Skip to main content
diego_garcia_del_rio's profile

Wed, Apr 7, 2021 10:32 PM

Optical monitoring not possible on ports with link down?

Am I missing something or the optical monitoring only works when the link is up? I am trying to troubleshoot some fiber connections which were unreliable / not coming up and when I use the `show optical-monitor x/y/z` command, I get nothing. Just comes back to the prompt.

If the same port with the same optical module has link, then I do get a proper readout of the optical monitor command (tx power / rx power / temps / current).

Being able to monitor a non-working link is a pretty basic thing to do to be honest and having access to DDM/DOM/optical monitoring of down links lets you figure out if you have, for example, a broken fiber in one direction, a mis-plugged rx/tx pair, etc.

Is there any way to monitor the DDM/optical parameters while the link is down?

Thanks in advance!

Responses

Accepted Solution

Official Rep

 • 

101 Messages

 • 

2.4K Points

4 d ago

Hi Diego,

The optical monitor shows signal levels, but will only show statistics if the port is up:

device(config)# show optic 2/1/1
Port Temperature Tx Power Rx Power Tx Bias Current
+-----+-------------+-------------+--------------+---------------------+
2/1/1 32.2578 C -002.5157 dBm -002.8091 dBm 5.966 mA
Normal Normal Normal Normal

If Signal is not correct and media type and fiber not right type link will not come up.
You need to check show media e x/y/z on both side make sure fiber is of right type.


Hope this helps.

If you need further help please open a  ticket and work with our TAC team.

https://support.ruckuswireless.com/contact-us

Thanks

Hahsim

143 Messages

 • 

2.6K Points

Hi Hashim,

thanks. Its not really useful to be honest, as in my case, the media matches on both ends but the link is not coming up. Especially when running a link across campus, you can't always trust the fiber plant (As its my case at the moment)

On other vendor's switches I was always able to show DOM/DDM/optical-monitoring parameters for ports in down state which can help a lot to troubleshoot why the link is not working.

In fact, one would argue that there is very little use for DOM when the link is up and ok. If my interface is not coming up because my RX power is too low, I want to be able to see that.

Thanks in advance

Official Rep

 • 

101 Messages

 • 

2.4K Points

4 d ago

Hi Diego,

The optical monitor shows the signal.  If port is down it will not display the signal.

You can use show media x/t/z and show int e x/y/z  for the port in question.

Please paste the above two outputs, as well as show version show mod and show license for your switch.

Thanks

Hashim

143 Messages

 • 

2.6K Points

4 d ago

Hi Hashim,

As I mentioned before, I have used this exact feature on other vendors (with link down I mean). I can see, for example, rx power for an un-plugged optic at -40dbm for example. Which pinpoints to a broken fiber for example or a reversed rx-tx pair.

Also its very useful when a link is on the verge of working / not working like when you have too much attenuation on the link

For example, if my link is flapping becasue im at -14 / -15 dbm.. i can only see that if I get to catch the "show optic" command at exactly the time that the link is up.

Or, if im having issues with a link, seeing its voltage or temperature can be a  very helpful troubleshooting step.

I will try to get the show commands asked for tomorrow.

But it feels like I'll have to open an RFE to see if it will be possible to get it in a future release.

Official Rep

 • 

101 Messages

 • 

2.4K Points

4 d ago

Hi Diego,

Like i said working as designed here is a lab snippet:


CORE-ICX-7850-10G(config)#sh optic  2/1/20
 Port   Temperature    Voltage       Tx Power      Rx Power    Tx Bias Current
+-----+-------------+-------------+-------------+-------------+---------------+
2/1/20   20.0468 C    3.2566 volts  -002.4336 dBm   -003.2605 dBm     5.600 mA
        Normal          Normal       Normal         Normal         Normal


CORE-ICX-7850-10G(config)#int e 2/1/20
CORE-ICX-7850-10G(config-if-e25000-2/1/20)#dis

CORE-ICX-7850-10G(config-if-e25000-2/1/20)#sh optic 2/1/20

CORE-ICX-7850-10G(config-if-e25000-2/1/20)#
CORE-ICX-7850-10G(config-if-e25000-2/1/20)#

It shows nothing when port is down.

Hope this clarifies.

Thanks

Hashim

Official Rep

 • 

101 Messages

 • 

2.4K Points

4 d ago

Also i asked you paste the output of your problem switch but i do not yet see it

show media x/y/z

show interface e x/y/z

show license

show version

Please share

Thanks

Hashim

10 Messages

 • 

430 Points

2 d ago

Hello,

I have ICX-7150 with 08.0.95a.... can you please help me to configure the DHCP server on this switch?

Thanks.

Official Rep

 • 

101 Messages

 • 

2.4K Points

Hi Claude,

Hope you are doing great.

From  the DHCP guide:

https://support.ruckuswireless.com/documents/3465-fastiron-08-0-95-ga-dhcp-configuration-guide

Configuring the DHCP server and creating an address pool

Perform the following steps to configure the DHCP server. Before you can configure the various DHCP server options, you must create an addresspool on your FastIron device.

1.Enter global configuration mode by issuing the configure terminal command.device# configure terminal

2.Enable the DHCP server.

device(config)# ip dhcp-server enable

3.Create a DHCP server address pool.

device(config)# ip dhcp-server pool cabo

4.Configure the DHCP server address pool.

device(config-dhcp-cabo)# network 172.16.1.0/24

device(config-dhcp-cabo)# domain-name ruckuswireless.com

device(config-dhcp-cabo)# dns-server 172.16.1.2 172.16.1.3

device(config-dhcp-cabo)# netbios-name-server 172.16.1.2

device(config-dhcp-cabo)# lease 0 0 5

5.To disable DHCP, enter the no ip ip dhcp-server enable command.

device(config)# no ip dhcp-server enable

6.Use the clear ip dhcp-server binding command to delete a specific lease or all lease entries from the lease binding database.

device(config)# clear ip dhcp-server binding

*The asterisk used in the example above clears all the IP addresses.

Hope this helps.

Thanks

Hashim