Example for Configuring OLC
Networking Requirements
On the network shown in Figure 1, users on different network segments access the Internet through the Switch. Because many users connect to the Switch, the CPU of the Switch receives a large number of protocol packets, such as ARP Request packets, ARP Reply packets, and ARP Miss packets, and frequently processes tasks such as the ARPA task. As a result, the CPU usage increases sharply, affecting service processing. The customer expects that the Switch can generate an alarm and rate-limit these protocol packets and tasks when the CPU usage exceeds 90%, so that processing of other services will not be affected and the CPU usage is reduced to a stable range.
Configuration Roadmap
The configuration roadmap is as follows:
- Enable the OLC function.
- Enable the OLC function for the ARP Request, ARP Reply, and ARP Miss packets.
- Enable the OLC function for the ARPA task.
- Enable the OLC alarm function.
- Set the OLC start threshold to 90%.
Procedure
- Enable the OLC function.
<HUAWEI> system-view [HUAWEI] sysname Switch [Switch] undo cpu-overload-control disable slot 0
- Enable the OLC function for the ARP Request, ARP Reply, and ARP Miss packets.
[Switch] undo cpu-overload-control packet-type arp-request arp-reply arp-miss disable slot 0 - Enable the OLC function for the ARPA task.
[Switch] cpu-overload-control task ARPA enable slot 0 - Enable the OLC alarm function.
[Switch] undo cpu-overload-control alarm disable
- Set the OLC start threshold to 90%.
[Switch] cpu-overload-control threshold1 90 slot 0 Warning: The value of threshold 1 affects the service processing capability when the CPU is overloaded. Continue? [Y/N]:y [Switch] quit - Verify the configuration.
# View the OLC configuration.
<Switch> display cpu-overload-control configuration slot 0 CPU OLC Status: enable. Alarm Status : enable. Low Threshold: 90%. High Threshold: 98%. Ajustfactor : 10. Total Weight : 10000. ---------------------------------- Task Weight Enable ---------------------------------- ARPA 2500 Y ACL 2500 N ---------------------------------- ---------------------------------- Protocol Weight Enable ---------------------------------- 8021x 290 Y 8021x-1st 90 Y 8021x-other 200 Y arp-request 290 Y arp-reply 290 Y icmp 290 Y dhcp 290 Y arp-miss 290 Y igmp 290 Y ttl-one 290 Y ip-frag 290 Y fib-hit 290 Y icmpv6 290 Y dhcpv6 290 Y nd 290 Y mld 290 Y cos-4 250 Y cos-3 240 Y cos-2 200 Y cos-1 150 Y cos-0 100 Y ----------------------------------# View OLC statistics.
<Switch> display cpu-overload-control statistics slot 0 -------------------------------------------------------------------------------- Task Total Runtime Total Delaytime Average Runtime Average Delaytime (ms) (ms) (ms) (ms) -------------------------------------------------------------------------------- ARPA 0 0 0 0 ACL 0 0 0 0 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Protocol Total Pass Total Drop Average Pass Average Drop (packet) (packet) (packet) (packet) -------------------------------------------------------------------------------- 8021x-1st 0 0 0 0 8021x-other 0 0 0 0 arp-request 0 0 0 0 arp-reply 0 0 0 0 icmp 0 0 0 0 dhcp 0 0 0 0 arp-miss 0 0 0 0 igmp 0 0 0 0 ttl-one 0 0 0 0 ip-frag 0 0 0 0 fib-hit 0 0 0 0 icmpv6 0 0 0 0 dhcpv6 0 0 0 0 nd 0 0 0 0 mld 0 0 0 0 cos-4 0 0 0 0 cos-3 0 0 0 0 cos-2 0 0 0 0 cos-1 0 0 0 0 cos-0 0 0 0 0 --------------------------------------------------------------------------------