3850 Stack Swapping Switch Type

[Ben Duff]

Hi,

We have a 3850 stack that has 2x 3850-48T and 1x 3850-48P. We want to remove the 3850-48P and replace it with a new 3850-12X48U, this will have the 8x10G module, the existing 3850-48P has a 4x10G module.

How do we achieve this when the switch type is different, do we provision a new switch (switch 4) and copy the config and renumber it later?

Understand the software will need to be the same version.

Thanks

[Rolando Valenzuela]

Who will be the master of the stack? one of the 3850-48T?

I think the easier way will be to add the 3850-12X48U as fourth member to discard any compatibility issues (at this moment your stack ring will be broken).

1- 3850-48T

2- 3850-48T

3- 3850-48P

4- 3850-12X48U 

Once that is sorted remove, remove the 3850-48P.

1- 3850-48T

2- 3850-48T

3- #Removed#

4- 3850-12X48U

Renumber the 3850-12X48U and the configuration should just fall in place.

1- 3850-48T

2- 3850-48T

3- 3850-12X48U

In the worse case at this point you just need to paste the previous configuration.

[Ben Duff]

Hi,

Thanks for responding, the stack was running 3.7.5, we downgraded the new one before adding it.

I provisioned the new switch as number 4 and copy/pasted the config from the one we're replacing which is number 1, only change was ports 37-48 are mgig and are a tengigabit interface.

We added the new one and moved the cables, all went smoothly, removed the old switch from the stack.

Question is what next, we should use no switch 1 to remove the config of the old. Then what, we renumber switch 4 to 1, what happens to the config when this happens?

Thanks

Ben

[educruz]

Hi Ben,

I am glad to hear that the replacement went smooth.

These other links explain what exactly happens in terms of renumbering.

https://supportforums.cisco.com/t5/network-infrastructure-documents/changing-a-switch-member-number-in-a-3850-stack/ta-p/3160671

https://www.cisco.com/en/US/docs/switches/lan/catalyst3850/software/release/3se/consolidated_guide/b_consolidated_3850_3se_cg_chapter_01101101.html#con_1112897

In your scenario, the approach I would use is to un-provision switch #1 (if that switch does not exist anymore), and renumber switch #4 to #1, as follows:

3850# configure terminal
3850(config)# no switch 1 provision
3850(config)# end
3850# switch 4 renumber 1
3850# wr
3850# reload slot 4

However, I would do that under a maintenance window, to be prepared for any inconveniences.

Hope this helps.

Eduardo.

[Ben Duff]

Thanks,

I don't think renumbering moves the config, I did the renumber but no config came across and had to reenter it, does that sound right? I should have removed switch 1 and then provisioned switch 1 prior to renaming? Seems good now, will now remove switch 4 as it's still listed after the renumber?

Ben

[educruz]

Hi Ben,

Just for confirmation, did switch #1 have its previous provisioning configuration removed prior to renumbering #4 to #1? The answer might explain why the configuration had to be re-entered. 

Correct - if switch #1 is configured and the stack seems fine, one can just remove this provisioning configuration off switch #4. A reload might be required for the stack CLI to stop showing this non-existing "switch #4" as "Removed".

Hope this helps,

Eduardo.

[Ben Duff]

Switch 1 config was unprovisioned before renumbering, the switch had different interfaces so thought it wouldn't work anyway. Will remove switch 4 and we're done. Thanks.

[educruz]

Good day,

As far as I know, there is no compatibility issues from a hardware standpoint between a multi Gig switch  (XS or 3850-12X48U) and a non multiGig switch (a regular 24/48P).

However, the approach that Rolando suggests looks fine, because I could not find a document that ensures this. Also, please take into consideration that multiGig switches can only run 03.07.x.E and 16.x software versions.  They cannot run any 03.06.x.E software.

If your 48P stack runs 03.06.x.E you may need to change the software. Also, keep in mind that the switches must have the same software and license levels for them to be stacked. 

Lastly, in order to prepare your configuration for this offline multi Gig switch, please take a look at the provisioning section of the following document:

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/ha_stack_manager/configuration_guide/b_hastck_3se_3850_cg/b_hastck_3se_3850_cg_chapter_010.html#con_1178943

513E.C.28-3850-3#show ver | inc WS
cisco WS-C3850-12XS (MIPS) processor with 4194304K bytes of physical memory.
Model Number                       : WS-C3850-12XS
*    1 16    WS-C3850-12XS      03.07.05.E        cat3k_caa-universalk9 BUNDLE 

513E.C.28-3850-3#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
513E.C.28-3850-3(config)#switch 1 pro
513E.C.28-3850-3(config)#switch 1 provision ?
  ws-c3650-24pd    Catalyst 3650 Series Switch with 24 GE POE and 2GE+2TenGE
                   Interfaces
  ws-c3650-24ps    Catalyst 3650 Series Switch with 24 GE POE and 4 GE
                   Interfaces
  ws-c3650-24td    Catalyst 3650 Series Switch with 24 GE and 2GE+2TenGE
                   Interfaces
  ws-c3650-24ts    Catalyst 3650 Series Switch with 24 GE and 4 GE Interfaces
  ws-c3650-48pd    Catalyst 3650 Series Switch with 48 GE POE and 2GE+2TenGE
                   Interfaces
  ws-c3650-48pq    Catalyst 3650 Series Switch with 48 GE POE and 4 TenGE
                   Interfaces
  ws-c3650-48ps    Catalyst 3650 Series Switch with 48 GE POE and 4 GE
                   Interfaces
  ws-c3650-48td    Catalyst 3650 Series Switch with 48 GE and 2GE+2TenGE
                   Interfaces
  ws-c3650-48tq    Catalyst 3650 Series Switch with 48 GE and 4 TenGE
                   Interfaces
  ws-c3650-48ts    Catalyst 3650 Series Switch with 48 GE and 4 GE Interfaces
  ws-c3850-12s     Catalyst 3850 Series Switch with 12 1GE SFP Interfaces
  ws-c3850-12x48u  Catalyst 3850 Series Switch with 36 GE and 12 TenGE UPOE
                   Interfaces
  ws-c3850-12xs    Catalyst 3850 Series Switch with 12 10GE SFP Interfaces
  ws-c3850-24p     Catalyst 3850 Series Switch with 24 GE POE Interfaces
  ws-c3850-24s     Catalyst 3850 Series Switch with 24 1GE SFP Interfaces
  ws-c3850-24t     Catalyst 3850 Series Switch with 24 GE Interfaces
  ws-c3850-24u     Catalyst 3850 Series Switch with 24 GE UPOE Interfaces
  ws-c3850-24xs    Catalyst 3850 Series Switch with 24 10GE SFP Interfaces
  ws-c3850-24xu    Catalyst 3850 Series Switch with 24 TenGE UPOE Interfaces
  ws-c3850-48p     Catalyst 3850 Series Switch with 48 GE POE Interfaces
  ws-c3850-48t     Catalyst 3850 Series Switch with 48 GE Interfaces
  ws-c3850-48u     Catalyst 3850 Series Switch with 48 GE UPOE Interfaces
  ws-c3850-48xs    Catalyst 3850 Series Switch with 48 10GE Interfaces and 4
                   40G Interfaces

Hope this helps.

Eduardo.

[educruz]

I found the document:

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/white-paper-c11-734429.html

StackWise-480 supports a mixed stack of any Catalyst 3850 models (48 ports 10/100/1000, 24 ports 10/100/1000, and 12/24 Ethernet SFP ports; see Figure 1). You can mix the switches with different number of access ports (48, 24, and 12), different type of access ports (copper and fiber, PoE, and non-PoE-capable), and different network modules. But all switches in one stack must have the same version of IOS XE and the same feature set license. A mixed stack of LAN base switches with IP base or IP services is not supported. Catalyst 3850 Series Switches with a LAN base feature set can only stack with other Catalyst 3850 Series LAN base switches. The same applies to IP base and IP services as well.

[jkilleda]

Hello Ben,

You can do it either ways either you can provision the switch and renumbering later .

The below is the difference between the two models.

Models	Total GE	Default AC	Optional	Stack
	Ethernet Ports	Power Supply/	Network Module	Power
		Available PoE Power
WS-C3850-48T-L	48	350W/- no PoE	4 x 1GE	Yes*
			2 x 10GE
			4 x 10GE
WS-C3850-48P-L	48 PoE+	715W/435W	4 x 1GE	Ye
			2 x 10GE
			4 x 10GE