Users Guide

• Edge ports — The uplinks and downlinks on the leaves.

• Uplinks — An edge port link on the first two leaves in the distributed core fabric that connects to the

edge WAN, which typically connects to an internet server provider (ISP). The uplink can also connect

to a router gateway or an external switch.

• Downlinks — An edge port link that connects the leaves to the data access layer; for example, servers

or ToR elements.

NOTE: Specify an even number of uplinks. The minimum number of uplinks is two. One uplink is

for redundancy.

• Fabric Interlinks — Links that connect the spines to the leaves. The fabric interlink bandwidth is fixed:

10 Gb or 40 Gb.

• Fabric over-subscription ratio — Varies the maximum number of available interconnect links. This

ratio determines the number of fabric interlinks (the number of communication links between the

spine and leaf devices). The specified ratio depends on the bandwidth, throughput, and edge port

requirements. The interlink over-oversubscription ratio does not come off the edge port downlinks.

As you increase the fabric over-subscription ratio:

– The total number of ports for the downlinks increases.

– The number of interconnect links from the leaves to the spines decreases.

– The maximum number of available ports increases.

For non-blocking (line rate) between the leaves and spines, select the 1:1 fabric over-subscription

ratio. This ratio is useful when you require a large amount of bandwidth but not many ports.

The following image illustrates a distributed core fabric.

Supported Fabric Types