Quick Stackwise Question on 3750

[Dean Romanelli]

Hi All,

So I have a 4x stack of 3750. Below are the specs:

Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 12 WS-C3750G-12S 12.2(35)SE5 C3750-IPSERVICES-M
2 52 WS-C3750-48P 12.2(35)SE5 C3750-IPSERVICES-M
3 52 WS-C3750-48P 12.2(35)SE5 C3750-IPBASE-M
4 52 WS-C3750-48P 12.2(35)SE5 C3750-IPBASE-M

I want to add a 2nd ISP and control fail-over via IP SLA w/ route tracking on this stack. However, that is an IP Services feature only, and as can be seen, half of the stack is IP Services, half of the stack is IP Base?

Will I be able to make this happen as long as I plug both ISP lines into one of the switches with IP Services?  Does the switch I plug those lines into have to be the master? Or can I plug both lines into switch 2 and have switch 1 be the master?

[Philip D'Ath · Accepted solution]

This is a little messy.  This only works on the 3750's as well.  You can't mix feature sets on the 3850's.

From memory in a 3750 stack, the entire stack gets the feature set of the switch that is the master.  If the stack fails over to a switch with only IP Base then any config dependent on IP Services will stop working.

So make sure switch 1 is the first priority, and switch 2 is the second priority.

On 3750's, I'm 90% confident IP Base supports IP SLA and route tracking.

[Philip D'Ath]

I stand corrected.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/configuration/guide/scg3750/swipsla.html

A switch running the IP base image supports only IP SLAs responder functionality. The switch must be running the IP services image for full IP SLAs functionality.

However as you have "IP Services" this is a non-issue.

[Dean Romanelli]

Thank you Philip.  Also, totally agree with you about it being messy.  Unfortunately I don't have the budget currently to upgrade the 2 IP base models.

So just to confirm, as long as switch 1 or 2 is the master, then it shouldn't matter which switchport on which switch I plug the ISP lines into because everything will behave like IP Services since these are 3750's right?

[Philip D'Ath]

That is my understanding.