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vinish milton

Bandwidth high


I have ws-c3750x-48 switch. 34 serves connected to this switch. Up link(10mbps) will connected to Port no 48. Last some days I have face some problem in Port no 48. Every day 4 pm to 6:30pm bandwidth is very high (Graph attached). I would like to know how can I find out who utilize this much bandwidth or which application running? How can I decrees bandwidth?


Latchum Naidu


To know which source is using the more bandwidth you need to have either 1. NetFlow analyzer tool OR 2. enable IP accounting on the switch.
To limit the bandwidth usage you can use bandwidth limit commands on the particular interface.

Please rate the helpfull posts.



Thanks for the quick response, can you guide me how can i configure IP accounting on the swithch ?


Is there any possible to configure IP accounting or Net flow on below model switch.

Switch Ports Model              SW Version            SW Image

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

*    1 54    WS-C3750X-48       12.2(55)SE3           C3750E-UNIVERSALK9-M

Switch#sh license

Index 1 Feature: ipservices

        Period left: 8  weeks 3  days

        License Type: Evaluation

        License State: Active, Not in Use, EULA accepted

        License Priority: Low

        License Count: Non-Counted

Index 2 Feature: ipbase

        Period left: Life time

        License Type: Permanent

        License State: Active, In Use

        License Priority: Medium

        License Count: Non-Counted

Index 3 Feature: lanbase

        Period left: Life time

        License Type: Permanent

        License State: Active, Not in Use

        License Priority: Medium

        License Count: Non-Counted

Leo Laohoo
VIP Community Legend

My question for you is what is this client connected to port 48.  It's obvious that it's got to be some kind of file server or a mail server.

At the end of the business day, people start saving files and/or sending out emails.


If the port 48 is configured as a routed port enable ip cache flow at the other end of the switch and check the output of show ip cache flow . You can see the source and destination ip addres details with the utilization

Hi Ikbal.

   Can you pl provide the commands, so that i can configure the same.


Please use the below config inorder to enable ip-accounting on the particular interface use the below commands.


interface FastEthernet1/48
ip accounting output-packets

show ip accoun out

And use the below command to enable ip route-cache flow before to that make sure it is routed port.

ip route-cache flow

Please rate the helpfull posts.


You can check CPU utilization of the device using the command show process cpu. If it is normal you can configure ip route cache-flow under the physical interface of other end device(May be router or Core switch).Then use the command

show ip cache flow

Last coulumn shows number of pkts. Search for the source and destination pair having high number of pkts(may be in K).

After the use you can remove the command since it will use more process

when i enter show ip cache flow  it showing inut detected.

Switch#show ip cache flow

Switch#show ip cache flow


% Invalid input detected at '^' marker.

Can you check,What is connected to Port 48?

1) A server may be connected and there may be sechuduled back up configured.

2)Even an Live Scheduled antivirus scan can cause this issue.

Since you are facing issue daily at 4 pm to 6:30pm,there is a high possiblity of Scheduled activity and the port may be connected to a Tape drive or a Backup server

   Port 48 connected to Uplink of ISP (10Mbps)

where are you configuring ip cache flow commoand?  your switch is connected to ISP router? do you have access to ISP Router. If it is connectedre to ISP router and have access , configure the command under the interface of the router where the switch is connected.

i try to configure ip cache flow commanand in Port no 48,  Port no 48 connected to ISP router, i dont have access to  ISP router.

3750x 12.2 55(SE) won'tsupport  show ip cahce flow or show ip accounting. Better get in touch with ISP to provide top talkers during the time high traffic happens.

Otherwise you have to go with SPAN session of the port