Communication protocol testing can be done with a test architecture consisting of remote Tester and local Responder processes. By ignoring interaction primitive parameters and additional state variables, it is possible to adapt test sequence generation techniques for finite state machines (FSM) to generate sequences for protocols specified as incomplete finite state machines. / For real protocols, tests can be designed based on the formal specification of the protocol which uses an extended FSM model in specifying the transition types. The transition types are transformed into a simpler form called normal form transitions which can be modelled by a control and a data flow graph. Furthermore, the data flow graph is partitioned to obtain disjoint blocks representing the different functions of the protocol. Tests are designed by considering parameter variations of the input primitives of each data flow function and determining the expected outputs. This methodology gives complete test coverage of all data flow functions and tests for unspecified cases can be designed using the control and data flow graphs. The methodology is applied to two real protocols: Transport protocols Classes 0 and 2.

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A mobile social network (MSN) is defined as a mobile network that uses social relationships to allow its nodes to communicate. Many wireless networks including ad hoc networks do not reflect a real world deployment because of routing implementation difficulties. However, with the enormous use of social network sites (SNSs) including Twitter and Facebook, MSNs are expected to make the implementation of routing easier. Thus, some research activity has been devoted to routing protocols in such networks. This task is very challenging, thus only a few MSN routing protocols have been proposed in the literature. However, these protocols suffer from either a low delivery ratio or high memory requirements. This thesis presents a new routing protocol (Status) for MSNs which has excellent performance in terms of delivery ratio and memory requirements. Status takes advantage of the online status of a node to make forwarding decisions. Status has a low overhead ratio, low average delay and low computational complexity at the node level. All of these features are examined in this thesis. Simulation results are presented which show that Status outperforms other routing protocols such as Epidemic and PRoPHET with a realistic mobility model, namely, the shortest path movement based model (SPMBM). Status does not have high memory requirements since it does not store the online status of other nodes. Instead, an instance check is done when two nodes meet. Since messages are forwarded without probability calculations based on contact history, Status also has low computational complexity. / Graduate

Traditional reliable unicast protocols (e.g., TCP), known as sender-initiated schemes, do not scale well for one-to-many reliable multicast due mainly to implosion losses caused by excessive rate of feedback packets arriving from receivers. So, recent multicast protocols have been devised following the receiver- initiated approach: scalability (in terms of control traffic, protocol state and end-systems processing requirements) is achieved by making the sender independent from receivers; the sender does not know the membership of the destination group. However, this comes with a cost: the lack of knowledge about and control of receivers at the sender has negative implications with respect to throughput, network cost (bandwidth required), and degree of reliability offered to applications. This thesis follows an alternative approach: instead of adopting the receiver-initiated scheme, it greatly enhances the scalability of the sender-initiated scheme, by means of polling-based feedback and hierarchy. The resulting protocol is named PRMP: polling-based Reliable Multicast protocol. Its unique implosion avoidance mechanism polls receivers at carefully planned timing instants achieving a low and uniformly distributed rate of feedback packets. The sender retains controls of receivers: the main PRMP mechanisms are based on a one-to-many sliding window mechanism, which efficiently and elegantly extends the abstraction from reliable unicasting to reliable multicasting. The error control mechanism of PRMP incorporates the use of NACKs and selective, cumulative acknowledgment of packets; additionally, it can wait and judiciously decide between multicast and selective unicast retransmissions. The flow control mechanism prevents unnecessary losses caused by the overrunning of receivers, despite variations in round-trip times and application speeds. The scalability provided by the polling mechanism is further extended by an hierarchic organization to exploit distributed processing and local recovery: receivers are organized according to a tree-structure. However, unlike other tree-based protocols, PRMP is "fully-hierarchic": each parent node forwards data via multicast to its children, and retains/explores the control of and knowledge about its children while autonomously applying error, flow, congestion and session controls in the communication with them. Two congestion control mechanisms, one window-based and another rate-based, have been incorporated to PRMP. As shown through simulation experiments, the resulting protocol q,chieves high though put with cost- effective reliable multicasting. They also show the scalability and effectiveness of PRMP mechanisms. PRMP can achieve reliable multicast with the same kind of reliability guarantees provided by TCP but without incurring prohibitive costs in terms of network cost or recovery latency found in other protocols.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 42-44).