- Green, 3000 points or more
I am looking at storm control on a Cat4500 and I have just read something in the configuration guide that has spooked me:
When storm control is enabled on an interface, the switch monitors packets received on the interface and determines whether or not the packets are broadcast. The switch monitors the number of broadcast packets received within a one-second time interval. When the interface threshold is met, all incoming data traffic on the interface is dropped. This threshold is specified as a percentage of total available bandwidth that can be used by broadcast traffic. If the lower threshold is specified, all data traffic is forwarded as soon as the incoming traffic falls below that threshold.
Hardware does not provide support for multicast suppression on the WS-X4515, WS-X4014, and WS-X4013+ supervisor engines. One consequence of using software-based broadcast suppression on these modules is that all incoming data packets are dropped. Irrespective of your selecting to configure broadcast suppression only, multicast packets are filtered as well on stub and blocking gigabit ports. The non blocking gigabit ports that do provide broadcast suppression in hardware also do not filter multicast packets.
Does it really mean that ... all data traffic is dropped, including unicast? If so, that makes storm-control probably more dangerous than not having storm-control, and certainly not something you would want on your distribution layer. It makes it really only useful on access ports. If this is the case, I would think twice about implementing it, and I would be very careful where I implemented it. I could kill the network stone dead simply by connecting a broadcast generator ... which is really what storm control is supposed to avoid.
If it is software based storm control, when reach the threshold all data traffic will be dropped (include broadcast, multicast and unicast). If it is hardware based storm control, only broadcast packets are dropped when threshold is hit.
Hardware based storm control is supported on all ports after supIV.