45. Session-level Packet Distribution

This section describes the internals of the Session-level Packet Distribution implementation in ns. The section is in two parts: the first part is an overview of Session configurationSectionsec:config, and a ``complete'' description of the configuration parameters of a Session. The second part describes the architecture, internals, and the code path of the Session-level Packet distribution.

The procedures and functions described in this chapter can be found in ~ns/tcl/session/session.tcl.

Session-level Packet Distribution is oriented towards performing multicast simulations over large topologies. The memory requirements for some topologies using session level simulations are:

2048 nodes, degree of connectivity = 8	$$	40	MB
2049-4096 nodes	$$	167	MB
4097-8194 nodes	$$	671	MB

Note however, that session level simulations ignore qeueing delays. Therefore, the accuracy of simulations that use sources with a high data rate, or those that use multiple sources that get aggregated at points within the network is suspect.