5000 Series Uplink Ports to 7520 - Module Interoperability Question

[cemcjk]

Before I try this out, I wanted to see if anyone else has tried this; I have some 7520 switches that I plan on using in an aggregation layer, and 5(3/4/5)20s at the Edge. All switches are running VOSS/FabricEngine. 

I was hoping to use the U1/U2 ports on the 5000 Series Switches as uplinks to the 7520s, but without consuming the few 40/100G ports on the 7520s, trying to use the 10G ports. I currently have 40G QSFPs in the 5520s, and the modules are being seen by the switch so I don't think there's a problem there - but I thought I would be able to link these to 10G ports on the 7520s. 

My fallback is to try to use either 4x10G QSFPs on the 5520s and channelize - though I'd like to avoid having a bunch of MPO breakout harnesses in the racks to make this work, or, try to use 25G SFP28s on the 7520s and try to connect those to the QSFP ports on the 5520s. 

Has anyone done/seen anything similar? 

Thanks

[alfredo594]

Hello,

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@cemcjk wrote:

Before I try this out, I wanted to see if anyone else has tried this; I have some 7520 switches that I plan on using in an aggregation layer, and 5(3/4/5)20s at the Edge. All switches are running VOSS/FabricEngine. 

I was hoping to use the U1/U2 ports on the 5000 Series Switches as uplinks to the 7520s, but without consuming the few 40/100G ports on the 7520s, trying to use the 10G ports. I currently have 40G QSFPs in the 5520s, and the modules are being seen by the switch so I don't think there's a problem there - but I thought I would be able to link these to 10G ports on the 7520s. 

My fallback is to try to use either 4x10G QSFPs on the 5520s and channelize - though I'd like to avoid having a bunch of MPO breakout harnesses in the racks to make this work, or, try to use 25G SFP28s on the 7520s and try to connect those to the QSFP ports on the 5520s. 

Has anyone done/seen anything similar? 

Thanks

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To connect 5520 switches to 7520 switches, use 4x10G QSFPs and channeling for optimal performance. Consider MPO breakout harnesses for simplified cabling. Ensure device compatibility and test the network configuration.

[jeronimo]

Not exactly, but a few comments on this.

Normally you try to have these things figured out before you buy the gear.

With Fabric Engine, the 2 x QSFP28 ports can be used as Ethernet uplink ports if in non-Fabric mode or if no VIM is present as of the VOSS 8.4.2 release.
I guess this is not a problem, otherwise you wouldn't be trying to use the U1/2 ports.

So you're essentially trying to use the U1/2 QSFP28 ports with a QSFP+ (40G) SFP in the 5520s and try to hook it up to an SFP+ module in one of the SFP28 ports in the 7520 😄

I'm not sure what speeds the U1/2 ports support, it doesn't really say in the specs, one would have to dig a bit deeper.

But I don't think you can just use a QSFP+ module on one side and a SFP+ on the other.
The port may be downward compatible, but you can't just mix and match the modules like that.
You could try first with an SFP+ on both sides and see if a 10G link establishes.

You may be fine also with a 40G to 10G breakout cable (there are DAC cables like that available)

EDIT Reading this again LOL, obviously you won't be able to use an SFP(+) module in a QSFP(+) port.
I guess the breakout is the way to go, or I haven't understood what you're trying.