Introduction

A SmartFabric-enabled network for VxRail will support Layer 3 upstream connectivity from either the leaf layer, or from the spine layer in a multirack network deployment. The initial uplinks for Layer 3 routing can be applied to interfaces on the first set of switches in the fabric using the user interface from the control switch. This method will be necessary for initial build of the VxRail cluster in order to apply an IP address to the VxRail external management virtual network ID to enable routing.

Layer 3 routing can be enabled by selecting the interfaces on either the leaf or spine switches, and applying the policy for static routing or using Border Gateway Protocol. Assigning Layer 3 routing properties directly to a VLAN used for upstream network traffic is also supported.

Point-to-point links

Layer 3 integration between the upstream network and SmartFabric network will require point-to-point links to carry the routed networks. Because the point-to-point links are between two ports, a private IP addressing scheme of ‘192.168.x.x/31’ is recommended.

Figure 20.          Point-to-point links between SmartFabric switches and external network

Dedicated physical cabling between the ports on the upstream and downstream switches must be in place to support the point-to-point links.

Layer 3 integration with static routing

Static routing can be configured for a SmartFabric network. At a minimum, the VxRail external management network must have passage upstream to enable connectivity to data center services and for connectivity to end users.

The ‘Static Point-to-Point Links’ in Appendix A: VxRail with SmartFabric network configuration tables can be used to capture the values to enable static routing.

• Identify the VxRail network addresses that will need passage to the upstream network. The IP address range should be defined in CIDR format (<IP Address>/<Prefix Length>). The VxRail external management network and VxRail guest networks will require passage upstream.
• Identify the interfaces on the switch fabric and on the upstream network switches are connected to support Layer 3 the point-to-point links.
• Capture the IP addresses for the point-to-point links. The next-hop address is the IP address assigned to the port upstream in the point-to-point link.
• Configure static routes on the upstream network to support passage for the VxRail external management network and VxRail guest networks.

Layer 3 integration with BGP

A SmartFabric network will support Layer 3 upstream connectivity from either the leaf layer, or the spine layer, in a multirack network deployment using BGP. Internal BGP (iBGP) is enabled within the SmartFabric network to share routing information within the ASN. External BGP is used for router sharing with the upstream network with a unique ASN representation.

The ‘BGP Point-to-Point Links’ and ‘BGP Autonomous System Numbers’ tables in Appendix A: VxRail with SmartFabric network configuration tables can be used to capture the settings for the BGP peering.

Figure 21.          BGP Point-to-point from leaf layer or spine layer

To prepare the data center upstream network to support BGP integration, the following tasks must be performed:

• Decide whether to enable BGP peering at either the leaf layer or the spine layer. For a new VxRail implementation with a new SmartFabric network, BGP peering must be done initially at the leaf layer. Routing can later to migrated to the spine layer if desired as a day 2 operation.
• Capture point-to-point link settings between the upstream network switches and switches at either the leaf layer or the spine layer. A private IP address range of ‘192.168.xxx.xxx/31’ is recommended for peer-to-peer links.
• Enable interfaces on upstream network switches for point-to-point connectivity with switches at either the leaf layer or the spine layer.
• Configure BGP on the upstream network that the SmartFabric switches will peer with. The settings for linking with downstream SmartFabric switches with a neighbor IP address and a neighbor ASN must be configured on the upstream network. Be aware that the SmartFabric ASN value differs between the leaf layer and spine layer, so be sure to capture and apply the correct ASN value.