|Op. System:||Windows Vista/2003/XP/2000/98/Me/NT|
|File size:||359 KB|
|Publisher:||Catalin Popescu / Udaya Shankar|
Publisher description for Net Solver
NetSolver computes the time evolution of instantaneous ensemble metrics of TCP/IP networks at a cost several orders cheaper than packet-level simulation. A TCP/IP network is described by nodes, links, and traffic classes. Nodes represent end-hosts, routers, and switches. Links interconnect nodes and are bi-directional. Traffic classes represent end-to-end TCP and UDP connections. NetSolver computes Link metrics such as average buffer occupancy, utilization, and loss rate at time t, and traffic-class metrics such as achieved throughput at time t. To do this, NetSolver models the TCP/IP network by a time-dependent queueing network and numerically solves the queueing differential equations using an approximation technique called the Z-iteration. A TCP source is modeled by a time-dependent stochastic source whose current rate is determined by its profile and the current network state. The profile is an empircally-obtained function expressing the instantaneous throughput of the source in terms of instantaneous roundtrip time and instantaneous loss rate. Different TCP implementations have different Profiles, which translates to significant differences in performance. In Net Solver 1.0, the user may choose between the TCP Reno implementations in NetBSD 1.2 and in the ns simulator. The user can easily compare results computed by NetSolver against those obtained by the ns network simulator. Specifically, NetSolver can generate the ns script of a network, run ns, and include the results in graphs.