Chapter 4

MOBILE DEVICE CONNECTIVITY

IN HOME NETWORKS

Section 4.1

Related Work

4.1 Related Work

Two standardization forums: ->Decentralized home network, targeted for home entertainment applications

1.Home Audio Video interoperability (HAVi) Based on 1394 Quality of Service (QoS). Non-IP networking

2.Digital Living Network Alliance (DLNA) Based on Universal-Plug-and-Play (UPnP) Aims at creating interoperability guidelines based on existing

standards.

4.1 Related Work Open Services Gateway Initiative (OSGi)-

>Centralized A framework that provides API and Java

execution environment for building integrated home networks and adaptation functions between UPnP-controlled devices.

Section 4.2

Basic Home Use Cases

4.2 Basic Home Use Cases

本圖取自 "Technologies for Home Networking". Edited by Sudhir Dixit and Ramjee Prasad, published by John Wiley, 2008.

4.2 Basic Home Use Cases

本圖取自 "Technologies for Home Networking". Edited by Sudhir Dixit and Ramjee Prasad, published by John Wiley, 2008.

Section 4.3

Home Networking Challenges

4.3 Home Networking Challenges

1. Self-configuring Buy-plug-and-play; incremental network deployment Intuitive user interface

2. Self-healing Radio interference Cross-talk Uneven wireless coverage …etc

Provide autoresume; easy-to-understand error explanation; easy-to-use debug tool

3. Security Wired Equivalent Privacy (WEP) Wi-Fi Protected Access (WPA) HTTP Secure (HTTPS) Bluetooth Security UPnP security ...etc

4.3 Home Networking Challenges

4. Remote Access: same experience as at home

Round-trip delay ( GPRS vs. DSL vs. 802.11), Cost ( Cellular vs. 802.11), Capabilities of the devices (Desktop vs. Laptop vs. Mobile

phone).

5. Dynamic IP addresses.6. Mobile devices connecting Users move in and out of range of local access points Battery life Screen size

Section 4.4

Architecture and Technologies for Local and Remote Home

Connectinity

Architecture : Centralized -> Decentralized Automatic configuration and ease-of-use features cannot

rely on a central element to hide technologies behind uniform APIs and middleware.

Based on a layered approach. Lower level : TCP/IP

Middle level: Control technologies ->UPnP , SLP

High level: Applications and media formats ensure interoperability and usability of the system.

4.4.1 Overview of Home Connectivity Architecture

4.4.2 Local Connectivity

本圖取自 "Technologies for Home Networking". Edited by Sudhir Dixit and Ramjee Prasad, published by John Wiley, 2008.

4.4.2 Local Connectivity

Infrastructure-based : AP, switch, router, DHCP server Connect : Fixed

Ad hoc (Peer-to-Peer) based: Connect : Opportunistic Point-to-Point interactions between two

devices

4.4.2 Local Connectivity

Link-level technologies:802.3 (Ethernet 10/100/1000 Mbps): High data-rates, Low delays Used for fixed home devices and mobile (No

moving) Requires cabling the home

802.11 a/b/g (Wi-Fi) Allows for mobility within the home Seamless support for Ethernet and IP Unlicensed spectrum -> Signal fluctuation

4.4.2 Local Connectivity Bluetooth Short-range, Low data-rates Support for Ethernet encapsulation with BENP Mainly used in ad hoc mode

UltraWideBand (UWB; WiMedia) Emerging wireless technology Short-range, High-speed communication Availability of the Wireless USB specification Main issue: Delay the wide deployment in home

networks due to lack of broad consensus in standardization

4.4.2 Local Connectivity

IEEE 802.15.4 Low data-rates (hundreds of Kbps), conserving

power Home automation applications involving sensors

and actuators Suitable for connecting a large number of devices

HomePlug High data-rates ( Tens of Mbps) Plugged in regular electrical power sockets Suitable for transmission of multimedia content

4.4.2 Local Connectivity

IEEE 1394 (FireWire) Serial bus wireline technology Synchronous mode that can guarantee

bandwidth. Suitable for connecting several devices at the

same time Under pressure from USB 2.0

Near-Field Communications (NFC) Two-way communication between two devices Suitable for IP traffic exchange

4.4.2 Local Connectivity

Mobile can use any of the above wireless or wireline

link-level bearers to connect locally.

Two problems to overcome: To reduce power and conserve energy

To deal with frequent disconnections caused by signal fluctuations, interference, user mobility.

4.4.3 Remote ConnectivityThree Challenges:1. A broadband connection uses dynamic IP

addresses that in many cases are not even public.

->Dynamic DNS

2. Traversing firewalls and NATs

3. Ensure the security of the remote connection

VPN (Virtual Private Network)

4.4.3 Remote Connectivity

本圖取自 "Technologies for Home Networking". Edited by Sudhir Dixit and Ramjee Prasad, published by John Wiley, 2008.

4.4.3 Remote Connectivity

Several ways to implement remote access:

1. Proxy solution Use distributed middleware (UPnP) Authentication by TLS/ Secure Sockets Layer

(SSL)

2. VPN-based solution Requires VPN gateway at the Internet gateway

and VPN client at the remote terminal