Dell PowerSwitch S4112F-ON 10GbE Switch

The Dell PowerSwitch S4112F-ON is a half-rack-width 1U switch with 12 ports of 10GbE SFP+ and three 100GbE QSFP28 uplinks, delivering 840 Gbps of non-blocking switching in a chassis 8.28 inches wide. Two of them mount side by side in a single rack unit.

Where the S4112F-ON sits in a data center

This is the small-cabinet member of the S4100 family. A 48-port ToR switch is the wrong tool for a rack holding six or eight servers - you pay for ports, power and depth you will never use, and in a shallow or shared cabinet the 17-inch chassis may not physically suit. The S4112F-ON is built for that case: enough 10GbE access ports for a small compute island, and 100GbE uplinks so the island still connects to a modern spine at full speed.

The half-rack width is the reason to choose it. Two units side by side give you a redundant pair in 1U rather than 2U, which matters in a colocation cabinet billed by the rack unit and in edge sites where the whole footprint is a handful of Us. It is also useful as a dedicated out-of-band or management fabric switch alongside a larger production ToR pair.

Port layout and breakout math

Twelve SFP+ ports handle 1GbE or 10GbE access. Three QSFP28 cages carry the uplinks and are multi-rate: each will run 100GbE, 40GbE, 2x 50GbE, 4x 25GbE or 4x 10GbE. Breaking out all three to 4x 10GbE gives 12 additional 10GbE ports on top of the 12 fixed ones, which is the sheet's maximum 10GbE density of 24. Maximum densities are 24x 10GbE, 12x 25GbE, 3x 40GbE, 6x 50GbE and 3x 100GbE.

Three uplinks rather than an even number is deliberate: it allows two uplinks into a spine pair plus one for a VLT peer link, or three-way spine attachment. Port-to-port latency is 800 nanoseconds, the same as the fibre 48-port models - the fabric is smaller, not slower.

Fixed power supplies and fans - and what that means

The S4112-ON is the exception in the S4100 family. Every other model has hot-swappable power supplies and fan modules; on the S4112 both are redundant but fixed, built into the chassis and not field-replaceable. The spec sheet states this directly and then excludes the S4112 from both the replacement-PSU and replacement-fan accessory tables.

Two practical consequences. First, airflow direction is set at manufacture and cannot be changed afterwards - not by swapping parts, because there are no parts to swap. Order the direction that matches your aisle layout. Second, a power supply fault is a chassis fault. The unit keeps running on the surviving supply because the pair is redundant, but restoring redundancy means replacing the switch rather than the module. Factor that into sparing: for a small site, a cold spare unit is the equivalent of a spare PSU on the larger models.

The upside of the same design is that there is nothing to mis-order, nothing to fit backwards, and no chance of the mismatched-airflow alarm that catches people out on the modular models.

Operating system and licensing

ONIE is pre-installed and the switch runs Dell EMC Networking OS10 Enterprise Edition, with the same L2/L3 feature set as its larger siblings: OSPF, BGP, policy-based routing, VRF-lite and VLT for multi-chassis redundancy, plus hardware VXLAN gateway support and the full data-center-bridging stack (PFC, ETS, DCBx, iSCSI TLV). As an open-networking platform it will also accept a third-party network operating system.

One difference worth knowing: IEEE 1588v2 precision time is supported in hardware only on the 48-port models. If you need PTP, this is not the right chassis.

Choosing between the S4000-series models

• S4112T-ON - the copper twin. Same chassis and fabric, 12x 10GBASE-T instead of SFP+. Choose it for RJ45 in-rack runs; latency is higher at 2500 ns because of the 10GBASE-T PHY.
• S4128F-ON - full-width, 28x SFP+ and 2x 100GbE, with hot-swappable PSUs and fans.
• S4148F-ON - full-width, 48x SFP+ with 2x 40GbE and 4x 100GbE.
• S4148U-ON - adds unified ports for Fibre Channel.

Step up from the S4112F-ON when you outgrow twelve access ports or when you need replaceable power supplies. Stay with it when width and rack units are the constraint.

Condition, testing and warranty

Refurbished units are cleaned, inspected and functionally tested before they ship: every port is link-tested, both fixed power supplies are verified under load, the fans are checked, and the unit is booted and inspected for fault codes. Configuration is cleared. Units ship with warranty; the coverage tier is selected on this page.

Specifications