broadcast storms applicable on layer 3 switches?

[vandamt01]

Dear all,

Me and my collegue were wondering about the following on a cisco 3750 x layer 3 switch.

Lets assume we configure the 3750 without vlans so we create several networks on the 3750. For example fa 0/1 has as network 10.10.10.0/24 with 10.10.10.1 as it being the default gateway. Fa 0/2 has as network 10.10.11.0/24 with 10.10.11.1 as it being the default gateway.

The question is if a broadcast storm rages on network 10.10.10.0/24, would 10.10.10.0/24 only be affected by the broadcast storm or will network 10.10.11.0/24 also be affected due the broadcast?

If we assume the same settings but we would utilize vlans then anetwork is definitely not being affected by a broadcast storm happening on an other network right?

Thanks in advance for your help.

kind regards

[acampbell]

Hi,

When you configure an L3 port on your 3750

!
int f0/1
no switchport
ip add 10.10.10.1 255.255.255.0
no shut
!
!
int f0/2
no switchport
ip add 10.10.11.1 255.255.255.0
no shut
!

The key is NO SWITCHPORT

This takes the port out of L2 configuration therefore
it does not belong to any VLAN and does not operate like an L2 port
with regards to broadcast etc.

Have a look at this link from a 3750 config guide

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/configuration/guide/scg3750/swint.html#wpmkr2208885

Hope this helps
Regards
Alex