1. Mobile Networking Challenges1 5.6 Mobile Ad Hoc Networks  Ad hoc network does not have any preexisting centralized server nodes to perform packet routing, directory assistance, service discovery, resource management, and signaling.  MANET is defined as including both fully mobile multihop ad hoc networks and hybrid ad hoc networks.  A variety of potential applications Rescue operations and disaster recovery Military operations in a battlefield Conferences and events Remote monitoring and surveillance system Vehicular communication system

2. Mobile Networking Challenges2 5.6.1 MANET Categories  A vast of research effort in the domain of mobile computing. Topology control Routing Service discovery and access Data acquisition and aggregation Security and privacy 5.6.2 Topology Control in a MANET  Two key issues of topology control in a MANET 1. neighbor discovery 2. network organization  The basic idea is described as follows: Given a transmission graph that models node connectivity of a MANET, find a distributed algorithm that generates a subgraph comprised of optimal paths between any nodes with respect to network throughput and power consumption.

3. Mobile Networking Challenges3 5.6.3 Routing in MANET Routing protocols for MANET proactivehybridreactive DSDVOLSR2RP DSR AODV FSR TORA ABR

4. Mobile Networking Challenges4  Table 5.2 Unicast Ad Hoc Routing Protocols DSDVOLSRDSRAODVTORA Routing method Proactive On-demand Neighbor discovery Periodical broadcast of “hello” messages Multipoint relay of link state messages N/A Periodical broadcast of “hello” messages N/A Communi- cation overhead High LowMedium Routing delay No delay No delay if a route cache is available No delay No delay if a route cache is available

5. Mobile Networking Challenges5 LARLandmarkGrid Network organization Flat Hierarchy based on well-known root nodes Hierarchical grid Location discovery N/A Path to the root nodes Position in the grid Location maintenance On-demand Location server for each node Selected nodes in the grid hierarchy Communication overhead LowMediumHigh Scalability LowMediumHigh  Table 5.3 Location Based Ad Hoc Routing Protocols

6. Mobile Networking Challenges6 5.6.4 Service Discovery  To a mobile node, a MANET is a virtual server that provides a number of services. Network services, such as point-to-point or group communication, mobile access proxying, network performance monitoring, or power alert. Computational services, such as distributed job scheduling, distributed storage, or distributed caching. Application services, such as printing, web caching, or web services.

7. Mobile Networking Challenges7  Table 5.4 Service Discovery Protocols Universal Plug and Play (uPnP) JiniRendezvous Service Location Protocol (SLP) Directory NoYes Optional directory Addressing Dynamic host configuration protocol (DHCP) or auto IP Not specified Dynamic configuration of IPv4 link-local address Not specified Service discovery Simple service discovery protocol (SSDP) Directory-assisted remote method invocation (RMI) Multicast DNS service discovery (mDNS-SD) Multicast lookup Service locator and attributes Standard Service invocation Simple object access protocol (SOAP) Java ’ s RMI Not specified Not specified Communication method Unicast and multicast Multicast Service event and status notification Eventing and polling Notification Notification and polling Not specified

8. Mobile Networking Challenges8 5.7 Quality of Service in Mobile Computing  Quality of service (QoS) in a network refers to the capability of the network to prioritize traffic and guarantee performance of data communication. 5.7.1 An Overview of QoS  Key elements of a QoS provisioning mechanism are listed as follows: Traffic classification and marking - the process of classifying traffic into a set of classes Traffic policing - the process of discarding traffic that exceeds a profile Traffic scheduling and shaping - the process of controlling multiple queues and possibly delaying or dropping some packets according of some rules Resource reservation and signaling protocols - the process of explicitly reserving and allocating network resources such as bandwidth for specific traffic Admission control - the process of deciding if a packet stream should be allowed to enter a network

9. Mobile Networking Challenges9 5.7.2 End-to-End QoS Support in Mobile Computing  QoS provision in wireless networks is performed in one of two ways: resource reservation before traffic begins to flow or per-hop differentiated treatment while the traffic is flowing in the network  Some fundamental differences between wireless and wired networks have created an array of challenging issues in providing QoS in wireless networks and interconnected wireless systems. Link bandwidth on QoS Link quality on QoS Mobility on QoS Mobile devices on QoS