Cisco Nexus 9000 Series NX-OS Interfaces Configuration Guide, Release 7.x

Interface parameters

Interface parameters are configuration settings that

define the operational characteristics of network interfaces,
enable administrators to tailor interface behavior for specific roles, and
support enhancements to performance, security, and connectivity.

Cisco NX-OS supports multiple configuration parameters for each supported interface type. Most of these parameters are described in this guide. Some parameters are described in other documents

The table provides sources for more information about configurable interface parameters.

Table 1. Interface Parameters
Feature	Parameters	Further Information
Basic parameters	Description, duplex, error disable, flow control, MTU, beacon	“Configuring Basic Interface Parameters”
Layer 3	Medium, IPv4 and IPv6 addresses	“Configuring Layer 3 Interfaces”
Layer 3	Bandwidth, delay, IP routing, Virtual Routing and Forwarding (VRFs)	Cisco Nexus 9000 Series NX-OS Unicast Routing Configuration Guide Cisco Nexus 9000 Series NX-OS Multicast Routing Configuration Guide
Port channels	Channel group, Link Aggregation Control Protocol (LACP)	“Configuring Port Channels”
Security	Ethernet OAM Unidirectional (EOU)	Cisco Nexus 9000 Series NX-OS Security Configuration Guide

Best practice for Ethernet interfaces

Ethernet interfaces have these characteristics.

Ethernet interfaces include routed ports.

Best practices for quad group configuration on Cisco Nexus N9K-C9364C-GX and N9K-C93600CD-GX

Breakout port considerations on Nexus N9K-X9400-16W

Beginning with Cisco Nexus NX-OS Release 10.5(1), these guidelines and limitations are applicable:

Access ports

An access port is a Layer 2 switchport that carries traffic for only a single VLAN. This type of port is a Layer 2 interface only.

For more information on access ports, see the “Information About Access and Trunk Interfaces” section.

Routed ports

A routed port is a Layer 3 interface that you configure on a physical switch port (not a virtual interface). It routes IP traffic to another device.

For more information on routed ports, see the Routed Interfaces section.

Management interface

A management interface is a network interface that

provides dedicated connectivity for device administration,
operates independently from data traffic interfaces, and
supports remote access protocols such as Telnet and SNMP.

You use the management interface (commonly labeled as mgmt0) to detect connection types automatically. It supports full-duplex mode and operates at speeds of 10, 100, or 1000 Megabits per second.

For more information on the management interface, see the Cisco Nexus 9000 Series NX-OS Fundamentals Configuration Guide.

Port-Channel interfaces

A port-channel interface is a logical network interface that

aggregates multiple physical interfaces into a single channel,
increases bandwidth and enhances redundancy, and
supports up to 32 bundled Ethernet links.

You can bundle up to 32 individual links (physical ports) into a port channel to improve bandwidth and redundancy.

For more information about port-channel interfaces, see the Configuring Port Channels section.

Subinterfaces

A subinterface is a virtual interface that

operates under a parent physical or port-channel interface,
allows assignment of unique Layer 3 parameters such as IP addresses and routing protocols, and
enables division of a single physical interface into multiple, independently configured virtual interfaces.

You can create virtual subinterfaces by configuring a parent interface as a Layer 3 interface.

Loopback interfaces

A loopback interface is a virtual network interface that

has a single endpoint and is always operational,
immediately receives any packet it transmits, and
emulates the behavior of a physical interface without connecting to external devices.

Loopback interfaces are often used for testing, diagnostics, or internal routing purposes, as they guarantee the interface remains active regardless of hardware state. For more information about subinterfaces, see the Loopback Interfaces section.

Breakout interfaces

A breakout interface is a high-speed network port feature that

splits a single high-bandwidth physical port into multiple lower-speed logical interfaces,
enables a switch or router to connect to several lower-speed devices simultaneously, and
maximizes port utilization by allowing flexibility in network configuration.

Cisco NX-OS supports the breakout of a high-bandwidth interface into one or more low bandwidth interfaces at the module level or at the per-port level.

Module level breakouts on ports

A module-level breakout is a port configuration technique that

enables splitting of certain high-density ports into multiple lower-bandwidth ports,
provides increased network configuration flexibility, and
supports a range of port breakdown options such as 4x10G, 4x25G, 4x50G, etc.

You can configure the interface breakout command to split a high bandwidth interface of a module into multiple lower speed ports.

Some modules break down all the ports into 4x10G, 4x25G, 4x50G, 4x100G, 2x50G, or 2x100G configurations.

Example: Module level breakout

For example, a module level breakout of 4x10G splits a 40G interface into four 10G interfaces. When you execute the command, the module reloads and removes the existing interface configurations.

switch# configure terminal
switch(config)# interface breakout module 1
Module will be reloaded. Are you sure you want to continue(yes/no)? yes

To undo a breakout, use the no interface breakout module module_number command. This restores ports to their original configuration and deletes previous breakout configurations.

Dynamic breakout ports (concept)

A dynamic breakout port (also called per-port level breakout) lets you split a high-speed Nexus 9000 switch port into several lower-speed ports. It supports flexible port mappings such as 4x10G, 4x25G, 2x50G, 4x100G, and 2x200G, and enables per-port configuration without requiring a module reload.

You can configure dynamic breakout ports as 4x10G, 4x25G, 4x50G, 4x100G, 2x50G, 2x100G, and 2x200G.

Use the interface breakout command to split high bandwidth into smaller breakout ports.

The dynamic breakout ports are identified as Ethernet slot front-panel-port breakout-port . For example, Ethernet 1/2/1, Ethernet 1/2/2, Ethernet 1/2/3, and Ethernet 1/2/4.

If you break out one or more 40G interfaces at the per-port level, the system removes their configuration when you run the command.

Note

You do not need to reload the module when you use per-port level breakout.

Examples

Configuring a single breakout port


switch(config)# interface breakout module 1 port 1 map 10g-4xswitch(config)#

Configuring multiple breakout ports


switch(config)# interface breakout module 1 port 1-4 map 10g-4xswitch(config)#

Mixed configuration with 40G and 10G interfaces


switch(config-if)# show int eth1/49 transceiver 
Ethernet1/49
transceiver is present
type is QSFP-40G-SR-BD
name is CISCO-AVAGO 
part number is AFBR-79EBPZ-CS2 
revision is 01
			
switch(config-if)# show int eth1/52 transceiver
Ethernet1/52
transceiver is present
type is QSFP-Cazadero
name is CISCO-DNI 
part number is CAZADERO-R 
revision is 03
nominal bitrate is 10000 MBit/sec per channel
			
switch(config-if)# show int eth1/53 transceiver 
Ethernet1/53
transceiver is present
type is QSFP-Cazadero
name is CISCO-DNI 
part number is CAZADERO-R 
revision is 03
nominal bitrate is 10000 MBit/sec per channel
			
switch(config)# interface breakout module 1 port 52-53 map 10g-4x 
			
switch(config-if)# show int br | i up
mgmt0 -- up 10.122.160.192 100 1500
Eth1/49 -- eth routed up none 40G(D) —  Running 40G
Eth1/50 -- eth routed up none 40G(D) --
Eth1/52/1 -- eth routed up none 10G(D) — Broken out to 10G 
Eth1/53/1 -- eth routed up none 10G(D) --  Broken out to 10G

Undoing breakout configuration

To remove breakout ports, enter the no interface breakout command.

switch(config)# no interface breakout module 1 port 1 map 10g-4x
switch(config)#

Lane Selectors

A lane selector is a control panel feature that

consists of a push-button switch and four LEDs,
enables users to view the link or activity status of switch ports, and
supports switching between 1 x 40G and 4 x 10G configurations on compatible Cisco Nexus 9000 Series switches and the Cisco Nexus 3164 and 3232 switches.

Additional information

Lane selectors are located on the left side of the Cisco Nexus switch front panel and are labeled 'LS'.

When used in a 1 x 40G configuration, LEDs indicate the link/activity status of the main port. When configured for 4 x 10G, pressing the push button cycles the LEDs through the status of each 10G port. On the last press, all LEDs extinguish, and the display resets to the default mode.

By pressing the lane selector push button, the port LED shows the selected lane’s link/activity status.

The first time the push button is pressed, the first LED displays the status of the first port. Pressing the push button a second time displays the status of the second port, and so on. To display the status of each of the four ports, press the push button as described.

When you press the push button after displaying the status of the last port, all four LEDs extinguish, indicating that the lane selector has returned to display the status for the default 1 x 40G configuration.

Examples

If port 60 is configured as 4 x 10G, pressing the lane selector once displays the link status of 60/1/1, twice for 60/1/2, and so on.

Note

The lane selector does not manage ports not configured for link/activity monitoring.

Guidelines

When a port is in 10G breakout mode and no lane is selected, the 40G port's LED lights green, even if only one of the 10G breakout ports is up.

A 10G breakout port's LED blinks when the beacon feature has been configured for it.

Breakout port support on Cisco Nexus switches

The matrix provides detailed information about supported breakout modes (for example, 4x10G, 4x25G, 2x50G, etc.) for Cisco Nexus switches and line card platforms. For more information, see Cisco Nexus Data Sheets.

Table 2. Breakout Modes Support Matrix
Switches	4x10G	4x25G	2x50G	2x100G	2x200G	2x400G	4x50G	4x100G	8x100G
N9K-X9636C-RX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9636C-R	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9636Q-R	Yes	No	No	No	No	No	No	No	No
N9K-X96136YC-R	No	No	No	No	No	No	No	No	No
N3K-C3636C-R	Yes	Yes	Yes	No	No	No	No	No	No
N3K-C36180YC-R	Yes	Yes	Yes	No	No	No	No	No	No
N9K-93108TC-EX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-93180YC-EX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-93108TC-FX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-93180YC-FX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-9348GC-FXP	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9732C-EX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9736C-EX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9732C-EXM	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9736C-FX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9736Q-FX	Yes	No	No	No	No	No	No	No	No
N9K-X9788TC-FX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-X9732C-FX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C9348GC-FXP	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C9336C-FX2	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C93216TC-FX2	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C93360YC-FX2	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C9364C-GX	Yes	Yes	Yes	No	No	No	No	No	No
N9K-C9316D-GX	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-C93600CD-GX	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-X9716D-GX	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-C9332D-GX2B	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-C9348D-GX2A	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-X9400-16W	Yes	Yes	Yes	Yes	No	No	Yes	No	No
N9K-X9400-8D	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
N9K-X98900CD-A	Yes	Yes	No	Yes	Yes	No	Yes	Yes	No

Guidelines and limitations for breakout ports

The Cisco Nexus 9516 switch does not support breakout on Modules 8 to 16.
Starting with Cisco NX-OS Release 7.0(3)F2(1), the 36-port 100-Gigabit Ethernet QSFP28 line cards (N9K-X9636C-R) and the 36-port 40-Gigabit Ethernet QSFP+ line cards (N9K-X9636Q-R) support breakout to 4 x 10G.

Best practices for manual breakout configuration

You must use the interface breakout module module number port port range map breakout mapping command when performing manual breakout on Cisco Nexus devices.

When you upgrade a Cisco Nexus 9000 device to Cisco NX-OS Release 7.0(3)I7(2) or later, interfaces configured with manual breakout using a QSA are no longer supported. You must remove the configuration and manually reconfigure the breakout settings for the affected interface.

Note

As of Cisco NX-OS Release 7.0(3)I7(2), manual breakout of QSA ports is not supported.

Note

This restriction does not apply to the following platforms, where manual breakout remains fully supported—N9K-C93128TX, N9K-9332, N9K-C9396PX, N9K-C9396TX, N9K-C9372PX, N9K-C9372TX, N9K-C9332PQ, N9K-9432PQ, N9K-9536PQ, N9K-9636PQ, N9K-X9632PC-QSFP100, N9K-X9432C-S, N3K-C3132Q-V, N3K-C3164Q, N3K-C3132C, N3K-C3232C, N3K-C3264Q, N3K-C3264C, N3K-3064Q, N3K-3016, N3K-3172—because manual breakout is supported on these platforms.

When breaking out a 40G port into 4x10G ports using a QSFP breakout cable, not all subinterfaces can be added to a port channel by default.

If you receive a port not compatible [Buffer boost] error when using the channel-group command, you must configure no buffer-boost on all subinterfaces before you can add them to a port channel.


switch# channel-group 99 mode activecommand failed: port not compatible [Buffer boost]

Note

As a workaround, configure no buffer-boost on all of the subinterfaces. This enables the channel-group configuration to go through.

Using the force keyword on the port-channel does not enable all the interfaces to be added to the port-channel even though the error message suggests using the keyword.

Manual breakout is supported on the following platforms because auto-breakout does not does not occur successfully on them—N9K-C93128TX, N9K-9332, N9K-C9396PX, N9K-C9396TX, N9K-C9372PX, N9K-C9372TX, N9K-C9332PQ, N9K-C93120TX, N9K-9432PQ, N9K-9536PQ, N9K-9636PQ, N9K-X9632PC-QSFP100, N9K-X9432C-S, N3K-C3132Q-V, N3K-C3164Q, N3K-C3132C, N3K-C3232C, N3K-C3264Q, N3K-C3264C, N3K-3064Q, N3K-3016, N3K-3172.

Forward error correction (FEC) settings for breakout ports

FEC is required on all cable types except for 1-meter and 2-meter passive copper cables. Cisco switches use FC-FEC CL74 by default. You can configure RS-FEC Consortium 1.6, RS-FEC IEEE, and other FEC algorithms.

Note

Auto-FEC is not supported in Cisco NX-OS Release 7.0(3)I7(x)

There are two primary FEC algorithms used in 25G Ethernet.

- FC-FEC (also known as "FireCode," "BASE-R," or "Clause 74") provides low-latency error protection (under 100 nanoseconds) optimized for bursty error correction. It is used on 3- and 5-meter passive copper cables, as well as on active optical 25G cables up to 10 meters in length. This FEC type is also utilized across all 100G interfaces.
- RS-FEC (also referred to as "Reed Solomon," "Clause 91," or "Clause 108") offers better error protection. It is required for 25G multimode fiber (MMF) transceivers, such as Cisco SFP-25G-SR-S, supporting distances up to 100 meters. RS-FEC may also be necessary for active optical cables exceeding 10 meters.
All 25G devices support FC-FEC by default. The Cisco Nexus 9300-FX series supports RS-FEC.

Beginning with Cisco NX-OS Release 7.0(3)I7(3,) there are two additional options to configure FEC such as rs-cons16 and rs-ieee as per IEEE standards.

Enable the RS FEC IEEE (25G) using the fec rs-ieee command on Cisco Nexus 9000 switches to implement RS-FEC error correction on high-speed Ethernet interfaces.
```
switch# (config-if)# fec ?
auto FEC auto
fc-fec CL74(25/50G)off Turn FEC off
rs-cons16 RS FEC Consortium 1.6 (25G)
rs-fec CL91(100G) or Consortium 1.5 (25/50G)
rs-ieee RS FEC IEEE (25G)
```

Beginning with Cisco NX-OS Release 7.0(3)I7(7), you can display the admin and operational status of FEC interface information with the show interface fec command.

Example:


switch# show interface fec
---------------------------------------------------------------------------------------------------
Name		Ifindex	Admin-fec 	Oper-fec    Status 	Speed 	Type
---------------------------------------------------------------------------------------------------
Eth1/1  	0x1a000000	auto		auto	connected     10G	 SFP-H10GB-AOC2M
Eth1/2  	0x1a000200   			Rs-fec    notconneced    auto	QSFP-100G-AOC3M
Eth1/3/1	0x38014000	auto		auto	disabled	auto	QSFP-H40G-AOC3M
Eth1/3/2	0x38015000	auto		auto	disabled	auto	QSFP-H40G-AOC3M
Eth1/3/3	0x38016000	auto		auto	disabled	auto	QSFP-H40G-AOC3M
Eth1/3/4	0x38017000	auto		auto	disabled	auto	QSFP-H40G-AOC3M

High bandwidth interfaces

A high bandwidth interface is a type of network port that

transmits and receives large amounts of data at increased rates compared to standard interfaces, and
supports advanced features such as port breakout to subdivide a single high-capacity interface into multiple lower-speed interfaces.

Breakout support for high bandwidth interfaces is available only on these switches.

The X9636PQ, X9432PQ, X9536PQ, and X9732C-EX line cards on the Cisco Nexus 9500 Series switches
Cisco Nexus 9332PQ switch
Cisco Nexus 3164Q switch

Cisco Nexus C92160YC Switch

For 7.0(3)I3(1) and later, the Cisco Nexus C92160YC switch provides two different modes of operation:

Mode 1: 48 * 10G/25G + 4 * 40G + 2 * 100G (Default configuration)
- Hardware profile portmode 48x25G + 2x100G + 4x40G
- Breakout is supported in 2 * 100G ports
Mode 2: 48 * 10G/25G + 4 * 100G
- Hardware profile portmode 48x25G + 4x100G
- Breakout is supported on 3 * 100G ports (Ports 50,51 & 52).

Use the show running-config | grep portmode command to display the current operation mode.

Example:


switch(config-if-range)# show running-config | grep portmode

hardware profile portmode 48x25G+2x100G+4x40G

See the installation guide for the Cisco Nexus C92160YC switches for more information. ( Install and Upgrade Guides for Cisco Nexus 9000 Series Switches )

With the Cisco Nexus C92160YC switch , there are two breakout modes:

40G to 4x10G breakout ports
- Enables the breakout of 40G ports into 4 X 10G ports.
- Use the interface breakout module 1 port x map 10g-4x command.
100G to 4x25G breakout ports
- Enables the breakout of 100G ports into 4 X 25G ports.
- Use the interface breakout module 1 port x map 25g-4x command.

Cisco Nexus C9272Q Switch

For 7.0(3)I3(1) and later, the Cisco Nexus C9272Q Switch provides 72 40G ports. Ports 37 - 71 support breakout interfaces.

To configure a breakout interface, use the interface breakout module 1 port x map 10g-4x command.

Example:


switch(config)# interface breakout module 1 port 38 map 10g-4x
switch(config)# show interface ethernet 1/38 capabilities | grep -i break

      Breakout capable:      yes

Breakout modes on Cisco Nexus C9332PQ switches

A breakout mode is a network switch feature that

enables a single high-speed port (such as 40G) to be split into multiple lower-speed ports (such as 10G),
allows flexible connectivity for downstream devices or modules, and
is typically used for scaling network access or aggregation performance.

Starting with Cisco NX-OS release 7.0(3)I3(1), the Cisco Nexus C9332PQ switch supports breakout mode on 24 x 40G ports. Ports 1 to 12 and 15 to 26 support breakout mode. Ports 13 and 14 are reserved.

Note

All FEXs are supported.

Note

Only the Cisco Nexus 9332PQ switch provides interface breakout support for FEX fabric interfaces. (7.0(3)I3(1) and later)

Cisco Nexus 9000 C93180LC-EX switch - Operation and breakout modes

Operation and breakout modes are switch configuration profiles. These profiles let you group and set ports, split high-speed physical ports into multiple lower-speed logical ports, and find out which types of equipment and cabling you can use for each mode.

Cisco Nexus 9000 C93180LC-EX modes

Operation modes are switch configuration profiles that

determine available bandwidth and port groupings
enable different breakout capabilities, and
require you to use distinct configuration procedures to switch between modes.

The Cisco Nexus 9000 C93180LC-EX switch supports three operation modes (7.0(3)I7(1) and later):

Mode 1: 28 x 40G + 4 x 40G/100G (Default configuration)

This is a hardware profile port mode 4x100G + 28x40G ports. It supports:
- Breakout support of 10 x 4 on top ports from 1 to 27 (ports 1,3,5, 7...27).
  
  If you break out any of the top ports, the corresponding bottom port becomes non-operational.
  
  For example, if port 1 is broken out, port 2 becomes non-operational.
- 1 Gigabit and 10 Gigabit QSA support on ports 29, 30, 31, and 32. However, QSAs on the top and bottom front panel ports must be of same speed.
- Breakout support of 10 x 4, 25 x 4, and 50 x 2 on ports 29, 30, 31, and 32.
Mode 2: 24 x 40G + 6 x 40G/100G

This hardware profile port mode 6 x 100G + 24 x 40G ports. It supports:
- Breakout support of 10 x 4 on top ports from 1 to 23 (ports 1,3,5, 7...23). If any of the top port is broken out the corresponding bottom port becomes non-operational.
- Breakout support of 10 x 4, 25 x 4, and 50 x 2 on ports 25, 27, 29, 30, 31, and 32.
- 1 Gigabit and 10 Gigabit QSA support on ports 29, 30, 31, and 32. However, QSAs on the top and bottom front panel ports must be of same speed.
Mode 3: 18 x 40G/100G

This hardware profile port mode 18 x 100G that ports. It supports:
- Breakout support of 10 x 4, 25 x 4, and 50 x 2 on top ports from 1 to 27 (ports 1,3,5, 7...27) and on ports 29,30,31,32.
- 1 Gigabit and 10 Gigabit QSA on all the 18 ports.

To change from Mode 3 to another mode, enter the copy running-config startup-config command followed by reload command to take effect. However, to move between Modes 1 and 2, you only need to enter the copy running-config startup-config command.

Use the show running-config | grep portmode command to display the current operation mode.


            switch(config-if-range)# show running-config | grep portmode
            
            hardware profile portmode 4x100G+28x40G

Breakout modes

The Cisco Nexus C93180LC-EX switch has three breakout modes.

Support for 40G to 4 x 10G breakout ports
- This mode enables the breakout of 40G ports into 4 x 10G ports.
- To configure this mode, use the interface breakout module 1 port x map 10g-4x command.
Support for 100G to 4 x 25G breakout ports
- This mode enables the breakout of 100G ports into 4 x 25G ports.
- To configure this mode, use the interface breakout module 1 port x map 25g-4x command.
Support for 100G to 2 x 50G breakout ports
- This mode enables the breakout of 100G ports into 2 x 50G ports.
- To configure this mode, use the interface breakout module 1 port x map 50g-2x command.

Bias-Free Language

Results

Chapter: Overview

Overview

Licensing requirements

Supported platforms

Interface parameters

Best practice for Ethernet interfaces

Best practices for quad group configuration on Cisco Nexus N9K-C9364C-GX and N9K-C93600CD-GX

Breakout port considerations on Nexus N9K-X9400-16W

Access ports

Routed ports

Management interface

Port-Channel interfaces

Subinterfaces

Loopback interfaces

Breakout interfaces

Module level breakouts on ports

Example: Module level breakout

Dynamic breakout ports (concept)

Examples

Lane Selectors

Additional information

Examples

Guidelines

Breakout port support on Cisco Nexus switches

Guidelines and limitations for breakout ports

Best practices for manual breakout configuration

Forward error correction (FEC) settings for breakout ports

High bandwidth interfaces

Cisco Nexus C92160YC Switch

Cisco Nexus C9272Q Switch

Breakout modes on Cisco Nexus C9332PQ switches

Cisco Nexus 9000 C93180LC-EX switch - Operation and breakout modes

Cisco Nexus 9000 C93180LC-EX modes

Breakout modes

Virtual device contexts

High availability for interfaces

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