I want to know is it possible to check Internet speed directly in the cisco router thru any command or activating any service in the cisco router?

There are number of questions and confusions regarding internet speed.As it is seeen most of the times internet speed offer by ISP is different as compared to clients.and Clients most oftenly not satisfied with internet speed

The problem is that our ISP has given us 100MB leaased line.But when we deployed in production network the speed is same as DSL.We have reported this issue to ISP they then carried out Iperf test by connecting laptop directly with the ISP router.They have tested the speed and it shows about 94-96 Mbps and argu that it is up to the mark and there is problem at your side(i.e our internal network).

Now our internal network has cisco4321 router connected directly to ISP cisco router.Our router has minimum configuration as required to pass traffic out and in.Our internal 4321 router is connected to switch to which different clients are connected.We have performed some online tests using different speed checking websites and also perform real time tests by uploading and downloading files.The speed is much low as compared to 100Mbps and it is nearly or slightly higher then as DSL connection.

Now plz help us how can we check internet speed in the specified scenario/how can i get exact speed in my switch whatever speed isp sharing?

Is there any command or service available in cisco router to check internet speed as we want to check ISP connection speed directly thru 1841 router?

what about authenticity of online speed checking websites?

Any specialize software/tool you recommend to check Internet speed in specified scenario?

  • 3
    In one place you say 100MB and in another you say 100Mbps. These are very, very different things. Which is it? Also, when you say "nearly or slightly higher than a DSL connection", can you give us the actual measurements? There are 80Mbps DSL connections and there are 8Mbps DSL connections. (By the way, the 4321 can be maxed out by 50Mbps and rarely gets over 80Mbps.) Jan 19, 2018 at 11:48
  • 1
    I think you are missing "how to troubleshoot" knowledge... Get a laptop yourself and connect it directly to ISP, do you get expected speeds? If yes, connect router and plug in laptop there with nothing else. Expected speed? No, router issue... Yes, connect switch with no clients and test, getting expected speeds? How about with some/all clients connected? Eliminate/test each piece and the problem should become obvious.
    – acejavelin
    Jan 19, 2018 at 11:57

1 Answer 1


Given that the speed was fine on a laptop, it seems the connection speed is what is advertised (minus a few percent). So it would seem the problem is on your end.

On the Cisco website, I found that the aggregate throughput for the 4321 model is 50 Mbps to 100 Mbps. There is no way you can get up to 800Mbps (100MB) with that.

Based on this, I can't say anything else than that the ISP is right. You need to get a faster router.

There are dozens of speed testing websites online, for example speedtest.net.

  • actually guys my question is how to check the speed in my 4321 router? can 4321 router can provide a output of 100mbps ? in my core switch im getting only 45 mbps( uplink is 100mbps) Jan 19, 2018 at 12:37
  • 1
    What is 'the speed in my 4321 router'? That is not a specific metric. "the speed" could be anything: forwarding, SNAT, DNAT, access lists, etc. If you want specific answers, ask specific questions. Also, you have 4 different questions in your original post. Pick one and ask that. Plus, you're talking about a switch, which model? And how do you come up with "im getting only 45 mbps", how is that measured?
    – mtak
    Jan 19, 2018 at 12:38
  • my switch is sg 300 ,im testd the speed test of switch using ("legacy.speedtest.net ")this website,im able to get 45 mbpsonly but my uplink is 100 mbps.why im not getting a speed of 100mbps, ? Jan 20, 2018 at 5:27

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