Have an account?

  •   Personalized content
  •   Your products and support

Need an account?

Create an account

Cisco Nexus 3408-S Switch Data Sheet

Data Sheet

Available Languages

Download Options

  • PDF
    (627.9 KB)
    View with Adobe Reader on a variety of devices
Updated:February 12, 2021

Available Languages

Download Options

  • PDF
    (627.9 KB)
    View with Adobe Reader on a variety of devices
Updated:February 12, 2021


Cisco Nexus 3400-S overview

The Cisco Nexus® 3400-S is the first 400G capable switch in the Nexus 3000 portfolio with 50 Gbps PAM4 Serial-Deserializers (SerDes), designed for data centers with industry-leading performance-per-watt power efficiency at low latency, offering leading analytics.

Main benefits of the Cisco Nexus 3400-S switches:

     With the 12.8-Tbps ASIC, the Cisco Nexus 3408-S series provides 128 ports of 100G or 32 ports of 400G, allowing customers to grow at scale with fewer numbers of switches in their fabric, simplifying management and reducing cost and number of hops.

     At 400G, the Cisco Nexus 3400-S offers the lowest latency in the industry at high power efficiency.

     The Cisco Nexus 3400-S offers a programmable pipeline translated to flexible profiles, whether Longest-Prefix-Matching (LPM)-optimized or layer 3 host-optimized. Customers can choose the profile to match their deployment needs.

     Cisco Nexus 3400-S switches enable deep network analytics, offering per flow monitoring, queue forensics, and drop-packet forensics to help monitor customer networks.

The Cisco Nexus 3408-S (Figure 1) is a 4-Rack-Unit (RU), 8-slot chassis with the flexibility of 100G or 400G Line-Card Expansion Modules (LEMs) offering 128 ports of 100G or 32 ports of 400G. The Cisco Nexus 3408-S is the industry’s highest port radix in a compact and energy-efficient form factor. The Cisco Nexus 3408-S supports HVAC/DC power inputs with forward airflow direction.

Related image, diagram or screenshot

Figure 1.         

Cisco Nexus 3408-S

The Cisco Nexus 3408-S has the following hardware configuration:

     4RU, 8-slot chassis

     NXM-X16C LEM with 16 ports of Quad-Small-Form-Factor 28 (QSFP28)

     NXM-X4D LEM with 4 ports of Quad Small Form-Factor Pluggable – Double Density (QSFP-DD)

     Beacon LED

     Status LED

     Dual-redundant power supplies

     Redundant (2+1) fans

     One RS-232 console port

     One RJ45 and one SFP Management port

     One USB port

Related image, diagram or screenshot

Figure 2.         

Cisco Nexus NXM-X16C, 16 Ports of 100G

The 100G LEMs are 16 ports of QSFP28 supporting 100G native speed and 50, 40, 25, 10G breakout speeds.

The 400G LEMs are 4 ports of QSFP-DD that are backward-compatible with QSFP+, QSFP28, and QSFP56. Each QSFP-DD port can operate at 400, 200, 100, 40 native speeds and 200, 100, 50, 25, 10 Gbps breakout.

Cisco NX-OS software overview

Cisco NX-OS is a data center-class operating system built with modularity, resiliency, and serviceability at its foundation. Cisco NX-OS helps ensure continuous availability and sets the standard for mission-critical data center environments. The self-healing and highly modular design of Cisco NX-OS makes zero-impact operations a reality and provides exceptional operational flexibility.

Focused on the requirements of the data center, Cisco NX-OS provides a robust and comprehensive feature set that meets the networking requirements of present and future data centers. With an XML interface and a Command-Line Interface (CLI) like that of Cisco IOS® Software, Cisco NX-OS provides state-of-the-art implementations of relevant networking standards as well as a variety of true data-center-class Cisco innovations.

The Cisco Nexus 3400-S provides:

Wire-rate layer 2 and 3 switching on all ports, with up to 25.6 Terabits per second (Tbps) with 7.2 Bpps at ingress and 10 Bpps at egress.

Robust programmability, with support for Cisco NX-API, Linux containers, XML, and JavaScript Object Notation (JSON) APIs, Python.

High performance and scalability, with a four-core CPU, 32 GB of DRAM, and 70 MB of dynamic buffer allocation, making the switch excellent for massively scalable data centers and big data applications.


     The Cisco Nexus 3408-S supports break out for 2x200/50G, 4x100/50G/25G/10G, and 8x50G, supporting up to 128 ports of 100G or up to 168 ports of 50G.

     The NXM-X16C supports break out[1] for 2x50G and 4x25G/10G.

     The NXM-X4D supports break out1 for 2x200/50G or 4x100/50/25G/10G.

     Both fiber and copper cabling solutions are available for 10-, 25-, 40-, 50-, 100 and 400-Gbps connectivity, including an Active Optical Cable (AOC) and Direct-Attached Cable (DAC).

High availability

     Virtual Port Channel (vPC) technology provides layer 2 multipath through the elimination of Spanning Tree Protocol (STP). It also enables fully utilized bisectional bandwidth and simplified layer 2 logical topologies without the need to change the existing management and deployment models.

     The 512-way[2] Equal-Cost Multipath (ECMP) routing enables the use of layer 3 fat-tree designs. This feature allows organizations to prevent network bottlenecks, increase resiliency, and add capacity with little network disruption.

     Advanced reboot2 capabilities include hot and cold patching.

     The switch uses hot-swappable Power-Supply Units (PSUs) and fans.

Purpose-built Cisco NX-OS operating system with comprehensive, proven innovations

     Power-On Auto Provisioning (POAP) enables touchless bootup and configuration of the switch, drastically reducing provisioning time.

     Cisco Embedded Event Manager (EEM) and Python scripting enable automation and remote operations in the data center.

     Advanced buffer monitoring reports real-time buffer utilization per port and per queue, which allows organizations to monitor traffic bursts and application traffic patterns.

     Ethanalyzer is a built-in packet analyzer for monitoring and troubleshooting control-plane traffic and is based on the popular Wireshark open-source network protocol analyzer.

     Complete layer 3 routing protocol suites are supported, including Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), Enhanced Interior Gateway Routing Protocol (EIGRP), Routing Information Protocol Version 2 (RIPv2) and Intermediate System to Intermediate System (IS-IS).

Table 1.        Software licensing for Cisco Nexus 3408-S Switches

Software package

Features supported

System default (no license required)

  Comprehensive layer 2 feature set: VLAN, IEEE 802.1Q trunking, Link Aggregation Control Protocol (LACP), Unidirectional Link Detection (UDLD; Standard and Aggressive), Multiple Spanning Tree Protocol (MSTP), Rapid Spanning Tree Protocol (RSTP), and Spanning Tree Protocol (STP) guard
  Security: Authentication, Authorization, and Accounting (AAA), Access Control Lists (ACLs), storm control, and configurable Control-Plane Policing (CoPP)
  Management features: Cisco Data Center Network Manager (DCNM) support, Secure Shell Version 2 (SSHv2) access, Cisco Discovery Protocol, Simple Network Management Protocol (SNMP), syslog
  Monitoring features: Advanced buffer monitoring, SPAN, and ERSPAN

Base license

  Layer 3 IP routing: Inter-VLAN Routing (IVR), static routes, Routing Information Protocol Version 2 (RIPv2), ACLs, Open Shortest Path First Version 2 (OSPFv2; limited to 256 routes), Enhanced Interior Gateway Routing Protocol (EIGRP) stub, Hot Standby Router Protocol (HSRP), and Virtual Router Redundancy Protocol (VRRP)

Essential License

  Advanced layer 3 IP routing: OSPFv2, EIGRP, Border Gateway Protocol (BGP), Intermediate System to Intermediate System (IS-IS), and Virtual Routing and Forwarding Lite (VRF-Lite), DCNM and Telemetry Features: Buffer Drop Capture (BDC), High Delay Capture (HDC) and INT

Cisco Nexus Data Broker license (NDB-FX-SWT-K9)

  License for using the tap and SPAN aggregation functions with Cisco Nexus Data Broker; supported on the Essential License

Transceiver and cabling options

The Cisco Nexus 3400-S are Quad Small Form factor pluggable - Double Density (QSFP-DD) platforms that support the full range of optical transceivers, starting from Active Optical Cables (AOC), Direct Attach Cables (DAC).

Learn more details about the optical modules available and the minimum software release required for each supported optical module via the Transceiver Module Group (TMG) Compatibility Matrix.

Product specifications

The following table lists the product specification for Cisco Nexus 3408-S.

Table 2.        Product specifications


Cisco Nexus 3408-S


  4 RU, 8-slot chassis
  Beacon LED
  Status LED
  Dual-redundant power supplies
  Redundant (2+1) fans
  Two 100/1000Mbps SFP ports
  One RS-232 serial console port
  One RJ45 and one SFP management port
  One USB port


25.6-Tbps switching capacity

Table 3.           Hardware specifications common to all Nexus 3804-S Switches



Normal mode

Hardware tables and scalability

Number of MAC addresses


Number of IPv4/IPv6 unicast routes

440K / 360K

Number of IPv4/IPv6 hosts

192K / 96K

Number of IPv4 multicast routes

Up to 96K with 8K groups

Number of VLANS


Number of ACL entries

3.5K ingress and 1.5K egress

Number of spanning-tree instances

Rapid Spanning Tree Protocol (RSTP): 123

Multiple Spanning Tree (MST) Protocol: 64

Number of EtherChannels


Number of ports per EtherChannel

up to 128

Buffer size

70 Mb

Boot flash memory

128 GB


Number of power supplies

2 (redundant)

Power supply types

AC (forward airflow)

Input voltage

100 to 240 VAC


50 to 60 Hz

Power supply efficiency

89 to 91% at 220V


Forward airflow: Port-side intake (air enters through ports and exits through fan tray and power supplies)

Six individual, hot-swappable fans (5+1 redundant)


Dimensions (height x width x depth)

6.97 in. x 17.3 in. x 31.6 in.


N3K-C3408-S weight across configurations:

  68 lb (without LEMs, PSUs, or fans)
  107.7 lb (with eight 100G LEMs, PSUs, and fans)
  104.5 lb (with eight 400G LEMs, PSUs, and fans)

Individual LEMs:

  NXM-X16C (100G LEM) – 3.6 lb
  NXM-X4D (400G LEM) – 3.2 lb

Operating temperature

32 to 104° F (0 to 40°C)

Storage temperature

-40 to 158° F (-40 to 70°C)

Relative humidity

5 to 95% non-condensing

Altitude (Operating)

Up to 13,123 ft.

Altitude (Non-Operating)

Up to 16,000 ft.

Table 4.        Software features common to all Nexus 3000 Switches



Layer 2

  Layer 2 switch ports and VLAN trunks
  IEEE 802.1Q VLAN encapsulation
  Support for up to 4096 VLANs
  Rapid Per-VLAN Spanning Tree Plus (PVRST+) (IEEE 802.1w compatible)
  MSTP (IEEE 802.1s): 64 instances
  Spanning Tree PortFast
  Spanning Tree Root Guard
  Spanning Tree Bridge Assurance
  Cisco EtherChannel technology (up to 24 ports per EtherChannel)
  LACP: IEEE 802.3ad, IEEE 802.1ax
  Advanced PortChannel hashing based on layer 2, 3, and 4 information
  Jumbo frames on all ports (up to 9216 bytes)
  Link-level flow control (IEEE 802.3x)

Layer 3

  Layer 3 interfaces: Routed ports on interfaces, Switch Virtual Interfaces (SVIs), PortChannels, and subinterfaces (total: 1024)
  64-way equal-cost multipath (ECMP)
  4096 ACL entries
  Routing protocols: Static, RIPv2, EIGRP, OSPF, and BGP
  ACL: Routed ACL with layer 3 and 4 options to match ingress and egress ACLs
  VRF: VRF-Lite (IP VPN), VRF-aware unicast (BGP, OSPF, and RIP), and VRF‑aware multicast
  VRF route leaking
  Jumbo frame support (up to 9216 bytes)


  Ingress ACLs (standard and extended) on Ethernet
  Standard and extended layer 3 to 4 ACLs include IPv4, Internet Control Message Protocol (ICMP), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP)
  VLAN-based ACLs (VACLs)
  Port-based ACLs (PACLs)
  ACLs on virtual terminals (VTYs)
  Dynamic Host Configuration Protocol (DHCP) relay
  Control Plane Policing (CoPP)

Cisco Nexus Data Broker

  Topology support for tap and SPAN aggregation
  Traffic load balancing to multiple monitoring tools
  Packet truncation
  Traffic filtering based on layer 1 through layer 4 header information
  Traffic replication and forwarding to multiple monitoring tools
  Robust Role-Based Access Control (RBAC)
  Northbound Representational State Transfer (REST) API for all programmability support


  Power On Auto Provisioning (POAP)
  Python scripting
  Switch management using 10/100/1000-Mbps management or console ports
  CLI-based console to provide detailed out-of-band management
  In-band switch management
  Locator and beacon LEDs
  Configuration rollback
  AAA with RBAC
  Embedded packet analyzer
  SNMP v1, v2, and v3
  Enhanced SNMP MIB support
  XML (NETCONF) support
  Remote monitoring (RMON)
  Advanced Encryption Standard (AES) for management traffic
  Unified username and passwords across CLI and SNMP
  Microsoft Challenge Handshake Authentication Protocol (MS-CHAP)
  Digital certificates for management between switch and RADIUS server
  Cisco Discovery Protocol Versions 1 and 2
  SPAN on physical, PortChannel, and VLAN
  ERSPAN Versions 2 and 3
  Ingress and egress packet counters per interface
  Network Time Protocol (NTP)
  Cisco Online Health Management System (OHMS)
  Comprehensive bootup diagnostic tests
  Cisco DCNM
  Active buffer monitoring

Table 5.        Management and standards support



MIB support

Generic MIBs


Ethernet MIBs


Configuration MIBs


Monitoring MIBs



Security MIBs


Miscellaneous MIBs


Layer 3 and Routing MIBs



  IEEE 802.1D: Spanning Tree Protocol
  IEEE 802.1p: CoS Prioritization
  IEEE 802.1Q: VLAN Tagging
  IEEE 802.1s: Multiple VLAN Instances of Spanning Tree Protocol
  IEEE 802.1w: Rapid Reconfiguration of Spanning Tree Protocol
  IEEE 802.3z: Gigabit Ethernet
  IEEE 802.3ad: Link Aggregation Control Protocol (LACP)
  IEEE 802.1ax: Link Aggregation Control Protocol (LACP)
  IEEE 802.3ae: 10 Gigabit Ethernet
  IEEE 802.3ba: 40 Gigabit Ethernet
  IEEE 802.1ab: LLDP



  RFC 1997: BGP Communities Attribute
  RFC 2385: Protection of BGP Sessions with the TCP MD5 Signature Option
  RFC 2439: BGP Route Flap Damping
  RFC 2519: A Framework for Inter-Domain Route Aggregation
  RFC 2545: Use of BGPv4 Multiprotocol Extensions
  RFC 2858: Multiprotocol Extensions for BGPv4
  RFC 3065: Autonomous System Confederations for BGP
  RFC 3392: Capabilities Advertisement with BGPv4
  RFC 4271: BGPv4
  RFC 4273: BGPv4 MIB: Definitions of Managed Objects for BGPv4
  RFC 4456: BGP Route Reflection
  RFC 4486: Subcodes for BGP Cease Notification Message
  RFC 4724: Graceful Restart Mechanism for BGP
  RFC 4893: BGP Support for Four-Octet AS Number Space


  RFC 2328: OSPF Version 2
  8431RFC 3101: OSPF Not-So-Stubby-Area (NSSA) Option
  RFC 3137: OSPF Stub Router Advertisement
  RFC 3509: Alternative Implementations of OSPF Area Border Routers
  RFC 3623: Graceful OSPF Restart
  RFC 4750: OSPF Version 2 MIB


  RFC 1724: RIPv2 MIB Extension
  RFC 2082: RIPv2 MD5 Authentication
  RFC 2453: RIP Version 2
  IP Services
  RFC 768: User Datagram Protocol (UDP)
  RFC 783: Trivial File Transfer Protocol (TFTP)
  RFC 791: IP
  RFC 792: Internet Control Message Protocol (ICMP)
  RFC 793: TCP
  RFC 826: Address Resolution Protocol (ARP)
  RFC 854: Telnet
  RFC 959: FTP
  RFC 1027: Proxy ARP
  RFC 1305: Network Time Protocol (NTP) Version 3
  RFC 1519: Classless Interdomain Routing (CIDR)
  RFC 1542: BootP Relay
  RFC 1591: Domain Name System (DNS) Client
  RFC 1812: IPv4 Routers
  RFC 2131: DHCP Helper
  RFC 2338: VRRP

IP Multicast

  RFC 2236: Internet Group Management Protocol, version 2
  RFC 3376: Internet Group Management Protocol, Version 3
  RFC 3446: Anycast Rendezvous Point Mechanism Using PIM and MSDP
  RFC 3569: An Overview of SSM
  RFC 3618: Multicast Source Discovery Protocol (MSDP)
  RFC 4601: Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)
  RFC 4607: Source-Specific Multicast for IP
  RFC 4610: Anycast-RP using PIM
  RFC 5015: PIM BiDir
  RFC 5132: IP Multicast MIB

Regulatory standards compliance

The following table summarizes regulatory standards compliance for the Cisco Nexus 3000 Series.

Table 6.        Regulatory standards compliance: Safety and EMC



Regulatory compliance

  Products should comply with CE Markings per directives 2004/108/EC and 2006/95/EC


  UL 60950-1 Second Edition
  CAN/CSA-C22.2 No. 60950-1 Second Edition
  EN 60950-1 Second Edition
  IEC 60950-1 Second Edition
  AS/NZS 60950-1

EMC: Emissions

  47CFR Part 15 (CFR 47) Class A
  AS/NZS CISPR22 Class A
  CISPR22 Class A
  EN55022 Class A
  ICES003 Class A
  VCCI Class A
  KN22 Class A
  CNS13438 Class A

EMC: Immunity



RoHS 5 compliant except for lead press-fit connectors

Ordering information

The following table provides ordering information for Cisco Nexus 3408-S.

Table 7.        Ordering information

Part number




Nexus 100G Line Expansion Module


Nexus 400G Line Expansion Module


Nexus Blank Line Expansion Module


Nexus fan, forward airflow (port-side intake)


Nexus 2KW HV power supply, forward airflow (port-side intake)


Nexus 2KW DC power supply, forward airflow (port-side intake)


Nexus 2KW AC power supply, forward airflow (port-side intake)

Software Licenses


Nexus 3408-S Essential License including Layer-3 LAN Enterprise, DCNM and Telemetry features



Nexus 3408-S switch with 32 ports of QSFP-DD spare


Nexus 100G Line Expansion Module spare


Nexus 400G Line Expansion Module spare


Nexus Blank Line Expansion Module spare


Nexus fan, forward airflow (port-side intake) spare


Nexus 2KW HV power supply, forward airflow (port-side intake) spare


Nexus 2KW DC power supply, forward airflow (port-side intake) spare


Nexus 2KW AC power supply, forward airflow (port-side intake) spare


The Cisco Nexus 3000 Series Switches have a 1-year limited hardware warranty. The warranty includes hardware replacement with a 10-day turnaround from receipt of a Return Materials Authorization (RMA).

Service and support

Cisco offers a wide range of services to help accelerate your success in deploying and optimizing the Cisco Nexus 3000 Series in your data center. The innovative Cisco Services offerings are delivered through a unique combination of people, processes, tools, and partners and are focused on helping you increase operational efficiency and improve your data center network. Cisco Advanced Services uses an architecture-led approach to help you align your data center infrastructure with your business goals and achieve long-term value. Cisco SMARTnet® Service helps you resolve mission-critical problems with direct access at any time to Cisco network experts and award-winning resources. With this service, you can take advantage of the Cisco Smart Call Home service capability, which offers proactive diagnostics and real-time alerts on your Cisco Nexus 3000 Series Switches. Spanning the entire network lifecycle, Cisco Services helps increase investment protection, optimize network operations, support migration operations, and strengthen your IT expertise.

Cisco Capital

Flexible payment solutions to help you achieve your objectives

Cisco Capital makes it easier to get the right technology to achieve your objectives, enable business transformation and help you stay competitive. We can help you reduce the total cost of ownership, conserve capital, and accelerate growth. In more than 100 countries, our flexible payment solutions can help you acquire hardware, software, services and complementary third-party equipment in easy, predictable payments. Learn more.

For more information

For more information, visit https://www.cisco.com/go/nexus3000. For information about Cisco Nexus Data Broker, visit https://www.cisco.com/go/nexusdatabroker.



[2] Wire rate on all ports for packets greater than 200 bytes




[1] Refer to the break-out matrix in software configuration guide for details
[2] Refer to verified scalability guide for latest software support

Learn more