, and the Gateway IP.
      Step 4   Click Create Subnet button to create subnetwork.
      Step 5   Click Refresh button to see the subnetwork.

      Creating Routers using VMware

        Step 1   Select one of the VDS switches you had created, then click the Manage tab.
        Step 2   Select Cisco VTS Router tab, and click Add (+) to add the Router.
        Step 3   Select Tenant Name and enter the Router Name.
        Step 4   Click Create Router button to create the router.

        Attaching Network to Router

        To attach a network and subnetwork to a router:

          Step 1   Select one of the VDS switches you had created, then click Manage tab.
          Step 2   Select VTS Router tab and click the Router Name where network has to be added.

          The Router Details pop up appears.

          Step 3   Select Network and subnet and click Attach Subnet.

          Attaching a Virtual Machine to Network

          To create VMs:

            Step 1   Create network and subnet using vCenter Cisco VTC plugin. This will create portgroup for the network.
            Step 2   Create the VM in vCenter and attach the created portgroup to the VM.

            This will attach the VM to the network created via Cisco VTS.

            Creating a Network using Cisco VTS GUI

            To create a network from the Cisco VTS GUI:

              Step 1   Go to Overlay > Network. The Overlay / Network window appears. The Network table lists:

              • Network Name

              • Tenant

              • Zone

              • Admin state

              • Status

              • Subnet

              • Network Type

              • External Network

              • VNI

              • Inherit Extensions - (need more information)

              • Extended - (need more information)

                Note   
                • When Extend all networks toggle(in Editing Tenant) is set to YES at Tenant level, Inherit Exensions column will have toggle as Yes, and Extended column will have a checkmark.

                • When Extend all networks toggle(in Editing Tenant) is set to NO at Tenant level, Inherit Exensions column will have toggle as Yes, and Extended column will have a crossmark.

                • If Inherit Exensions column will have toggle as NO, then Extended column will have toggle button instead of a checkmark.

                • When you hover over Show Legend link, a popup shows various network icons.

              Step 2   Click Add (+) icon.
              Step 3   Select the Tenant for which you to create the network.
              Step 4   Select the Zone.
              Step 5   To enable or disable network extension, use the Extend networks toggle switch. By default, Extend all networks is Yes.
              Step 6   Enter the network name.
              Step 7   Select the External Network check box if you need to specify that the network is external.

              This implies that the network needs to be configured on the Border Leaf and DCI Gateway.

              Step 8   Click Save.

              You may also add a subnet, and add port.

              Creating a Subnetwork

              To create a subnetwork:

                Step 1   Click Add Subnet in the Subnet pane of the Add Network popup.
                Step 2   Enter the subnet name, the network address, and gateway IP, then click OK.
                Step 3   Click OK to save the subnet information.

                Attaching a Port

                To add a port:

                  Step 1   Go to Overlay > Network
                  Step 2   Click Port Attach, then click the add icon. The Attach Port popup appears.
                  Step 3   Specify whether it is a Physical Device or a Virtual Device, by selecting the appropriate radio button.

                  For Virtual Devices, the MAC address is required. For physical devices, it is optional.

                  You can use Static VLAN button if you want to specify a certain VLAN to be used for port attach. By default, VTS allocates a free VLAN from its bucket of VLANs, but you may specify one if you wish to.

                  Step 4   Enable Tagging by selecting the Tagging check box.
                  Step 5   Select the Device from the drop-down list.
                  Step 6   Specify the Interface. Select one of the following:

                  • Ethernet

                  • Port Channel

                  • VPC

                  • ESI

                  It lists the available interfaces, based on your selection.

                  Note   

                  • After importing ESI inventory you must manually create a device group on the VLAN Pool page from VTS GUI, and add the group of ESI devices into that device group. Also make sure a corresponding VLAN pool gets created for the ESI device group.

                  • Add the ESI device group to L2 and L3 GW groups in Admin Domain.

                  • ARP suppression needs to be disabled for ESI. It can be done from VTS GUI for L2 GW group in Admin Domain.

                  Step 7   Choose the desired interface, and click OK.

                  Creating Router using Cisco VTS GUI

                  To create a router using Cisco VTS GUI:

                    Step 1   Go to Overlay > Router. The Overlay / Router window appears.
                    Step 2   Click the Add (+) icon. The Add Router window appears.
                    Step 3   Select the tenant from the Select Tenant drop-down list.
                    Step 4   Select the Zone from the Select Zone drop-down list.
                    Step 5   Enter a VRF name. This is optional. If this is left empty, when the Save button is clicked, a default VRF name will be automatically generated.

                    • The custom VRF name accepts up to 24 characters.

                    • If there is no input for custom VRF name, a default VRF name will be generated in form of <tenant-name>-<router-name>. Both tenant-name and router-name accept up to 15 characters.

                      • If Cisco ASR 9000 series router is configured as DCI in the domain, and you have not given a the custom VRF name, then you must ensure that the default VRF name does not exceed 27 characters. Otherwise, the configuration will fail.

                      • If Cisco IOS XRv is configured, and you have not given a custom VRF name, then you must ensure that the default VRF name does not exceed 24 characters. Otherwise, the configuration will fail.

                      • If configuration fails because the default VRF name exceeds the limit, you can choose to use custom VRF name instead.

                    • If the configuration fails because the default VRF name exceeds 27 characters, an error message appears on the Network > Port Attach screen, which indicates invalid input for “bridge-domain” configured on Cisco ASR 9000 series router.

                    • For IOS XRv configuration, a similar error is displayed if the default VRF name exceeds 24 characters.

                    • If you modify the VRF name after saving the router, the Router Gateway IP address will be removed. You can reconfigure it back after saving the VRF name change.

                    Step 6   Select the router gateway from the Router Gateway drop-down list.
                    Step 7   Enter the Router Name.
                    Step 8   You may attach a template to the router. See Attaching Templates while Adding Routers for details.
                    Step 9   Click Add (+) icon. The Add Interface popup appears.
                    Step 10   Select the subnet from the drop down list, and click OK.
                    Step 11   Click Submit in the Add Router window to save the router and its interface.

                    Assigning BVI Interface IP Address

                    To assign a Bridge Group Virtual Interface (BVI) IP address:

                      Step 1   Go to Overlay > Network. The Overlay /Network page appears.
                      Step 2   Click the + icon. The Add Network page appears.
                      Step 3   Enter the Network name.
                      Step 4   Check the External Network check box.
                      Step 5   Click the + icon to assign a Subnet to the network created.

                      1. If a Subnet is assigned to this External Network, assign the Router Gateway IP address for BVI interface from this Subnet under Step 10.

                      2. If Subnet is not assigned to this External Network, any IP address can be assigned to Router Gateway IP address tab for BVI interface under Step 10.

                      Step 6   Go to Overlay > Router. The Overlay /Router page appears.
                      Step 7   Click the + icon. The Add Router page appears.
                      Step 8   Click the + icon to assign an Interface to the Subnet created. Note: This subnet belongs to the Internal network, and excludes the External network.
                      Step 9   Select an external network from the Router Gateway drop-down list. Router Gateway IP address field appears.
                      Step 10   Assign the Router Gateway IP address for the selected external network for BVI interface and click Save.
                      Step 11   Verify whether the configuration is pushed to DCI and the IP address is assigned to BVI interface.

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