Configuring FEC on Optic Modules

This chapter provides information on how to configure FEC on optica modules.

• Feature History for FEC Support on Optic Modules, on page 1• Information About FEC Support on Optic Modules, on page 1• FEC State Links, on page 1• Configuring FEC on a Transceiver Module, on page 2• Additional References, on page 3

Feature History for FEC Support on Optic ModulesThis table includes only the updates for those releases that have resulted in additions or changes to the feature.

Table 1: Feature History for FEC Support on Optic Modules

Feature InformationReleaseFeature Name

Added support for the FEC Support on OpticModules feature on the Cisco Nexus 7000Series Switches M3 100 Gigabit Ethernetmodule (N77-M312CQ-26L).

8.0(1)FEC Support on OpticModules

Information About FEC Support on Optic ModulesFrom Cisco NX-OS Release 8.0(1), Forward Error Correction (FEC) support is enabled on the Cisco Nexus7000 Series Switches M3 Gigabit Ethernet module (N77-M312CQ-26L).

FEC is a digital signal processing technique used to enhance data reliability. It is done by introducing redundantdata, called error correcting code, prior to data transmission or storage.

FEC State LinksThe following table list the expected link state when two devices are configured with different operationalFEC configuration values. The following values are applicable only for QSFP-100G-SR4 transceiver modules.

Configuring FEC on Optic Modules1

Link StateDevice 2 (Admin State)Device 1 (Admin State)

DownFEC OFFFEC AUTO

UPFEC AUTOFEC AUTO

UPFEC OFFFEC OFF

UPFEC AUTOFEC cl91

UPFEC AUTOFEC AUTO

UPFEC cl91FEC cl91

By default, the FEC admin state is AUTO. Operational state for all optics except QSFP-100G-LR4 transceivermodules will be negotiated to cl91 (ON). For QSFP, by default, the FEC operational state will negotiate toOFF. In a FEC set up, if one side of the link is set to AUTO and the other side of the FEC link is set to OFF,it can cause link failure (link down).

Note

Configuring FEC on a Transceiver ModuleProcedure

Step 1 Enter global configuration mode.

switch# configure terminal

Step 2 Specify an interface range to configure, and enter interface configuration mode.

switch(config)# interface interface-range

Step 3 Configure the Forward Error Correction feature for the interface range.

switch(config-if-range)# fec {auto | cl91 | off}

• auto—Enables the FEC feature based on the transceiver type.

• cl91—Enables clause 91 for 100 Gigabit interface.

• off—Disables FEC for the interface range.

The default admin mode is auto on all transceiver modules, but on the QSFP-100G-LR4 transceivermodule by default, the admin mode is auto and the operational state of FEC is OFF.

Note

Step 4 (Optional) Copy the running configuration as startup configuration.

switch(config)# copy running-config startup-config

Step 5 (Optional) Verify the FEC configurations.

Configuring FEC on Optic Modules2

Configuring FEC on Optic ModulesConfiguring FEC on a Transceiver Module

switch(config)# show interface interface-range status

Configuring FEC

This example shows how to configure and verify the FEC feature on a QSFP-100G-LR4 transceivermodule:switch# configure terminalswitch(config)# interface ethernet1/2,Ethernet 18/12switch(config-if-range)# fec cl91switch(config-if-range)# exitswitch(config)# copy running-config startup-configswitch(config)# exitswitch# show interface Ethernet1/2

Ethernet1/2 is upadmin state is up, Dedicated InterfaceHardware: 40000/100000 Ethernet, address: 00eb.d56e.9fd0 (bia 00eb.d56e.9fd0)MTU 9216 bytes, BW 40000000 Kbit, DLY 10 usecreliability 255/255, txload 1/255, rxload 1/255Encapsulation ARPA, medium is broadcastPort mode is accessfull-duplex, 40 Gb/s, media type is 40GBeacon is turned offAuto-Negotiation is turned onInput flow-control is off, output flow-control is offAuto-mdix is turned offRate mode is dedicatedSwitchport monitor is offEtherType is 0x8100EEE (efficient-ethernet) : n/aadmin fec state is auto, oper fec state is off

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Additional ReferencesRelated Documents

Document TitleRelatedTopic

Cisco Nexus 7000 Series NX-OS Interfaces Command Referencefec command

Configuring FEC on Optic Modules3

Configuring FEC on Optic ModulesAdditional References

Configuring FEC on Optic Modules4

Configuring FEC on Optic ModulesAdditional References