How can we enable the RS-FEC on 25gig Port on Cisco C93180YC-EX

[deepak.singh.rawat]

Hi Experts,

Can you help me how can i enable the RS-FEC on a 25Gig Port in isco Nexus9000 C93180YC-EX bootflash:///nxos.9.3.8.bin.

It gives me a error like below.

nx9000(config-if)# fec rs-fec
ERROR: FEC validation failed on eth1/18 due to incompatible configured speed or transceiver type
nx9000(config-if)# show running-config interface ethernet 1/18

Name           Ifindex                    Admin-fec  Oper-fec  Status           Speed             Type

Eth1/18       0x1a002200             auto           auto         notconnec     25G             SFP-H25GB-LR

Far end switch  is already 25gig RS-FEC with autoNegEnable false.

Thanks in advance

Regards,

Deepak

[Reza Sharifi]

Hi,

Do you have the speed and duplex command configured under the interface? if not add the command and try again.

HTH

[deepak.singh.rawat]

Hi Reza,

Current config on port is like below, i tried to do the full duplex and speed 25000 and then i try to put the fec to rs-fec but i got the same error.

interface Ethernet1/18
switchport mode trunk
dot1x pae authenticator
dot1x port-control auto
dot1x re-authentication
dot1x host-mode multi-host
switchport trunk allowed vlan 1968-1970
mtu 9216
speed 25000
duplex full

Regards,

Deepak Rawat

[Georg Pauwen]

Hello,

which FEC options are available for that interface ? There are some restrictions on which interfaces on which switcj model support which FEC,..the document below has a listing...

https://cordero.me/cisco-aci-auto-negotiation-and-forward-error-correction/

[deepak.singh.rawat]

Hi Georg,

The rs-fec option is coming on the port but when i try to enable it gives error.

version 9.3(8) Bios:version 07.69

interface Ethernet1/18
switchport mode trunk
dot1x pae authenticator
dot1x port-control auto
dot1x re-authentication
dot1x host-mode multi-host
switchport trunk allowed vlan 1968-1970
mtu 9216

nx9000(config-if)# interface ethernet 1/18
nx9000(config-if)# fec
auto fc-fec off rs-fec
nx9000(config-if)# fec rs-fec
ERROR: FEC validation failed on eth1/18 due to incompatible configured speed or transceiver type
nx9000(config-if)#

Regards,

Deepak Rawat

[Christopher Hart]

Hi Deepak,

Can you share the output of the show interface Ethernet1/18 transceiver details command from this switch?

Thank you!

-Christopher

[deepak.singh.rawat]

Hi Christopher,

Here is the output.

nx9000# show interface Ethernet1/18 transceiver details
Ethernet1/18
transceiver is present
type is SFP-H25GB-LR
name is ERICSSON
part number is SPBD-25GB4K1RE1
revision is A
serial number is 1948142B1200070
nominal bitrate is 25500 MBit/sec
Link length supported for 9/125um fiber is 15 km
cable type is singlemode fiber
cisco id is 3
cisco extended id number is 4

SFP Detail Diagnostics Information (internal calibration)
----------------------------------------------------------------------------
Current Alarms Warnings
Measurement High Low High Low
----------------------------------------------------------------------------
Temperature 19.93 C 93.00 C -48.00 C 88.00 C -43.00 C
Voltage 3.27 V 3.63 V 2.97 V 3.49 V 3.10 V
Current 45.23 mA 95.00 mA 10.00 mA 90.00 mA 15.00 mA
Tx Power 1.40 dBm 3.99 dBm -7.01 dBm 2.99 dBm -6.00 dBm
Rx Power -0.11 dBm 3.99 dBm -15.22 dBm 2.99 dBm -14.20 dBm
Transmit Fault Count = 0
----------------------------------------------------------------------------
Note: ++ high-alarm; + high-warning; -- low-alarm; - low-warning

Regards,

Deepak

[Leonardo Pena Davila · Accepted solution]

Hello,

For 9k ToR EX does not support RS-FEC but the new 9300-FX does.

Modular Linecard N9K-X97160YC-EX - With FC and RS FEC. This enables full distances achievable with 25G SR (100m) and 25G LR (10km) interfaces.
Fixed N9K-C93180YC-FX - With FC and RS FEC
Fixed N9K-C93180YC-EX - With FC FEC
Fixed N9K-C92160YC-X - With FC FEC

In addition take a look inline:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy03375?rfs=iqvred 

HTH

Leonardo

[deepak.singh.rawat]

Thanks you Leonardo for your reply. Thank you experts