X440-G2 10GB Uplink - bad snare if you miss 10GB LIC

[M_Nees]

Today we have a very painful and time-killing problem. Be careful NOT to run into the same issue.

We using X440-G2 with 10GB GBICs on the Uplink ports (51-52 - with Dual 10GB LIC) linked to 2x X670-G2 also with 10GB GBICs.
Some of my collegues configured the X440-G2 BUT do NOT install the 10GB License.

If you connect that Switch to the CORE you does not get a link. But light comes out of the fibre cable and seemed to be OK. If you check transceiver information on CORE switch you can see that you have excellent signal - but the link on the CORE Switch does not come up! Damn!

If you have a look at the X440-G2 the log tells you that the 10GB Port have a 10GB GBIC but you do NOT have a 10GB license, so the speed is reduced to 1GB!
Does this make sense ?

The result is that the 10GBIC sending out a signal but a 10GB GBIC cannot never run in 1GB mode. So there will never ever be a link. Talking with some other network guys telling me that a very usual mistake a lot of people running into this pitfall.

From my point of view it was better if the developers disable the 10GB GBIC completely to avoid such tricky problems!

Regards,
Matthias

[AnonymousM]

The customer could install a mirror inside the rear door of the rack. This would bring the term "port mirroring" to a new level. Just kidding! 😉
I agree that this would be helpful and from the past I remember that we also once had such kind of a solution. We will discuss this with PLM, but I don't think that we can change the HW design of the existing switches. But for new models this is a valid input.

[M_Nees]

Hi Drew,

another idea to make this problem more obviously will be that the regarding LED of that port is blinking amber.

Regards

[Drew_C]

I like that idea - I'll share it with the team as well. Thanks.

[Edward_Tsui]

Hi Mattias,

Thanks for your info. Did you ever try to change x670 to 1G and see if the port come UP or not?

[Curtis_Brabham]

Yes you can run an SFP+ at 1G. You have to manually set the ports on both sides to 1G full duplex in the EXOS CLI:

configure auto off speed 1000 duplex full

I have SFP+'s actively configured on SFP ports in production (awaiting a switch replacement with additional SFP+ ports).