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New Member

Packet drops in switched network

Hello Everyone

I have a switched network in my Data center    with 8-10 switches.

I am observing packet drops when one server is trying to communicate with another servver on LAN. Both are in same subnet , so router /routing is out of picture.

I have not observed any errors on switchports or high cpu & menmory utilization on any of switches. Switches I have is 4506 3750 and 2960 in my network

Is there any tool to trace which all switches come into picture when a frame travels from one server to another. Or how can I troubleshoot this.

Please help. Its urgent                

Everyone's tags (3)
New Member

Packet drops in switched network


Do the continuous ping, hope by hope and check the trace route result.

By that can find where the issue is.


Milan Verma

New Member

Packet drops in switched network

Hi Milan

Thanks for your reply, 

Both the server are on same lan segment so traceroute will not yield any results.

Guys need help.

Cisco Employee

Packet drops in switched network


Since when did you start noticing this drop issue? Was this working fine before? If yes were there any S/W or H/W changes been made on the device?

Have you check all the basic layer 1 issue:

1- Changing the cable

2- Setting the speed and duplex settings same

3- Clear the counters on the interface and check the link utilization and if there are any input or output drops.

4- To which switch are these servers connected to? R they connected to same switch r u facing the issue on all the ports of the switch




New Member

Packet drops in switched network

Hi Inayath

Thanks for your reply.

This drop issue has been happening sine 2-3 days. before it was working fine. There were no software /hardware changes in network or on server.

I have cleared counters on interface and checked link utilization. I did not found any errors or drops on interface.

Servers are connected to diffrent switches.


Deepak Khemani

Cisco Employee

Packet drops in switched network


How many servers are having the issue? R they belong to the same  VLan?

Did you try chanigng the cable and port ? If not can you try that?




New Member

Packet drops in switched network

Does it happen only between those two hosts or any hosts within the same VLAN?!

Also check Inayath's suggestions. It could be Layer 1!

I encountered a weird issue when trying to trunk 2960 and 2950 switches to a 4510 L3 (SUP-7-E), It just wont support it!


New Member

Re: Packet drops in switched network

Hi Deepak,

I just gone through your Problem discussion and it look like the issue is not in network. Some time due to high utilization or any other issues in server caused this issue.

Please do this test.

Disconnect the server and connect Laptop on both end configure same IP on Laptop that server has.

Extended Ping from one Laptop to other end laptop IP and see result.

If everything is normal then Investigate on server side.

If your still facing issue then check speed and duplex setting on switch port and server port. Check cabling.

Check Link utilization and erros and drops on Link.