Howto: Stack 3750g 12s with 3750g 48T?

Hello,

we bought a new core switch (3750G with 48 gig Ethernet Ports) and wanted to stack it with our old fibre optic 3750g 12s switch. First we ran into "unsupported Firmware" trouble, after a copy from old to new, they have same FW. But now the Master switch tells somthing about "SDM missmatch". After reading a lot of Cisco documentation i am not sure, what to do...

On the old 3750g 12s the default aggregation template is activated. Do i have to change this to desktop template?

And if yes, why?

Thank you in advance

cheers Johannes

Reply to
Johannes
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In general this is what you need to do....

Unstack both switches and reboot them. Make sure both switches are booting the SAME IOS binary file. If they are different versions it won't work. Save a copy of the both switches configurations on your PC (if you need to keep the configuration) Do a write erase on both switches. Power them both off. Stack them Power them both on (if you have a preference for which one you want as Master, power that one on first wait a few minutes and then power on the other one.)

Paste the configuration of one of switches and ONLY the interface configurations from the other. You may have to do a bit of editing of the interface names because they might change (The master will be 1/0/x and the other will be 2/0/x where before it was also 1/0/x).

Reply to
Thrill5

Hm,

as far as I read the articles on Ciscos website, it seems, that the

3750 12s has a bit more Memory, and default is the SDM agreggation template, which is not supported by the 3750 48T.

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So I only see 2 solutions

  1. We set the 3750 48T as Stack Master and he tells the other 3750 12s to switch to routing desktop template and reboot all other switches
  2. We set the routing desktop template manualy on the actual Stack master 3750 and reboot all other switches

Is that right?

Johannes

Reply to
Johannes

Hi Johannes,

Never seen that sorry...

Also never seen that.

My main advise is - Before doing anything, BACK UP ALL CONFIGS!!!

Just last Monday I REMOVED a pair of stacked 3750's -

3750-T12 (IE 12 Mini GBIC ports) 3750-T48 (IE 48 Gigabit RJ45 ports)

One of the FIRST things I found out about 3750's is that its best if they are running the EXACT same IOS image, to be able to stack, in fact I would say this is MANDATORY. NOTE: Sometimes they will stack using diverse images, but this is a very hit/miss affair, so its much better to ensure they have the same image BEFORE linking them via the Cables.

I also found it useful to have the BootROM set appropriately on each switch BEFORE stacking them. See the Cisco Docs for advise on this. We always set Switch 1 as the Primary Boot device and linked all SLAVE switches to Switch 1.

It may also help to REMOVE all Config from each switch BEFORE stacking them (using their default Config). This gives them the best chance of stacking correctly.

Then to stack them - (Note: From this point, ALL commands should be entered on the MASTER switch!) 1. Power BOTH switches OFF. 2. Connect the STACK cables. 3. ONLY Power ON the switch you wish to be MASTER. 4. Once it is up and running as MASTER, power on switch 2 and if it "sees" Switch 2 it SHOULD come up as SLAVE.

NOTE: If Switch 2 also comes up as MASTER (the light on the front of the switch tells you about this), then something is very wrong. Resolve this issue before proceeding.

  1. Insert the stack member commands into the config to ensure the Switches always start up the same way (IE Switch1 is G1/0/xx and switch 2 is G2/0/xx, etc). This helps with ensuring they ALWAYS come up the same way.

Note that it is possible to boot each Slave switch FROM the IOS in the MASTER, however this takes a little longer to boot, and may result in an issue if the Master SWitch dies and the Slaves need to reboot. We don't use this method so can't comment on this approach..

Stacking pretty much REQUIRES both switches to be using the same IOS, so I would set this to be the SAME on each switch. I can't say about the templates sorry because we have always kept them the same...

I hope this is useful................pk.

Reply to
Peter

Hello Peter,

Thank you for your help.

Today at 5am we scheduled a downtime for 15 minutes, and i linked the switches with Stack cables. Than i configured the master 3750 12s (with 8gbic modules) for usind "default desktop template" (#sdm prefer default desktop). After a reload, he submited this to the member switches and everything was fine, no more errors or missmatches.

The problem is an incompatibility of the memory usage templates, because the "out of the box" settings of a 3750 12s is "aggregation template", this kind of setting is not available on 3750 48t. Now, after switching to "default desktop template" the sdm matches on all switches.

Regards Johannes

Reply to
Johannes

hi johannes,

i'm currently having the same problem. as cisco's papers describe only WS-C3750-12S have got the ability to set sdm to an aggregate template.

Even doe Cisco says in their product specs that within a Series there are no hardware differencialitys, for some reason the WS-C3750-12-S is kind of special.

The 12-S is the only one capable of aggregate template. in order to stack a -12-S with other 3750 types, as you have done so, one needs to downgrade to an desktop sdm. I haven't seen it possible on any other WS-C35XX or WS-C37XX platform so far.

As i've read, the new WS-X3750 haven't got an aggregeat template...

if some one of Cisco would be as kind in order to tell us what kind of alternatives there are in order to address this problem, i realy would appreatiate this.

colin

"Johannes" schrieb im Newsbeitrag news: snipped-for-privacy@z3g2000yqz.googlegroups.com...

Reply to
colin

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