Nexus vs catalyst

[M.Sultan]

Hi,

since 2015 i'm managing and configuring Catalyst switches and later from the same family, i never configured Nexus switches, is the configuration the same as catalyst switches ?

Best wishes

[MHM Cisco World]

Not same.

[M.Sultan]

tnx can you brief the difference ?

[MHM Cisco World · Accepted solution]

https://netcraftsmen.com/ios-to-nx-os-converter-tool-from-cisco/

If you have cisco ID then you can check cisco to NXOS convert, this tool help you to migrate from catalyst to NXOS

[Joseph W. Doherty]

What to also watch for, NXOS platforms might not offer all the features found on an IOS device.

[stonent01 · Accepted solution]

The basic command structure is about 85% identical.  But you will find some commands that aren't identical.  The main thing on the Nexus switches is everything is Eth and not Gi or Te like it would be on a catalyst. So instead of Te1/0/1 it would be Eth1/1. NXOS doesn't distinguish differences between ports so when you get to the SFP modules they are just another port, so you might have Eth1/52.
On NXOS you can only use copy run start to save your config and not the write command.  So I got in the habit of never using write on anything any more.
Some things that seem like they should work, don't.  Like  "show int status vlan 150 | i connected" would work on a catalyst to show only the vlan 150 ports that are connected.  NXOS doesn't support adding the vlan to the show int status command.

Also int range doesn't work on NXOS, you just do int eth1/1, eth1/2, eth1/3 without the word range.

The software on a Nexus is more licensed than on IOS, so you may need to purchase a license to do some features since its designed to work more modularly for more performance.

Some things have to be more planned on Nexus switches to get best performance like knowing which ports are mapped to which ASIC and you may encounter limitations like even though you have 6 40Gb ports, you may not be able to use a 4x10 breakout cable on all the ports because of ASIC limitations.

Nexus doesn't do stacking like catalyst switches do, so there's no stackwise cabling in the back.  There's a variety of options to get similar outcomes to stacking like fabric extenders.  So you may see a large Nexus deployment like "Eth1/154" 

But basic command structure is very close and fairly easy to adapt to if you're just making vlan changes and stuff like that.

[Joseph W. Doherty]

Just wanted to add, Nexus support vPC (virtual PortChannel), their version of Catalyst VSS, with the major difference you still manage two devices.

@stonent01 mentions Nexus Fabric Extenders.  The Catalyst variant being IAs.

Besides licensing, on Nexus, you often need to enable OS modules to configure module features.

In general Nexus to Catalyst is somewhat like L3 switches to routers.  I.e. less features, more forwarding capacity.

[stonent01]

My experience is primarily with single or double 3k or 9k Nexus devices. At our main corporate data center (we're a step below them according to our internal rating system) they also use 2k, 5k and 7k Nexus devices, which I have no personal experience with.