troubleshooting upgraded wan link

[Raja_D]

Hi, 

How to troubleshoot the scenario where the bandwidth of a link is upgraded to 1MB from 512 kb but the throughput over the upgraded link is not getting beyond 500 kb when load is applied on the link. 

Example: 

=======

Cisco 1812

CE: 25.2.1.1

PE: 25.2.1.2

FE0 interface on the CE end router is connecting to the PE end router which was 512kb and is now upgraded to 1MB by the Service provider.  

Ping 25.2.1.2 size 8000 <bytes> repeat 1000 --- is generating BW utilization on the wan link FE0 which is observed max of 501 kb and the service provider using the wan killer software confirmed that the link is upgraded to 1MB from their end. 

please advise.. 

[Vinit Jain]

Hello James i would begin by saying ping is not a good tool to test bandwidth. It would be best if you can use an external software / hardware to test teh bandwidth.

Also, when u send a ping packet of size more than the interface MTU, it is going to fragment the packets which is going to use CPU resources as the fragmented packets are software processed.

Wan Killer is a good software. You can also try using some ftp application to upload or download a file to test ur bandwidth.

Hope this helps

Regards

Vinit

[Raja_D]

Vinit, 

Incase if the FTP application that is uploaded or downloaded does not get the throughput as supposed to be, like in the case i mentioned link is upgraded to 1MB which was earlier 512 kb and the throughput does not go beyond 500kb . what are the basic checks that can be done from the CE end router that can give estimated throughput properly as SP claims that the BW is upgraded to 1MB which was verified using the Wan killer software. 

[Vinit Jain]

Hello James

When the provider says they have upgraded the bandwidth, they usually make the changes in their QoS policy. the throughput you are checking is based on the ping test and not actual traffic (if  I am not mistaken). You can use a TCP based application or try downloading a huge movie or file and see if you are able to achieve proper throughput. If even with those tests you are not able to, then you may want to circle back with the provider.

can you try download the wan killer application as well and perform the test that the provider is talking about. i have heard about this software but never used it.

the only good way to test would be to send traffic higher than 1 mbps and see at what point it max's out.

Also, you might want to revisit any QoS configuration on your edge router if any.

Regards

Vinit

[Adel Barashed]

Agreed and above also I mentioned to use the same or over application like Jperf

[johnlloyd_13]

hi,

could you post a sanitized config?

you could set a downtime, bypass your 1812 router, connect the circuit and set your PC IP to 25.2.1.1 and do iperf or FTP tests.

[paul driver]

Hello,

Your ISP may have changed their end, However do you have any shaping/policing set on your CE wan facing interface?

res
Paul

[Adel Barashed]

To have better and accurate result:

1- Use iperf of Jperf tool to test the bandwidth from your end to end node

2- Or connect 2 machine 1 at each end and start copying the file and observe the speed rate

[Support07]

Hi,

The link should be 1MB symmetrical ?

On the PE the ISP has changed the Qos policy on the interface, there is a shapping configured on their side. On the CE have you a shapping in output ?