45.1 Network Setup

The implementation of Tmix in ns-2 is based on PackMime-HTTP (Chapter ), so it has a similar structure. A typical Tmix instance consists of four ns nodes: two initiator nodes and two acceptor nodes (Figure ).

Figure: Tmix Architecture. Each Tmix object controls an initiator cloud and an acceptor cloud. Each cloud can represent multiple initiator or acceptor Applications. For realistic two-way traffic, two sets of acceptors and initiators are required.

It is important to note that these nodes do not correspond to a single initiator or acceptor. A single Tmix initiator node generates TCP connections coming from a ``cloud'' of connection initiators. Likewise, a single Tmix acceptor node accepts and serves TCP connections destined for a ``cloud'' of connection acceptors.

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 ), derived from DelayBox (Chapter ).

We use the terms inbound and outbound to represent the directions of data flow. As in Figure , 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.