22-21
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-03
Chapter22 Configuring IP Unicast Routing Configuring IP Addressing
Beginning in privileged EXEC mode, follow these steps to use th e br id ging spann in g-tr ee data base to
flood UDP datagrams:
Use the no ip forward-protocol spanning-tree global configuration command to disable the flooding
of IP broadcasts.
In the Catalyst 3550 switch, the majority of packets are forwarded in ha rdware; most packets do not go
through the switch CPU. For those packets that do go to the CPU, you can speed up spa nning tree-based
UDP flooding by a factor of about four to five times by using turbo-flooding. This fea tur e is support ed
over Ethernet interfaces configured for ARP encapsulation.
Beginning in privileged EXEC mode, follow these steps to increas e spa nnin g-t ree-b ased fl oodi ng:
To disable this feature, use the no ip forward-protocol turbo-flood global configuration command.
Monitoring and Maintaining IP Addressing
When the contents of a particular cache, table, or database have beco me or are su spe cte d to b e i nv alid,
you can remove all its contents by using the cle ar privileged EXEC commands. Table22-3 lists the
commands for clearing contents.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 ip forward-protocol spanning-tree Use the bridging spanning-tree database to flood UDP datagrams.
Step3 end Return to privileged EXEC mode.
Step4 show running-config Verify your entry.
Step5 copy running-config startup-config (Optional) Save your entry in the configuration file.
Command Purpose
Step1 configure terminal Enter global configuration mode
Step2 ip forward-protocol turbo-flood Use the spanning-tree database to speed up flooding of UDP
datagrams.
Step3 end Return to privileged EXEC mode.
Step4 show running-config Verify your entry.
Step5 copy running-config startup-config (Optional) Save your entry in the configuration file.
Table22-3 Commands to Clear Caches, Tables, and Databases
Command Purpose
clear arp-cache Clear the IP ARP cache and the fast-switching cache.
clear host {name | *} Remove one or all entries from the host name and the address cache.
clear ip route {network [mask] |*} Remove one or more routes from the IP routing table.