D-Link DGS-1510 Series Reference Manual page 528

DGS-1510 Series Gigabit Ethernet SmartPro Switch CLI Reference Guide
The reasons of packets that are destined to the CPU can be classified into three groups: manage,
protocol and route. The sub-interface is a logical interface, which handles the CPU received packets
by different groups. Generally speaking, the protocol packets should have higher priority to make sure
the functions work normally. The CPU usually is not involved in the routing of packets. In few cases,
such as learning new IP address or if the default route is not specified, some packets will be sent to
the CPU for software routing. Use this command to limit the rate of routed packets to avoid the CPU
spending too much time for routing packets.
Example
This example shows how to configure the rate limit of packets for the management sub-interface and
the threshold is 1000 packets per seconds.
Switch# configure terminal
Switch(config)# cpu-protect sub-interface manage pps 1000
Switch(config)#
59-4 cpu-protect type
This command is used to configure the rate limit of traffic destined to the CPU by the protocol type.
cpu-protect type PROTOCOL-NAME pps RATE
no cpu-protect type PROTOCOL-NAME
Parameters
PROTOCOL-NAME
RATE
Default
None.
Command Mode
Global Configuration Mode.
Command Default Level
Level: 12.
Usage Guideline
The CPU must handle certain packets, such as routing protocols, Layer 2 protocols, and packets for
management. If the traffic destined to the CPU overloads it, the CPU will spend much time processing
unnecessary traffic and the routing processes are impacted. To mitigate the impact on the CPU, use
this command to control the threshold of individual protocol packets.
The following lists the reference for the supported protocols for the CPU protect type command.
According to the purpose of packets destined to CPU, the router creates three virtual sub-interfaces to
process the packets:

manage: The packets are destined to any router interface or system network management
interface via the interactive access protocol, such as Telnet and SSH.

protocol: The packets are protocol control packets which can be identified by the router.

route: Other packets traversing the router for routing that must be processed by the router's
CPU before it can be routed without the CPU's involvement.
The following table lists the supported protocol names for this command:
Protocol Name
Specifies the protocol name to be configured.
Specifies the threshold value. The unit is packets per second. When
set to 0, all packets of the specified protocol are dropped.
Description
525
Classification (sub-
interface)