An active network is a computer network in which new
protocols can be installed at run-time in any node
within the network. For example, the deployment of
Internet multicast technology has been slow because
service providers have been reluctant to upgrade and
reconfigure their routing nodes. Under the active
network scheme, users who desire multicast services
can have the service automatically installed without
any direct intervention by the user or the provider.
One major question in realizing active networks is how
the code for the new active library can be found, or
resolved, and retrieved. A model of the resolution and
retrieval mechanisms is the major focus of this research.
To validate the model, a proof-of-concept experimental
system that realizes a simple active network architecture
was developed. An active library resolution service
model, suitable for a global Internet, was investigated
using this experimental platform and a simulation system.
The two protocol components that were built and studied
are the active transport protocol and the active library
resolution protocol.
The experimental and simulation systems were used to
evaluate the extensibility, overhead, resolution time,
scalability, and policy constraint support of the service.
Extensibility and policy constraint support are an
integral part of the proposed design. For libraries
located on servers that are at most ten hops away from
the requesting source, the resolution time is under 2.6
seconds. Simulations of networks of different sizes and
with different error rates exhibit linear resolution time
and overhead characteristics, which indicates potential
scalability. Behavior under high loss rates showed
better than expected performance. The results indicate
that the library resolution concept is feasible and that
the proposed strategy is a good solution.
