The Cisco Nexus 2348UPQ is a 1RU fabric extender with 48 unified SFP+ host ports running at 1 or 10 Gbps and up to 6 QSFP+ fabric ports running at 10 or 40 Gbps. A fabric extender is not a switch: it behaves as a remote line card for a parent Nexus switch and does nothing at all without one, which is the first thing to establish before it is specified.
It does not work on its own, and Cisco says so
Fabric extenders behave like remote line cards for a parent Cisco Nexus switch. All configuration, all forwarding policy and all management live on the parent; the extender simply presents ports at the rack and carries traffic back over its fabric links. Cisco colours the fabric interfaces yellow precisely so that the uplink ports cannot be mistaken for host ports during installation.
The practical consequence is that a 2348UPQ bought without a compatible parent switch is an inert appliance. Anyone evaluating one as a cheap 48-port 10 Gigabit switch is evaluating the wrong product, and that misunderstanding is the single most common reason a fabric extender is returned.
| Specification | Nexus 2348UPQ |
|---|---|
| Rack height | 1RU |
| Host ports | 48 x unified SFP+, 1/10 Gbps |
| Fabric ports | Up to 6 x QSFP+, 10/40 Gbps |
| Fabric bandwidth | 240 Gbps each direction, 480 Gbps full duplex |
| Forwarding | 1440 Gbps, 2160 mpps |
| Oversubscription | Up to 2:1 |
| Shared buffer | 32 MB |
Which parent switches it attaches to
Cisco lists four parent platform families for this extender, each with its own minimum software release, and getting the release wrong is as blocking as getting the platform wrong.
| Parent platform | Minimum NX-OS release |
|---|---|
| Nexus 5500 and 5600 platforms | 7.0(3)N1(1) |
| Nexus 6000 Series | 7.0(3)N1(1) |
| Nexus 7000 Series and 7700 platform | 7.2.0D1(1) |
| Nexus 9300 and 9500 Series | 7.0(3)I2(1) |
Check the running release on the intended parent before ordering, because an extender attached to a parent below the minimum will not come online and the failure looks like a hardware fault rather than a software one.
The unified ports are conditional, and this is the trap
Unified port capability on the 2348UPQ is not a property of the extender alone. Cisco states that unified ports, and native Fibre Channel with them, work on the 2348UPQ only behind a Nexus 5600 parent running release 7.3 or later. Behind a Nexus 9300, a Nexus 7000 or a Nexus 5500, the same hardware operates as an Ethernet and FCoE fabric extender and nothing more.
That means the letters UP in the model designation describe a capability the parent has to unlock rather than one the box delivers by itself. A storage design that assumes native Fibre Channel from this extender behind a 9300 parent is a design that will not work, and the failure will only surface at commissioning.
What a fabric extender changes in a rack design
Managed device count is what a fabric extender reduces, and that is its commercial argument rather than raw port cost. Every top-of-rack switch in a data centre is a device with its own configuration, its own software image, its own upgrade cycle and its own place in a change window. An extender has none of those: it inherits all of them from the parent, so adding a rack adds ports without adding a managed node to the estate.
The cost of that simplification is a hard dependency. The extender cannot be configured locally, cannot be repurposed onto another vendor's switch, and cannot survive the retirement of the parent platform it was bought for. Where a parent refresh is already on the roadmap, the extender population has to be part of that plan rather than an afterthought discovered during it.
Where the 2348UPQ sits against the other extender we carry
| Model | Host ports | Fabric ports | Buffer |
|---|---|---|---|
| Nexus 2348UPQ | 48 x unified SFP+, 1/10G | Up to 6 x QSFP+, 10/40G | 32 MB |
| Nexus 2248TP-E | 48 x 100/1000BASE-T | 4 x SFP+, 10G | 32 MB |
The choice between them is host media: fibre or direct-attach copper at 10 Gigabit on this model, twisted-pair copper at 100 Megabit or 1 Gigabit on the 2248TP-E. Parent-switch compatibility differs between the two generations and must be checked per model rather than assumed across the family. Candidate 9300-class parents in our range include the Nexus 93180YC-EX and the Nexus 9372TX, both subject to the minimum release above. The full range is on the Cisco networking hardware page.
Condition, testing and what ships
Units are refurbished enterprise hardware carrying the original Cisco part number, tested on receipt and tested again on the bench after assembly and configuration, immediately before despatch. Each unit carries the Enterasource warranty stated on its listing, and shipping is free FedEx Ground to the lower 48 states.
Fabric transceivers and cables are quoted separately, and the fabric link type must match the parent switch port it lands on. Cisco software entitlement does not transfer with used hardware.
Frequently Asked Questions
Can a Nexus 2348UPQ be used as a standalone switch?
No. Cisco describes fabric extenders as behaving like remote line cards for a parent Nexus switch, with the fabric interfaces existing solely to connect upstream to that parent. Without a supported parent switch the unit has no control plane, no configuration and no forwarding function. It is not a low-cost alternative to a 48-port 10 Gigabit switch and cannot be repurposed as one.
Which switches can act as the parent for a Nexus 2348UPQ?
Cisco lists the Nexus 5500 and 5600 platforms, the Nexus 6000 Series, the Nexus 7000 Series and 7700 platform, and the Nexus 9300 and 9500 Series. Each carries a minimum software release: 7.0(3)N1(1) on the 5500, 5600 and 6000, 7.2.0D1(1) on the 7000 and 7700, and 7.0(3)I2(1) on the 9300 and 9500. Confirm the running release before ordering.
Do the unified ports give native Fibre Channel on any parent switch?
No, and this is the most consequential detail on the page. Cisco states that unified port capability and Fibre Channel on the 2348UPQ work only behind a Nexus 5600 parent running release 7.3 or later. Behind a Nexus 9300, 7000 or 5500 parent the extender operates as an Ethernet and FCoE device, so a storage design depending on native Fibre Channel needs the 5600 parent specifically.
How much bandwidth does the fabric link carry?
Two hundred and forty gigabits per second in each direction, or 480 Gbps full duplex, across up to 6 QSFP+ fabric ports. Forwarding is 1440 Gbps at 2160 million packets per second and the shared buffer is 32 MB. Oversubscription is up to 2:1, so a fully loaded rack of 10 Gigabit hosts should be planned against the number of fabric links actually cabled rather than the maximum.
How many fabric links should a Nexus 2348UPQ be cabled with?
As many as the traffic requires rather than as many as the chassis accepts, because oversubscription is set by the ratio between host bandwidth and cabled fabric bandwidth. With up to 6 QSFP+ fabric ports available and up to 2:1 oversubscription supported, a rack of lightly loaded hosts may run on fewer links while a rack of storage nodes will want the full complement.
What condition are your refurbished fabric extenders in?
They are tested on arrival, cleaned and returned to stock as known-good units, then reassembled, configured and bench tested again before they are packed for despatch. Cosmetic condition is graded per unit rather than described generically, and any physical defect found during either test pass is written into that unit's listing before it goes on sale.
