Mininet transmission delay

Question

I have a topology in mininet that comprises of two hosts (h1 and h2) and three routers (r1, r2, r3). I configured the bandwidth to be 100 (bw = 100 ) and the delay is zero.

H1 - R1 - R2 - R3 - H2

I need to measure the transmission time from h1 to h2. In order to do this I send ping packets of 1408 bytes size:

ping -c 10 -s 1400 h2

And in order to capture the traffic,I use tcpdump on the egress interface of h1 and on the ingress interface of h2, and I subtract the two timestamps.

tcpdump -i h1-eth0 --time-stamp-precision=micro -ttt -w egress.pcap

Based on the inputs (packet size = 1408, bandwidth = 100Mbit etc.), every hop must take approximately 112.64 microseconds and the total transmission delay should be 112.64 x 3 = 337,92 microseconds.

The times that I took from the captured traffic are on average 60 microseconds.

How can it be such a big difference? What am I missing?

Thank you.