I've been reading Data Communication book by Forouzan it says that
"The physical addresses will change from hop to hop, but the logical addresses usually remain the same."
So, according to this line the physical address changes as the data passes through different devices. Now look at this figure:
Router 1, changes its physical address from
99 while it was creating a new frame!
I think a router should have same physical address but how it changes? Please explain.