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Cisco 1841: High CPU utilization when Skype-call over VPN

Anton Pestov
Level 1
Level 1

Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 15.1(4)M2, RELEASE SOFTWARE (fc1)

When the client on a Branch Office LAN realizes calls to skype, there is a sharp loading of CPU on Branch router Cisco1841 (all Inet traffic goes through DMVPN-Tunnel Interface to proxy on Central Office).

CPU utilization for five seconds: 89%/81%; one minute: 44%; five minutes: 41%

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

121    30971272    10952019       2827  6.65%  5.59%  5.75%   0 IP Input

   2      125984      229295        549  1.28%  0.12%  0.10%   0 Load Meter

  96     1774568   141763543         12  0.64%  0.75%  0.78%   0 Ethernet Msec Ti

117      515872    35077439         14  0.56%  0.17%  0.16%   0 IPAM Manager

336     2617980   276339056          9  0.48%  1.70%  1.79%   0 IP SLAs Responde

203      929984   275753650          3  0.24%  0.79%  0.86%   0 HQF Shaper Backg

330      796120    55876200         14  0.16%  0.26%  0.28%   0 MFIB_mrib_write

314      414120    11711507         35  0.08%  0.12%  0.10%   0 IGMP Input

315      966264    25445473         37  0.08%  0.21%  0.23%   0 PIM Process

240      278164    35693249          7  0.08%  0.09%  0.08%   0 MMON MENG

TLLN-CE1#sh ip flow top-talkers

SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP Bytes

Tu253         10.101.0.20     Vl1           10.108.1.32     06 1F90 C709  6974K

Tu253         10.101.0.20     Vl1           10.108.1.32     06 1F90 C72E  3289K

Vl1           10.108.1.32     Tu254*        10.101.0.20     06 C709 1F90  1568K

Tu254         10.100.0.14     Vl1           10.108.1.34     06 0D3D 0408  1311K

Tu253         10.101.1.233    Vl1           10.108.1.37     06 0D3D 040A   541K

5 of 5 top talkers shown. 44 flows processed.

FastEthernet 0/0 - WAN Interface (for Tunnel Source):

TLLN-CE1#sh int f0/0

FastEthernet0/0 is up, line protocol is up

  Hardware is Gt96k FE, address is 58bc.2771.5f8e (bia 58bc.2771.5f8e)

  Description: WAN

  Internet address is x.x.x.x/y

  MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

     reliability 254/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/s, 100BaseTX/FX

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:13, output 00:00:00, output hang never

  Last clearing of "show interface" counters 04:12:34

  Input queue: 43/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: Class-based queueing

  Output queue: 0/1000/0 (size/max total/drops)

  30 second input rate 1909000 bits/sec, 244 packets/sec

  30 second output rate 356000 bits/sec, 30 packets/sec

     1875022 packets input, 808226627 bytes

     Received 535 broadcasts (0 IP multicasts)

     0 runts, 0 giants, 0 throttles

     6431 input errors, 0 CRC, 0 frame, 0 overrun, 6431 ignored

     0 watchdog

     0 input packets with dribble condition detected

     763186 packets output, 200182523 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 unknown protocol drops

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier

     0 output buffer failures, 0 output buffers swapped out

All Skype traffic application auto mark as DSCP EF, and then router applies the next outbound policy on WAN Fast0/0:

class-map match-any CLASS-VOICE

match ip dscp ef

!

...

!

policy-map POLICY-QOS-OUT

description *** Global QoS Policy ***

class CLASS-ROUTING

  bandwidth percent 3

class CLASS-VOICE

  priority percent 18

class CLASS-VIDEO-CONF

  priority percent 15

class CLASS-STREAM-VIDEO

  bandwidth percent 10

class CLASS-MISSION-CRIT

  bandwidth percent 12

  random-detect dscp-based

  random-detect dscp 25 32 40

class CLASS-VOICE-CONTROL

  bandwidth percent 2

class CLASS-TRANSACT

  bandwidth percent 8

  random-detect dscp-based

  random-detect dscp 25 32 40

class CLASS-NETWORK-MGMT

  bandwidth percent 2

class CLASS-BULK

  bandwidth percent 8

  random-detect dscp-based

  random-detect ecn

  random-detect dscp 25 32 40

class CLASS-SCAVENGER

  bandwidth percent 10

class class-default

  fair-queue

  random-detect dscp-based

  random-detect dscp 25 32 40

!

policy-map POLICY-INET-10M-OUT

class class-default

  shape average 8500000 850000

  service-policy POLICY-QOS-OUT

!

interface FastEthernet0/0

description WAN

ip address x.x.x.x y.y.y.y

no ip redirects

no ip unreachables

no ip proxy-arp

ip nat outside

ip virtual-reassembly in

ip verify unicast reverse-path allow-self-ping 150

load-interval 30

duplex auto

speed auto

service-policy output POLICY-INET-10M-OUT

!

TLLN-CE1#sh ip traffic

IP statistics:

  Rcvd:  102808 total, 3682 local destination

         0 format errors, 0 checksum errors, 252 bad hop count

         0 unknown protocol, 0 not a gateway

         0 security failures, 0 bad options, 1337 with options

  Opts:  0 end, 0 nop, 0 basic security, 0 loose source route

         0 timestamp, 0 extended security, 0 record route

         0 stream ID, 0 strict source route, 1337 alert, 0 cipso, 0 ump

         0 other

  Frags: 0 reassembled, 0 timeouts, 0 couldn't reassemble

         90 fragmented, 180 fragments, 0 couldn't fragment

  Bcast: 65 received, 1 sent

  Mcast: 1476 received, 797 sent

  Sent:  100833 generated, 451516 forwarded

  Drop:  0 encapsulation failed, 0 unresolved, 0 no adjacency

         0 no route, 0 unicast RPF, 0 forced drop

         0 options denied

  Drop:  0 packets with source IP address zero

  Drop:  0 packets with internal loop back IP address

         0 physical broadcast

  Reinj: 0 in input feature path, 0 in output feature path

ICMP statistics:

  Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 190 unreachable

        0 echo, 0 echo reply, 0 mask requests, 0 mask replies, 0 quench

        0 parameter, 0 timestamp, 0 timestamp replies, 0 info request, 0 other

        0 irdp solicitations, 0 irdp advertisements

        0 time exceeded, 0 info replies

  Sent: 0 redirects, 0 unreachable, 0 echo, 0 echo reply

        0 mask requests, 0 mask replies, 0 quench, 0 timestamp, 0 timestamp replies

        0 info reply, 0 time exceeded, 0 parameter problem

        0 irdp solicitations, 0 irdp advertisements

TCP statistics:

  Rcvd: 1018 total, 0 checksum errors, 0 no port

  Sent: 1067 total

BGP statistics:

  Rcvd: 0 total, 0 opens, 0 notifications, 0 updates

        0 keepalives, 0 route-refresh, 0 unrecognized

  Sent: 0 total, 0 opens, 0 notifications, 0 updates

        0 keepalives, 0 route-refresh

EIGRP-IPv4 statistics:

  Rcvd: 0 total

  Sent: 0 total

PIMv2 statistics: Sent/Received

  Total: 336/685, 0 checksum errors, 0 format errors

  Registers: 0/0 (0 non-rp, 0 non-sm-group), Register Stops: 0/0,  Hellos: 183/181

  Join/Prunes: 105/352, Asserts: 1/105, grafts: 47/0

  Bootstraps: 0/0, Candidate_RP_Advertisements: 0/0

  Queue drops: 0

  State-Refresh: 0/0

IGMP statistics: Sent/Received

  Total: 299/713, Format errors: 0/0, Checksum errors: 0/0

  Host Queries: 90/30, Host Reports: 209/358, Host Leaves: 0/0

  DVMRP: 0/0, PIM: 0/0

  Queue drops: 0

UDP statistics:

  Rcvd: 907 total, 0 checksum errors, 41 no port

  Sent: 974 total, 0 forwarded broadcasts

OSPF statistics:

  Last clearing of OSPF traffic counters 00:29:47

  Rcvd: 169 total, 0 checksum errors

        125 hello, 0 database desc, 0 link state req

        31 link state updates, 13 link state acks

  Sent: 154 total

        125 hello, 0 database desc, 0 link state req

        17 link state updates, 12 link state acks

ARP statistics:

  Rcvd: 367 requests, 0 replies, 0 reverse, 0 other

  Sent: 0 requests, 239 replies (0 proxy), 0 reverse

  Drop due to input queue full: 0

What can cause sharp loading of CPU? ...throughput performance 1841, it seems, allows to process traffic

1 Accepted Solution

Accepted Solutions

paolo bevilacqua
Hall of Fame
Hall of Fame

You have some configuration complexity, try simplifying.

View solution in original post

3 Replies 3

paolo bevilacqua
Hall of Fame
Hall of Fame

You have some configuration complexity, try simplifying.

Configuration optimum. When I apply shaping policy for Branch-client on CO-router (shape average 500k), then  loading of Branch-router 1841 CPU became less...

Skype-client connect to virtual NLB IP Proxy (from two FTMG in cluster), if Skype-client connect to phisycal IP one of two FTMG-proxy, that problems with loading of CPU aren't present!

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