Redundant Layer-3-Only Data Center Fabrics

Articles » Redundant Layer-3-Only Data Center Fabrics

I’m often getting the same question when delivering online courses or webinars focused on data center fabrics or cloud infrastructure:

Is it possible to build a redundant layer-3-only fabric with no VLANs stretched across multi switches, and use X (for example, VMware NSX) on such a fabric?

Layer-3-only fabric... without redundant server connections
Source: Leaf-and-Spine Fabric Architectures

In this document, we’ll explore the problem of using multiple IP addresses from same or different subnets on clients or servers. Using loopback addresses and routing on servers (the usual solution) is outside of the scope of this document, explore Routing on Servers part of Leaf-and-Spine Fabric Architectures webinar for more details.

You can find the in-depth description of various fabric-based workarounds in EVPN Technical Deep Dive webinar (in particular in the EVPN Multihoming versus MLAG section).

Before moving on, a quick spoiler: while iSCSI Multipath I/O in vSphere supports layer-3-only fabrics (and even full path separation between A and B networks), the designers of VMware NSX never got the memo.

More Information

If you’re building a cloud infrastructure, explore the webinars from the Cloud Infrastructure and Software-Defined Data Centers series, in particular the Designing Cloud Infrastructure and Designing Active-Active and Disaster Recovery Data Centers.

If you’re building a data center fabric, start with the Leaf-and-Spine Fabric Architectures and Designs webinar and use the information from Data Center Fabric Architectures webinar when selecting vendors and equipment.

You get all the above webinars with the subscription.