Broadcast Storm Control on 2948G

[Pluttur]

Hi!

Does the 2948G support broadcast storm control?
All I can find is unicast-flood, but that's not quite what I want.

If they support it, how do I configure it? Can't find it =)

Also, do they have support for blocking dhcp-responses (e.g. a user sets up his own dhcpd which will interfere with ours)?

It runs CatOS k8.8
Thanks
/Pluttur

 

[DallasBPF]

STP helps prevent broadcast storms, so yes it does support it so long as you configure your ports properly on the switch... don't use auto anything if possible (speed/duplex) or switchport, hard code it all. Also, if you are connecting it to another switch make that port a trunk on both sides and not desireable. And for all other ports make them access ports with portfast enabled. OH! and another thing if you REALLY want to see a broadcast storm (to play around a lil =P)

1) plug an unmanaged linksys/dlink switch into a port on the 2948 that you have turned into an access port with portfast on

2) plug a computer into one of the linksys ports

3) test connectivity

4) take another cable and plug it back into it self...

had a guy at our office do that a couple of years ago, brought our network to its knee's within a few minutes... was even more fun trying to figure it out lol

------------------------------------
Dallas, Texas
Telecommunications Tech
CCVP, CCNA, Net+

CCNP in the works

 

[vipergg]

Only make user ports as spanning tree portfast , any uplinks to other networking gear disable portfast. As far as catos goes and broadcast supression it is not supported on the 2948G or cat 4000 line , the 6500's do support it . It would be the "set port broadcast" command.

 

[NetworksMD]

I believe that the 2948 will support broadcast storm, multi-cast storm, and uni-cast storm control. It is set a physical interface or etherchannel connection. Go to a specific port and type "storm-control ?" This is also what makes it difficult to fine-tune. It can be set either as a percentage of the percentage bandwidth(or traffic I can't remeber) or as packets per second. You can then set it to either filter the traffic, shutdown the port, or send an SNMP trap.

I thought there was a way to apply an ACL to an individual switch port to block DHCP, but I can't remeber if it actually worked.