03-30-2010 07:03 AM - edited 03-04-2019 07:58 AM
Hi,
I have a cisco 2811 with the latest 12.4.25c (I just upgrade to try to solve without success).
With 2 E1.
I monitor via SNMP this router and I have a strange issue, the CPU graph follow the bandwith utilisation of the multilink.
It don't sounds so bad.. but the cpu is reaching 85% when the 2 link are on 90% of utilization.
I try several command like fair queue, ppp multilink interleaving,...
I confirm that the CEF is activate and runnig on the box.
If I do the sh proc cpu, I see the high level of cpu but I didn't any specific process higher than 2% ??? Where is going my % then .. ???
Some end customer begin to complain about packet loss or degradation. It's perhaps due to the congestion sometime of the link, but this high CPU is not good for me.
Any idea ???
1) why the CPU is so high and follow the traffic
2) why I didn't see any process higher than 2% where my total is above 65%
!
controller E1 0/0/1
framing NO-CRC4
channel-group 0 timeslots 1-31
!
controller E1 0/1/0
framing NO-CRC4
channel-group 0 timeslots 1-31
!
interface Multilink1
ip address 10.57.252.138 255.255.255.252
fair-queue
ppp multilink
ppp multilink interleave
ppp multilink group 1
!
!
interface Serial0/0/1:0
no ip address
encapsulation ppp
fair-queue
ppp multilink
ppp multilink group 1
!
interface Serial0/1/0:0
no ip address
encapsulation ppp
fair-queue
ppp multilink
ppp multilink group 1
!
rt3-lon1-uk#sh int multilink 1
Multilink1 is up, line protocol is up
Hardware is multilink group interface
Internet address is 10.57.252.138/30
MTU 1500 bytes, BW 3968 Kbit/sec, DLY 100000 usec,
reliability 255/255, txload 234/255, rxload 182/255
Encapsulation PPP, LCP Open, multilink Open
Listen: CDPCP
Open: IPCP, loopback not set
Keepalive set (10 sec)
DTR is pulsed for 2 seconds on reset
Last input 00:43:59, output never, output hang never
Last clearing of "show interface" counters 00:47:40
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 23886
Queueing strategy: weighted fair
Output queue: 0/1000/64/23874 (size/max total/threshold/drops)
Conversations 0/95/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 2976 kilobits/sec
5 minute input rate 2842000 bits/sec, 2164 packets/sec
5 minute output rate 3645000 bits/sec, 5732 packets/sec
5377753 packets input, 864748837 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
13534973 packets output, 1078282678 bytes, 0 underruns
12 output errors, 0 collisions, 3 interface resets
0 unknown protocol drops
12 output buffer failures, 0 output buffers swapped out
0 carrier transitions
rt3-lon1-uk#
rt3-lon1-uk#sh proc cpu sorted
CPU utilization for five seconds: 60%/57%; one minute: 63%; five minutes: 67%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
144 161504 76765001 2 1.75% 1.76% 1.81% 0 HQF Shaper Backg
147 66416 6627 10022 0.47% 0.19% 0.10% 514 Virtual Exec
179 53288 9661804 5 0.39% 0.39% 0.39% 0 PPP manager
rt3-lon1-uk#sh proc cpu | include PPP
100 0 22 0 0.00% 0.00% 0.00% 0 PPP Hooks
108 64 25 2560 0.00% 0.00% 0.00% 0 PPP IP Route
109 4 26 153 0.00% 0.00% 0.00% 0 PPP IPCP
141 0 2 0 0.00% 0.00% 0.00% 0 PPP Bind
142 0 2 0 0.00% 0.00% 0.00% 0 PPP SSS
179 53292 9663098 5 0.39% 0.39% 0.39% 0 PPP manager
180 55704 9664553 5 0.15% 0.19% 0.21% 0 PPP Events
181 576 309485 1 0.00% 0.00% 0.00% 0 Multilink PPP
rt3-lon1-uk#
03-31-2010 05:29 AM
Hello S.Balon,
>> CPU utilization for five seconds: 60%/57%; one minute: 63%; five minutes: 67%
most of cpu usage is caused by interrupts probably because most of traffic is not processed by CEF but it is sent to cpu
see the following document to further investigate the issue
http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml
I would consider to use the two links as parallel L3 Links this could solve this issue if it is caused by multilink PPP
Hope to help
Giuseppe
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