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New Member

Switch back plane utilization ( Packet drop )


we are  facing  packet  drop at  some of the interfaces of a 7609 switch .

Output drop rate is keep  increasing  now .   It is mainly  effecting on the  Cisco  SIP ( SPA  intertface  card instance ) interface


      1)      Will  it  happen  because of the  high utilization  of the back plane ?

2)      How can   we check the  backplane utilization of the switch .

3)      Is there   any other  reason for this issue

Regards ,


Hall of Fame Super Gold

Re: Switch back plane utilization ( Packet drop )

You should contact the TAC and provide all the necessary information.

No supposition or diagnosis can be done with a minimal description like your.

New Member

Re: Switch back plane utilization ( Packet drop )

Hi ,

Thanks for the update.

Can you  please  suggest me how can  i find the  current   utilization  of the Back plane ( Apart from checking each interface  utilization and summing up ) .

I  am just suspecting this is happening like a bottle neck .


  XXXXXXXXX#sh fabric utilization
slot    channel      speed    Ingress %     Egress %
    1          0        20G            1            0
    1          1        20G            0            0
    4          0         8G            0            0
    5          0        20G            0            0
    9          0        20G            0            0

  But i dont think the  ingress and  Egress  is zero . If  you have any other  command set to  check the same please  suggest me

Regards ,


Hall of Fame Super Silver

Re: Switch back plane utilization ( Packet drop )

Hello Sinjish,

at least provide

show module

show ver

some SIP linecards are not serviced by the most efficient switching fabric or they miss a DFC

Hope to help


New Member

Re: Switch back plane utilization ( Packet drop )

Hi  Giuslar ,

Thanks  for your response .

Here  we have created the instances in the  SIP  trunk  as the  below given

service instance 2412 ethernet

  encapsulation dot1q 2412

  rewrite ingress tag pop 1 symmetric

    bridge-domain 2412


service instance 2416 ethernet

  encapsulation dot1q 2416

  rewrite ingress tag pop 1 symmetric

    bridge-domain 2416

We  also found , if we are  increasing the  packet size more than 1000 , the drop rate is increasing very much .

I also  request  you to share  me any  trouble shooting  commands  for the  SPA  ( If any commands  effects the normal switch operation please mention that also )

Please find the  below switch details :

ROM: System Bootstrap, Version 12.2(17r)S2, RELEASE SOFTWARE (fc1)

BOOTLDR: Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVIPSERVICESK9-M), Version 12.2(33)SRD4, RELEASE SOFTWARE (fc2)

XXXXXX uptime is 11 weeks, 4 days, 20 hours, 49 minutes

Uptime for this control processor is 11 weeks, 4 days, 20 hours, 51 minutes

System returned to ROM by s/w reset (SP by power-on)

System restarted at 01:09:07 gmt Mon Jul 5 2010

System image file is "disk1:c7600s72033-advipservicesk9-mz.122-33.srd4.bin"

Last reload type: Normal Reload

isco CISCO7609 (R7000) processor (revision 1.0) with 983008K/65536K bytes of memory.

Processor board ID FOX080703L5

SR71000 CPU at 600Mhz, Implementation 0x504, Rev 1.2, 512KB L2 Cache

Last reset from power-on

1 SIP-400 controller (5 GigabitEthernet).

1 Ethernet interface

57 Virtual Ethernet interfaces

24 Gigabit Ethernet interfaces

2 Ten Gigabit Ethernet interfaces

1917K bytes of non-volatile configuration memory.

8192K bytes of packet buffer memory.

65536K bytes of Flash internal SIMM (Sector size 512K).

Configuration register is 0x2102


  XXXXXXXX#sh module

Mod Ports Card Type                              Model              Serial No.

--- ----- -------------------------------------- ------------------ -----------

  1   16  SFM-capable 16 port 1000mb GBIC        WS-X6516A-GBIC     SAL10478NCY

  5    2  Supervisor Engine 720 (Active)         WS-SUP720-3BXL     SAD08260HT4

  7    0  4-subslot SPA Interface Processor-400  7600-SIP-400       JAE1211B202

  8    2  7600 ES+                               7600-ES+2TG3C      JAE14190XNM

Mod MAC addresses                       Hw    Fw           Sw           Status

--- ---------------------------------- ------ ------------ ------------ -------

  1  001a.6d39.d7a0 to 001a.6d39.d7af   4.5   7.2(1)       8.7(0.22)SRD Ok

  5  0011.21ba.22d8 to 0011.21ba.22db   4.0   8.1(3)       12.2(33)SRD4 Ok

  7  001f.6cd8.d980 to 001f.6cd8.d9ff   2.5   12.2(33)SRD4 12.2(33)SRD4 Ok

  8  5475.d0d1.bc80 to 5475.d0d1.bc8f   1.3   12.2(33r)SRD 12.2(33)SRD4 Ok

Mod  Sub-Module                  Model              Serial       Hw     Status

---- --------------------------- ------------------ ----------- ------- -------

  5  Policy Feature Card 3       WS-F6K-PFC3BXL     SAD082605GR  1.3    Ok

  5  MSFC3 Daughterboard         WS-SUP720          SAD082604YT  2.1    Ok

7/0 5xGE SPA                    SPA-5X1GE-V2       JAE1213CMF9  1.2    Ok

  8  7600 ES+ DFC LITE           7600-ES+3C         JAE14170T8G  1.1    Ok

  8  7600 ES+ 2x10GE XFP         7600-ES+2TG        JAE14190T5I  1.1    Ok

Mod  Online Diag Status

---- -------------------

  1  Pass

  5  Pass

  7  Pass

7/0 Pass

  8  Pass

Regards ,