Establishing An Ip Broadcast Address; Flooding Ip Broadcasts - Cisco IE-4000 Software Configuration Manual

Configuring IP Unicast Routing
Configuring IP Addressing
Switch(config)# ip forward-protocol udp
Switch(config)# end

Establishing an IP Broadcast Address

The most popular IP broadcast address (and the default) is an address consisting of all ones (255.255.255.255).
However, the switch can be configured to generate any form of IP broadcast address.
DETAILED STEPS
Command
1. configure terminal
2. interface interface-id
3. no shutdown
4. ip broadcast-address ip-address
5. end
6. show ip interface [interface-id]
7. copy running-config startup-config
To restore the default IP broadcast address, use the no ip broadcast-address interface configuration command.
EXAMPLE
The following example specifies an IP broadcast address of 0.0.0.0:
Switch# configure terminal
Enter configuration commands, one per line.
Switch(config)# interface ethernet 0
Switch(config-if)# ip broadcast-address 0.0.0.0
Switch(config-if)# end

Flooding IP Broadcasts

You can allow IP broadcasts to be flooded throughout your internetwork in a controlled fashion by using the database
created by the bridging STP. Using this feature also prevents loops. To support this capability, bridging must be
configured on each interface that is to participate in the flooding. If bridging is not configured on an interface, the
interface can receive broadcasts but it never forwards the broadcasts it receives, and the router never uses that interface
to send broadcasts received on a different interface.
Packets that are forwarded to a single network address using the IP helper-address mechanism can be flooded. Only
one copy of the packet is sent on each network segment.
To be considered for flooding, packets must meet these criteria. (Note that these are the same conditions used to
consider packet forwarding using IP helper addresses.)

The packet must be a MAC-level broadcast.

The packet must be an IP-level broadcast.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the
interface to configure.
Enable the interface if necessary. By default, UNIs and
ENIs are disabled and NNIs are enabled.
Enter a broadcast address different from the default, for
example 128.1.255.255.
Return to privileged EXEC mode.
Verify the broadcast address on the interface or all
interfaces.
(Optional) Save your entries in the configuration file.
End with CNTL/Z.
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