Using IP SLA as a traffic generator

[ThomasKlausen]

Greetings.

We have recently upgraded the bandwidth on one of our overseas Internet links, from 200 Mbps to 400 Mbps. However, we would like to verify that the link can in fact support 400 Mbps - or, at the least, that it's not still throttled at 200. While I could start identifying spots on our network where an iperf host could be placed, I would much rather see if I could find a solution that only involved the router(s).

IP SLA could conceivably be made to fit the bill, but my lab attempts have so failed to put the traffic much over 15 Mbits/sec - and while that's respectable, it's not going to solve my problem.

We're looking at an ISR 4451, running IOS-XE.

The config that I have had the most luck with so far is this - everything should be dialed in for maximum outbound traffic:

ip sla 5
udp-jitter 192.168.100.100 17019 num-packets 10000 interval 4
request-data-size 15000
threshold 0
timeout 0
frequency 1

Has anyone else run into this? Any thoughts? Or will I have to get our server team to build some remote iperf workstations?

Best regards,

Thomas Klausen

[e.ciollaro]

Hi,

I didn't exactly understand what you mean by "overseas Internet links"; you are connected to a ISP backbone routers that is in another continent or do you mean that you use that access to make a VPN  to a  remote site but ISP?s router is in your country ?

Generally speaking, in my experience the right way to test a link is using a specific appliance. I work for an ISP and, when our customer has this kind of request, we use a specific tool and give them a report with the result. So first of all try ask you ISP.

Consider that ISP usually consider themself responsible just form the path between CPE and their Edge routers (I mean their interconnections other ISP).

Testing the link require the test tool is directly connected to the CPE in your, to the ISP's router on the other side and that nothing else is connected to the CPE. 

Using other tool like Iperf can be usuful but also challenging because it's hard to tune them, for example define the right TCP window, been sure that nothing else could reduce the  amount of traffic (I mean if you run Iperf on a server, you have to be sure the the bottleneck is not the workstation itself or it's connection to the network).

Bye

enrico

[ThomasKlausen]

Thanks!

For clarification, when I said "overseas", I simply meant to convey that I don't have physical access to the link, nor an easy way to arrange install of any sort of probe or tool.

I think you may have the right answer - a link test from the ISP could turn out to be the best approach.

[rasmus.elmholt]

At one point Cisco had a Pagent IOS for traffic generation, but I am not sure if they support it anymore. http://www.ciscoconsole.com/nms/traffic-generation-using-cisco-pagent-ios.html/

A 3-party tool would be your best solution

[ThomasKlausen]

Thanks - didn't know about that, but I don't think I'll be able to sell the idea of changing IOS internally. Good info for lab purposes or the like, though.

[e.ciollaro]

Hi just an idea to work on: what about using ttcp ? I don't know if it can generated 400Mbps of traffic but it could be something to check