Dell Active Fabric Manager, Deployment Manual

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• Downlinks — An edge port link that connects the leaves to the data access layer; for example, servers or ToR
elements. Downlinks are always 10 GbE.
NOTE: Specify an even number of uplinks. The minimum number of uplinks is 2. One uplink is for
redundancy.
• Fabric Interlinks — Links that connect the spines to the leaves. The fabric interlink bandwidth is fixed: 40 GbE or
10 GbE.
• 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 ratio that you specify 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, use the 1:1 fabric over-subscription ratio. When you
require a lot of bandwidth and not a lot of ports, use this ratio. The following image illustrates a distributed core
fabric.
Important: In a single distributed fabric, all the leafs can act as non-ToR or as a ToR, not both at the same
time.
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