The implementation of Tmix in ns-2 is based on PackMime-HTTP (Chapter 43), so it has a similar structure. A typical Tmix instance consists of four ns nodes: two initiator nodes and two acceptor nodes (Figure 44.1).
In order to simulate different RTTs, bottleneck links, and/or loss rates for each connection, Tmix should be used in conjunction with Tmix_DelayBox (see Section 44.4), derived from DelayBox (Chapter 22).
We use the terms inbound and outbound to represent the directions of data flow. As in Figure 44.1, traffic initiated outside of the circle (which could be thought of as a campus) is designated as inbound, and traffic initiated inside the circle is designated as outbound.
Tom Henderson 2011-11-05