Wireless Networks - Chapter 15

List and briefly define some of the key Android system services.

Android OS: - Android OS is a mobile OS developed by Google. - The Android OS is mainly used for touchscreen mobiles, tables and devices. - The Android OS can manipulate mobile Devices with finger movements that can mirror common motions such as tapping swiping and pinching. - Google employs this OS in watches televisions and cars. Android System services: - Activity Manager - Window Manager - Content Providers - View System - Notification Manager - Power Manager Activity Manager: - Activity Manager can manage the lifecycle of the android applications - It can stop, start, and resume various android applications Window Manager: - Window Manager can facilitate apps to define their client area, and utilize features such as the status bar Content Providers: - Content Providers can encapsulate app data to be shared between android apps View System: - View system can offer the user interface primitives such as list boxes, buttons, data pickers, and UI events Notification Manager: - The notification manager can manage events such as appointments and receiving messages Power Manager: - The power manager can enhance the capability to perform power management and offer an interface to the Linux kernel features added

List and briefly define the architecture layers of Android

Android OS: - Android OS is a mobile OS developed by Google. - The Android OS is mainly used for touchscreen mobiles, tables and devices. - The Android OS can manipulate mobile Devices with finger movements that can mirror common motions such as tapping swiping and pinching. - Google employs this OS in watches televisions and cars. Architecture layers of Android: - Application and Framework layer and API - Binder Inter- Process Communication (Binder IPC) - Android system services. - Android runtime or Dalvik layer. - Hardware Abstraction Layer. - Linux Kernel API Application and Framework: - API and Application and Framework layer facilitate access to lower layer services. - It also offers high-level building blocks that coders utilize to build new applications. - It can also offer a set of general-purpose applications. Binder IPC: - Binder IPC can facilitate the application framework in crossing process boundaries and call into the service code of the Android System. Android System services: - These services can access the underlying kernel functions and hardware. - System services can include Window Manager, Activity Manager, View System, Content Provides, Power Manager, and Notification Manager. Android Runtime or Dalvik layer: - This layer can offer Dalvik virtual machine and the Android runtime component. Hardware Abstraction Layer: - This layer can offer a standard interface to device drivers of the kernel layer. Linux Kernel: - The linux kernel can offer core system services such as memory management, security, process management, driver model, and network stack. - This kernel can also act as an abstraction layer between the software stack and the hardware.

Describe the Android activity lifecycle

Android activity lifecycle: Six callbacks: - onCreate(): called when the activity is created first - onStart(): called when the activity becomes evident to the user. - onResume(): called when the activity jumps to interact with the user. - onPause(): called when the activity becomes obscure to the user. - onStop(): called when the activity is no longer evident to the user. - onDestroy(): called when the activity is demolished

What features unique to mobile devices are typically accessible via APIs by programmers?

Application Programming Interface (API): - An API is a set of protocols, routines, and tools to build software applications. - An API can specify how software components must interact. - Also APIs can be used while coding Graphical User Interface (GUI) components. Accessible features: APIs usually facilitate the programmer in accessing the following features: - GUI interaction with the user. - Communication with remote servers. - Available sensor data. - Account authentication and access.

What is the relationship between Mobile IP discovery and ICMP?

Mobile IP discovery: The Mobile IP has three fundamental operations and they are as follows: • Discovery. • Registration. • Tunneling. In Mobile IP discovery, a mobile node makes use of discovery functions for recognizing foreign agents and home agents. Internet Control Message Protocol (ICMP): The Internet Protocol standard requires that an implementation must implement ICMP. • ICMP can offer a way to transfer messages from a router to a host or one host to another. • ICMP can also offer feedback about issues in the communication environment. Relationship between ICMP and Mobile IP discovery: The relationship between ICMP and Mobile IP discovery is provided below: • The discovery operation in the Mobile IP is same as that of the router advertisement operations in the Internet Control Message Protocol. • Agent discovery can utilize router advertisement messages of ICMP with one or more extensions very specific to the Mobile IP. Therefore, the Mobile IP discovery can make use of the existing Internet Control Message Protocol. By adding suitable extensions to the ICMP, the existing ICMP can be used by the Mobile IP discovery

What is tunneling?

Mobile Internet Protocol (Mobile IP): • With the extensive increase in the popularity of mobile systems, Mobile IP was designed for enabling computer systems for maintaining Internet connectivity when going from one Internet connection point to another. • To support the Mobile IP operations, the mobile IP has three capabilities; the capabilities are listed below: o Discovery. o Registration. o Tunneling Tunneling: • Tunneling is defined as a process in which an Internet Protocol datagram is encapsulated with an outer Internet Protocol header. • Tunneling can transmit the Internet Protocol datagram across the Internet utilizing the destination address and the outer header's parameters. • Tunneling can be used for forwarding Internet Protocol datagrams from a home address (HA) to a care-of address (CoA).

List and briefly define the capabilities provided by Mobile IP.

Mobile Internet Protocol (Mobile IP): • With the extensive increase in the popularity of mobile systems, Mobile IP was designed. • Mobile IP can facilitate computer systems to preserve Internet connectivity when going from one Internet connection point to another. • To support the Mobile IP operations, the mobile IP has three capabilities; the capabilities are listed below: o Discovery. o Registration. o Tunneling. Discovery: • A mobile node can use a discovery process for identifying prospective foreign agents and foreign agents. Registration: • A mobile node can use an authenticated registration process for informing its home agent of its care-of address. Tunneling: • Tunneling can be used for forwarding Internet Protocol datagrams from a home address (HA) to a care-of address (CoA).

Explain the distinction between a mobile user and a nomadic user.

Mobile User: is a user who connects to one or more apps in the internet is called mobile user. Nomadic user: is a user who wanders around the environment is called nomadic user. Mobile User vs Nomadic user: Mobile User: - User can connect to one or more apps in the internet - The point of attachment of the user changes dynamically - Automatically all connections are maintained regardless of the dynamic change of point of attachment Nomadic User: - User wanders around the environment - The point of attachment of the user changes dynamically - The connection will be automatically terminated when the user moves. The user has to manually dial back in for a new connection

What are the two different types of destination addresses that can be assigned to a mobile node while it is attached to a foreign network?

Mobile node: • A router or a host that changes its point of connection from one subnetwork or network to another is called a mobile node. • A mobile node can change its location without changing its Internet Protocol address. It can communicate continuously with other nodes at any location using its constant Internet Protocol address. Types of address: When a mobile node is attached to a foreign network, the destination address that can be assigned to the node is of two types and they are as follows: • Foreign agent address. • Co-located address.

List some commonalities between mobile platform OSs and traditional desktop/ laptop OSs

Operating System (OS) is the most significant program that can run on a computer system and mobile system. - The OS can be used to run software programs and applications. - The OS can perform basic operations such as recognizing input from the input device, sending output to the display device and so on. Commonalities: Some commonalities between traditional desktop operating system and mobile platform operating system are listed below: - Memory management - Process scheduling - Security - Device drivers

What is Dalvik?

Process Virtual Machine: - A process virtual machine can facilitate users to execute a single process as an application on a host machine - Java Virtual Machine (JVM) is one of the best examples of the process virtual machine. - JVM can facilitate any system to execute the Java app as if it was native to the system Dalvik: - Dalvik is a process virtual machine for the Android OS which is very similar to JVM - Dalvik can be implemented for optimizing the mobile platforms on which apps can run by managing resources in a way personalized for mobile platforms - DV can optimize the memory, performance, and battery life of the Android mobile devices

Under what circumstances would a mobile node choose to use each of the types of address referred to in Question 15.11?

Refer to Review Question 15.11 in "Chapter 15" in the textbook. Types of address: When a mobile node is attached to a foreign network, the destination address that can be assigned to the node is of two types and they are as follows: • Foreign agent address. • Co-located address. Circumstances: • When the foreign agent is available on the foreign network, the mobile node chooses to use the foreign agent address. • On the foreign network, when foreign agents are not available or foreign agents are busy, the mobile node chooses to use the co-located address.