XS1930 Series User’s Guide
226
C
HAPTER
29
Error Disable
29.1 Error Disable Overview
This chapter shows you how to configure the rate limit for control packets on a port, and set the Switch
to take an action (such as to shut down a port or stop sending packets) on a port when the Switch
detects a pre-configured error. It also shows you how to configure the Switch to automatically undo the
action after the error is gone.
29.1.1 CPU Protection Overview
Switches exchange protocol control packets in a network to get the latest networking information. If a
switch receives large numbers of control packets, such as ARP, BPDU or IGMP packets, which are to be
processed by the CPU, the CPU may become overloaded and be unable to handle regular tasks
properly.
The CPU protection feature allows you to limit the rate of ARP, BPDU and IGMP packets to be delivered
to the CPU on a port. This enhances the CPU efficiency and protects against potential DoS attacks or
errors from other network(s). You then can choose to drop control packets that exceed the specified
rate limit or disable a port on which the packets are received.
29.1.2 Error-Disable Recovery Overview
Some features, such as loop guard or CPU protection, allow the Switch to shut down a port or discard
specific packets on a port when an error is detected on the port. For example, if the Switch detects that
packets sent out the port(s) loop back to the Switch, the Switch can shut down the port(s)
automatically. After that, you need to enable the port(s) or allow the packets on a port manually via the
web configurator. With error-disable recovery, you can set the disabled port(s) to become active or
start receiving the packets again after the time interval you specify.
29.1.3 What You Can Do
• Use the
Errdisable Status
) to view whether the Switch detected that
control packets exceeded the rate limit configured for a port or a port is disabled according to the
feature requirements and what action you configure, and related information.
• Use the
CPU Protection
screen (
) to limit the maximum number of control
packets (ARP, BPDU and/or IGMP) that the Switch can receive or transmit on a port.
• Use the
Errdisable Detect
screen (
) to have the Switch detect whether the
control packets exceed the rate limit configured for a port and configure the action to take once the
limit is exceeded.
• Use the
Errdisable Recovery
) to set the Switch to automatically
undo an action after the error is gone.
