Publication Date: 2012-07-27 | Views: 3 | Downloads: 0 | Author: liuyongchang | Document ID: EKB0000535960
1.topology
N/A
2.version:
V600R001C01SPC600
3.problem detail:
Customer face the issue found one LPU board CPU-usage 99%, the 3G services effect.
dis device slot 3
Slot 3's detail information:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Description: Line Processing Unit F-21-A
Board status: Normal
Register: Registered
Uptime: 2011/08/01 08:05:50
CPU Utilization(%): 99%
Mem Usage(%): 58%
display alarm all hist
290 Error 11-07-29 00:52:05 LPU 3 is failed, NP-3 PCS Status of PI
C0 is abnormal
291 Error 11-07-29 00:52:36 LPU 3 is failed, NP-3 PCS Status of PI
C0 is abnormal, Resume
1. first check the configuration on interface.
interface GigabitEthernet3/1/1.10
description NE-MUX-NODE-B-vlan-2000-to-2111
control-vid 10 dot1q-termination
dot1q termination vid 10
dot1q termination vid 2000 to 2111
dot1q vrrp vid 10
ip binding vpn-instance IUB
ip address 10.72.149.2 255.255.255.128
vrrp vrid 10 virtual-ip 10.72.149.1
arp broadcast enable
2.check the cpu-usage on LPU board.found the ARP process have 74%.
dis cpu-usage slot 3
CPU Usage Stat. Cycle: 60 (Second)
CPU Usage : 99% Max: 99%
CPU Usage Stat. Time : 2011-08-01 15:49:19
CPU utilization for five seconds: 99%: one minute: 99%: five minutes: 99%.
...
ARP 74% 0/6e37bd6a ARP
...
3.after check the arp message queue,found this queue have congestion.that means ARP requrest process use the high usage.
[NE40E-PUN-1-hidecmd]display message-queue slot 3
*******************************************************
Max Queue Count = 256
Current Queue Count = 163
Total Created Count = 163
Default Queue Size = 0x300
-------------------------------------------------------
QID Mode TotLen CurLen MaxSize Name
-------------------------------------------------------
1 FIFO SYN 200 3 16 PATQ
......
143 FIFO ASY 10000 8825 16 Q2PK
......
also the Que0 currlen the rate of growth had sustained,that means the CPU usage will come to high.
[NE40E-PUN-1-hidecmd]display umsg queue utask-id 53 slot-id 3
-----------------------------------------------------
QueName MaxLen CurrLen Status
-----------------------------------------------------
Que0 100 13561 UnLock
Que1 100 0 UnLock
[NE40E-PUN-1-hidecmd]display umsg queue utask-id 53 slot-id 3
-----------------------------------------------------
QueName MaxLen CurrLen Status
-----------------------------------------------------
Que0 100 15860 UnLock
Que1 100 0 UnLock
When use the Dot1q termination sub-interface receives a large number of unknown unicast packets, ARP Miss packets are triggered. Each ARP Miss packet causes the system to write a UMSG message to the Utask task. The system schedules UMSG messages to send ARP requests. As the LPU keeps receiving unknown unicast packets, ARP Miss packets are generated frequently. The system processes UMSG messages at a speed lower than the speed at which ARP Miss packets trigger ARP Requests. As a result, memory usage of the LPU increases. After the memory usage exceeds the pre-configured threshold, the LPU is reset.
Suggestion update the new patch. patch name V600R001C00SPC026.