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Incoming Traffic Problem



I am having a strange problem on my network, where traffic that is incoming from my internet uplink behaves as if it is being shaped.  After it hits about 60Mbps, it drops right down - sometimes to as low as 300k, although usually somewhere in the 2 - 10Mb range.  I can confirm that the internet supplier is sending all of the traffic, and if I ssh onto router (a 7201) and check the interface I can see from the rx/load that all traffic is being received into the interface - it seems like it's just not being passed on.  I've attached a graph, below, to illustrate this.


I can confirm the link is 1000Mbps, full duplex and showing no errors.  Neither I nor the internet supplier are doing any traffic shaping.  Can anybody offer any guidance?  I can post more details, configs, spec, etc, if need be.


3 Replies 3

Tharak Abraham


Is there an experience of slowness from a hosts perspective ?

Also if you could generate a granular report with respective to the X axis it would help.

Off business hours, you may have to test the throughput preferrably using TCP and check the statistics to see further.

Hi.  Yes, there definitely are reports of slowness.  It's difficult to get a more granular x axis due to the polling and graphing of the monitoring software, this is about as good as I can do:

It's a two hour sample from the same time period shown in the first graph.

This shows the same period as above, but is a graph of traffic sent to us from our internet connection:

We're not doing any shaping, all of our QoS policies are turned off, there are no errors on the interface, the rx/load counter matches what the internet supplier graph shows, there are no drops..... I have no idea what's happening to that traffic, it seems to just vanish.

Alessio Andreoli

Hi There,

start a sniffing session 4 hours long with wireshark or span (rspan) the traffic over a PC and analyse what is the trafic that is doing this peaks. This is the first step to understand the next step to do. If all the traffic generated is "normal" then start to shape your network otherwise you will know that new policies should be in place.



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