814
Configuring IP Unicast Routing
Configuring IP Addressing
The packet must be a TFTP, DNS, Time, NetBIOS, ND, or BOOTP packet, or a UDP specified by the
ip
forward-protocol udp
global configuration command.
The time-to-live (TTL) value of the packet must be at least two.
A flooded UDP datagram is given the destination address specified with the
ip broadcast-address
interface
configuration command on the output interface. The destination address can be set to any address so it might change
as the datagram propagates through the network. The source address is never changed. The TTL value is decremented.
When a flooded UDP datagram is sent out an interface (and the destination address possibly changed), the datagram is
handed to the normal IP output routines and is, therefore, subject to access lists, if they are present on the output
interface.
BEFORE YOU BEGIN
Ensure that bridging is configured on each interface that is to participate in the flooding.
DETAILED STEPS
Use the
no ip forward-protocol spanning-tree
global configuration command to disable the flooding of IP broadcasts.
EXAMPLE
The following example permits IP broadcasts to be flooded through the internetwork in a controlled fashion:
Switch#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#
ip forward-protocol spanning-tree
Switch(config)#
end
Speeding up STP-Based UDP Flooding
In the switch, the majority of packets are forwarded in hardware; most packets do not go through the switch CPU. For
those packets that do go to the CPU, you can speed up spanning tree-based UDP flooding by a factor of about four to
five times by using turbo-flooding. This feature is supported over Ethernet interfaces configured for ARP encapsulation.
BEFORE YOU BEGIN
Enable the flooding of IP broadcasts as described in the
Flooding IP Broadcasts, page 813
.
Command
Purpose
1.
configure terminal
Enter global configuration mode.
2.
ip forward-protocol spanning-tree
Use the bridging spanning-tree database to flood UDP
datagrams.
3.
end
Return to privileged EXEC mode.
4.
show running-config
Verify your entry.
5.
copy running-config startup-config
(Optional) Save your entry in the configuration file.
Summary of Contents for IE 4000
Page 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Page 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Page 108: ...104 Configuring Switch Clusters Additional References ...
Page 128: ...124 Performing Switch Administration Additional References ...
Page 130: ...126 Configuring PTP ...
Page 140: ...136 Configuring CIP Additional References ...
Page 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Page 192: ...188 Configuring Switch Based Authentication Additional References ...
Page 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Page 298: ...294 Configuring VLANs Additional References ...
Page 336: ...332 Configuring STP Additional References ...
Page 408: ...404 Configuring DHCP Additional References ...
Page 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Page 490: ...486 Configuring SPAN and RSPAN Additional References ...
Page 502: ...498 Configuring Layer 2 NAT ...
Page 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Page 930: ...926 Configuring IP Unicast Routing Related Documents ...
Page 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Page 978: ...974 Dying Gasp ...
Page 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Page 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Page 996: ...992 Ethernet CFM ...
Page 1066: ...1062 Using an SD Card SD Card Alarms ...