noob Upgrading 2960 to 3850, what's the best way to transfer config?

[imrankatela]

noob to Cisco switches here

Replacing two WS-C2960-24PC-L with a WS-C3850-48P for the gigabit speed. Looking to update the firmware first as it's running 03.06.10.E and then I need to transfer the config from the 2960 to the 3850. Is there an easy way to do this or do I have to manually configure the 3850 looking at the 2960's configuration?

[marce1000]

  - In principle you can copy the running configuration of the 2960 to an external repository and import that on the 3850(s) ; but you will probably have to review it first and change some basics , such as the address used for management e.g.

  M.

[Joseph W. Doherty]

"Is there an easy way to do this or do I have to manually configure the 3850 looking at the 2960's configuration?"

I would suggest the latter.  However, much as @marce1000 suggests, I found having the original config at hand, from which I can clip and paste sections, works well.  Of course, as I paste segments, I'm watching for messages.

Something else I'll do, I'll use the switch's diff feature to compare the original (perhaps with some pre-edits, like port numbers) with the new configuration, reviewing differences.

Good chance you'll be making a big enough IOS version jump that some syntax has changed, and possibly some commands either eliminated, their defaults changed, and/or what configuration statements device doesn't show, without using a show run all.

As an aside, when you do IOS upgrades on the same device, where you're only jumping one or few version numbers, going "up" usually is without problem, but going "down", or going "up" by a "large" delta, or jumping between different device families, needs to be done with care.

Unless you're using "exotic" IOS features, you'll probably find the configuration migration rather easy and without problems.

One last thing, your 2960-L is a limited L2 configuration.  Your 3850 is a L3 switch with additional features, also depending on the feature set it's licensed for.  You might find being able to route on it, useful.

[Jens Albrecht]

You are moving from 2 switches with FastEthernet ports to 1 switch with GigabitEthernet ports so a simple export and import won't work. Moving from IOS to IOS-XE on the other hand is not a big deal as the commands for most of the routine stuff are pretty much the same.

The best way depends on how consistant the configuration of your switchports is today.
If you have for example 3 standard port configs for PCs, printers and phones, then I would use an editor to prepare interface range commands for these standard configs and paste them into the new device after setting the basics like IP address, etc.
If you have lots of different port configurations, then it might be faster to use an editor with Find&Replace to make the necessary changes like FastEthernet ot GigabitEthernet or changing the port numbers for the second switch from 1-24 to 25-48.

I've done this kind of upgrades quite a few times in the past and personally prefer the method using interface range commands with standardized port configs for PCs, printers, phones, etc. In case a customer had messy configs, I spent some time first to define such standards as this makes life much easier in the future. Such upgrades are always a good chance to clean up the config and improve the security of your network.

HTH!

[Richard Burts]

I agree with Jens that you can not simply copy config from 2960 and use on 3850. Perhaps the most obvious issue is that interface names will not match. My suggestion is that before actually configuring that you create a chart in which you match 2960 info with 3850 information. A column for 2960 interface name (both physical and virtual), a column for corresponding 3850 name, additional columns for other config elements such as vlan assignment, ip address, etc. Some things such as approach to routing (static or dynamic etc), console, vty, etc should pretty much transfer between devices. Once you have gone through the configs and figured what the correspondences are you should be able to create a config for the 3850. As you use the config for the 3850 I would not just paste the complete config in one pass, I would go section by section, and watch for any messages generated as you input the new config, and resolve any issues identified.