Cisco 10Gbit port to 1Gbit port?

[abillybob]

Hi All

 

Hopefully someone can help me. I just want to test a switch that I've configured on the network although when plugging in some compatible SFP modules it won't work. I presume it's because the switch I'm trying to plug in is 10Gbit and to test I need to be able to plug it into a 1Gbit port as a temporary measure.

 

Does anyone know of a way to configure a port on a Cisco switch as 1GigabitEthernet rather than 10 or is there no way to do this? When running the 'Show Run' command it only specify's 10Gbit interfaces unlike some other Cisco switches that show two separate interfaces for 1Gbit and 10Gbit on the same port?

 

The switch I'm trying to test is a Cisco 9500-40X-A if that helps!

 

Thanks all

[Norphy]

Can I just clarify? One switch is a 10gbe switch and has a 10gbe transceiver, while the other is a 1gbe switch with a 1gbe transceiver? If so, that won’t work as you’ve found.

 

Our 10gbe HP switches work with 1gbe transceivers in their 10gbe ports, can you put a 1gbe transceiver in your 10gbe switch?

[abillybob]

No, no. Both switches have 1gbe transceivers in them with just a cable hooked up. The ports on the 1gbe switch light up green and flash rapidly but the ports on the 10gbe switch light up orange and flash in a constant sequence, looking at what the port colours say is that amber flashing constantly in a pattern means it's a mismatch in speed.

[Norphy]

Are the SFP+ ports on the faster switch rated to work at 1gbps?

 

/edit looking at the Cisco website, that’s a hard yes. Is it possible the SFP module you’re using isn’t compatible with the faster switch?

Edited December 11, 2019 by Norphy

[abillybob]

Are the SFP+ ports on the faster switch rated to work at 1gbps?

/edit looking at the Cisco website, that’s a hard yes. Is it possible the SFP module you’re using isn’t compatible with the faster switch?

Cheers for helping mate, sorry haven't got back I have no internet when I'm testing.

 

The SFP modules I'm using are just "Cisco" branded SFP module so I would have thought it would work plus the other switch was getting an uplink. I don't think it is the case that it's to do with speeds now, you're right the 1gbps modules should work fine and I have just eliminated that by trying to use a 10gbe switch port to this 10gbe switch so same speed but still can't ping it.

 

It's probably something I've messed up in the config, it's supposed to be replacing our core switch so it does all the routing for each VLAN. All I've done is literally copy the config from the old core switch to this one using console and then tried to replace them but it hasn't seemed to of worked. I've never configured a core switch from new before so I'm probably doing something wrong although the configs are like for like when I perform a "show run" command so I'm not sure what I've done.

[abillybob]

Figured it out, it was me being a tool! All the Vlan interfaces where shutdown.. I've just spent two hours wondering why this wasn't working... I'm off to have a McDonalds! Cheers @Norphy for your help though, most appreciated!

[Norphy]

Figured it out, it was me being a tool! All the Vlan interfaces where shutdown.. I've just spent two hours wondering why this wasn't working... I'm off to have a McDonalds! Cheers @Norphy for your help though, most appreciated!

 

Glad you got it sorted. We've all made mistakes like that.

 

The SFP modules I'm using are just "Cisco" branded SFP module so I would have thought it would work

 

I can't speak for Cisco as I've not used it to any great degree but be careful when making that assumption. With our Aruba/HPE gear, we have to be very careful about the SFP/SFP+ modules that we buy for our switches. For example, we were updating the equipment at one of our sites. The site has crappy fibre so we bought some LRM SFP+ modules for our switches so we could get 10gbps uplinks without having to change the fibre. It turned out the the LRM modules didn't work with the Aruba 2540 switch, despite working with the 2530, 2920s and 5400Rs that we've got. Be careful to check the HCL when you're looking for modules.

[jtotheb]

Does anyone know of a way to configure a port on a Cisco switch as 1GigabitEthernet rather than 10 or is there no way to do this? When running the 'Show Run' command it only specify's 10Gbit interfaces unlike some other Cisco switches that show two separate interfaces for 1Gbit and 10Gbit on the same port?

 

That's normal for those models. The 9500 series that we've got lists the ports with a single label of their max speed regardless of the SFP/SFP+ inserted. It still makes my head hurt having a 1gig connection showing as TWEx/x/x.