Cisco Nexus 93600CD-GX 28-Port 100GbE Switch

Two port speeds sit on one rack unit of the Cisco Nexus 93600CD-GX: twenty-eight ports at 100 or 40 Gigabit Ethernet, and eight at 400 or 100 Gigabit Ethernet. Cisco publishes 12 Tbps of switching capacity, 4.0 billion packets per second, 32 GB of memory and a 128 GB solid-state disk on board. Two port tiers on two connector types is what lets one switch serve as a dense leaf or a small spine.

Ports, interfaces and what this switch presents

QSFP28 and QSFP-DD are two different optical cages, and the Nexus 93600CD-GX carries both: twenty-eight of the first at 100 or 40 Gigabit, and eight of the second at 400 or 100. The cages are not interchangeable. A QSFP28 optic belongs in a QSFP28 port and a QSFP-DD optic belongs in a QSFP-DD port, so the port face is a decision about where each kind of link lands rather than a pool of identical sockets.

Cisco describes the eight QSFP-DD ports more widely in its product overview than in its specification table, and the wider description is worth carrying: those ports are given as 10, 25, 40, 50, 100, 200 and 400 Gigabit. The specification table states the same ports as 400 and 100 Gigabit, which is the pair a data centre will normally build on. Both come from Cisco, and the longer list is the one that tells a buyer what the cage is capable of accepting rather than what it is usually ordered for.

Management is separate from the data plane: two management ports, one RJ-45 and one SFP, plus a single USB port and an RS-232 console. Those are the interfaces a rack build has to plan cabling for alongside the optics.

Switching capacity and forwarding rate

Cisco publishes 12 Tbps of switching capacity and 4.0 billion packets per second for this switch. The two figures answer different questions. Switching capacity is the aggregate the fabric can carry; the forwarding rate is how many packet decisions the platform can make each second, which is what small-packet traffic actually consumes. A fabric that is sized on capacity alone can still run out of forwarding rate first if the traffic profile is dominated by short packets.

Behind both sits an 80 MB system buffer and a four-core control-plane processor. The buffer is what absorbs the bursts that a leaf position generates when many servers transmit toward the same uplink at the same moment, and it is a specification worth reading on any switch that will sit under a dense compute row.

What optics these ports take, and how the ports break out

The transceiver form factors Cisco associates with this platform are QSFP-DD, QSFP28, QSFP+, SFP+, SFP28 and QSFP56. That is a list of classes rather than part numbers, and it is the useful level to shop at: the class fixes the cage and the reach family, and the specific part is chosen against the fibre plant at quote time.

Breakout is where this switch earns its position, and Cisco publishes the map port by port. Ports 1 to 24 break out to two 50 Gigabit links on every port, and to four 10 Gigabit or four 25 Gigabit links on the odd-numbered ports with the even-numbered neighbours purged. Ports 25 to 28 break out to two 50 Gigabit, four 10 Gigabit or four 25 Gigabit links on every port with no such condition. Ports 29 to 36 break out to two 50 Gigabit, four 10 Gigabit and four 25 Gigabit links, and to four 100 Gigabit links on converted downlinks. A 10 Gigabit link on a QSFP port is reached through a QSA adapter.

The odd-and-even rule on the first twenty-four ports is the trap. A design that assumes every port in that block can be broken out to four links will lose the even-numbered neighbours when the odd ones are configured, and the port budget that looked sufficient on paper stops being sufficient in the rack. Read that block as pairs.

Memory, storage and what they are for

The switch carries 32 GB of memory and a 128 GB solid-state disk. NX-OS uses the memory for the control plane and for the tables that hold routing and forwarding state, and it uses the disk for the image, for logs and for the files that features such as telemetry and streaming write locally. Neither figure is a data-plane specification; both are the reason a switch can run a large feature set without the control plane becoming the limit.

The Cisco Nexus 9316D-GX carries the same two figures, and Cisco publishes them in its own column of the same table rather than in a shared row. That distinction matters when reading any specification across a series: two models agreeing is a finding, and carrying a figure from one part number to another because the hardware looks similar is how wrong specifications get published.

Power supplies, fans and airflow direction

Cisco offers six power supplies for this platform, in three input families and two airflow directions: NXA-PAC-1100W-PI2 and NXA-PAC-1100W-PE2 for AC, NXA-PDC-1100W-PI and NXA-PDC-1100W-PE for DC, and NXA-PHV-1100W-PI and NXA-PHV-1100W-PE for high-voltage input. Fans are NXA-FAN-35CFM-PI and NXA-FAN-35CFM-PE. The accessory kit, NXK-ACC-KIT-1RU, is a single part with no directional variant.

The suffixes are the whole decision. PI is port-side intake and PE is port-side exhaust, and the direction has to agree across the fan modules and the power supplies. A chassis fitted with intake fans and exhaust supplies is not a build with a compromise in it; it is an invalid build, and it is the kind of error that is discovered at rack rather than at order. Specify the direction first, then pick the input family, then pick the parts.

Those part numbers belong to this platform. Fan and supply parts are not shared with the earlier Nexus 9300 platforms, and a supply that fits a different chassis in the same range is not evidence about this one.

How the 93600CD-GX compares with the Nexus 9316D-GX

These two switches are the 400 Gigabit pair in the range, and they are built for different jobs. The 93600CD-GX carries two port tiers on two cage types; the 9316D-GX carries one tier on one cage and puts a larger fabric behind it.

The trade reads cleanly off those rows. The 9316D-GX draws less at both the typical and the maximum figure and Cisco rates it for a longer mean time between failures; the 93600CD-GX carries more ports and a wider set of optics classes. Where the requirement is 25 Gigabit server access rather than 100, the Cisco Nexus 93180YC-EX is the platform to look at, and the rest of the range sits on the Cisco Nexus 9000 pages.

Condition, testing and warranty

This is the same part number and the same hardware Cisco ships, sold refurbished. Every unit follows one process: inbound test on receipt, disassembly, cleaning, inventory, pick, assembly, configuration and an outbound test before it leaves. Whole systems carry a 2-year Enterasource warranty and ship free by FedEx Ground to the lower 48 states. No Cisco warranty transfers with second-hand hardware and we make no claim that it does.

Optics, power supplies, fan modules and rails are separate line items unless a listing includes them, and on this platform the fan and supply airflow pair is confirmed rather than assumed. Software licenses and subscriptions are a separate order line; an entitlement bought by a previous owner belongs to that owner's account rather than to the chassis. For 400 Gigabit builds across vendors, our AI fabric and high-speed data center switches pages cover the wider category, and the rest of our refurbished Cisco switches and routers is catalogued separately.

Frequently Asked Questions

What is the difference between QSFP28 and QSFP-DD on the Nexus 93600CD-GX?

They are two different optical cages carrying two different port tiers on the same switch. The twenty-eight QSFP28 ports run at 100 or 40 Gigabit and take QSFP28 optics; the eight QSFP-DD ports are given by Cisco at 10, 25, 40, 50, 100, 200 and 400 Gigabit and take QSFP-DD optics. A transceiver built for one cage does not belong in the other, so the port face has to be planned as two separate pools rather than as thirty-six equivalent sockets.

Why does a 100 Gigabit access switch need 400 Gigabit uplinks?

Because the uplink tier has to carry the traffic that the access tier aggregates. Twenty-eight ports of 100 Gigabit attached to servers or to a row of racks produce far more offered load than any single 100 Gigabit link upstream can absorb, so the eight QSFP-DD ports exist to move that aggregate into the fabric. It is the same architectural reason a leaf switch has been built with faster uplinks than downlinks for as long as leaf switches have existed; the numbers have simply moved up a tier.

What is 32 GB of memory on a Nexus switch for?

It runs the control plane rather than the data path. NX-OS uses system memory for routing protocol state, for the tables that hold forwarding and address information, and for the processes behind features such as telemetry, automation and programmable interfaces. A larger memory figure is what allows a switch to hold a big table set and a wide feature set at the same time. Both GX models carry 32 GB, each published in its own column of Cisco's specification table rather than shared between them.

Which airflow direction should I order on a Nexus 93600CD-GX?

Order the direction that matches the hot aisle in the rack it is going into, and then order every module to match. PI marks port-side intake and PE marks port-side exhaust, and both are offered across the AC, DC and high-voltage supplies as well as across the two fan modules. The constraint that catches people out is that the fans and the power supplies have to agree with each other: a mixed-direction chassis is not a valid build, and the direction is fixed at order rather than changed afterwards.

What state does a refurbished 93600CD-GX arrive in?

Tested, cleaned and configured to the specification agreed on the order. Each unit is checked on receipt, stripped down, cleaned, inventoried, picked, rebuilt, configured and tested again before it ships. The part number and the hardware are what Cisco built. Whole systems come with an Enterasource warranty, stated in full on the listing, and go free by FedEx Ground to the lower 48 states. We do not publish a burn-in duration, a pass rate or a certification name we cannot evidence.

How do you quote a Nexus 93600CD-GX build?

Tell us the airflow direction, the input family for the supplies, and the optics classes the fibre plant needs on each of the two port tiers, and we will price the build against that specification. We source this platform rather than holding every variant on the shelf, so availability is confirmed with the quote rather than assumed ahead of it. If what we can source differs in any respect from what was specified, you hear about it before anything is committed.