The VxBlock System 1000 supports one configuration using Layer 3 routing protocols and the other using Layer 2 links.
Both routing topologies are supported on the management plane and the data plane. The VxBlock System 1000 is configured with a pair of ToR Cisco Nexus 9300 Series Switches. If more connectivity is required, you can add extra Cisco Nexus 9300 Series Switch pairs.
Layer 3 routing protocols
The VxBlock 1000 implements the OSPF, EIGRP, or static routing protocol. These protocols provide Layer 3 routing services for east-west traffic within the Cisco Nexus 9300 Series Switches and north-south flows for traffic leaving the VxBlock 1000.
Layer 2 links
The VxBlock 1000 is uplinked to the external network with Layer 2 links. Routing for all VxBlock 1000 and external VLANs occurs at the external network. This scenario applies if you need Layer 2 adjacency between endpoints both inside and outside of the VxBlock 1000. Layer 2 links allow workload mobility without requiring a network overlay, such as VXLAN, since a subnet can be consumed both inside and outside of the VxBlock 1000.
Layer 2 links reduce the amount of traffic traversing the uplinks to the external network for VxBlock 1000 inter-VLAN communications and improves overall performance.