Abstract
In this thesis, the performance of a state-of-the-art path capacity estimation algorithm is evaluated
in terms of its suitability for being part of a measurement-based admission controller in a
military Internet Protocol (IP) network.
The strive towards Network Enabled Capability (NEC) in miltary organizations drives the need
for interconnecting all the actors taking part in an operation. The resulting network is an IPbased,
heterogeneous Wide Area Network (WAN), comprising of a variety of fixed and mobile
communication links with different capacities.
In military IP networks, Quality of Service (QoS) cannot be guaranteed when there is congestion.
This is due to the use of IPsec, which forms a cryptographic boundary between the traffic
source and forwarding routers, thus rendering end-to-end resource reservation impossible. This
calls for the implementation of a congestion avoidance policy through Measurement-based Admission
Control (MBAC).
Based on a literature study, the estimation algorithms combining the use of packet-pair dispersion
and delay analysis, were found to be the most suited for providing low-intrusive, fast and
reliable measurements of the path capacity. One of these algorithms, Ad Hoc Probe, was extensively
evaluated in a test bed based on link technologies typically found in military networks.
A number of performance limiting factors were identified, including a lack of support for
Time Division Multiple Access (TDMA)-based links, restrictions on the number of hops in
contention-based Mobile Ad Hoc Networks (MANETs) and a minimum required capacity that
made the algorithm unfit for use in networks containing narrowband, low-capacity links.