Slow data transfer

[eash]

I am facing slow data transfer in my LAN. In the LAN I have one Cisco 3750 L3 switch connected to two Cisco 2960 L2 switch in the same rack. There is no VLAN configured. The transfer is very slow i get about 1 MB/sec to 2 MB/sec for any data transfer between server to user PC or vice versa and also between user PC's. When we access any excel file on the server, the files either hangs or does not open.

For testing we disconnected all the users PC and tested by connected 2 PC's directly on the L3 switch and tested it reaches 11MB/sec.

Next we connected one PC to the L3 switch and other PC to the first L2 switch the transfer speed varies between 5MB/sec to 2MB/sec.

After that we connected the PC to the second L2 switch the transfer speed is between 1MB/sec to 2MB/sec.

The first L2 switch is connected to the L3 by fiber and second L2 switch is connected to the L3 switch by copper.

We are using windows platform for copying files We not are running any QoS.

Request to resolve this crazy issue.

Regards,

Eash

[Flavio Miranda]

Hi,

 Could you provide 'show run interface' , 'show interface status' , 'sh interfaces  counters errors' , 'show spanning-tree' from all switches and  interface involved on this flow?

-If I helped you somehow, please, rate it as useful.-

[eash]

Hi Favio,

Please find the required capture enclosed.

Regards,

Eash

[Georg Pauwen]

Hello,

based on the description of your network, the 3750 switch should probably be the root for Vlan 1, make sure it is. In the output of 'show spanning-tree vlan 1' look for the line 'This bridge is the root'. If it is not there, configure the 3750 to be the root switch:

3750(config)#spanning vlan 1 root primary

That said, even 10 or 11MB seems low. Are the Windows hosts with Fast/GigabitEthernet NIC's ? 

[eash]

Hi Georg

I have configured 3750(config)#spanning-tree vlan 1 root primary

Please let me know if there is anything more to configure. I have the L3 show run.

Regards,

Eash

[Georg Pauwen]

Hello,

what is the output of 'show spanning-tree vlan 1' after you configured this ? You should see something like 'This bridge is the root'...

[eash]

Hello,

Yes L3 is showing is the root'...

Please check the sh run and sh spanning-tree capture enclosed.

Regards,

Eash

[eash]

Hi All,

Any suggestions for this issue. 

Regards, 

Eash

[Flavio Miranda]

@eash

We can see that there are error on the output of show interfaces counters errors.

The question is: Are those errors increasing?  I suggest you to take all the interfaces involved and monitor for a period of time issuing this command repetitively times and see if the counter increase. If does, you may have some issue. 

Also, I saw interface in half duplex mode:

a1/0/1 connected 1 a-half a-100 10/100BaseTX

This is terrible. Verify this urgently.

And lastly, you have interface force in full. This can be a problem sometimes. It is recommend keep it in auto unless some specific requirement.

-If I helped you somehow, please, rate it as useful.-

[eash]

Hi Flavio,

I checked the error count was not increasing.

The port showing  half duplex that system is not used much. 

I have attached the config of the L3 and the two L2 switch.

The file transfer is very very slow. I have configured backup exec.  one of the server connected to L3 switch and tape drive also connected to the same L3 switch. The backup is completed even after 3 days.

Any other suggestion to improve the situation.

Regards,

Eash

[eash]

I configured storm-control to avoid broadcast, Multicast and unicast on all ports of the 3750 L3 switch. The file transfer speed dropped to 750kb/sec. After disabling the storm-control command the file reached to about 2mb/sec. I checked the packet capture of wireshark the not many broadcast packets.

The file transfer rate is not crossing 2mb/sec.

Any other suggestions. 

Regards, 

Eash

[Georg Pauwen]

Hello,

on both of your switches, try and remove the 'system mtu routing 1500' line. Also, enable route caching on the Vlan 1 interfaces (ip route-cache).

That said, what is the uptime of the switches ? Since the configuration is minimal, I would 'write erase' the current configuration and reload the switches. All you need to enter is the IP address for the Vlan 1 interface...

[eash]

Hi Georg,

Thanks for your suggestion. We are requesting a customer for downtime for re configuring the swiches.

In meantime when I go through the wireshark capture of about 10000 packets, I found 60% of the packet are arp request for an non existing IP address in the LAN and 25% of the packets are for DHCP broadcast whereas we are not using DHCP in the LAN.

Any suggestion for the occurrence such strange packets.

Regards,

Eash