Ping Packets Are Lost
1. Checking Whether the Link Flaps
If the interface through which ping packets pass alternate between Up and Down, ping packets will be lost. Run the terminal debugging and terminal monitor commands in the user view to enable debugging:
<HUAWEI> terminal debugging <HUAWEI> terminal monitor
Check whether the interface alternates between Up and Down, and then disable debugging:
Sep 9 2009 14:57:29 HUAWEI %%01IFNET/4/IF_STATE(l): Interface GigabitEthernet1/0/24 has turned into UP state. Sep 9 2009 14:56:54 HUAWEI %%01IFNET/4/IF_STATE(l): Interface GigabitEthernet1/0/24 has turned into DOWN state. <HUAWEI> undo terminal debugging <HUAWEI> undo terminal monitor
If the interface status changes, check whether the interface rate and duplex mode are correct and whether the attributes on connected interfaces are consistent. Try to remove or replace the Ethernet cable or optical module to solve the problem. For details, see Interconnected Optical Ports Cannot Go Up or Interconnected Electrical Interfaces Cannot Go Up.
You can run the display interface interface-type interface-number command to view the interface status.
<HUAWEI> display interface gigabitethernet 0/0/24 GigabitEthernet0/0/24 current state : UP Line protocol current state : UP Description:117.40.161.123 Switch Port, PVID : 625, TPID : 8100(Hex), The Maximum Frame Length is 9216 IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is fce3-3cb0-adf0 Last physical up time : 2015-08-09 21:41:37 UTC+08:00 Last physical down time : 2015-08-09 21:41:35 UTC+08:00 Current system time: 2015-08-11 09:57:58+08:00 Port Mode: COMMON COPPER Speed : 100, Loopback: NONE Duplex: FULL, Negotiation: ENABLE Mdi : AUTO, Flow-control: DISABLE ... ...
2. Checking Whether the Loop Prevention Protocol Flaps
Check whether a loop prevention protocol, such as STP, is enabled and is flapping. If the protocol flaps, ICMP forwarding and processing are affected.
<HUAWEI> display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/24 ALTE DISCARDING NONE 0 GigabitEthernet1/0/35 ROOT FORWARDING NONE
Check the loop prevention protocol status repeatedly during ping packet loss to confirm whether the protocol flaps:
01MSTP/6/SET_PORT_DISCARDING(l)[182103]:In MSTP process 0 instance 0, MSTP set port Eth-Trunk2 state as discarding. MSTP/6/SET_PORT_LEARNING(l)[182104]:In process 0 instance 0, MSTP set port Eth-Trunk2 state as learning.
Check whether the interface status frequently changes according to Checking Whether the Link Flaps.
3. Checking Whether the Interface Has Lost or Error Packets
Run the display interface command to check whether the number of discarded or error packets on the interface increases.
[HUAWEI] display interface gigabitethernet 2/0/24 GigabitEthernet2/0/24 current state : UP Line protocol current state : UP Description:117.40.161.123 Switch Port, PVID : 625, TPID : 8100(Hex), The Maximum Frame Length is 9216 IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is fce3-3cb0-adf0 Last physical up time : 2015-08-09 21:41:37 UTC+08:00 Last physical down time : 2015-08-09 21:41:35 UTC+08:00 Current system time: 2015-08-11 09:57:58+08:00 Port Mode: COMMON COPPER Speed : 100, Loopback: NONE Duplex: FULL, Negotiation: ENABLE Mdi : AUTO, Flow-control: DISABLE Last 300 seconds input rate 588352 bits/sec, 72 packets/sec Last 300 seconds output rate 61816 bits/sec, 54 packets/sec Input peak rate 99999992 bits/sec, Record time: 2015-08-05 10:24:34 Output peak rate 70510728 bits/sec, Record time: 2015-08-07 07:24:41 Input: 3870781459 packets, 3935937483889 bytes Unicast: 3870781452, Multicast: 0 Broadcast: 7, Jumbo: 0 Discard: 0, Pause: 0 Total Error: 0 CRC: 0, Giants: 0 Jabbers: 0, Fragments: 0 Runts: 0, DropEvents: 0 Alignments: 0, Symbols: 0 Ignoreds: 0, Frames: 0 Output: 38638073 packets, 4927079332 bytes Unicast: 38638073, Multicast: 0 Broadcast: 0, Jumbo: 0 Discard: 2843, Pause: 0 Total Error: 0 Collisions: 0, ExcessiveCollisions: 0 Late Collisions: 0, Deferreds: 0 Buffers Purged: 0
The packets are discarded due to congestion. Configure rate limiting according to QoS Configuration in the product manual.
4. Checking Whether Route Flapping Occurs
Run the display ip routing-table command to check whether route flapping occurs.
[HUAWEI] display ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 16 Routes : 16 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 Static 60 0 RD 192.168.108.1 MEth0/0/1
Observe the next hop entry of the route to the destination IP address and check whether the outbound interface information has changes. If the information changes frequently, check whether IP addresses conflict or interface flaps.
5. Checking Whether ARP Flapping Occurs
Run the display arp command to check whether ARP flapping occurs.
[HUAWEI] display arp IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPN-INSTANCE VLAN/CEVLAN ------------------------------------------------------------------------------ 192.168.108.1 0018-82c6-682d 12 D-1 MEth0/0/1 ------------------------------------------------------------------------------ Total:1 Dynamic:1 Static:0 Interface:1
Check whether ARP flapping occurs, including whether the MAC address entries, VLAN IDs, and outbound interfaces are changed. The aging time of ARP entries is slowly decreased from 20 minutes. If the aging time is suddenly changed to 20 minutes, ARP entries are updated. In this situation, check whether IP addresses conflict or a loop has occurred.
6. Checking Whether MAC Address Flapping Occurs
Run the display trapbuffer command to check whether a MAC address flapping alarm has been reported.
The MAC address flapping alarm message is as follows:
L2IFPPI/4/MFLPVLANALARM:OID 1.3.6.1.4.1.2011.5.25.160.3.7 MAC move detected, VlanId = 22, MacAddress = 0000-5e00-0116, Original-Port = Eth-Trunk1, Flapping port = Eth-Trunk11. Please check the network accessed to flapping port.
Check whether the MAC address of the device related to ping packet loss is flapping. If so, solve the problem according to MAC Address Flapping Occurs on a Layer 2 Network.
7. Checking Whether ICMP Packets Are Discarded by CPCAR
Run the display cpu-defend statistics packet-type icmp all command repeatedly to check whether packets are discarded by CPCAR.
<HUAWEI> display cpu-defend statistics packet-type icmp all Statistics on slot 1: -------------------------------------------------------------------------------- Packet Type Pass(Packet/Byte) Drop(Packet/Byte) Last-dropping-time -------------------------------------------------------------------------------- icmp 100 10 - 10200 1020 --------------------------------------------------------------------------------
Check whether ICMP packets are discarded. If so, increase the CPCAR value.
For example, change the CIR value for ICMP packets from 256 Kbit/s to 512 Kbit/s.
<HUAWEI> system-view [HUAWEI] display cpu-defend configuration packet-type icmp Car configurations on slot 1. ---------------------------------------------------------------------- Packet Name Status Cir(Kbps) Cbs(Byte) Queue Port-Type ---------------------------------------------------------------------- icmp Enabled 256 48128 3 UNI ---------------------------------------------------------------------- [HUAWEI] cpu-defend policy test //test is the name of the customized attack defense policy. [HUAWEI-cpu-defend-policy-test] car packet-type icmp cir 512 //Increase the CIR value. [HUAWEI-cpu-defend-policy-test] quit [HUAWEI] undo cpu-defend-policy global [HUAWEI] cpu-defend-policy test global
8. Checking the CPU Usage
Run the display cpu-usage command to view the CPU usage. If the CPU usage of an LPU or MPU is too high, solve the problem according to CPU Usage Is High.
9. Collecting Information and Seeking Technical Support
Collecting Fault Information
Collect operation results of the preceding steps and record the results in a file.
Collect all diagnostic information and export the information to a file.
Run the display diagnostic-information file-name command in the user view to collect diagnostic information and save the information to a file.
<HUAWEI> display diagnostic-information dia-info.txt Now saving the diagnostic information to the device 100% Info: The diagnostic information was saved to the device successfully. When the diagnostic file is generated, you can export the file from the device using FTP, SFTP, or SCP.
NOTICE:
You can run the dir command in the user view to check whether the file is generated.
You can also run the display diagnostic-information command and save terminal logs in a diagnostic file on a disk.
If this command displays a long output, press Ctrl+C to abort this command.
This command displays diagnostic information, which helps locate faults but may affect system performance. For example, CPU usage may become high. Therefore, do not use this command when the system is running properly.
Running the display diagnostic-information command simultaneously on multiple terminals connected to the device is prohibited. This is because CPU usage of the device may obviously increase and the device performance may be degraded.
Collect the log and trap information on the device and export the information to files.
Run the save logfile all command in the user view to save the logs in the user log buffer area and diagnostic log buffer area to the user log file and diagnostic log file, respectively.
<HUAWEI> save logfile all Info: Save logfile successfully. Info: Save diagnostic logfile successfully.
When the diagnostic file is generated, you can export the file from the device using FTP, SFTP, or SCP.
NOTE:
You can also run the display logbuffer and display trapbuffer commands to view the log and trap information on the device, and save the information in diagnostic files on a disk.
If you need any help, please feel free to contact [email protected].
NOTE:
Technical support personnel will provide instructions for you to submit all the collected information and files, so that they can locate faults.
