We implemented the Egress Admission Control algorithm on a testbed consisting of seven PCs running FreeBSD v3.2 as depicted below. Please refer to the paper Design and Implementation of Scalable Admission Control for detailed information about experiments and results.

• Timestamping. To communicate packet arrival time at the ingress node (router A in the above picture) to the egress node (router C), we first use NTP synchronize the clocks of the edge routers. In this module, we modified the FreeBSD v3.2 kernel to insert timestamp into fields of the IP header at the ingress node.
• Traffic Generation. This module generates Pareto on/off flows. Before each flow is established, an RSVP signalling message is generated to request admission by the egress node.
• Traffic Measurement. At the egress node (router C), we capture the timestamp inserted at the ingress node and calculate the path service envelope based on that. In this module, we modified tcpdump to capture packet information.
• Admission Control. We modified the RSVP v4.2a4 daemon to call our egress admission control program upon receipt of a new reservation request.

Available downloads for egress admission control are

• Implementation source code
• Visualization tool that animates the evolution of arrival and service envelopes over time (illustrated below).
• C++ ns-2 modules and tcl scripts
• Report comparing testbed measurements to simulation experiments