STP vs Storm Control

[LynK]

Hey guys,

Can some of you shed some light on these two topics. If I have storm control, if there a need for STP at all? I know Storm Control does not block STP packets, etc. But does it replace it?

There has got to be something I am missing here

[wintermute000]

Storm control mitigates flooding. It doesn't stop loops

[LynK]

but dont all l2 loops cause broadcast storms?

[dlots]

If STP isn't stopping it yes.

However not all flooding is because of loops.

I have seen a PC go crazy and just send out butt loads of broadcast traffic, and cause some real issues.

[wintermute000]

yep good old intel nic ipv6 ND spam (seen it twice!). THe best one I saw sent the traffic to a WLC which then used multicast - unicast replication and tried to send it to all hundred WAPs as a unicast. LOL


unless you use some specific broadcast/multicast app in your network that requires silly bandwidth its usually safe to just shove a 10% limit on all standard user ports, probably safe to go lower

[mlan]

I have seen a PC go crazy and just send out butt loads of broadcast traffic, and cause some real issues.

PC's, printers, phones, etc.  I recommend both bpduguard and storm-control on all your client access ports, as well as additional port-security parameters (max # of MAC's, etc.)

[icecream-guy]

Storm control mitigates flooding. It doesn't stop loops

3 types of flooding for storm control

broadcast
multicast
unicast


write up here

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/4_1/nx-os/security/configuration/guide/sec_nx-os-cfg/sec_storm.html

http://www.netcraftsmen.com/understanding-cisco-traffic-storm-control/

[Nerm]

yep good old intel nic ipv6 ND spam (seen it twice!). THe best one I saw sent the traffic to a WLC which then used multicast - unicast replication and tried to send it to all hundred WAPs as a unicast. LOL

Yep seen this as recently as this last summer. That network now has full storm control policies in place lol.