Broadcast Radiation - Misinterpretations

Misinterpretations

1. A common misinterpretation is that routing loops have anything to do with broadcast storms. Working at Layer 3, routers (unlike Layer 2 equipment) do not forward MAC-level broadcast traffic.
2. Another misinterpretation is that routers cannot forward broadcasts under special circumstances. Some routable protocols support the use of internetwork-level broadcasts. If the router is configured to forward them, the broadcast domain segmentation is compromised.
3. Most commonly it is believed that only routers can impact the broadcast domain or filter broadcasts. As we have seen, switches can blur the layer line (e.g. with VLANs) and can do filtering (they still need a router for forwarding however).
4. A misinterpretation is that a broadcast can be responded to with a broadcast. This is not true. A broadcast can, however, be issued to gather information needed to respond to an initially received broadcast. In a redundant looped topology this second broadcast can reach the interface that sent the initial broadcast.