The optical link doesn't work

[lizochkanovichenko]

Hi, everyone! 

I have problem with optical link (1000SX) on Cisco Catalyst 9300 (C9300-48T). This switch C9300 uses GLC-SX-MMD transciver but port don't up. 

Confuguretion this port: 

Switch#sh run int Te1/1/3
interface TenGigabitEthernet1/1/3
description uplink
switchport mode trunk
ip arp inspection trust
ip dhcp snooping trust
end

Onother swicth C9200 connects to this port Te1/1/3. I think this problem is in only C9300 because we have onether problems with optical cables on C9300. 

1. I upgrated Cisco IOS to 17.12.03 but it didn't solve the problem.

2. I used 'speed nonegotiate' command on both side but it didn't solve the problem too.

3. I reconnected cable to onther port (Te1/1/2 and Te1/1/4) - it didn't solve the problem too.

4. I reconnected cable to Te1/1/1 port which is working fine with GLC-LX-SM-RGD trancivers. And it didn't solve the problem too.

Have you experienced this problem and what can you recommend?

Thanks. 

[marce1000]

  - Make sure the SFP's are compatible per device according to : Cisco Optics-to-Device Compatibility Matrix
     + start with minimum needed port settings only (trunk , nothing else , or even try a simple on vlan link to start)
     + checkout show sfp defails on (SMB) switches

 - Check logs on 9300 and other device when trying to make a link
 - Use latest advisory software version for the platform , 

 M.

[lizochkanovichenko]

This transciver GLC-SX-MMD is compatible for C9300-48T. 

When I reconnected links I see only this logs:

%PLATFORM_PM-6-MODULE_REMOVED: SFP module with interface name Te1/1/3 removed

Also I configured port like:

interface TenGigabitEthernet1/1/3
switchport mode trunk
switchport trunk allowed vlan all
end

[Midfielder]

Have you checked that SFP tranceiver is recognised by switch? Are you using original Cisco supported or 3rd party SFP? On 9300 we had a lot of problems with 3rd party SFPs.

However commands service unsupported-transceiver and no errdisable detect cause gbic-invalid solved this issue for us.

[lizochkanovichenko]

We use original Cisco transcivers. 

NAME: "Te1/1/3", DESCR: "1000BaseSX SFP"
PID: GLC-SX-MMD , VID: V03 , SN: XXXXXX

[Midfielder]

Is SFP at connected swicth C9200 the same as the one at C9300? Both 1G?

[lizochkanovichenko]

yes, right. 

[Leo Laohoo]

Loop each SFP to itself.  Did the port go up or go into error-disable?

[Marvin Rhoads]

When you are connected but it is failing, what does "show interface <int name> transceiver detail" show at each end?

[lizochkanovichenko]

C9300:

sh int Te1/1/3 transceiver detail
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

High Alarm High Warn Low Warn Low Alarm
Temperature Threshold Threshold Threshold Threshold
Port (Celsius) (Celsius) (Celsius) (Celsius) (Celsius)
--------- ----------------- ---------- --------- --------- ---------
Te1/1/3 34.4 89.0 85.0 -5.0 -9.0

High Alarm High Warn Low Warn Low Alarm
Voltage Threshold Threshold Threshold Threshold
Port (Volts) (Volts) (Volts) (Volts) (Volts)
--------- ----------------- ---------- --------- --------- ---------
Te1/1/3 3.31 3.60 3.50 3.10 3.00

High Alarm High Warn Low Warn Low Alarm
Current Threshold Threshold Threshold Threshold
Port Lane (milliamperes) (mA) (mA) (mA) (mA)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/3 N/A 5.7 13.0 12.4 2.0 1.0

Optical High Alarm High Warn Low Warn Low Alarm
Transmit Power Threshold Threshold Threshold Threshold
Port Lane (dBm) (dBm) (dBm) (dBm) (dBm)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/3 N/A -4.5 1.0 -3.0 -9.5 -13.5

Optical High Alarm High Warn Low Warn Low Alarm
Receive Power Threshold Threshold Threshold Threshold
Port Lane (dBm) (dBm) (dBm) (dBm) (dBm)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/3 N/A -6.2 4.0 0.0 -17.0 -21.0

C9200:

sh int Te1/1/1 transceiver detail
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

High Alarm High Warn Low Warn Low Alarm
Temperature Threshold Threshold Threshold Threshold
Port (Celsius) (Celsius) (Celsius) (Celsius) (Celsius)
--------- ----------------- ---------- --------- --------- ---------
Te1/1/1 28.4 89.0 85.0 -5.0 -9.0

High Alarm High Warn Low Warn Low Alarm
Voltage Threshold Threshold Threshold Threshold
Port (Volts) (Volts) (Volts) (Volts) (Volts)
--------- ----------------- ---------- --------- --------- ---------
Te1/1/1 3.32 3.60 3.50 3.10 3.00

High Alarm High Warn Low Warn Low Alarm
Current Threshold Threshold Threshold Threshold
Port Lane (milliamperes) (mA) (mA) (mA) (mA)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/1 N/A 5.9 13.0 12.4 2.0 1.0

Optical High Alarm High Warn Low Warn Low Alarm
Transmit Power Threshold Threshold Threshold Threshold
Port Lane (dBm) (dBm) (dBm) (dBm) (dBm)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/1 N/A -4.4 1.0 -3.0 -9.5 -13.5

Optical High Alarm High Warn Low Warn Low Alarm
Receive Power Threshold Threshold Threshold Threshold
Port Lane (dBm) (dBm) (dBm) (dBm) (dBm)
--------- ---- --------------- ---------- --------- --------- ---------
Te1/1/1 N/A -23.0 4.0 0.0 -17.0 -21.0

[Marvin Rhoads]

So the transceiver on the 9300 is transmitting -4.5 dbM while the corresponding receive power on the 9200 transceiver is way down at -23.0 dbM. That's a link loss of 18.5 dB. An optical receive level below -21.0 dbM will result in no link.

Contrast that with the opposite direction: -4.4 dbM transmit from the 9200 and -6.2 dbM received on the 9300 = only 1.8 dB loss.

We typically expect between 0.3 and 0.5 dB insertion loss per patch so a loss of 18.5 dB means either a very bad (dirty or loose) patch or a damaged cable strand in the path. It would help to get a cleaning kit for both the patch cable ends and patch panels themselves and clean all the patch points end to end. If the problem persists, try a different or replacement fiber (patch cables or the inter-location runs).