[LAN/Switch] How to calculate the rate charge of an interface ?

[VincentM633]

Dear all,

During a troubleshooting, I asked myself a question:

Context : I have two physical interface (each is a link of 1Gbps) which form an ether-channel (So 2 Gbps).
But how do we calculate the load rate of an interface ?

• Int gi 1/0/1 : reliability 255/255, txload 141/255, rxload 96/255

30 second input rate 377964000 bits/sec, 44754 packets/sec

30 second output rate 554931000 bits/sec, 51984 packets/sec

So 377,964 Mbit/s inbound è37.7% of physical link

So 554,931 Mbit/s outband è55.4% of physical link

Total utilization of physical link 1Gbps : 93.1% ??? Do we need to add the inbound and outband traffic on an interface in order to have the total charge of the interface ?

• Int gi 2/0/1 : reliability 255/255, txload 1/255, rxload 1/255

30 second input rate 29000 bits/sec, 28 packets/sec

30 second output rate 4357000 bits/sec, 3680 packets/sec

Thank you in advance for your help.

Best regards.

[Joseph W. Doherty · Accepted solution]

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Posting

Do we need to add the inbound and outband traffic on an interface in order to have the total charge of the interface?

You could, but assuming the link is full duplex you often want to track loading, for ingress/egress, separately.  However, if you were to compute a composite loading, you wouldn't just add the two percentages, you would take the total traffic volume and divide it by the duplex bandwidth.  E.g. 378 Mbps + 555 Mbps = 933 Mbps / 2 Gbps = 47%

BTW, if those two links are part of the same bundle, you might double check if you're using the most optimal hashing algorithm.

[VincentM633]

Hi,

Thank you very musch for your reply, and sorry for the delay of answer.

Yes this is my second question, the algorithm.

The thing is that I use a L2 link between my access switch and my distribution switch.
Is it possible to use src-dst-IP even on L2 link ?

Thank you in advance.

[Joseph W. Doherty]

Is it possible to use src-dst-IP even on L2 link ?

If the devices supports it, yes.

[VincentM633]

Thank you for your help, I will try to do this.