## Tuesday, October 21, 2008

This post should be my first post in this blog.

A mobile ad-hoc network (MANET) is a kind of wireless ad-hoc network, and is a self-configuring network of mobile routers (and associated hosts) connected by wireless links – the union of which form an arbitrary topology. The routers are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidly and unpredictably. Such a network may operate in a standalone fashion, or may be connected to the larger Internet.

Mobile ad-hoc networks became a popular subject for research as laptops and 802.11/Wi-Fi wireless networking became widespread in the mid to late 1990s. Many of the academic papers evaluate protocols and abilities assuming varying degrees of mobility within a bounded space, usually with all nodes within a few hops of each other, and usually with nodes sending data at a constant rate. Different protocols are then evaluated based on the packet drop rate, the overhead introduced by the routing protocol, and other measures.

The Children's Machine One Laptop per Child program has developed a cheap laptop for mass distribution (>1 million at a time) to developing countries for education. The laptops will use IEEE 802.11s based ad hoc wireless mesh networking to develop their own communications network out of the box.

Vehicular Ad Hoc Networks (VANET) are a form of MANETs used for communication among vehicles and between vehicles and roadside equipment.

Intelligent vehicular ad hoc network (InVANET) is a kind of Intelligence in Vehicle(s) which provide multiple autonomic intelligent solutions to make automotive vehicles to behave in intelligent manner during vehicle-to-vehicle collisions, accidents, drunken driving etc. InVANET uses WiFi IEEE 802.11 b/802.11g/802.11p and WiMAX IEEE 802.16 for providing easy, accurate, effective communication between multiple vehicles on dynamic mobility. Effective measures to track the automotive vehicles, media download /upload, conference between vehicles are also preferred. InVANET can also be applied for artillery vehicles during warfare, battlefield, and peace-time operations. Mesh networking in mobile applications have been demonstrated in multiple military scenarios.[1]

In September 2007, the Swedish company TerraNet AB presented a mesh network of mobile phones allowing for the routing of calls and data between participating hand sets, without the need to involve cell sites [Source].

## Sunday, October 19, 2008

### DSR

The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. DSR allows the network to be completely self-organizing and self-configuring, without the need for any existing network infrastructure or administration.

DSR has been implemented by numerous groups, and deployed on several testbeds. Networks using the DSR protocol have been connected to the Internet. DSR can interoperate with Mobile IP, and nodes using Mobile IP and DSR have seamlessly migrated between WLANs, cellular data services, and DSR mobile ad hoc networks.

The protocol is composed of the two main mechanisms of "Route Discovery" and "Route Maintenance", which work together to allow nodes to discover and maintain routes to arbitrary destinations in the ad hoc network. All aspects of the protocol operate entirely on-demand, allowing the routing packet overhead of DSR to scale automatically to only that needed to react to changes in the routes currently in use.

The protocol allows multiple routes to any destination and allows each sender to select and control the routes used in routing its packets, for example for use in load balancing or for increased robustness. Other advantages of the DSR protocol include easily guaranteed loop-free routing, support for use in networks containing unidirectional links, use of only "soft state" in routing, and very rapid recovery when routes in the network change. The DSR protocol is designed mainly for mobile ad hoc networks of up to about two hundred nodes, and is designed to work well with even very high rates of mobility (Source).

## Saturday, October 18, 2008

### SAODV

In an ad hoc network, from the point of view of a routing protocol,
there are two kinds of messages: the routing messages and the datamessages. Both have a different nature and different security needs.Data messages are point-to-point and can be protected with any point-to-point security system (like IPSec). On the other hand, routingmessages are sent to immediate neighbors, processed, possiblymodified, and resent.Another consequence of the nature of the transmission of routingmessages is that, in many cases, there will be some parts of thosemessages that will change during their propagation. This is verycommon in Distance-Vector routing protocols, where the routingmessages usually contain a hop count of the route they are requestingor providing. Therefore, in a routing message one could distinguishbetween two types of information: mutable an non-mutable. It isdesired that the mutable information in a routing message is securedin such a way that no trust in intermediate nodes is needed.Otherwise, securing the mutable information will be much moreexpensive in computation, plus the overall security of the systemwill greatly decrease.Moreover, as a result of the processing of the routing message, anode might modify its routing table. This creates the need for theintermediate nodes to be able to authenticate the informationcontained in the routing messages (a need that does not exist inpoint-to-point communications).SAODV is an extension of the AODV routing protocol that protectsthe route discovery mechanism providing security features likeintegrity and authentication. It uses digital signatures toauthenticate the non-mutable fields of the messages, and hash chainsto secure the hop count information (the only mutable information inthe messages).SAODV can use the Simple Ad hoc Key Management (SAKM) as a keymanagement system. (Related link)

## Friday, October 17, 2008

### AODV

The Ad hoc On Demand Distance Vector (AODV) routing algorithm is a routing protocol designed for ad hoc mobile networks. AODV is capable of both unicast and multicast routing. It is an on demand algorithm, meaning that it builds routes between nodes only as desired by source nodes. It maintains these routes as long as they are needed by the sources. Additionally, AODV forms trees which connect multicast group members. The trees are composed of the group members and the nodes needed to connect the members. AODV uses sequence numbers to ensure the freshness of routes. It is loop-free, self-starting, and scales to large numbers of mobile nodes.

As the RREP propagates back to the source, nodes set up forward pointers to the destination. Once the source node receives the RREP, it may begin to forward data packets to the destination. If the source later receives a RREP containing a greater sequence number or contains the same sequence number with a smaller hopcount, it may update its routing information for that destination and begin using the better route.

As long as the route remains active, it will continue to be maintained. A route is considered active as long as there are data packets periodically travelling from the source to the destination along that path. Once the source stops sending data packets, the links will time out and eventually be deleted from the intermediate node routing tables. If a link break occurs while the route is active, the node upstream of the break propagates a route error (RERR) message to the source node to inform it of the now unreachable destination(s). After receiving the RERR, if the source node still desires the route, it can reinitiate route discovery.

Multicast routes are set up in a similar manner. A node wishing to join a multicast group broadcasts a RREQ with the destination IP address set to that of the multicast group and with the 'J'(join) flag set to indicate that it would like to join the group. Any node receiving this RREQ that is a member of the multicast tree that has a fresh enough sequence number for the multicast group may send a RREP. As the RREPs propagate back to the source, the nodes forwarding the message set up pointers in their multicast route tables. As the source node receives the RREPs, it keeps track of the route with the freshest sequence number, and beyond that the smallest hop count to the next multicast group member. After the specified discovery period, the source node will unicast a Multicast Activation (MACT) message to its selected next hop. This message serves the purpose of activating the route. A node that does not receive this message that had set up a multicast route pointer will timeout and delete the pointer. If the node receiving the MACT was not already a part of the multicast tree, it will also have been keeping track of the best route from the RREPs it received. Hence it must also unicast a MACT to its next hop, and so on until a node that was previously a member of the multicast tree is reached.

AODV maintains routes for as long as the route is active. This includes maintaining a multicast tree for the life of the multicast group. Because the network nodes are mobile, it is likely that many link breakages along a route will occur during the lifetime of that route. The papers listed below describe how link breakages are handled. The WMCSA paper describes AODV without multicast but includes detailed simulation results for networks up to 1000 nodes. The Mobicom paper describes AODV's multicast operation and details simulations which show its correct operation. The internet drafts include descriptions of both unicast and multicast route discovery, as well as mentioning how QoS and subnet aggregation can be used with AODV. Finally, the IEEE Personal Communications paper and the Infocom paper details an in-depth study of simulations comparing AODV with the Dynamic Source Routing (DSR) protocol, and examines each protocol's respective strengths and weaknesses. (Source)

## Wednesday, July 2, 2008

### LaTeX

My Professor asked me to write down my thesis by LATEX. Actually, I am not so familiar with LATEX... lets see in wikipedia, what is the meaning of LATEX.
LATEX is a document markup language and document preparation system for the TeX typesetting program. LaTeX is used because of the high quality of typesetting achievable by TeX. The typesetting system offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing, tables and figures, page layout and bibliographies.
Now, how can we use LaTeX? I found a blog which derive us how to install LaTeX. The blog is so familiar with me, thats one of my lecturer blog (Bu Yuhana). She gave us detail information of LaTeX installation in Indonesia Language. So, I try to translate into English in my blog. I install LaTeX on my notebook using windows operating system.
oke, let we try... how powerful LaTex, we will make some introduction by writing "HelloWorld" on LaTeX.
• Open Texmaker and make a new file
• write down this script on Texmaker :
\documentclass{article}

\begin{document}

Hello World!

\end{document}

• Save the document in "Hello.tex"
• Finally, convert the file into PDF by using PDFTEX in tool bar
Here is some references of how to write LaTeX.
http://www.ctan.org/tex-archive/info/lshort/english/lshort.pdf

### Install NS-2.31 on Ubuntu 8.04

Hello everyone... I have done my installation using console mode on my Ubuntu 8.04. Of course your PC should connect to internet to download the source file and update some part of Ubuntu, here are the basic steps of the installation :

$wget http://nchc.dl.sourceforge.net/sourceforge/nsnam/ns-allinone-2.31.tar.gz • Un-tar the source file$tar -xzfv ns-allinone-2.31.tar.gz
• Install build-essential, autoconf, automake & libxmu-dev
$sudo apt-get install build-essential autoconf automake libxmu-dev • Run installation by using this script below. User should in ns-allinone-2.31 directory of ns-allinone$./install

• Setting environment variable
$gedit ~./bashrc Add this script bellow on your bashrc file (the last line), remember to rename "/home/nra" based on your computer name. ------------------------------------------------------------------------------------------- # LD_LIBRARY_PATH OTCL_LIB=/home/nra/ns-allinone-2.31/otcl-1.13 NS2_LIB=/home/nra/ns-allinone-2.31/lib X11_LIB=/usr/X11R6/lib USR_LOCAL_LIB=/usr/local/lib export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$OTCL_LIB:$NS2_LIB:$X11_ LIB:$USR_LOCAL_LIB

# TCL_LIBRARY
TCL_LIB=/home/nra/ns-allinone-2.31/tcl8.4.14/library
USR_LIB=/usr/lib
export TCL_LIBRARY=$TCL_LIB:$USR_LIB

# PATH
XGRAPH=/home/nra/ns-allinone-2.31/bin:/home/nra/
ns-allinone-2.31/tcl8.4.14/unix:/home/nra/ns-allinone-2.31/tk8.4.14/unix
NS=/home/nra/ns-allinone-2.31/ns-2.31/
NAM=/home/nra/ns-allinone-2.31/nam-1.13/
PATH=$PATH:$XGRAPH:$NS:$NAM
----------------------------------------------------------------------------------------------------

Run this script to affect the setting

$source ~./bashrc • Test NS2 installation, run this script. If '%' mark appear it mean your installation is complete. If not, you should reboot your system.$ns
$% • Validate NS2. Under directory ns-allinone-2.31/ns-2.31 run this script. It will take several time to complete the validation.$./validate

Reference : Alkautsarpens

### Hello World

# Introduction of my Blog #
puts "Hello World"
puts "Blog Title : A Little Note about Knowledge"
###################