L3 Switch with IP Routing

[mhabdrah]

Hi everyone,

Regarding activating IP Routing on a l3 Switch I am a bit puzzled about how that would work.

Let's say we have a 24 ports switch on which we have sdm prefer and IP Routing commands applied.

If we no switchport port 0-11, while keeping ports 12-23 as switchport what happens when ports 12-23 receive an unknown unicast?

Will that get flooded only between ports 12-23 or will that get flooded onto all ports?

Thanks for your clarifications.

[Joseph W. Doherty · Accepted solution]

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@mhabdrah wrote:

Will that get flooded only between ports 12-23 or will that get flooded onto all ports?

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Just ports 12-23, assuming all same VLAN, also excluding ingress port.

[MHM Cisco World · Accepted solution]

Only port from 12-23 will receive unknown unicast 

The l3 port is boundary of broadcast abd it never allow flood of any types of broadcast pass through 

MHM