Switching

Hello,

I have an EX4300 virtual chassis that I am trying to uplink to an EX4600 chassis. There are 7 EX4300's and the first 2 QSFP ports (0 and 1) are vc-ports.

I am trying to take port 3 on member 0 and uplink it to the EX4600. I am using a QSFP DAC cable to connect the EX4300 chassis with the EX4600.

The problem is that I do not get any link whatsoever. I made sure that port 3 on member 0 is not configured as a vc-port, and I confirmed the same for the EX4600. I have tried several known working DAC cables with no luck. I even looped up port 3 on member 0 in the EX4300 chassis with port 3 on member 1 and I get link. 

But as soon as I connect port 3 on member 0 to the EX4600 chassis, I get nothing. Both ports are configured as trunks. I am running 14.x code.

Am I missing something? Is there a known incompatibility here?

Did you check that EX4600 interface is not set to vc-port?  Even if set, from what I've seen link should still come up.  Maybe bad HW interface on the EX4600??

Yes, good point.

I made sure that the interface on the EX4600 was not configured as a vc-port. It's set up as a trunk interface.

I also looped up interface et-0/0/27 (the interface I'm trying to use for my uplink to the EX4300 chassis) and et-1/0/27 on the EX4600 and I get link. This tells me it's not a hardware issue on either chassis.

We tried the connection with some 40Gb optics instead of DAC cables, and the interfaces came up.

At this point, it looks like a bug in the code. We have had a case open with JTAC for over a week, and they don't know what the problem is either.

We found the solution - using DAC cables, we disabled auto negotiation and this allowed the interfaces to come up. Interestingly, the 40Gb fiber QSFPs did not have any problem with auto negotiation. 

Thanks for this info--it also solved our problem of connecting a 4300 and QFX5100 over 40Gb DAC.

--Paul

Did you disable auto-neg on just the EX4300 or EX4600 alone, or was it required to be set on both sides?  Thanks

Once I disabled on the EX4300 side it came up--however I disabled on both sides to be thorough.