Tuesday, November 7, 1995:
Advanced Technology Seminar 1: Mobile-IP Protocols
Description:
Mobile-IP is a means by which mobile computers can use Internet
protocols (IP) to communicate data with network resources
transparently to application software. The mobile client supplies
information to a router, called its home agent, about its current
whereabouts using a simple registration protocol. The mobile
client uses the same IP address as it moves from place to place,
and the problem of enabling mobility for IP clients is translated
into the problem of allowing a home agent to determine a current
path to the unchanging destination address of its mobile client.
Subsequently, the home agent delivers data to the mobile client at
its current location by a tunneling mechanism. Since the mobile-IP
protocol does not depend on the characteristics of any particular
subnetwork protocol, the same mechanism works for every wireless
medium, as well as existing wired media like Ethernet. The seminar
will explain the details of the mobile-IP model, as well as the
registration protocols and tunneling mechanisms. Once the basic
operation has been shown, additional mechanisms will be described
to avoid the need for routing packets through the (possibly
distant) home agent, providing an faster route between mobile
clients and their correspondents. If there is time, the speaker
will recount some of the history of the mobile-IP working group
within the Internet Engineering Task Force, and describe some of
the competing proposals that have been considered by that working
group.
The Dynamic Host Configuration Protocol (DHCP) will also be
introduced and its usefulness for mobile users explained. After
describing the basic DHCP client/server model, the speaker will
apply it in some likely scenarios for mobile computing, and show
the advantages and the disadvantages of using DHCP. Perhaps even
more than static computers, mobile computers will be used by people
uninterested in performing administrative duties, and the speaker
will describe the use of a new option for DHCP which allows the
acquisition of IP addresses appropriately configured for use with
the mobile-IP protocols.
If there is time, the speaker will also give a brief overview of
the additional protocol improvements for mobility available using
the new (128-bit) version of IP. Last, but perhaps not least, the
speaker defines the terms and describes some technical approaches
to achieving ad-hoc networking -- that is, the ability of mobile
computers to initiate and maintain a connectivity framework among
themselves automatically, without any help from existing Internet
routers.