-1

We can see everyday our bandwidth is calculated by ISP's , Mobile Telecoms and Cloud Services.
But how exactly they calculate this bandwidth?
Do they count number of tcp/udp packets in layer 4? If so, do they ignore icmp packets?

Akhil
  • 105
  • 5
  • 3
    I think you are confusing bandwidth and throughput. The bandwidth is a function of the physical network. For example, 100Base-TX ethernet has a bandwidth of 100 Mbps, but there are factors that reduce the throughput to something less than that, even though the bandwidth is always 100 Mbps. – Ron Maupin Apr 10 '19 at 13:40

1 Answers1

2

Networking concepts don't really map well to OSI layers: https://en.wikipedia.org/wiki/Internet_protocol_suite#Layer_names_and_number_of_layers_in_the_literature

But typically a provider will count traffic at the lowest level it can measure and distinguish individual customers and use that as the input for their bandwidth calculations, fair use policy and/or billing.

Typically that will be either the internet layer or the link layer

How that maps to the OSI model depends on where that provider operates, probably somewhere between layer 1 and layer 4 :

  • a cloud operator will probably monitor traffic in the network virtualization software component on the hypervisor where a virtual server instance runs and not on the switch port that the hypervisor is wired into. Such a virtual network that exists only in software would technically be the transport layer I think.
  • your ISP might count the bytes in frames on your ADSL subscriber line
  • etc.
HBruijn
  • 77,029
  • 24
  • 135
  • 201