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Unicast flooding on Catalyst Switches

I have a question regarding unicast flooding on C2980 switches:

We have vlans defined on one C2980. One of the ports is a span port (source: one of the vlans). This span port is connected to a second C2980. All unicast frames coming in from the span port on the first switch are flooded to all ports in the same vlan on the second C2980 (because the cam-table does not know anything about the MAC-addresses coming in).

Does this unicast flooding hit the CPU on the second C2980 and can this cause any load problems?

What about STP frames crossing the link?

What about VTP?

What about CDP?

Please understand that this is not implemented yet, so we have no experience yet how this affects the load on the second switch.


Re: Unicast flooding on Catalyst Switches

Perhaps it would help if you could explain why you have chosen not to use a ISL or DOT1Q trunk to connect the two switches. ?

New Member

Re: Unicast flooding on Catalyst Switches

Because we need to capture traffic. If we use a trunk, packets not destined for the second switch are not forwarded (MAC-adresses are learned, the cam-table is filled).

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