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2811 vs 2911 CPU

Hello,

We are thinking of replacing our router 2811 with a newer model 2911 dude to high CPU utilizaiton. Can anyone please give us a comparison of the CPU of the routers if applicable? I mean if a 2811 with CPU going up to 80% would it be wize to be replaced with a 2911?

Regards,

Nick

TIA, Nicos Nicolaides
11 Replies 11

Reza Sharifi
Hall of Fame
Hall of Fame

Nick,

Whether you use 2800 series or 2900, 80% utilization is usually high, unless you are connected to the Internet and carry full routing table with limited memory.  Do you have large BGP routing table? what does "sh cpu pros" shows?

HTH

Joseph W. Doherty
Hall of Fame
Hall of Fame

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

2811 is rated by Cisco at 120 Kpps, the 2911 at 352 Kpps.  So it's possible, but not guaranteed, that the newer 2911 will decrease your CPU usage by the same ratio, i.e. from 80% to about 27%.

smogra
Cisco Employee
Cisco Employee

80% cpu is always bad whether it is 2811 or 2911. Before moving to 2911, try checking on 2811 what is the reason which is causing the high cpu and if you can lower it down. May be you are deploying complete routing and that the reason cpu is raising.

Sweta

Hi Nick,

could you please post this command out put

show proc cpu | excl 0.00%__0.00%__0.00%

LOGBG#sh proc c h

LOGBG   08:45:55 AM Monday Sep 12 2011 EEST

    666666666655555888886666666666666666666655555555555555544444

    444441111155555111117777777777999999999955555222228888888888

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)

    575666657557855444433532325534232232233356223211321111111111

    879570011944552304574293568858454219753553610416482062764519

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%

    672274435367443763347882222443224343445844447342313665343334888998898997

    325622124252824962854758444096785298131064186890564918839241544552769367

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%

LOGBG#

LOGBG#show proc cpu | excl 0.00%__0.00%__0.00%

CPU utilization for five seconds: 62%/56%; one minute: 58%; five minutes: 50%

PID Runtime(ms)     Invoked      uSecs   5Sec   1Min   5Min TTY Process

   2      272828      293557        929  0.07%  0.11%  0.08%   0 Load Meter      

   3        1008         237       4253  0.00%  0.48%  0.12% 514 SSH Process     

   4     3645068      222629      16372  0.00%  0.17%  0.16%   0 Check heaps     

  32       38284     1467725         26  0.07%  0.00%  0.00%   0 GraphIt         

  37      106084      615653        172  0.07%  0.01%  0.00%   0 Net Background  

  41     3294548     1467831       2244  0.31%  0.30%  0.28%   0 Per-Second Jobs 

  51      668700       24732      27037  0.00%  0.03%  0.00%   0 Per-minute Jobs 

  55       30864      440026         70  0.07%  0.00%  0.00%   0 HC Counter Timer

  64      164144     5867890         27  0.07%  0.02%  0.00%   0 Netclock Backgro

105    65222224    51633232       1263  3.19%  3.96%  3.48%   0 IP Input        

114      123500     1466986         84  0.07%  0.01%  0.00%   0 Spanning Tree   

129      146028     2273125         64  0.00%  0.02%  0.00%   0 CEF: IPv4 proces

149       66800     2862115         23  0.07%  0.01%  0.00%   0 Inspect process 

152       64936     2862101         22  0.07%  0.00%  0.00%   0 CCE DP URLF cach

160     7925468   352843182         22  1.91%  2.13%  2.10%   0 HQF Shaper Backg

180       19776        9640       2051  0.00%  0.03%  0.00%   0 TPLUS           

206      190112     7333659         25  0.00%  0.03%  0.01%   0 Atheros LED Ctro

244     1691236     2888208        585  0.15%  0.18%  0.17%   0 IP NAT Ager     

246      149624     2186849         68  0.07%  0.01%  0.00%   0 IP VFR proc     

248      996848     1137371        876  0.00%  0.04%  0.04%   0 IP SNMP         

249      254144      565129        449  0.00%  0.01%  0.00%   0 PDU DISPATCHER  

250      870884      565199       1540  0.00%  0.03%  0.02%   0 SNMP ENGINE     

254     2219252     7973160        278  0.15%  0.15%  0.14%   0 NAT MIB Helper 

LOGBG#

Here it is. Note that we started work 45 minutes ago.

TIA, Nicos Nicolaides

What is the IOS version?

What is your WAN speed?

LOGBG#sh ver

Cisco IOS Software, 2800 Software (C2800NM-ADVSECURITYK9-M), Version 12.4(24)T3, RELEASE SOFTWARE (fc2)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2010 by Cisco Systems, Inc.

Compiled Tue 23-Mar-10 06:43 by prod_rel_team

ROM: System Bootstrap, Version 12.4(1r) [hqluong 1r], RELEASE SOFTWARE (fc1)

LOGBG uptime is 2 weeks, 2 days, 23 hours, 55 minutes

System returned to ROM by power-on

System restarted at 09:01:46 EEST Fri Aug 26 2011

System image file is "flash:c2800nm-advsecurityk9-mz.124-24.T3.bin"

This product contains cryptographic features and is subject to United

States and local country laws governing import, export, transfer and

use. Delivery of Cisco cryptographic products does not imply

third-party authority to import, export, distribute or use encryption.

Importers, exporters, distributors and users are responsible for

compliance with U.S. and local country laws. By using this product you

agree to comply with applicable laws and regulations. If you are unable

to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:

http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to

export@cisco.com.

Cisco 2811 (revision 53.51) with 247808K/14336K bytes of memory.

Processor board ID FCZ101470JQ

7 FastEthernet interfaces

1 Serial(sync/async) interface

1 Virtual Private Network (VPN) Module

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2102

LOGBG#

Find attached the sh tech-support file.

Note that there are 2 internet lines: One ADSL of 12 Mb/s down and 1Mb/s up (f0/1) and one metro internet line with 4Mb/s down and 20Mb/s up f(0/0).

TIA, Nicos Nicolaides

Disclaimer

The    Author of this posting offers the information contained within this    posting without consideration and with the reader's understanding that    there's no implied or expressed suitability or fitness for any  purpose.   Information provided is for informational purposes only and  should not   be construed as rendering professional advice of any kind.  Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In    no event shall Author be liable for any damages whatsoever  (including,   without limitation, damages for loss of use, data or  profit) arising  out  of the use or inability to use the posting's  information even if  Author  has been advised of the possibility of such  damage.

Posting

From your additional postings, it appears router may be just loaded pushing traffic.  If your WAN interfaces tend to load up, i.e. the 12, 4 and 20 Mbps, that would be enough to account for your high CPU load.

Your process CPU loading is a bit higher than it ideally should be, but not enough that it should be a major issue.

I notice this 2811 also has 7 FastEthernet interfaces.  Does it do any LAN-to-LAN routing in addition to WAN routing?

If I recall correctly, Cisco recommends at 2811 for only a couple of T1 lines.  From my experience, it will top out at 100% at about 20 Mbps duplex.

The switch card is used only for monitor session; no inter VLAN routing is performed. So there is a throughput issue here; Can you verify that a 2911 will be a future-proof solution for our scenario?

TIA, Nicos Nicolaides

Disclaimer

The     Author of this posting offers the information contained within this     posting without consideration and with the reader's understanding  that    there's no implied or expressed suitability or fitness for any   purpose.   Information provided is for informational purposes only and   should not   be construed as rendering professional advice of any kind.   Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In     no event shall Author be liable for any damages whatsoever   (including,   without limitation, damages for loss of use, data or   profit) arising  out  of the use or inability to use the posting's   information even if  Author  has been advised of the possibility of  such  damage.

Posting

Not knowing what you might want to do in the future, cannot guarantee a 2911 will be "future proof".  However, Cisco recommends a 2911 for up to 35 Mbps WAN bandwidth and their recommendations tend to be rather conservative.  Assuming you don't expect to have more than that, you're likely "future proof".

PS:

Since one of your links is ADSL, wondering if its PPPoE, and if so, if MTU is less than 1500 whether you've configured to allow for that.  If not, might account for your IP Input being a higher than necessary.

Hi,

the CPU seems to be overloaded due to interrupts.

See

http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml

for issues to check.

HTH,

Milan

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