Mean Hop Count

[Ohoud]

Hello,

In flow monitor, the mean hop count per flow can be calculated using the following formula

hopCount = (timesForwarded / rxPackets +1)

Does timesForwarded value include non-received packets in the flow?

[Konstantinos]

No, 

if a packet is not received, it is not accounted in the hop-count or delay calculations.

[Micheal Ulasi]

Hi Konstantinos,

I have a problem, and it has to do with the mean hop count that I saw in "FlowMonitor - a network monitoring framework for the

Network Simulator 3 (NS-3) mean hop count: hopcount = 1 + timesForwarded rxPackets" 

Please, can you explain to me why the "1 +" in the formula?

Kind regards 

Michael

[Konstantinos]

Hi Micheal,

The variable timesForwarded is defined as: "timesForwarded Contains the number of times a packet has been reportedly forwarded, summed for all packets in the flow;"

So, in order to account also the 'first hop' that the packet is not forwarded, we add this +1. 

Regards,

K.

[Tommaso Pecorella]

In other words, if you have a 1-hop node (sender and receiver are connected directly), the hop count is 1, but the packet have never been forwarded.

In a 2-hop network (sender, repeater, receiver), the packet will be forwarded one time, but we have 2 hops.

By induction, the above formula can be derived.

Cheers,

T.

[Micheal Ulasi]

Hi Konstantinos and Tommaso, 

thanks for your quick responds.

So, the "1 +" is just the movement of the packet from the sending node to the first receiving node in the flow, right?

Kind regards

Michael

On Saturday, November 7, 2015 at 8:04:24 PM UTC+1, Konstantinos wrote:

[Tommaso Pecorella]

yes.

T.

[Micheal Ulasi]

Thanks a lot.

Kind regards

Michael