Link is established only one-way

[JensWeber73]

Hi,

i want to connect two Switches via fibre link (62,5µm). Both Switches have a 1000BaseLX SFP inserted.

When i do a sh int status, one of the Switches shows a connected state, but the opposite side does not.

Both Interfaces are configured in same way:

 switchport trunk native vlan 999
 switchport trunk allowed vlan 1-1005
 switchport mode trunk

The distance between both Switches is less than 550m but nearly 540m.

Could this be the reason?

I thought that 550m would be Minimum range.

Why does one Switch detect a link and the opposite side does not?

Does anybody have experience with this issue?

Thanks

Jens

[Marvin Rhoads]

See if your transceivers support Digital Optical monitoring (DOM) by using the command:

     show interface <int name> transceiver detail

If supported, that will give you a reading of the Rx and Tx optical power levels.

[JensWeber73]

Hi Marvin,

thanks for the answer.

Unfortunately the command is not supported on both switches.

Do you have experience with max. length of LX/LH SFP? I thought, that 540m should be possible on 62,5µm fibre.

Thanks

Jens

[mvsheik123]

Hi,

Minimum cable distance is 6.2 feet (2m). Maximum (theoretical) distance is 550m. But in practical conditions you may not get 550m. You may want to look into SMF. Here is spec link..

http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/product_data_sheet0900aecd8033f885.html

Thx

MS