WAN link utilization

[Adnan Khan]

I have a 100 MB WAN link and if traffic input rate is 52 Mbps and output rate is 48 Mbps  It will be consider as fully utilized link (chocked link) or if input rate is 100Mbps and output is also 100Mbps then it will be fully utilized link?

#show int gi0/0/0 | i 5 minute



5 minute input rate 52000000 bits/sec, 7031 packets/sec
5 minute output rate 48000000 bits/sec, 6113 packets/sec

[Jon Marshall]

Assuming you have the full bandwidth allowance on that link then it is 100Mbps in and 100Mbps out. 

Jon

[Adnan Khan]

So below is not fully saturated in this case 

5 minute input rate 52000000 bits/sec, 7031 packets/sec   (52 Mbps)
5 minute output rate 48000000 bits/sec, 6113 packets/sec (48 Mbps)

It will be fully saturated if output is as below.

5 minute input rate 100000000 bits/sec  (100 Mbps)
5 minute output rate 100000000 bits/sec  (100 Mbps)

[Jon Marshall · Accepted solution]

Yes, again assuming there is no limiting on the link from the provider end. 

Also assuming your router can support a full 100Mbps on the link. 

Jon

[Adnan Khan]

Understand, when usually ISP gave 100 Mbps link and its 50 Mbps in and 50 Mbps out is the rates then its half utilized not full. 

[Joseph W. Doherty]

As already noted, by @Jon Marshall, for a 100 Mbps WAN link (which generally are full duplex), you have 100 Mbps for both in and out.  So, for such a link, 100% utilization would be 100 Mbps both in and out.

However, it's not unusual to have asymmetric bandwidth usage, so something like 100 Mbps in or out, with the other direction having less usage, even zero, might also be referred to as fully utilized since you've reached (at least in one direction) the maximum capacity of the link (again, in one direction).

BTW, you asked about:

It will be fully saturated if output is as below.

5 minute input rate 100000000 bits/sec (100 Mbps)
5 minute output rate 100000000 bits/sec (100 Mbps)

In the real-world, often 100% usage, in either direction is difficult to achieve unless you try to transfer more than 100% of capacity, and if you do have such stats, you often also have a high rate of packet drops/discards.

Also in the real-world, having stats showing less than 100% utilization, doesn't always confirm you don't have issues due to insufficient bandwidth.

Lastly, in the real-world, usage stats, like what you're asking about are based on 5 minute averages.  Much "bad" can happen in a few milliseconds, which is why whatever percentage usage is shown, might not "correctly" represent whether its a "good" or "bad" usage situation.