09-24-2012 06:36 AM - edited 03-04-2019 05:39 PM
I have a particular site that is causing me trouble, this site is connected in a back to back configuration using 2811 at CO and 2621XM at CPE. The CO end is also the CO for 3 other sites so has a total of 4 wics installed (WIC-1SHDSL-v2), these other sites also have 2621XMs for the CPE.
The problem i am getting is when one site in particular transfers large files to/from client machines, the CPU on the 2811 jumps to 99%:
CPU utilization for five seconds: 99%/98%; one minute: 26%;
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
11 12881868 37249378 345 0.49% 0.50% 0.51% 0 ARP Input
54 8548592 30375358 281 0.40% 0.45% 0.41% 0 XDSL BACKGROUND
78 4947460 15276755 323 0.16% 0.15% 0.16% 0 IP Input
77 31240 104868206 0 0.16% 0.15% 0.11% 0 IP ARP Retry Age
72 36984 104868210 0 0.08% 0.09% 0.13% 0 ACCT Periodic Pr
As a result the latency for all 4 sites shoots through the roof and also dropping packets. The same CPU utilisation is not shown at the CPE end, the CPU useage is still low.
Here is the config from the 2811 showing the problem:
controller DSL 0/3/0
mode atm
line-term co
line-mode 2-wire line-zero
dsl-mode shdsl symmetric annex B
line-rate auto
interface ATM0/3/0
bandwidth 2196
no ip address
no ip route-cache cef
no ip route-cache
no atm ilmi-keepalive
!
interface ATM0/3/0.1 point-to-point
bandwidth 2196
ip address 172.25.200.241 255.255.255.252
no ip route-cache
no ip mroute-cache
cdp enable
pvc 0/32
vbr-nrt 2188 2188 1
no broadcast
encapsulation aal5snap
service-policy output Torbay_VOIP
The DSL is configured to auto negotiate and is running at 2312Kbps:
DSL 0/3/0 controller UP
Globespan xDSL controller chipset
Line Mode: Two Wire
DSL mode: Trained with SHDSL Annex B
Frame mode: Utopia
Configured Line rate: Auto
Line Re-activated 26 times after system bootup
LOSW Defect alarm: ACTIVE
CRC per second alarm: ACTIVE
Line termination: CO
FPGA Revision: 0xB3
Current 15 min counters
CRC : 0 LOSW Defect : 0 ES : 0 SES : 0 UAS : 0
Previous 15 min counters
CRC : 0 LOSW Defect : 0 ES : 0 SES : 0 UAS : 0
Current 24 hr counters
CRC : 11 LOSW Defect : 8 ES : 2 SES : 0 UAS : 91
Previous 24 hr counters
CRC : 0 LOSW Defect : 0 ES : 0 SES : 0 UAS : 0
Line-0 status
Chipset Version: 0
Firmware Version: R4.2.1
Modem Status: Data, Status 1
Last Fail Mode: No Failure status:0x0
Line rate: 2312 Kbps
Framer Sync Status: In Sync
Rcv Clock Status: In the Range
Loop Attenuation: 12.5 dB
Transmit Power: 14.5 dB
Receiver Gain: 28.5420 dB
SNR Sampling: 36.3590 dB
Receive HEC Error Count: 0
Dying Gasp: Present
Any ideas how i can track down what is causing such high useage?
Regards
Jeff
Solved! Go to Solution.
09-24-2012 06:47 AM
Hi,
You are seeing high CPU due to interrupts. Basically your CPU is being interrupted by the interface drivers and is asked to do the job of packet switching and this is being done frequently due to high rate of traffic.
Do you see this high CPU usage only with huge file transfers?
You are seeing high cpu due to interrupts.
http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml#cd
To start with can you turn on CEF on all the interfaces. I see CEF turned off on the WAN interface
interface ATM0/3/0.1 point-to-point
bandwidth 2196
ip address 172.25.200.241 255.255.255.252
no ip route-cache >>>>>>>>
no ip mroute-cache >>>>>>>>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_tech_note09186a00801e1e46.shtml
Check if CPU reduces. If not, please provide the following info.
- CPU model
- 'show interface summ' when CPU is high
- 'sh run' if possible else 'show ip int'
Thanks.
09-24-2012 06:47 AM
Hi,
You are seeing high CPU due to interrupts. Basically your CPU is being interrupted by the interface drivers and is asked to do the job of packet switching and this is being done frequently due to high rate of traffic.
Do you see this high CPU usage only with huge file transfers?
You are seeing high cpu due to interrupts.
http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml#cd
To start with can you turn on CEF on all the interfaces. I see CEF turned off on the WAN interface
interface ATM0/3/0.1 point-to-point
bandwidth 2196
ip address 172.25.200.241 255.255.255.252
no ip route-cache >>>>>>>>
no ip mroute-cache >>>>>>>>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_tech_note09186a00801e1e46.shtml
Check if CPU reduces. If not, please provide the following info.
- CPU model
- 'show interface summ' when CPU is high
- 'sh run' if possible else 'show ip int'
Thanks.
09-25-2012 02:03 AM
Thanks for that, turning on CEF on the WAN interface dropped the CPU right back down again when transferring large files.
Regards
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