Computer Systems A Programmer‘s Perspective Second Edition
Of course, we are glossing over many difficult issues here. What if different net-
works have different maximum frame sizes? How do routers know where to for-
ward frames? How are routers informed when the network topology changes?
What if a packet gets lost? Nonetheless, our example captures the essence of the
internet idea, and encapsulation is the key.
the essence of the internet idea
原文：http://www.cnblogs.com/yuanjiangw/p/6188823.html
