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In a lot of locations, we have only one Cisco ASA 5505 each and one or more WiFi APs, besides the provider router. No servers or PCs, just WiFi service for occasional visitors. I want to remotely check if the provider gives us the contracted bandwidth. I could see used bandwidth on the ASA monitoring, and test one direction by sending traffic to the ASA using Iperf on my side.

Is there any way to let the ASA generate substantial traffic?

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"I want to remotely check if the provider gives us the contracted bandwidth" - You have done this with iPerf. You can send and receive traffic with it in both directions to test your upload and download, so you have already done this? Why do you want to generate the traffic from the ASA it's self? – javano May 9 at 13:31
@javano iPerf doesn't help me with receiving if nobody on the remote site generates the traffic. That's why I would like to let the ASA produce the traffic and watch it incoming on my local site (Iperf), since it's our only capable device there. The rest are controller based WiFi APs which don't help in this regard. – Stefan May 9 at 13:55
Sorry I think I misinterpreted, so do you not have any machines (computers/servers/laptops) outside the ASA from which you can generate the incoming traffic then? If so, this isn't clear in your question. – javano May 9 at 14:32
@javano Thanks! I updated the question. We could remove our comments to clean up. I'll remove mine soon. – Stefan May 9 at 15:23

7 Answers

(Just noticed your comment about Raspberrys, and I want to follow up)

We have a large MPLS network where we need to measure bandwith and jitter across sites to make sure that our most sensitive applications isn't hurting.

One great way of doing this is, like you mentioned, deploying Raspberrys. They are small enough, so you can install them nearly anywhere. One great toolf for testing bandwith/jitter is iperf, which you then can set up to run as a (filtered!) daemon on each PI. Then just initiate tests from a central management station.

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Rasperrys make brilliant "leave it over there" black boxes as testing nodes. – SimonJGreen May 10 at 15:02
@Pauska Have you actually tested this, or know of anyone that has, or seen it configured anywhere? I would be sceptical at best, that Raspbbery Pis could push any large amount of bandwidth at all. – javano May 11 at 9:00
@javano I suppose the OP hasn't defined the speed of this link so it may not be suitable of the link is large. That said a 5505 is pretty limited, I'm sure you could max one out with a Rasp Pi. – SimonJGreen May 11 at 16:40
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Relevant discussion raspberrypi.org/phpBB3/viewtopic.php?f=28&t=12679 – SimonJGreen May 11 at 16:41
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@SimonJGreen As I suspected, the result on that page are all a bit slow. It might also be worth noting that the Ethernet NIC is on the same bus as the USB ports. Any USB reading or writing during a speed test (if you have any devices attached) could affect the consistency of the results. – javano May 12 at 9:56
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Downstream you might be able to download something to null: on the ASA but upstream you would be limited of how much the flash disk can transfer which is usually not that much.

Your best bet would be to connect a PC and run the tests but that requires someone to be on site of course.

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The first thing that comes to mind would be uploading the ASA and ASDM images.

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Thanks, that's a good point, however the flash size is too small to produce substantial traffic, and also the flash speed is a limit. – Stefan May 9 at 12:44

Perhaps passive monitoring is a better approach. There are plenty of systems out there that will track interface state/errors/discards/bandwidth. Does a bandwidth graph fit your needs?

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I use Icinga (Nagios) for monitoring bandwidth usage long term. It's just that upstream traffic of clients is rarely high enough to come near to the contracted bandwidth, and one doesn't know if the local WiFi may be the limit. Perhaps I should sent out Raspberry Pis to all places ... I hoped there would be a possibility on ASA OS such as ttcp on IOS of Cisco routers. – Stefan May 9 at 20:44

I had a similar requirement many moons ago with a remote router running IOS. Ended up using tcp-small-servers chargen service on router - runs on tcp/19. It will generate a stream of random characters etc. and can be scaled out using multiple telnet sessions from the remote router to other routers running chargen. Nowhere near the rich control/functionality of host based iperf tests. Also as we know ASA does not support telnet locally so this won't work here...

ASA does have that packet tracer utility since 7.0 to generate interesting traffic for tunnel configs but doesn't allow rate tuning. Such functionality would also be an interesting attack vector if exploited remotely and at scale... Any such native functionality on ASA would likely peg the control plane and any variety of inherent control plane policing would need to restrict the generated traffic rate.

I agree with above that Raspberry Pi is a good solution here. We just dropped some in to drive NOC style screens. They're awesome.

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I actually was stuck with a similar request last week (of course the remote site was on the other side of the country). What I ended up doing was using mgen to send unidirectional udp and just verifying the counters on the remote side device. If you aren't comfortable with mgen, you could do the same with nping or one of the nmap tools.

As you pointed out, the issue with iperf, IxChariot, and so many other tools is that they require a remote responder. mgen, nping, and a few others do not.

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Also from IxChariot, Qcheck is free: ixchariot.com/products/datasheets/qcheck.html – Peter May 25 at 15:40

If you have Solar Winds Engineering Tool Kit, you can use "WAN Killer" between the two locations. Make sure your ACL's allow both ends to talk to each other this way, and flood with the appropriate level of echo's or discard's from Point A to B and visa versa.

We use this to test the networks ability to handle traffic across VPN and MPLS connections, whether it's measuring the raw throughput from A to B and the PPS from A to B.

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