Solved: Cisco 1841 Router throughput issue

vvujicevic · ‎12-17-2014

Hello,

We have a Cisco 1841 Router at the edge of our company, we recently upgraded our WAN link from 6 Mbit/s to 15 Mbit/s leased line, the problem i have is that i only get arround 9-10 Mbit/s on the LAN side. When i connect directly to provider's media converter i get full 15. All the info i could get on the internet about this router's throughput says it should have 38. I have removed everything from the interface (VPN, ACL's) exept NAT offcourse, and it has some improvement, it gets up to 11-11,5...

Is that all this Router can do? If it is what model should we upgrade to?

Thank you

Aaron Harrison · ‎12-17-2014

I would replicate the throughput problem and see what the CPU usage is during the period where the throughput it maxed out... it's not clear whether the output you posted is during congestion or otherwise?

At any rate, if IP Input is the highest CPU culprit, see : http://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/41160-highcpu-ip-input.html

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

View solution in original post

kellylevine · ‎12-18-2014

I had a lot of issues with this 1841 router though put speed I was natting a cable modem into our network which had a speed of 60 meg download speeds I was only getting 7-10meg with the statement in there. Turned out to be a command on my interfaces " no ip route-cache cef". I'm not sure if it is a default config have no idea how it got in there. Now my config just has IP CEF nothing on the interfaces.

https://learningnetwork.cisco.com/thread/21603

ip dhcp pool CLIENT
import all
network 10.10.10.0 255.25
default-router 10.10
dns-server 68.105
!
!
ip cef
ip name-server 68.1
ip name-server 68.
ip name-server 68.
no ipv6 cef

View solution in original post

Aaron Harrison · ‎12-17-2014

Hi

What's your processor utilization currently? Show proc cpu?

Have you verified your interfaces are clear of errors?

It's possible that it's underspecced, even just NAT might take a good chunk out of the 38Mb max throughput...

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

vvujicevic · ‎12-17-2014

Interfaces dont have a relevant error numbers, 1077547231 packets input, 1081247 errors, 822 CRC before clearing counters for the first time. I think it should be >1% to consider faulty interface, and i have changed the cable already.

After i took off VPN and ACL's it had arround 5% cpu utilization and no improvement on WAN speed.

Aaron Harrison · ‎12-17-2014

Hi

So your CPU is pretty low which suggests the router isn't struggling, does it peak when you are running throughput tests?

Perhaps you have a duplex misconfig generating those errors, that would negatively affect throughput. What's your interface config?

Maybe post up your whole config for review.

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

vvujicevic · ‎12-17-2014

duplex and speed are both auto. Sh interface shows them at full duplex - 100 Mbps.

interface FastEthernet0/0

description LAN

ip address 10.5.0.1 255.255.255.0

ip nat inside

ip virtual-reassembly in

ip tcp adjust-mss 1360

duplex auto

speed auto

interface FastEthernet0/1

description LL-WAN

ip address xxxx

ip nat outside

ip virtual-reassembly in

no ip route-cache

duplex auto

speed auto

crypto map kriptomap

Unfortunately i cant post full config. :S

This is current cpu util:

Eherc-Mo#sh processes cpu sorted
CPU utilization for five seconds: 16%/4%; one minute: 8%; five minutes: 13%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
119 1561265576 631764673 2471 9.59% 4.03% 7.81% 0 IP Input
253 123362540 158292107 779 0.55% 0.47% 0.58% 0 Crypto PAS Proc
95 5735268 885622940 6 0.55% 0.55% 0.56% 0 Ethernet Msec Ti
130 84 56 1500 0.47% 0.06% 0.01% 194 Virtual Exec
182 3049444 236333478 12 0.15% 0.18% 0.16% 0 PPP manager
115 1687576 230576124 7 0.15% 0.13% 0.15% 0 IPAM Manager
319 1990308 236333478 8 0.15% 0.11% 0.13% 0 PPP Events
47 1009768 1724342 585 0.15% 0.01% 0.00% 0 Net Background
263 295544 38067157 7 0.07% 0.01% 0.00% 0 Atheros LED Ctro
138 262880 29740004 8 0.07% 0.01% 0.00% 0 SSS Feature Time
29 2618040 7856037 333 0.07% 0.05% 0.04% 0 ARP Input
239 1727164 236974957 7 0.07% 0.09% 0.08% 0 MMON MENG
64 271144 7622694 35 0.07% 0.02% 0.00% 0 Per-Second Jobs
14 0 1 0 0.00% 0.00% 0.00% 0 IPC Session Serv
13 1464 126887 11 0.00% 0.00% 0.00% 0 IPC Dynamic Cach
16 59052 7424407 7 0.00% 0.00% 0.00% 0 IPC Periodic Tim
12 13388 1522214 8 0.00% 0.00% 0.00% 0 IPC Event Notifi
15 0 1 0 0.00% 0.00% 0.00% 0 IPC Zone Manager
11 0 1 0 0.00% 0.00% 0.00% 0 OIR Handler
20 3232 435019 7 0.00% 0.00% 0.00% 0 IPC Check Queue
21 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat RX Cont
22 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat TX Cont
17 54036 7424412 7 0.00% 0.00% 0.00% 0 IPC Deferred Por
18 0 1 0 0.00% 0.00% 0.00% 0 IPC Process leve
10 0 1 0 0.00% 0.00% 0.00% 0 License Client N
26 0 1 0 0.00% 0.00% 0.00% 0 Crash writer
27 0 1 0 0.00% 0.00% 0.00% 0 Exception contro
19 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat Manager
23 5808 761348 7 0.00% 0.00% 0.00% 0 IPC Keep Alive M
30 103320 7932300 13 0.00% 0.00% 0.00% 0 ARP Background
31 0 2 0 0.00% 0.00% 0.00% 0 ATM Idle Timer
32 0 1 0 0.00% 0.00% 0.00% 0 ATM ASYNC PROC
33 0 1 0 0.00% 0.00% 0.00% 0 CEF MIB API
34 0 1 0 0.00% 0.00% 0.00% 0 AAA_SERVER_DEADT
35 0 1 0 0.00% 0.00% 0.00% 0 Policy Manager
36 0 2 0 0.00% 0.00% 0.00% 0 DDR Timers
24 21908 1522316 14 0.00% 0.00% 0.00% 0 IPC Loadometer
25 2944 253762 11 0.00% 0.00% 0.00% 0 Environmental mo
39 0 2 0 0.00% 0.00% 0.00% 0 Serial Backgroun
40 0 1 0 0.00% 0.00% 0.00% 0 RMI RM Notify Wa

Aaron Harrison · ‎12-17-2014

I would replicate the throughput problem and see what the CPU usage is during the period where the throughput it maxed out... it's not clear whether the output you posted is during congestion or otherwise?

At any rate, if IP Input is the highest CPU culprit, see : http://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/41160-highcpu-ip-input.html

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

vvujicevic · ‎12-17-2014

its production time now, so its never higher than ATM. here is 1 min ago:

sh proc cpu hist

02:15:08 PM Wednesday Dec 17 2014 UTC

2222444448888844444444446666644444111113333344444 666662
111155555000005555500000999997777722222666669999988888222224
100
90
80 *****
70 ***** *****
60 ***** ***** *****
50 *************** ********** ***** *****
40 ****************************** ********** *****
30 ****************************** ********** *****
20 ********************************** ********** ******
10 ************************************************************
0....5....1....1....2....2....3....3....4....4....5....5....6
0 5 0 5 0 5 0 5 0 5 0
CPU% per second (last 60 seconds)

6663249543 1113494449425515374311222332234563597932211226752
246061211392306011186303378354478666270036336650777786186801
100 * * *
90 * * * * *
80 * * * * * * *
70 * * * * * *** **
60 *** # * * * * * **** **
50 *** #* * ** ** * * *** **** ***
40 *** *#** ******#* ** * ** * ********* *#*
30 ###***#*** **#***#* #* ***** ***** ******#***** *##*
20 ###***#*** ########*#****###**#####***###*#####******###*
10 ############################################################
0....5....1....1....2....2....3....3....4....4....5....5....6
0 5 0 5 0 5 0 5 0 5 0
CPU% per minute (last 60 minutes)
* = maximum CPU% # = average CPU%

999988993439234887796899997999993389332372294899899999999889989986232888
797976502651529997984699879587969504486789193699996969898439549930512666
100 **** * * **** ***** * ** ******** ** **
90 ******** * ** * ***** ***** * * ************ ** ** ***
80 ******** * ***** *********** ** * * *****************#** ***
70 ******** * *#*** *********** ** * * **********#########* ***
60 ******** * *#*************** ** * * **********#########** ***
50 ******** * * *##*************** ** * * *********##########** ***
40 ******** *** *##******************* * ** ***********###########* ***
30 **#************###****#******************* ***#***#**############*** ***
20 ####*##********###****####*####*********#*****###################*******
10 ########***#***#########################################################
0....5....1....1....2....2....3....3....4....4....5....5....6....6....7..
0 5 0 5 0 5 0 5 0 5 0 5 0
CPU% per hour (last 72 hours)
* = maximum CPU% # = average CPU%

sh proc cpu sor
CPU utilization for five seconds: 24%/6%; one minute: 35%; five minutes: 26%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
119 1561396868 631813753 2471 14.93% 22.94% 16.51% 0 IP Input
253 123371280 158306059 779 1.11% 1.19% 0.99% 0 Crypto PAS Proc
5 13480684 1299964 10370 1.03% 0.20% 0.17% 0 Check heaps
95 5735652 885695035 6 0.47% 0.54% 0.55% 0 Ethernet Msec Ti
182 3049712 236352887 12 0.23% 0.20% 0.18% 0 PPP manager
319 1990472 236352887 8 0.15% 0.12% 0.13% 0 PPP Events
314 1017728 14994008 67 0.07% 0.03% 0.02% 0 IP NAT Ager
239 1727292 236994484 7 0.07% 0.08% 0.07% 0 MMON MENG
29 2618360 7856983 333 0.07% 0.04% 0.05% 0 ARP Input
130 1024 197 5197 0.07% 0.20% 0.16% 194 Virtual Exec
115 1687708 230595170 7 0.07% 0.14% 0.15% 0 IPAM Manager
11 0 1 0 0.00% 0.00% 0.00% 0 OIR Handler
10 0 1 0 0.00% 0.00% 0.00% 0 License Client N
12 13388 1522341 8 0.00% 0.00% 0.00% 0 IPC Event Notifi
13 1464 126897 11 0.00% 0.00% 0.00% 0 IPC Dynamic Cach
16 59060 7425026 7 0.00% 0.00% 0.00% 0 IPC Periodic Tim
14 0 1 0 0.00% 0.00% 0.00% 0 IPC Session Serv
9 0 78 0 0.00% 0.00% 0.00% 0 WATCH_AFS
19 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat Manager
20 3232 435055 7 0.00% 0.00% 0.00% 0 IPC Check Queue
8 0 2 0 0.00% 0.00% 0.00% 0 Timers
15 0 1 0 0.00% 0.00% 0.00% 0 IPC Zone Manager
17 54048 7425031 7 0.00% 0.00% 0.00% 0 IPC Deferred Por
24 21908 1522443 14 0.00% 0.00% 0.00% 0 IPC Loadometer
25 2944 253783 11 0.00% 0.00% 0.00% 0 Environmental mo
18 0 1 0 0.00% 0.00% 0.00% 0 IPC Process leve
27 0 1 0 0.00% 0.00% 0.00% 0 Exception contro
28 22088 319294 69 0.00% 0.00% 0.00% 0 CRYPTO IKMP IPC
21 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat RX Cont
30 103324 7932961 13 0.00% 0.00% 0.00% 0 ARP Background
31 0 2 0 0.00% 0.00% 0.00% 0 ATM Idle Timer
32 0 1 0 0.00% 0.00% 0.00% 0 ATM ASYNC PROC
33 0 1 0 0.00% 0.00% 0.00% 0 CEF MIB API
22 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat TX Cont
35 0 1 0 0.00% 0.00% 0.00% 0 Policy Manager
36 0 2 0 0.00% 0.00% 0.00% 0 DDR Timers
23 5808 761412 7 0.00% 0.00% 0.00% 0 IPC Keep Alive M
26 0 1 0 0.00% 0.00% 0.00% 0 Crash writer
39 0 2 0 0.00% 0.00% 0.00% 0 Serial Backgroun
40 0 1 0 0.00% 0.00% 0.00% 0 RMI RM Notify Wa
41 0 2 0 0.00% 0.00% 0.00% 0 SMART
42 65016 7614055 8 0.00% 0.00% 0.00% 0 GraphIt
43 0 2 0 0.00% 0.00% 0.00% 0 Dialer event
44 0 1 0 0.00% 0.00% 0.00% 0 SERIAL A'detect
34 0 1 0 0.00% 0.00% 0.00% 0 AAA_SERVER_D

Aaron Harrison · ‎12-17-2014

Hi

So usage is peaking regularly - I'd verify the IP INput related stuff in the doc I posted earlier. You can try to reduce the utilisation by looking at the steps there... perhaps even doing a pcap on the inside and outside interfaces do see if there are lots of broadcasts or other types of traffic that might bump it up.

Otherwise you could look at a higher spec router.

The info is all in that doc..

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

vvujicevic · ‎12-23-2014

Turns out CEF was disabled for some reason... Im blind for not seeing it in first place. Thanks for your help

kellylevine · ‎12-23-2014

Glad I could help I was about to remove that router an blame it on slow CPU sure works good now.

kellylevine · ‎12-18-2014

I had a lot of issues with this 1841 router though put speed I was natting a cable modem into our network which had a speed of 60 meg download speeds I was only getting 7-10meg with the statement in there. Turned out to be a command on my interfaces " no ip route-cache cef". I'm not sure if it is a default config have no idea how it got in there. Now my config just has IP CEF nothing on the interfaces.

https://learningnetwork.cisco.com/thread/21603

ip dhcp pool CLIENT
import all
network 10.10.10.0 255.25
default-router 10.10
dns-server 68.105
!
!
ip cef
ip name-server 68.1
ip name-server 68.
ip name-server 68.
no ipv6 cef