Output rate vs input rate on interface

[isaaco001]

Dear community,

Kindly requesting for explanation of the following output on an physical interface facing the service provider g0/1

int g0/1(wan)

30 second input rate 5570000 bits/sec, 1223 packets/sec
30 second output rate 2079000 bits/sec, 758 packets/sec

On the lan interface facing the lan side g0/0

int g0/0(lan)

5 minute input rate 3759000 bits/sec, 987 packets/sec
5 minute output rate 7541000 bits/sec, 1502 packets/sec

What's the difference between the two data rates on each interface in terms of bandwidth utilization or how much traffic is coming from the wan side to the lan side and vice versa?

Regards,

Isaac.

[M02@rt37]

Hello @isaaco001,

The key difference is the time interval over which the rates are calculated. The physical interface uses a 30-second interval, while the LAN interface uses a 5-minute interval. This difference in time interval affects the reported data rates. Additionally, the numbers reflect the amount of data in bits and the number of packets being transmitted or received within the given time frame on each interface.

[Joseph W. Doherty]

In addition to what M02@rt37 correctly describes, there's no other interfaces involved?  (I assume not.)

Second, even if both interfaces were using the same time averaging period (e.g. 30 seconds for both), are they measuring across the same time interval, not just measuring across the same time duration?

Because of such factors, rate measurements will often differ.  You'll also see similar across a p2p link between two devices, for their interface stats.

[isaaco001]

Hi Joseph,

Thanks for your feedback and sorry to throw you off on my query. My interest in more on concept. when we see input rate and output rate bits/sec on an interface, how is the bandwidth being utilized and in what direction.

I would like to know how much bandwidth the interface is consuming therefore be able to tell if the traffic traversing the interface is congested or not. From a ISP perspective, how can I tell how much traffic am receiving vs the one am sending?

You can see that the input vs output rates are different. Its only two interfaces, why are the bandwidths changing on interface g0/1(wan) vs g0/0(lan)

int g0/1(Wan)

30 second input rate 5570000 bits/sec, 1223 packets/sec
30 second output rate 2079000 bits/sec, 758 packets/sec

int g0/0(lan)

5 minute input rate 3759000 bits/sec, 987 packets/sec
5 minute output rate 7541000 bits/sec, 1502 packets/sec

[Joseph W. Doherty]

Well, if the data stream is only crossing two interfaces, one interface's in is the other's out.

Because of the issues I described in my prior post, interface rate counters will likely never be exactly the same.  (A possible exception would be if using just fixed rate flows, for long enough.)

What I didn't mention, egress congestion drops and/or ACL in and/or out drops would reduce rate on an interface that might cause a transmission rate difference between interfaces.

As to determining congestion, in/out rates, alone, can be misleading.

[MHM Cisco World]

I send you message check it