Network Programming · AAT 2026–27 · B.M.S. College of Engineering

Smart Emergency Alert Broadcasting

A crashed car warns the traffic behind it over IEEE 802.11p using UDP broadcast sockets. We compare blind flooding, gossip and our Smart Relay in ns-3.45 across 180 simulation runs.

Guide: Dr. Sowmya K S · Dept. of CSE · Team: [Name 1] · [Name 2] · [Name 3] · [Name 4]

Replay frame: three copies of the same highway 1.5 ms after a crash, flooding saturating the channel while Smart Relay has made one transmission

Live demo

Watch the alert spread

The same traffic replayed three times from the ns-3 trace, with only the relay rule changed. It slows down automatically during each alert wave.

Open the replay →

96–99.3 %alerts delivered from 60 cars up (flooding 71–94 %)

−67 %transmissions per alert at 120 cars

−95 %frames lost to collisions

5.5–10.8 msmean delay, far under the 100 ms budget

Report

40 pages on the college cover template, 11 chapters, 16 verified references.

Presentation

19 slides with speaker notes. The main PowerPoint also previews correctly on a Mac.

Code and data

The ns-3 program, the experiment scripts and every measured number.

Results

Delivery ratio against traffic density — Delivery ratio

Transmissions per alert against traffic density — Transmissions per alert

Frames lost to collisions against traffic density, log scale — Frames lost to collisions

Mean delay against traffic density — Mean delay

Goodput against traffic density — Throughput (goodput)