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This chapter has the following sections:
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.
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.
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.
As part of overlay provisioning, you may need to:
This can be done using the VMM or Cisco VTS GUI.
![]() 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 using VMWare, see the following sections:
For information about creating Network and Router using Cisco VTS GUI, see the following sections:
To create a network:
Before you create the subnetwork, you need to create the network in which the subnetwork has to be created.
To create subnetworks:
To attach a network and subnetwork to a router:
To create VMs:
To create a network from the Cisco VTS GUI:
To create a subnetwork:
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:
It lists the available interfaces, based on your selection.
| ||
Step 7 | Choose the desired interface, and click OK. |
To create a router using Cisco VTS GUI:
Step 1 | Go to . 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.
|
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. |
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. |
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. |