help!too many switches, too many blinking lights

[bwana]

I have recently upgraded to FIOS from verizon. They supply an actiontec router

http://www.actiontec.com/products/product.php?pid=189

It has an coaxial wan port(that's what connects to the box where the fiber comes in to). it also has a wan ethernet port (unused) and 4 100 mbps lan ports. I have 12 ethernet cables that come to the router location. There is a 5 port gigabit switch and an 8 port 100 mbps switch that are plugged into the router allowing these ethernet cables connectivity. These cables go to various locations in the facility and terminate in rj45 jacks. some of the jacks are also connected to 5 port switches.

My question is this: Do unmanaged switches clog the network with a lot of "noise"? I know that hubs were very "noisy" broadcasting every packet to every port. I thought switches helped this somewhat by making connections between source and destination ip addresses to eliminate packet collisions . But dont they still broadcast the multicast address to all ports? Is that why the lights on my central switches are always blinking-even when data is not being sent across the network?

How do managed switches and IGMP snooping reduce network congestion even further?

 

[thiggins]

Hubs send information received on any port out to all ports.

Switches connect only sender and receiver based on the MAC address in the packet header.

Both send broadcast traffic to all ports (that's why they call it broadcast).

If you block broadcast traffic, then ARP won't work and clients won't see each other.

If all switch port lights are constantly blinking very fast, then you have a network storm. Look for more than one cable between switches or the switches connected in a loop. Best configuration is a star, i.e. one central switch with a single link to other switches. Next best is a chain, with, again, one link between each switch.

If lights are occasionally blinking, it could be Windows network discovery or perhaps one of your machines is a zombie. Strip the network down to a minimum point, then add switches and systems back in to find the culprit.