Cisco Cisco Virtual Topology System 1.5 White Paper

 

 

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8.  In case L3 networks need to be created, OpenStack user creates a router and attaches interfaces to the two 

networks. Virtual Topology System provisions a Layer 3 VXLAN that spans all ToR switches and VTFs 

supporting those networks. It also provisions the SVI with an anycast gateway configuration under the VLAN 

interface. 

 

Virtual Topology System implements a highly scalable MP-BGP extension called EVPN as the overlay control 

plane to: 

● 

Distribute attached host MAC and IP addresses and avoid the need for the flood-and-learn mechanism for 

broadcast, unicast, and multicast traffic 

● 

Use a unicast network core (without multicast) and ingress replication for forwarding Layer 2 multicast and 

broadcast packets 

● 

Terminate ARP requests early and avoid flooding 

The BGP route reflector could be implemented in the Virtual Topology System using the Cisco IOS XRv virtual 

machine in the control plane or on the network spine. Figure 6 shows the steps for EVPN control-plane route 

distribution.