Users Guide

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.

Figure 5. Extra-Large Core

NOTE: In a single distributed fabric, all the leaves can act as a non-ToR or as a ToR, not both at

the same time.

Gathering Useful Information for a Distributed Core

Gather the following useful information for a Layer 3 distributed core fabric before you begin:

• The comma-separated values (CSV) file that contains the system media access control (MAC)

addresses, Service Tag, and serial numbers for each switch provided from Dell manufacturing or

manually enter this information

• The location of the switches, including the rack and row number from your network administrator or

network operator

Supported Fabric Types