Cisco N9300-FX3 Series Architecture for 400G AI/ML Data Center Fabrics

The Cisco N9300-FX3 Series comprises fixed 1RU data-center switches for leaf, access, server, border-leaf, and high-density Ethernet deployments. The family combines copper, multigigabit copper, 1/10/25G SFP28, and 40/100G QSFP28 interfaces with Cisco ACI, Cisco NX-OS VXLAN EVPN, Cisco Nexus Hyperfabric on selected models, IP Fabric for Media, Cisco Nexus Data Broker, and routed or switched Layer 2 fabrics.

Product selection by model

The 93180YC-FX3 is the primary fiber-oriented model. Its 48 SFP28 ports can operate at 1, 10, or 25 Gbps, while the six QSFP28 ports operate at 40 or 100 Gbps. It also supports standard PTP telecom profiles, SyncE, and PTP boundary clock functionality for telecommunications data-center edge deployments. It provides the only model-specific timing interfaces in the family: GPS 1PPS input or output, GPS 10 MHz input or output, a Time of Day RJ-45 interface, and an antenna connection for GNSS.

The 93108TC-FX3 provides 48 copper ports supporting 100 Mbps, 1 Gbps, or 10 Gbps. Its uplink architecture supports up to six 40/100G ports or combinations of 1, 10, 25, 40, 50, and 100 Gbps connectivity, subject to supported optics, breakout, and software configuration.

The 93108TC-FX3P adds 2.5G and 5G copper operation and PoE. All 48 downlinks support 100M/1/2.5/5/10G BASE-T, with PoE, PoE+, and UPoE capability. This is the appropriate selection when endpoint speed flexibility and powered-device support are required.

The 9348GC-FX3 is optimized for 1G copper access. It includes four SFP28 ports for 1/10/25G connectivity and two QSFP28 ports for 40/100G or supported combinations of 10, 25, 40, 50, and 100G connectivity.

The 9348GC-FX3PH combines 40 standard 1G copper ports with eight 10/100M half-duplex ports. The final eight ports are limited to 10 and 100 Mbps and half-duplex operation. It also supports PoE on ports 1 through 48, making it suitable where legacy half-duplex devices and powered endpoints must coexist.

Architecture, operating modes, and protocols

The switches support two principal operating models:

• Cisco ACI for centralized, policy-driven fabric automation.
• Cisco NX-OS for programmable, standards-based network operation.

The family supports VXLAN EVPN fabrics, including hierarchical multisite operation, and three-tier BGP architectures for nonblocking IPv6 fabrics. Layer 3 IPv4 and IPv6 unicast and multicast protocols include BGP, OSPF, IS-IS, EIGRP, RIPv2, PIM-SM, SSM, and MSDP. Segment Routing and SRv6 support traffic engineering and MPLS forwarding without RSVP traffic engineering.

Cisco Nexus Hyperfabric is supported on selected models. The minimum listed Hyperfabric release is Hyperfabric 26-03 for the 93180YC-FX3 and 93108TC-FX3. The 93108TC-FX3P, 9348GC-FX3, and 9348GC-FX3PH list Hyperfabric as not applicable.

Cisco Nexus Dashboard is included with Cisco N9000 tiered licenses. Nexus Dashboard Fabric Controller requires a DCN Essentials license. Nexus Dashboard Orchestrator requires a DCN Advantage license. Nexus Dashboard Insights requires a DCN Premier license or a DCN Day 2 Ops add-on license.

Automation, telemetry, and security

The platform supports Power On Auto Provisioning for Day-0 deployment, Ansible integrations, Native YANG, OpenConfig, RESTCONF, NETCONF, and gNMI. A REST API interacts with the Data Management Engine. Model-driven telemetry provides structured operational data, and Cisco Application Framework supports third-party application hosting.

IEEE 802.1ae MACsec capability is available on all ports. This allows physical-layer traffic encryption for server access, border-leaf connections, and leaf-to-spine links.

Forwarding tables support up to two million shared entries. Published scalability values include:

The published Fabric Extender scale applies only to the 93180YC-FX3 and 93108TC-FX3P. Software release validation should be checked against the applicable verified scalability guide before committing a design to the maximum values.

AI/ML and congestion management

The switches provide mechanisms intended for high-throughput, congestion-sensitive fabrics. Priority Flow Control uses priority-specific pause signaling to reduce frame drops. Explicit Congestion Notification marks packets affected by congestion without dropping them and provides ECN statistics.

Data Center Bridging support includes:

• Enhanced Transmission Selection for bandwidth allocation by priority class.
• Data Center Bridging Exchange Protocol for exchanging priority and bandwidth information with endpoints.
• RoCE lossless transport support.
• Weighted Random Early Detection for congestion avoidance.
• Intelligent buffer management for differentiating short-lived mice flows and long-lived elephant flows.
• Approximate Fair Dropping with Elephant Trap for identifying elephant flows after they cross a configured byte-count threshold.
• Dynamic Packet Prioritization for placing mice and elephant flows into separate queues.

For AI/ML or RoCE designs, the presales assessment must include the traffic classes, PFC scope, ECN thresholds, queue allocation, oversubscription, uplink topology, and endpoint DCB configuration. The presence of PFC alone does not establish an end-to-end lossless design.

Availability and forwarding design

Virtual Port-Channel provides Layer 2 multipathing while reducing reliance on Spanning Tree Protocol. VXLAN environments can use fabric links to eliminate the requirement for peer-to-peer vPC in applicable designs. The platform supports 64-way ECMP in the feature description and a maximum of 128-way ECMP paths in the scalability table; the applicable software and topology must determine the usable value.

The switches support hot-swappable power supplies and fans with N+1 redundancy. Software Maintenance Upgrades address specific defects, while In-Service Software Upgrades allow supported software changes while traffic continues to be forwarded.

Presales designs should specify:

1. Whether redundancy is required at the PSU level.
2. Whether airflow must be port-side intake or port-side exhaust.
3. Whether both switches in a pair require matching hardware and software.
4. Whether the design uses vPC, VXLAN EVPN, ACI, or routed ECMP.
5. Whether MACsec, PFC, ECN, or timing features are mandatory.
6. Whether the selected model supports the required FEX, Hyperfabric, or telemetry scale.

System resources and interfaces

All models use a four-core CPU, a 128 GB SSD, and a 40 MB system buffer. Memory varies by model:

PoE capacity and sizing

Only the 93108TC-FX3P and 9348GC-FX3PH support PoE. All ports 1 through 48 are PoE-capable on both models. Supported modes are PoE at 15 W and PoE+ at 30 W. The 93108TC-FX3P also supports UPoE at 60 W, while the 9348GC-FX3PH lists PoE++ at 60 W.

PoE sizing must use the selected PSU operating mode, not only the nominal wattage printed on the power supply. Redundant-mode capacity is materially lower than non-redundant capacity. The design should calculate the simultaneous powered-device load, startup requirements, redundancy condition, and desired 15 W, 30 W, or 60 W endpoint mix.

Power, cooling, and physical installation

All models are 1RU and support port-side intake and port-side exhaust variants. AC input is 100 to 240V at 50 to 60 Hz. The 93180YC-FX3, 93108TC-FX3, 9348GC-FX3, and 9348GC-FX3PH support 200 to 277V HVAC, -48 to -60V DC, and -240 to -380V HVDC. The 93108TC-FX3P does not list HVAC, DC, or HVDC input support.

Power supply selection must match the chassis, airflow direction, facility voltage, and PoE requirement. Do not mix intake and exhaust assumptions within the same rack row without validating the thermal design.

Acoustic noise

The published acoustic values are as follows:

These values are relevant to office-adjacent data rooms, laboratory environments, and edge sites. Rack placement should account for sustained fan speed under thermal or PoE load.

Environmental, reliability, and compliance specifications

Operating temperature is 0 to 40 degrees C. Storage temperature is -40 to 70 degrees C. Relative humidity is 5 to 95 percent, noncondensing. Operating altitude is 0 to 4,000 meters.

All models are RoHS compliant. The product family lists CE compliance, NEBS, UL 60950-1, CAN/CSA-C22.2, EN 60950-1, IEC 60950-1, AS/NZS 60950-1, GB4943, Class A emissions standards, EMC immunity standards, and RoHS-6 compliance with stated exceptions for leaded BGA balls and lead press-fit connectors.

Ordering matrix

Base switches

Power supplies

Fans and accessories

Software, optics, warranty, and services

The default software includes Layer 2 security and management capabilities. Additional licensing is required for functions including Layer 3 IP unicast routing, IP multicast routing, and Cisco Nexus Data Broker. Subscription and perpetual licensing options are available. Optics support and minimum software requirements vary by module and must be matched to the selected switch and software release.

The N9300-FX3 Series includes a one-year limited hardware warranty. Hardware replacement is provided with a ten-day turnaround from receipt of a Return Materials Authorization.

Available professional and support services include Data Center Quick Start Service, Data Center Accelerated Deployment Service, Cisco Migration Service, Cisco Product Support, solution support for Cisco ACI, Cisco SMARTnet service, and Cisco Smart Net Total Care service. Services cover planning, design, implementation, migration, operational readiness, and ongoing hardware and software support.