| International Journal of Computer Applications |
| Foundation of Computer Science (FCS), NY, USA |
| Volume 187 - Number 125 |
| Year of Publication: 2026 |
| Authors: Debashis Roy |
10.5120/ijca5817bb54a8e2
|
Debashis Roy . PathAB: Hybrid Two-Phase Probing for Available Bandwidth Estimation with Standalone Support. International Journal of Computer Applications. 187, 125 ( Jul 2026), 7-15. DOI=10.5120/ijca5817bb54a8e2
Accurate estimation of end-to-end available bandwidth is essential for network-aware applications including adaptive streaming, congestion control, and traffic engineering. Existing active probing techniques either assume fluid cross-traffic models, require cooperative software at both endpoints, or exhibit high estimation error when cross-traffic conditions vary. This paper presents PathAB, a hybrid active probing method that estimates available bandwidth in two phases: a single exponentially spaced probing train provides a rapid coarse estimate, followed by multiple Poisson-distributed probing trains that refine the estimate using a linear regression model. PathAB supports both client–server and standalone modes. In standalone mode, small 28-byte echo packets are placed behind larger probe packets to minimize reverse-path interference, eliminating the need for receiver-side software. The algorithm is evaluated through NS-2 simulations at four bottleneck capacities (1.5, 5, 10, and 15 Mbps) under four utilization levels, and through network test-bed experiments in single-hop, multi-hop, and 100 Mbps configurations. PathAB is compared against PathChirp, PoissonProb, IGI, Spruce, Pathload, and a stochastic model. Results show that PathAB achieves RMS estimation error below 10% under moderate utilization in both modes, and maintains stable accuracy under high-utilization conditions where competing methods degrade substantially.