Involved Products and Versions

S9300 V200R001

Networking

As shown in Figure 1-1, the S9300 is connected to a camera through the interface GE2/0/10.

Figure 1-1 Networking diagram for the fault that the S9300 fails to ping a camera

Fault Symptom

The S9300 fails to ping a camera.

Cause Analysis

The rate limit is enabled for ICMP packets, and ICMP packets are discarded. As a result, the S9300 fails to ping the camera.

Troubleshooting Procedure

                          Step 1     Run the display cpu-defend statistics all command to check statistics about the packets sent to the CPU. The command output shows that a large number of ICMP packets are discarded.

<S9300> display cpu-defend statistics all
 Statistics on mainboard:
-------------------------------------------------------------------------------
Packet Type         Pass(Bytes)  Drop(Bytes)   Pass(Packets)   Drop(Packets)
-------------------------------------------------------------------------------
icmp                  754529686            0         9672793               0
-------------------------------------------------------------------------------
 Statistics on slot 1:
-------------------------------------------------------------------------------
Packet Type         Pass(Bytes)  Drop(Bytes)   Pass(Packets)   Drop(Packets)
-------------------------------------------------------------------------------
icmp                   40999663        18688          405269              20
-------------------------------------------------------------------------------
 Statistics on slot 2:
-------------------------------------------------------------------------------
Packet Type         Pass(Bytes)  Drop(Bytes)   Pass(Packets)   Drop(Packets)
-------------------------------------------------------------------------------
icmp                 353711830k      9195452      5522622743          138905

                          Step 2     Run the display logbuffer command. The command output shows that the global rate of ICMP packets and the rate of ICMP packets on the interface exceed the limit.

Jun 30 2017 11:10:07+08:00 S9306 %SECE/4/ICMP_GLOBAL_RATELIMIT(l)[159]:Rate of global icmp packets exceeds the limit( Threshold=100 packets per second).
Jun 30 2017 11:05:05+08:00 S9306 %SECE/4/ICMP_GLOBAL_RATELIMIT(l)[161]:Rate of global icmp packets exceeds the limit( Threshold=100 packets per second).
Jun 30 2017 10:55:02+08:00 S9306 %SECE/4/ICMP_GLOBAL_RATELIMIT(l)[165]:Rate of global icmp packets exceeds the limit( Threshold=100 packets per second).
Jun 30 2017 09:01:28+08:00 S9306 %SECE/4/ICMP_INTF_RATELIMIT(l)[219]:Rate of icmp packets on interface exceeds the limit(SourceInterface=GigabitEthernet2/0/10, Threshold=100 packets per second).
Jun 30 2017 08:56:27+08:00 S9306 %SECE/4/ICMP_INTF_RATELIMIT(l)[221]:Rate of icmp packets on interface exceeds the limit(SourceInterface=GigabitEthernet2/0/10, Threshold=100 packets per second).

                          Step 3     By default, the rate limit is enabled for ICMP packets in the S9300 V200R001 (by running the icmp rate-limit enable command), and the ICMP packet rate limit on interfaces and global rate limit are 100 pps.

Run the undo icmp rate-limit enable command to disable the global ICMP rate limit, or run the icmp-reply fast command to enable fast ICMP reply. Then the S9300 can ping the camera.

----End

Conclusions and Suggestions

In the S9300 V200R001 and earlier versions, the rate limit is enabled for ICMP packets. In versions later than V200R001, the rate limit is disabled for ICMP packets.