Cisco Catalyst 1000 series Stack/Single IP Mangement traffic behavior

[joakimlemb]

We are considering replacing some old Cisco 2960S stacks with either C1000 or C9200L series.

Regarding features we use C1000 should do the job, but I'm finding the documentation for  "Single IP Mangement" to be lacking regarding how it differs from a "normal" Cisco Stack setup.

Does the ports designated for Single IP Management also forward traffic between members? or are the Single IP Management ports only for config/management?

Consider the following scenario, 3 stack members, 2 uplinks on separate stack members, SFP for Uplink1 dies and the port goes down.
For 2960S, STP changes Uplink2 to Forwarding status and the downtime is barely noticeable.
Will the "Single IP Mangement" stack for C1000 series work the same way? (We don't use or need MEC.)

Or does the C1000 require uplinks for each physical switch member in "Single IP Mangement" stack?

[M02@rt37 · Accepted solution]

Hello @joakimlemb,

The "Single IP Management" feature is not related to data forwarding between stack members. It is solely for management and control plane communication. The designated management ports used for "Single IP Management" are used for configuration, management, and control traffic, but they do not forward regular data traffic between the stack members.

In the scenario you described with three stack members and two uplinks, if one of the uplinks fails on the C1000 series stack, the failover behavior is different from the behavior you observed on the 2960S stack with STP. The "Single IP Management" feature does not handle automatic failover or traffic forwarding between the uplinks in the same way as STP.

To achieve failover and load balancing for regular data traffic in a stack, you would need to configure link aggregation or STP on the uplinks of the C1000 stack. With link aggregation configured, if one of the uplinks fails, the remaining active uplink will continue forwarding traffic without noticeable downtime.

[joakimlemb]

Thank you, your answer is a lot easier to understand compared to the official docs regarding this.

[MHM Cisco World]

I will check you Q update you soon.

[M02@rt37]

You're welcome @joakimlemb 

[MHM Cisco World]

switch 1 hstack-port 1 uplink1 
swithc 3 hstack-port 1 uplink3

these two port will form one group,  the Mater of stack select one of them for management, 
when it down it will use other ONE.
Note the port is change the IP is same and the SW that only use this IP is master SW

NOTE:- the port when config with single IP management will not forward data traffic any more. it use only for mgmt.
thanks 
MHM