Configure FEC on a Port

About this task

Use this procedure to configure Forward Error Correction (FEC) on supported ports.

Procedure

  1. Enter Interface Configuration mode:

    enable

    configure terminal

    interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]} or interface vlan <1–4059>

    Note

    Note

    If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.

  2. Optional: Specify the port or ports to configure for FEC:

    fec port {slot/port[/sub-port][-slot/port[/sub-port]][,...]}

  3. Configure FEC on a port:

    fec {auto | cl108 | cl74 | cl91}

  4. Verify the configuration:

    show interfaces gigabitEthernet config {slot/port[/sub-port][-slot/port[/sub-port]][,...]}

Examples

Configure Clause 108 FEC on a 25 Gbps port 1/1:

Switch:1>enable
Switch:1#configure terminal
Switch:1(config)#interface gigabitethernet 1/1
Switch:1(config-if)#fec cl108

Verify the configuration when a 25 Gbps optic is present:

Switch:1(config-if)#show interfaces gigabitEthernet config 1/1
==========================================================================================
                                  Port Config
==========================================================================================
PORT                         DIFF-SERV    QOS   MLT   VENDOR            
NUM      TYPE                EN    TYPE   LVL   ID    NAME              
------------------------------------------------------------------------------------------
1/1      25GbCX              true  core   1     0     Extreme                  
==========================================================================================
                                  Port Config
==========================================================================================

PORT   ADMIN   OPERATE AUTO     ACCESS-SERV  RMON     FLEX-UNI  ADMIN  APPLICABLE  OPERATE
NUM    ROUTING ROUTING RECOVER  EN                              FEC    FEC         FEC
------------------------------------------------------------------------------------------
1/1   Enable   Disable Disable false         Disable  Disable   Auto  CL108      CL108

Verify the configuration when a 10 Gb optic is present in a 25 Gb port:

Switch:1(config-if)#show interfaces gigabitEthernet config 1/1
================================================================================================
                                  Port Config
================================================================================================
PORT                         DIFF-SERV    QOS   MLT   VENDOR            
NUM      TYPE                EN    TYPE   LVL   ID    NAME              
------------------------------------------------------------------------------------------------
1/1      10GbSR              true  core   1     0     Extreme           

PORT   ADMIN   OPERATE AUTO     ACCESS-SERV  RMON     FLEX-UNI  ADMIN  APPLICABLE        OPERATE
NUM    ROUTING ROUTING RECOVER  EN                              FEC    FEC               FEC
------------------------------------------------------------------------------------------------
1/1   Enable   Disable Disable  false        Disable  Disable   Auto  Not Applicable     Off

Variable Definitions

The following table defines parameters for the fec command.

Variable

Value

port {slot/port[/sub-port] [-slot/port[/sub-port]] [,...]}

Identifies the slot and port in one of the following formats: a single slot and port (slot/port), a range of slots and ports (slot/port-slot/port), or a series of slots and ports (slot/port,slot/port,slot/port). If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.

{auto | cl108 | cl74 | cl91}

Configures one of the following options for FEC on the port:

  • auto

  • Clause 91

  • Clause 108

  • Clause 74

Note:

On a 100 GbE port, only the Clause 91 and Clause 108 options are supported. On 100 GbE channelized ports (operating at 25 Gbps speed), you can configure Clause 108 for extra latency or Clause 74 for reduced latency.

Configuration of FEC is not supported on a management port or on 100 GbE ports operating at 40 Gbps speed.

Important:

On ports that support FEC, always configure the same option on both end-points. Otherwise, the link does not come up.
9037588-00 Rev AA