Broadcast Storms

[kerpow]

I am currently studying the CCNA course and in particular Cisco Switches. What exactly causes broadcast storms? I'm guessing that it is caused by not having STP enabled on a segment of switches and or bridges but can't find anywhere that will confirm this. Will any other circumstances cause it aswell. Incorrect bridging tables?

Also, what is a partitioned port and what effect can it have on a LAN?

thnx "Very funny Scotty, now beam my clothes down aswell".

 

[baddos]

If you have a loop in your switch/hub setup with stp disabled or not working.

 

[wybnormal]

broadcast storms can be caused by a varity of things. Spanning tree is just one thing. A poorly configured netware network where it sends a list of services can be one, networks where resources drop in and out of the network can set up a boradcast storm, bad NICs, bad ports, poorly configured Windows servers and the list goes on.

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[clahnum]

The switch always needs a router connected to it if it's going to route packets between vlans!
A serious problem with switches.
Switches by default forward broadcasts. If your switch topology contains redundant paths or bridge loops, a broadcast storm of Biblical proportions could result.
· Routers on the other hand, do not have this problem because they do not forward broadcasts.
· Switches use something called the Spanning Tree Protocol to ensure a loop free topology.
The world of Spanning Tree has two warring factions, each bent on the destruction of the other. The two factions are the IEEE and DEC. These two spanning tree protocols are not compatible and should never be enabled on the same network simultaneously. Use the IEEE version of Spanning Tree unless you work at DEC.
Problems relating to spanning tree can easily create broadcast storms the lock up routers so bad you can't even get a console connection!

 

[clahnum]

try

http://www.networkuptime.com

tip of the moment
Broadcast storms

also

http://www.cisco.com/warp/public/473/22.html#before

Multicast in a Campus Network: CGMP and IGMP
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