Chapter 29 Error Disable
GS1920 Series User’s Guide
242
29.4  CPU Protection Configuration 
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). Then, you can choose to drop or bypass the control 
packets, decrease the priority value to CPU of control packets that exceed the specified rate limit or 
disable a port on which the packets are received.
Use this screen to limit the maximum number of control packets (ARP, BPDU and/or IGMP) that the 
Switch can receive or transmit on a port. Click the Click Here link next to CPU protection in the 
Advanced Application > Errdisable screen to display the screen as shown. 
Note: After you configure this screen, make sure you also enable error detection for the 
specific control packets in the Advanced Application > Errdisable > Errdisable 
Detect screen.
Figure 177   Advanced Application > Errdisable > CPU protection 
Status This field displays the errdisable status
• Forwarding: The Switch is forwarding packets. Rate-limitation mode is always in 
Forwarding status.
• Err-disable: The Switch disables the port on which the control packets are received 
(inactive-port) or drops specified control packets on the port (inactive-reason)
Recovery 
Time
This field displays the time (seconds) left before the port(s) becomes active of Errdisable 
Recovery.
Total 
Dropped
This field displays the total packet number dropped by this port where the packet rate 
exceeds the rate of mode rate-limitation.
Table 113   Advanced Application > Errdisable > Errdisable Status  (continued)
LABEL DESCRIPTION