Nexus 3550 Datasheet for the 48-Port 25G FPGA Network Platform

The Cisco Nexus 3550-T Programmable Network Platform is a fixed 19-inch, 1RU top-of-rack application platform with 48 SFP28 ports, a dynamically reconfigurable FPGA, an x86 management CPU, and a firmware development environment for low-latency networking and custom packet-processing applications.

Product role and deployment model

The Nexus 3550-T is designed for deployments that require deterministic, low-latency packet handling combined with application-specific network processing. It is not presented as a conventional fixed-function Ethernet switch. Its forwarding and application capabilities are built around a Xilinx Virtex UltraScale Plus VU35P FPGA with a “-3” speed grade and 8GB of onboard High Bandwidth Memory.

The platform provides up to 48 Ethernet connections in a single rack unit. All 48 ports connect directly to the FPGA. An Intel Atom management processor with 8 cores operating at up to 1.7 GHz provides the x86 control and management environment.

The architecture supports three principal design patterns:

• Ultra-low-latency Layer 2 switching
• Ultra-low-latency Layer 3 switching and routing
• FPGA-based custom applications developed with the Nexus Firmware Development Kit

The platform is suited to applications where packet processing, network visibility, traffic manipulation, timing, or application-specific intelligence must be performed close to the network interface. The hardware is also appropriate for top-of-rack installations where a compact 1RU appliance must provide a high port count without adding a separate FPGA appliance or external packet-processing system.

The product should be evaluated as a programmable network appliance rather than solely by port count. The relevant sizing questions are the required interface rates, transceiver types, latency sensitivity, application functions, management model, timing requirements, power-feed design, and the need for custom FPGA logic.

Hardware architecture

The 48 SFP28 interfaces are backward compatible with SFP+ and SFP modules. The interface design therefore supports a mixture of 25GbE, 10GbE, and 1GbE connections, subject to the applicable software and firmware capabilities.

The architecture does not describe integrated copper access ports for data connectivity. Copper Direct Attach support is listed for SFP+ connectivity, while the RJ45 interface is identified as a management port. Port planning should therefore distinguish between SFP28/SFP+/SFP data interfaces, SFP+ copper direct attach, and the dedicated RJ45 management interface.

Port and transceiver planning

The connectivity options identified for the platform include:

• 48 SFP28 ports
• SFP+ fiber for 10GBASE-SR
• SFP+ fiber for 10GBASE-LR
• SFP+ fiber for 10GBASE-LRM
• SFP fiber for 1000BASE-SX
• SFP fiber for 1000BASE-LX
• SFP+ copper Direct Attach
• A 10G SFP+ management port
• A 1G RJ45 management port
• An RJ45 industry-standard serial console port
• A Micro USB port used for firmware upgrades
• SMA interfaces for PPS input and output
• An SMA input for GPS

The PPS interface is specified as 3.3V with a 50 Ohm signal interface. Timing-related deployments must validate the electrical characteristics of the attached timing source before installation.

A port schedule should identify, for every interface:

1. Required Ethernet rate.
2. SFP, SFP+, or SFP28 module type.
3. Fiber type and reach requirement.
4. Direct-attach cable requirement, if applicable.
5. Application ownership of the port.
6. Timing, management, or data role.
7. Firmware and software support for the selected rate.

The product footnote distinguishes software support by operating environment. EXOS supports 1G and 10G. NXOS supports 10G at the current documented capability, while 1G and 25G support with NXOS require a firmware update and are identified as roadmap items in the source material. This distinction is material during presales qualification. A design should not assume that physical 1G or 25G capability automatically means that the selected software environment supports those rates.

Management and operational control

The platform provides several management paths:

• CLI through the serial port
• CLI through SSH
• CLI through Telnet
• JSON RPC API for all CLI commands
• Automatic configuration through DHCP
• SNMP
• TACACS+ authentication
• Multiuser support
• ACLs on the management interface
• BASH shell access
• Python scripting
• Onboard cron jobs
• Time-series logging

The CLI is designed for low-latency FPGA configurations. Every CLI command is also available through the remote JSON RPC API. This provides a consistent automation model: an operator can validate a configuration interactively and then invoke the same command set through an orchestration or management system.

Management-plane security should be designed separately from data-plane application logic. The platform supports ACLs on the management interface and TACACS+ authentication, but the source does not specify the number of ACL entries, supported cipher suites, role granularity, or specific SNMP versions. Those items should be confirmed during detailed technical validation.

Firmware updates can be performed through SFTP, TFTP, HTTP, and USB. The availability of multiple update methods supports centralized operations as well as isolated or restricted environments. USB is particularly relevant for service procedures where the management network is unavailable or intentionally disconnected.

Presales sizing rules for management include:

• Provide at least one independent management path for initial provisioning.
• Confirm whether SSH is mandatory and whether Telnet is prohibited by the customer security standard.
• Determine whether TACACS+ integration is required before deployment.
• Define the source and distribution method for firmware images.
• Confirm whether DHCP is acceptable for initial configuration or whether static addressing is required.
• Include time synchronization requirements in the design rather than treating them as a post-installation task.

Programmability and application development

The Nexus Firmware Development Kit provides the development framework for adding application-specific intelligence to the FPGA platform. The FDK is described as providing the components required to build, run, and maintain FPGA-based intelligent applications and accelerate network applications.

This capability is relevant when a customer requires functions that are not available in a standard switch operating system or when packet processing must occur with minimal software-path overhead. Candidate use cases include packet aggregation, exchange traffic handling, data brokering, tap aggregation, WAN policing, custom filtering, and application-specific metadata processing.

A custom application proposal should identify:

• Packet classification criteria.
• Required ingress and egress behavior.
• Expected traffic rates.
• Required buffering and state.
• Timing or synchronization dependencies.
• Management and observability requirements.
• Upgrade and rollback procedures.
• Ownership of the application lifecycle.
• Validation method for FPGA logic and software integration.

The FDK does not eliminate the need for application qualification. A customer should define how a custom application will be tested, versioned, deployed, monitored, and recovered. The platform provides the programmable foundation, but the final operational characteristics depend on the selected firmware and application implementation.

Supported applications

The documented application set includes the following functions. Several entries are marked as future releases in the source material and must not be treated as generally available without release-specific confirmation.

The documented descriptions are functional summaries rather than performance guarantees. Specific throughput, latency, flow scale, NAT scale, filtering capacity, timing accuracy, and application resource limits are not provided in the supplied material. These values should be obtained from the relevant release documentation and validated against the proposed traffic model.

Statistics and diagnostics

The firmware provides packet-aware statistics without latency cost on the critical path. The platform can monitor transmitted and received packet and byte counts, transmit and receive errors, link state, link changes, and hardware health information.

The listed statistics and diagnostics include:

• Receive packet counters
• Transmit packet counters
• Current receive link state
• Receive link change count
• CRC error counters
• Receive temperature information
• Power-supply sensor information
• Fan speed
• Light levels
• Operating temperatures
• Transceiver capabilities

These functions support operational troubleshooting and presales acceptance criteria. A deployment should define which counters are polled, retained, alerted, and correlated with application events. Time-series logging is available on the platform and can be used to track changes in link state, environmental condition, fan behavior, and power status.

A practical acceptance test should include link establishment, transceiver recognition, receive and transmit counters, CRC monitoring, power-supply status, fan speed reporting, and temperature visibility. For a timing deployment, PPS, GPS, PTP, and NTP behavior should also be tested.

Power, cooling, and physical installation

The platform has dual hot-swappable power supplies. Standard AC input is 90-264V at 47-64 Hz, and IEC C13-C14 cables are included. Optional DC input is specified at 40-72V. Maximum power consumption is 150W.

The published mechanical and environmental information is:

Power planning should use the 150W maximum consumption figure rather than nominal load assumptions. Dual power supplies should be connected to separate power sources when the installation requires supply-level redundancy. The selected airflow direction must match the equipment row, adjacent devices, and facility cooling pattern.

The supplied material does not specify the chassis depth, width, or height in dimensional units beyond the 19-inch, 1RU rack designation. Rack installation planning should obtain the detailed mechanical drawing before ordering rails, cabinets, cable management, or front-to-rear and rear-to-front airflow accessories.

Environmental, acoustic, and reliability considerations

The stated operating temperature range is -5 C to 45 C, with operating humidity from 5% to 90% noncondensing. Storage conditions extend from -40 C to 70 C, with storage humidity from 5% to 95% noncondensing.

MTBF is not specified in the supplied product material. It should therefore not be used as a contractual availability input or compared directly with competing platforms without a documented reliability figure.

Acoustic noise is also not specified. This is important for offices, laboratories, trading rooms, and other locations where rack equipment may be installed outside a dedicated data center. The dual fan modules and 150W maximum power envelope indicate that active cooling is required, but they do not establish a sound-power or sound-pressure rating.

Detailed chassis dimensions are not specified beyond the 19-inch, 1RU format. Before final site approval, obtain:

• Chassis width, depth, and height.
• Rail and mounting requirements.
• Front and rear service clearance.
• Cable bend radius requirements.
• Airflow direction options.
• Acoustic rating.
• Installation altitude limits, if applicable.
• MTBF and component-level service information.

SKU and configuration matrix

The supplied product material identifies one platform designation and does not provide orderable PID or SKU numbers. The matrix below separates the documented platform from configurable characteristics without inventing order codes.

No separate SKU numbers, transceiver part numbers, rail kit numbers, power supply identifiers, or airflow option codes are included in the supplied material. Procurement should obtain the current ordering guide before issuing a bill of materials.

Warranty and service planning

Warranty duration, warranty coverage, advance replacement terms, software support entitlement, service-level options, and technical support details are not specified in the supplied product material. These items must be treated as commercial and contractual workstreams rather than inferred from the hardware description.

A presales proposal should explicitly capture:

• Hardware warranty duration.
• Return-to-depot or advance-replacement model.
• Coverage for power supplies and fan modules.
• Firmware entitlement and update access.
• Support for custom FDK applications.
• Severity definitions and response targets.
• Replacement logistics for the customer location.
• Requirements for serial-number registration.
• Software maintenance and release access.
• Responsibility for application validation after firmware updates.

For a custom FPGA deployment, standard hardware support may not by itself cover customer-developed application logic. The support boundary between platform hardware, firmware, FDK components, and customer application code should be documented before purchase.

Sizing and qualification checklist

Use the following rules during technical discovery:

1. Confirm the required port count and reserve capacity for growth, test ports, and management separation.
2. Map every connection to 1GbE, 10GbE, or 25GbE and validate software support for the selected rate.
3. Identify SFP, SFP+, SFP28, optical, and Direct Attach requirements.
4. Determine whether the workload uses Layer 2 switching, Layer 3 routing, security, timing, visibility, or a custom FPGA application.
5. Confirm whether the application is a documented function or requires FDK development.
6. Validate whether functions marked as future release are acceptable for the deployment schedule.
7. Design redundant power feeds and select AC or optional DC input based on the facility.
8. Match airflow direction to the rack cooling design.
9. Confirm temperature, humidity, service clearance, acoustic, MTBF, and mechanical requirements with the site owner.
10. Define management authentication, automation, firmware transfer, logging, and time synchronization requirements.
11. Establish application testing, rollback, and support ownership for custom firmware.
12. Obtain orderable SKU and service information before final quotation.

This qualification process prevents the physical 48-port capability from being treated as a complete solution definition. The final design depends on software support, application selection, transceiver compatibility, environmental constraints, timing requirements, and the service model.