The full dissertation is available here
We describe a new type of network layer address, the hybrid address,
which contains a Partial Destination Identifier, a Unique ID, and a
Location Sequence number. The Partial Destination Identifier, which
changes as a mobile ES re-locates between areas of an internetwork,
allows for efficient routing, while the Unique ID is used for ES
identification at the lowest layers of a routing hierarchy. Finally,
the Location Sequence Number, which a mobile ES increments as it
relocates between areas, is used to compare the age of multiple
addresses for a given mobile ES.
We present a mobility design that incorporates the hybrid address, and
is based on the ISO OSI connectionless routing architecture and
protocols. Each mobile ES has a home address and a current
address. The home address is stored in a global database, and the ES's
home area keeps track of the current address. After a mobile ES
relocates to a new area, it sends Reconnect messages to the home and
previous areas, each of which caches a forwarding pointer for the
mobile ES. ESs that communicate with a mobile ES send datagrams
directly to the mobile ES. To accomplish this, each ES maintains cache
entries for its mobile correspondents. When a datagram containing an
out-of-date address is forwarded by an area, a Rewrite message is
sent to the source ES, which updates its cache entry for the
destination. An ES also updates its cache based on the source
addresses of incoming datagrams.
The mobility algorithm has been implemented and tested in a simulation
environment, and performs quite well. We also present the results of a
study on strategies for caching mobile ES forwarding pointers at
Intermediate Systems in the interior of an internetwork, based on the
type and contents of transit control messages. Caching at interior
Intermediate Systems based on Reconnect messages yields the greatest
benefit, for both tree-shaped and general topology internetworks,
while caching based on transit Rewrite messages is not recommended.
1994
This thesis explores the provision of End System (ES) mobility on large, data-
gram-based, internetworks.