Building the Mobile Internet

Chapter 4. Data Link Layer Mobility

The fundamental architecture of the Internet is built upon a foundation of associating an IP address, not with a host, but with an interface of a host. Associating an IP address with a host would certainly have facilitated mobility, but as John Day describes¹, when IP was first proposed in 1975, “problems of multicast and mobility were many years off.”

These architectural issues are compounded by the way in which the upper layers, dealing with applications, are coupled to lower layers, dealing with IP transport. Chapter 2, “Internet ‘Sessions’,” has introduced the concept of Internet sockets that are used to allow communications between remote application processes on different hosts. An Internet socket is ...