Hi @nabinmaraseni,
Sounds like you have a loop on the network. Follow this procedure to troubleshoot:
https://support.huawei.com/enterprise/en/doc/EDOC1000091883/c23d67b9/checking-loops
Loop is a common cause for packet loss, and is difficult to detect. For example, on a large-sized network, if the administrator incorrectly connects switch interfaces, loops can easily occur, which will cause packet loss.
Check whether the following symptoms occur:
In addition to packet loss, loops may cause the following symptoms:
Run the display trapbuffer command to check whether a MAC flapping alarm is reported,
The MAC flapping alarm 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 flapping occurs on the device with ping packet loss.
Run the mac-address flapping detection command to configure MAC address flapping detection, and then run the display mac-address flapping record command to check whether MAC address flapping occurs.
<HUAWEI> system-view[HUAWEI] mac-address flapping detection<HUAWEI> display mac-address flapping record
S : start time
E : end time
(Q) : quit VLAN
(D) : error down
------------------------------------------------------------------------------
Move-Time VLAN MAC-Address Original-Port Move-Ports MoveNum
-------------------------------------------------------------------------------
S:2011-08-31 17:22:36 300 0000-0000-0007 Eth-Trunk1 Eth-Trunk2 81
E:2011-08-31 17:22:44
-------------------------------------------------------------------------------
Total items on slot 2: 1
Run the display mac-address command for multiple times. If the MAC address is learned by different interfaces, MAC flapping exists.
<HUAWEI> display mac-address-------------------------------------------------------------------------------
MAC Address VLAN/VSI Learned-From Type
-------------------------------------------------------------------------------
0022-0022-0033 100/- GE1/0/1 dynamic
0000-0000-0001 -/HUAWEI GE1/0/2 static
-------------------------------------------------------------------------------
Total items displayed = 2
Run the display interface brief | include up command to view traffic statistics on each Up interface. If an interface has a loop, the values of InUti and OutUti increase, or even approximate 100%. The values outdistance the service traffic volume.
First query:
<SwitchA> display interface brief | include up
...
Interface PHY Protocol InUti OutUti inErrors outErrors
GigabitEthernet0/0/2 up up 0.56% 0.56% 0 0
...
Last query:
<SwitchA> display interface brief | include up ...
Interface PHY Protocol InUti OutUti inErrors outErrors
GigabitEthernet0/0/2 up up 76% 76% 0 0
...
The output of the display interface command shows that a large number of broadcast packets are received on an interface.
Indicators of interfaces in the VLAN where a loop has occurred blink faster than usual.
The CPU usage of a switch exceeds 80%.
<SwitchB> display cpu-usage CPU Usage Stat. Cycle: 60 (Second)
CPU Usage : 95% Max: 97%
CPU Usage Stat. Time : 2013-08-21 16:38:44
CPU utilization for five seconds: 95%: one minute: 95%: five minutes: 95%
Max CPU Usage Stat. Time : 2013-08-21 09:51:04.
....
To obtain the CPU usage of a switch, run the display cpu-usage command. Network loops may cause the switch to stay at a high CPU usage, and consequently the switch may discard packets without processing them.
MAC flapping frequently occurs.
Loop alarms are generated after loop detection is enabled.
Table 8-5 lists the loop alarms.
Table 8-5 Loop alarms on switchesAlarm ID | Alarm Message | Description |
|---|
1.3.6.1.4.1.2011.5.25.174.3.1 | LDT/4/DetectLoop: OID [oid] The port detected loop. (InterfaceIndex: [INTEGER] InterfaceName: [OCTET] VlanListLow: [OCTET] VlanListHigh: [OCTET]) | If the packets that a port sends are sent back to the port through the local VLAN, the packets are looped. A loop may cause a broadcast storm. This alarm is generated when a loop is detected. |
1.3.6.1.4.1.2011.5.25.174.3.2 | LDT/4/LoopResume: OID [oid] The detected loop is removed. (InterfaceIndex: [INTEGER] InterfaceName: [OCTET] VlanListLow: [OCTET] VlanListHigh: [OCTET]) | This recovery notification is generated when the packet loop of the current port is removed. |
1.3.6.1.4.1.2011.5.25.174.3.3 | LBDT/4/PORTTRAP: OID [OID] Loopback exists on interface([INTEGER1]) [OCTET1] ([OCTET2]), loopback detection status: [INTEGER2].(1:normal; 2:block; 3:shutdown; 4:trap; 5:nolearn; 6:quitvlan) | This alarm is generated if a loop is detected on the Layer 2 network connected to a port. |
1.3.6.1.4.1.2011.5.25.174.3.4 | LBDT/4/PORTTRAP: OID [OID] Loopback is removed on interface([INTEGER1]) [OCTET], loopback detection status: [INTEGER2].(1:normal; 2:block; 3:shutdown; 4:trap; 5:nolearn; 6:quitvlan) | The loop on the interface is removed. |
Select an appropriate method based on the loop information and networking.
Observe interface indicators and collect traffic statistics on interfaces to locate the interfaces undergoing broadcast storms.
Check the devices hop by hop according to the topology to locate the devices that cause the loop.
Locate the interfaces that cause the loop and shut down the interfaces to remove the loop.
On the preceding campus network, GE0/0/2 may have a loop, so ping packets on switch B are dropped. To determine whether the packet loss on switch B is caused by a loop, shut down GE0/0/2 of switch B, and then perform a ping test.
# Shut down GE0/0/2 of switch B.
<SwitchB> system-view [SwitchB] interface gigabitethernet 0/0/3 [SwitchB-GigabitEthernet0/0/3] shutdown [SwitchB-GigabitEthernet0/0/3] quit
# Perform a ping test.
<SwitchB> ping -c 100 192.168.2.21
PING 192.168.2.21: 56 data bytes, press CTRL_C to break
Reply from 192.168.2.21: bytes=56 Sequence=1 ttl=255 time=1 ms
...
Reply from 192.168.2.21: bytes=56 Sequence=100 ttl=255 time=2 ms
--- 192.168.2.21 ping statistics ---
100 packet(s) transmitted
100 packet(s) received
0.00% packet loss
round-trip min/avg/max = 1/1/19 ms
Shutting down the interface is not the final solution to the loss of ping packets. To solve the problem, remove the loop from the connected network. Typically, the RRPP, SEP, Smart Link, or STP/RSTP/MSTP protocol can be deployed to prevent loops.
If the fault persists, collect network information (including interface connections) and logs (log.log files or the output of the display logbuffer command), and provide the collected information to Huawei switch resellers.
Here are some detailed guides for your reference:
https://support.huawei.com/enterprise/en/doc/EDOC1000091883/d29f9463/fault-locating-procedure
https://support.huawei.com/enterprise/en/doc/EDOC1000091883/c21bc0b8/how-to-quickly-remove-a-loop
https://support.huawei.com/enterprise/en/doc/EDOC1000091883/c3ad9b7/checking-whether-the-loop-is-caused-by-recent-construction-or-configuration-modification
https://support.huawei.com/enterprise/en/doc/EDOC1000091883/52a4dd29/hardening-and-optimizing-the-network
