A process calculus for Mobile Ad Hoc Networks

Abstract

a b s t r a c tWe present the ω-calculus, a process calculus for formally modeling and reasoning about Mobile Ad Hoc Wireless Networks (MANETs) and their protocols. The ω-calculus naturally captures essential characteristics of MANETs, including the ability of a MANET node to broadcast a message to any other node within its physical transmission range (and no others), and to move in and out of the transmission range of other nodes in the network. A key feature of the ω-calculus is the separation of a node's communication and computational behavior, described by an ω-process, from the description of its physical transmission range, referred to as an ω-process interface.Our main technical results are as follows. We give a formal operational semantics of the ω-calculus in terms of labeled transition systems and show that the state reachability problem is decidable for finite-control ω-processes. We also prove that the ω-calculus is a conservative extension of the π-calculus, and that late bisimulation equivalence (appropriately lifted from the π-calculus to the ω-calculus) is a congruence. Congruence results are also established for a weak version of late bisimulation equivalence, which abstracts away from two types of internal actions: τ -actions, as in the π-calculus, and µ-actions, signaling node movement. We additionally define a symbolic semantics for the ω-calculus extended with the mismatch operator, along with a corresponding notion of symbolic bisimulation equivalence, and establish congruence results for this extension as well. Finally, we illustrate the practical utility of the calculus by developing and analyzing formal models of a leader election protocol for MANETs and the AODV routing protocol.

A Step Towards Checking Security in IoT

“…[16,18] to cite only a few. Also relevant are the papers that formalised wireless, sensor and ad hoc networks, among which [17,20,19]. We shared many design choices with the above-mentioned proposals, while the main difference consists in the underlying coordination model.…”

A Timed Process Algebra for Wireless Networks with an Application in Routing

“…If the routing table entry to oip is invalidated by exp rt, its expiration time ltime nhip N # (oip) is extended by DELETE PERIOD. This preserves (34). Pro 5, Line 2: The argument is exactly as in the previous case, but using RREP instead of RREQ and dip instead of oip.…”

“…A potential cause of routing loops, sketched in Figure 1, is a situation where a node B has a valid 12 By a plausible interpretation of a protocol standard written in English prose we mean an interpretation that fills the missing bits, and resolves ambiguities and contradictions occurring in the standard in a sensible and meaningful way. 13 The proofs in [30] and [3] are incorrect; the model of [34] We refer to this scenario as a case of premature route expiration.…”

“…An update cannot make a valid entry invalid, erase an invalid entry, or shorten the lifetime of an entry. For this reason, (34) is maintained under applications of update. The same applies to applications of setTime rt.…”

“…Hence invariant (34) is maintained. Using the antecedent of (33), ltime ip N (oip) ≥ now N ≥ now N # , so (34) implies that the routing table entry to oip cannot be deleted by exp rt. If the routing table entry to oip is invalidated by exp rt, its expiration time ltime nhip N # (oip) is extended by DELETE PERIOD.…”