Chapter 17 Configuring Unicast Flood Blocking; Understanding How Unicast Flood Blocking Works - Cisco WS-C2948G-GE-TX Configuration Manual

Configuring Unicast Flood Blocking
This chapter describes how to configure unicast flood blocking on the Catalyst enterprise LAN switches.
For complete syntax and usage information for the commands that are used in this chapter, refer to the
Note
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Command
Reference.
This chapter consists of these sections:
•
•
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Understanding How Unicast Flood Blocking Works

You can enable unicast flood blocking on any Ethernet port on a per-port basis. Unicast flood blocking
allows you to drop unicast flood packets on an Ethernet port that has only one host that is connected to
the port. All Ethernet ports on a switch are configured to allow unicast flooding. With unicast flood
blocking, you can drop unicast flood packets before they reach the port.
You must have a static CAM entry that is associated with the Ethernet port before you enable unicast
Caution
flood blocking. If you do not have a static CAM entry that is associated with the port, you will lose
network connectivity if you enable unicast flood blocking. You can verify that a static CAM entry exists
by entering the show cam static command.
Note If you are configuring unicast flood blocking on a secure port; see
Security."
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Understanding How Unicast Flood Blocking Works, page 17-1
Configuration Guidelines for Unicast Flood Blocking, page 17-2
Configuring Unicast Flood Blocking on the Switch, page 17-2
C H A P T E R
Chapter 16, "Configuring Port
17
17-1