ZyXEL Communications OLT2406, Руководство пользователя

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OLT2406 User’s Guide
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C
HAPTER
30
Error Disable
30.1 Static Routing Overview
This chapter shows you how to configure the rate limit for control packets on a port, and set the OLT to
take an action (such as to shut down a port or stop sending packets) on a port when the OLT detects a
pre-configured error. It also shows you how to configure the OLT to automatically undo the action after
the error is gone.
30.1.1 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.
30.1.2 Error-Disable Recovery Overview
Some features, such as loop guard or CPU protection, allow the OLT to shut down a port or discard
specific packets on a port when an error is detected on the port. For example, if the OLT detects that
packets sent out the port(s) loop back to the OLT, the OLT 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.
30.1.3 What You Can Do
• Use the CPU Protection screen ( Section 30.3 on page 267 ) to limit the maximum number of control
packets (ARP, BPDU and/or IGMP) that the OLT can receive or transmit on a port.
• Use the Errdisable Detect screen ( Section 30.4 on page 269 ) to have the OLT 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 screen ( Section 30.5 on page 269 ) to set the OLT to automatically undo
an action after the error is gone.