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   5 <TITLE>IP Routing Simulation</TITLE>
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   9 <font color="black" size="4" face="arial"><h1>IP Routing Simulation</h1></font>
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  11 <a href="http://www.raduniversity.com">Back to Rad University</a>&nbsp;&nbsp;&nbsp;
  12 <a href="#Questions">How to Use This Applet</a><br><br>
  13
  14 <APPLET CODE="mtutr/IPKit.class" ARCHIVE="mtutr.jar" width=750 height=640>
  15
  16 </APPLET>
  17
  18 <br><br>
  19 Written by:
  20 <ul type="disc">
  21 <li>Gil Messerman</li>
  22 <li>Gilad Karni</li>
  23 <li>Uri Braun</li>
  24 </ul>
  25
  26 Written for "Protocols and Computer Networks" course at Tel Aviv University.
  27
  28 <br><br>
  29 -------------------------------------------------------------------------------
  30 <br><br>
  31 <a name="Questions"></a><h2>Questions: How do I...</h2>
  32
  33 <a name="Network"></a><img src="21.gif" width = 70 height = 48>
  34 <br><b>Network</b> <ul type="disc">
  35 <li><a href="#Adding a network">Add a network</a></li>
  36 <li><a href="#Adding a host to a network">Add a host to a network</a></li>
  37 <li><a href="#Editing a network">Edit a network</a></li>
  38         <ul type="disc">
  39         <li><a href="#Defining network's address pool">Define network's address pool</a></li>
  40         <li><a href="#Defining network's MTU">Define network's MTU</a></li>
  41         </ul>
  42
  43 <li><a href="#Set network's default gateway">Set network's default gateway</a></li>
  44 <li><a href="#Connecting a router to a network">Connect a network to a router \ Disconnect a network from a router</a></li>
  45 <li><a href="#Removing a network">Remove a network</a></li>
  46 </ul>
  47
  48 <a href="#"></a>
  49
  50 <a name="Router"></a><img src="29.gif">
  51 <br><b>Router</b> <ul type="disc">
  52 <li><a href="#Adding a router">Add a router</a></li>
  53 <li><a href="#Editing a router">Edit a router</a></li>
  54 <li><a href="#Connecting a router to a network">Disconnect a router from a network \ Disconnect a router from a network</a></li>
  55 <li><a href="#Removing a router">Remove a router</a></li>
  56 </ul>
  57
  58 <a name="Host"></a><img src="19.gif">
  59 <br><b>Host</b> <ul type="disc">
  60 <li><a href="#Adding a host to a network">Add a host to a network</a></li>
  61 <li><a href="#Removing a host">Remove a host</a></li>
  62 </ul>
  63
  64 <a name="Datagram"></a><img src="10.gif">
  65 <br><b>Datagram</b> <ul type="disc">
  66 <li><a href="#Adding a datagram">Add a datagram</a></li>
  67 <li><a href="#Editing a datagram">Edit a datagram</a></li>
  68         <ul type="disc">
  69         <li><a href="#Setting a datagram's source & target hosts">Set a datagram's source & target hosts</a></li>
  70         <li><a href="#Setting a datagram's source host">Set a datagram's source host</a></li>
  71         <li><a href="#Setting a datagram's target host">Set a datagram's target host</a></li>
  72         <li><a href="#Setting a datagram's length">Set a datagram's length</a></li>
  73         <li><a href="#Setting a datagram's TTL">Set a datagram's TTL</a></li>
  74         </ul>
  75 <li><a href="#Sending a datagram">Send a datagram</a></li>
  76 <li><a href="#Removing a datagram">Remove a datagram</a></li>
  77 </ul>
  78
  79 <a name="FAQ"></a><b>FAQ</b> <ul type="disc">
  80 <li><a href="#PlaceNetworks">What is the purpose of "<b><i>Place Networks</i></b>"?</a></li>
  81 <li><a href="#Why can't I add a host to a network?">Why can't I add a host to a network?</a></li>
  82 <li><a href="#RemoveAll">How can I remove all objects from main panel?</a></li>
  83 <li><a href="#Why can't I send a datagram?">Why can't I send a datagram?</a></li>
  84 <li><a href="#How does a host gets its IP address?">How does a host get its IP address?</a></li>
  85 </ul>
  86
  87
  88
  89
  90 <br>---------------------------------------------------------------------------<br>
  91
  92 <h2>Answers: How do you...</h2>
  93 <a name=""></a>
  94
  95 <img src="21.gif" width = 70 height = 48>
  96 <br><b>Network</b> <ul type="disc">
  97 <li><a name="Adding a network"></a><u>Add a network</u>
  98 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
  99         <br>
 100         <br><ul type="disc">Right clicking on the main panel will cause a menu to pop up.
 101         <br>Choose "<i><b>Add Network</b></i>" and a new network will show up on the main panel.<br><img src="3.jpg"></ul>
 102         <br>
 103 <li><a name="Adding a host to a network"></a><u>Add a host to a network</u>
 104 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 105         <ul type="disc">
 106         <br>Right clicking on the network will cause a menu to pop up.
 107         <br>Choose "<i><b>Add Host</b></i>" and a host will be added to the network.
 108         <br><img src="2.jpg"><br>
 109         <br><a href="#Why can't I add a host to a network?"><b>FAQ</b></a> - "<i><b>Add Host</b></i>" is disabled. Why can't I add a host to a network?
 110         <br><a href="#How does a host gets its IP address?"><b>FAQ</b></a> - How does a host gets its IP address?</ul>
 111         <br>
 112 <li><a name="Editing a network"></a><u>Edit a network</u>
 113 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 114         <ul type="disc">
 115         <br>
 116         <a name="IPPoolDefine"></a>
 117         <li><a name="Defining network's address pool"></a><u>Define network's address pool</u>
 118         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 119                 <ul type="disc">
 120                 <br>Right click on the network you want to edit.
 121                 <br>A menu will pop up. Choose "<i><b>Edit Network</b></i>" and a window with the network properties will be opened.
 122                 <br><img src="15.jpg">
 123                 <br>You can also double-click on the network in order to open the same window.
 124                 <br>
 125                 <br>In that window you can define the network's address pool (Class based or CIDR based).
 126                 <br><img src="5.jpg">
 127                 <br>
 128                 <br>After defining a network's address pool the network's address
 129                 <br>pool will appear on the network's icon:
 130                 <br><img src="22.jpg">
 131                 <br>
 132                 <br></ul>
 133         <li><a name="Defining network's MTU"></a><u>Define network's MTU</u>
 134         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 135                 <ul type="disc">
 136                 <br>Right click on the network you want to edit.
 137                 <br>A menu will pop up. Choose "<i><b>Edit Network</b></i>" and a window with the network properties will be opened.
 138                 <br><img src="15.jpg">
 139                 <br>You can also double-click on the network in order to open the same window.
 140                 <br>
 141                 <br>In that window you can define the network's MTU.
 142                 <br><img src="20.jpg">
 143                 <br></ul>
 144         </ul>
 145         <br>
 146 <li><a name="Set network's default gateway"></a><u>Set network's default gateway</u>
 147 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 148         <ul type="disc">
 149         <br>When connecting a network to a router for the first time,
 150         <br>the router is automatically set to be the network's default gateway.
 151         <br>
 152         <br>The default gateway of a network is denoted with a "<b>d</b>" on the line
 153         <br>connecting the network and the default gateway.
 154         <br><img src="13.jpg"><br>
 155         <br>
 156         <br>However, if your network is connected to more than one router and you
 157         <br>want to change the default gateway of network, you need to perform
 158         <br>a right click on the selected network and choose "<i><b>Set Default Gateway</b></i>"
 159         <br>on the menu that will pop up.
 160         <br><img src="32.jpg">
 161         <br>
 162         <br>A bar indicating you are now choosing the default gateway will appear at the head of the main panel.
 163         <br><img src="17.jpg">
 164         <br>
 165         <br>Then, all possible default gateways will be marked with a <font color="blue" size="3" face="arial">blue</font> rectangle.
 166         <br>You can choose any of them to be the default gateway of the network.
 167         <br>The Chosen default gateway will be marked with a <font color="green" size="3" face="arial">green</font> rectangle.
 168         <br><img src="6.jpg">
 169         <br>
 170         <br>When you're done choosing the default gateway, click the button "<i><b>Done</b></i>" at the bar at the head of the panel.
 171         <br>The default gateway will be set.
 172         <br>
 173         <br>Read more about removing default gateways <a href="#removedg">here</a>.
 174         </ul>
 175         <br>
 176 <li><u>Connect a network to a router \ Disconnect a network from a router</u>
 177 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 178         <ul type="disc">
 179         <br>
 180         <a href="#Connecting a router to a network">Click Here</a></ul>
 181         <br>
 182 <li><a name="Removing a network"></a><u>Remove a network</u>
 183 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Network">Network</a></font></li>
 184         <ul type="disc">
 185         <br>Right clicking on a network will cause a menu to pop up.
 186         <br>Choose "<i><b>Remove Network</b></i>".
 187         <br><img src="27.jpg">
 188         <br>
 189         <br>The network will be removed from the main panel along with its hosts.
 190         <br>
 191         </ul>
 192 </ul>
 193
 194 <br><br>---------------------------------------------------------------------------<br><br>
 195
 196
 197 <img src="29.gif"><br>
 198 <b>Router</b> <ul type="disc">
 199 <li><a name="Adding a router"></a><u>Add a router</u>
 200 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Router">Router</a></font></li>
 201         <ul type="disc"><br>Right clicking on the main panel will cause a menu to pop up.
 202         <br>Choose "<i><b>Add Router</b></i>" and a new router will show up on the main panel.
 203         <br><img src="4.jpg">
 204         <br>
 205         <br></u></ul>
 206
 207 <li><a name="Editing a router"></a><u>Edit a router</u>
 208 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Router">Router</a></font></li>
 209         <br>
 210         <br>Right clicking on the router will cause a menu to pop up.
 211         <br>Choose "<i><b>Edit Routing Table</b></i>".
 212         <br><img src="16.jpg"><br>
 213         <br>
 214         <br>This will cause an opening of a new window:
 215         <br><img src="43.jpg">
 216         <br>
 217         <br>This window allows the user to define a routing table for the selected router.
 218         <br>The structure of a routing table is a list of lines where each line contains 4 elements:
 219         <br>
 220         <table cellpadding="14">
 221                 <tr>
 222                         <td valign="top"><b>Network destination</b></td>
 223                         <td>Used to define destination network. This value is compared with part of datagram's target
 224                                 <br>IP address according to <b>Netmask</b> value. The network destination value might be either
 225                                 <br>IP address of one of the defined networks or an address that aggregates several networks
 226                                 <br>(supernet).
 227                                 <br>For example in order to route a datagram to either network 192.168.10.0 or
 228                                 <br>192.168.11.0 using same <b>Interface</b> of selected router, the user may define network
 229                                 <br>destination to be 192.168.0.0 with appropriate <b>Netmask</b> (255.255.0.0).</td>
 230                 </tr>
 231                 <tr>
 232                         <td valign="top"><b>Netmask</b></td>
 233                         <td>Used to differ the prefix of datagram's target IP, which should be compared with the current
 234                                 <br>entry's <b>Network destination</b> value.</td>
 235                 </tr>
 236                 <tr>
 237                         <td valign="top"><b>Next hop</b></td>
 238                         <td>Used to define a router to which a datagram will be forwarded from current router in case
 239                                 <br><b>Network Destination</b> matches to defined prefix of datagram's target IP address.
 240                                 <br>Two different cases of selection are available for this field:
 241                                 <ol type="i" start="1">
 242                                         <li>In case the datagram's destination network is not one of the networks that selected router
 243                                                 <br>is connected to, the user should select the next hop to be a router's IP address that will
 244                                                 <br>handle this datagram further.</li>
 245                                         <li>In case the router is connected directly to datagram's destination network,
 246                                         <br>then the user should select the IP address of the selected router (on this network).
 247                                         <br>In other words, in case the value of this field is an address of the selected router
 248                                         <br>itself, the system will attempt to send the datagram directly to the target host.</li>
 249                                 </ol></td>
 250                 </tr>
 251                 <tr>
 252                         <td valign="top"><b>Interface</b></td>
 253                         <td>Used to select router's network connection to which datagram will be forwarded if this routing table entry
 254                                 <br>will match the datagram's target IP address.</td>
 255                 </tr>
 256         </table>
 257         <br> In addition, to the right of each line, there is a "<b><i>Remove</i></b>" button that, when pressed, deletes the appropriate line from the table.
 258         <br>
 259         <br> To add a new empty line to routing table the user should click "<b><i>Add new line</i></b>" button. The empty line will appear
 260         <br> and it must be properly configured, before saving the table or moving to another line in routing table.
 261         <br>
 262         <br> In order to create basic routing table, which will be based on current configuration, the user may click, "<b><i>Add entries for
 263         <br> each interface</i></b>" button. This will add a line for each connected network, which configures the ability to
 264         <br> forward datagrams directly to hosts that are connected to selected router's network.
 265         <br>
 266         <br> In order to create a default routing entry in routing table (to indicate where to forward a datagram that does not
 267         <br> match any of other entries) the user may click "<b><i>Add default entry</i></b>" button. This will add a line where
 268         <br> network destination and netmask will match to any datagram and all user has to do is to configure where the datagram
 269         <br> should be forwarded.
 270         <br>
 271         <br>
 272 <li><a name="Connecting a router to a network"></a><u>Connect a router to networks \ Disconnect a router from networks</u>
 273 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Router">Router</a></font></li>
 274         <ul type="disc">
 275         <br>Right clicking on the router will cause a menu to pop up.
 276         <br>Choose "<i><b>Connect to Networks</b></i>".
 277         <br><img src="9.jpg"><br>
 278         <br>A bar will show up in the head of the applet indicating you are now connecting the router to a network.
 279         <br><img src="30.jpg">
 280         <br>
 281         <br>A click on a network will mark it with a <font color="green" size="3" face="arial">green</font> rectangle.
 282         <br>Another click will unmark the <font color="green" size="3" face="arial">green</font> rectangle.
 283         <br>The <font color="green" size="3" face="arial">green</font> rectangle indicates that the router is connected to the
 284         <br>network.
 285         <br><img src="8.jpg">
 286         <br>
 287         <br>When you finish connecting \ disconnecting, click the button "<i><b>Done</b></i>" at the bar at the head of the panel.
 288         <br>The connections you chose to make will be performed.
 289         <br><img src="7.jpg">
 290         <br>
 291         <br></u></ul>
 292 <li><a name="Removing a router"></a><u>Remove a router</u>
 293 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Router">Router</a></font></li>
 294         <ul type="disc">
 295         <br>Right clicking on a router will cause a menu to pop up.
 296         <br>Choose "<i><b>Remove Router</b></i>".
 297         <br><img src="28.jpg">
 298         <br>
 299         <br>The router will be removed from the main panel.
 300         <br>
 301         <br><a name="removedg"></a>If you'll choose to remove a router that is happen to be a default gateway
 302         <br>of a certain network, three cases are possible:
 303                 <ol type="i" start="1">
 304                 <li><u>The network is not connected to other routers besides the default gateway</u>:
 305                 <br>In this case, a message notifying that the default gateway has been removed
 306                 <br>will be presented on the screen.</li>
 307                 <li><u>There's exactly one more router connected to the network besides the default gateway</u>:
 308                 <br>In this case, the other router will be automatically set to be the default gateway.</li>
 309                 <li><u>The network is connected to more than one router besides the default gateway</u>:
 310                 <br>In this case, the user will have the option to choose the default gateway of the network.</li>
 311         </ol>
 312         </ul>
 313 </ul>
 314
 315 <br><br>---------------------------------------------------------------------------<br><br>
 316
 317 <img src="19.gif"><br>
 318 <b>Host</b> <ul type="disc">
 319 <li><a name="Adding a host to a network"></a><u>Add a host to a network</u>
 320 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Host">Host</a></font></li>
 321         <ul type="disc">
 322         <br>Right clicking on a network will cause a menu to pop up.
 323         <br>Choose "<i><b>Add Host</b></i>" and a host will be added to the network.
 324         <br><img src="2.jpg">
 325         <br>
 326         <br><a href="#Why can't I add a host to a network?"><b>FAQ</b></a> - "<i><b>Add Host</b></i>" is disabled. Why can't I add a host to a network?
 327         <br><a href="#How does a host gets its IP address?"><b>FAQ</b></a> - How does a host gets its IP address?
 328         <br>
 329         <br></ul>
 330 <li><a name="Removing a host"></a><u>Remove a host</u>
 331 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Host">Host</a></font></li>
 332         <ul type="disc">
 333         <br>Right clicking on a host will cause a menu to pop up.
 334         <br>Choose "<i><b>Remove Host</b></i>". The host will be removed from the main panel.
 335         <br><img src="26.jpg"><br></ul>
 336 </ul>
 337
 338 <br><br>---------------------------------------------------------------------------<br><br>
 339
 340 <img src="10.gif"><br>
 341 <b>Datagram</b> <ul type="disc">
 342 <li><a name="Adding a datagram"></a><u>Add a datagram</u>
 343 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 344         <ul type="disc">
 345         <br>Right clicking on the main panel will cause a menu to pop up.
 346         <br>Choose "<i><b>Add Datagram</b></i>" and a new datagram will show up on the main panel.
 347         <br><img src="1.jpg">
 348         <br>
 349         <br></ul>
 350 <li><a name="Editing a datagram"></a><u>Edit a datagram</u>
 351 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 352         <ul type="disc"><br>
 353         <li><a name="Setting a datagram's source & target hosts"></a><u>Set a datagram's source & target hosts</u></li>
 354                 <ul type="disc">
 355                 <br>Right clicking on a datagram will cause a menu to pop up.
 356                 <br>Choose "<i><b>Set Source & Target</b></i>".
 357                 <br><img src="34.jpg">
 358                 <br>
 359                 <br>A bar saying you now have to select the source host will appear
 360                 <br>at the head of the panel.
 361                 <br><img src="36.jpg">
 362                 <br>
 363                 <br>You can, obviously, select only one source.
 364                 <br>Select the source host by clicking it.
 365                 <br>A successful selection will result in marking the host with a green rectangle.
 366                 <br><img src="18.jpg">
 367                 <br>
 368                 <br>When finishing selecting the source host, click "<i><b>Done</b></i>" at the bar at the head of the panel.
 369                 <br>The bar will then instruct you to select the target host.
 370                 <br><img src="37.jpg">
 371                 <br>
 372                 <br>Repeat the process above for the target host.
 373                 <br>
 374                 <br></ul>
 375         <li><a name="Setting a datagram's source host"></a><u>Set a datagram's source host</u>
 376         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 377                 <ul type="disc">
 378                 <br>Right clicking on a datagram will cause a menu to pop up.
 379                 <br>Choose "<i><b>Set Source Only</b></i>".
 380                 <br><img src="33.jpg">
 381                 <br>
 382                 <br>A bar saying you now have to select the source host will appear
 383                 <br>at the head of the panel.
 384                 <br><img src="36.jpg">
 385                 <br>
 386                 <br>You can, obviously, select only one source.
 387                 <br>Select the source host by clicking it.
 388                 <br>A successful selection will result in marking the host with a green rectangle.
 389                 <br><img src="18.jpg">
 390                 <br>
 391                 <br>When finishing selecting the source host, click "<i><b>Done</b></i>" at the bar at the head of the panel.
 392                 <br>
 393                 <br></ul>
 394         <li><a name="Setting a datagram's target host"></a><u>Set a datagram's target host</u>
 395         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 396                 <ul type="disc">
 397                 <br>Right clicking on a datagram will cause a menu to pop up.
 398                 <br>Choose "<i><b>Set Target Only</b></i>".
 399                 <br><img src="35.jpg">
 400                 <br>
 401                 <br>A bar saying you now have to select the target host will appear
 402                 <br>at the head of the panel.
 403                 <br><img src="37.jpg">
 404                 <br>
 405                 <br>You can, obviously, select only one target.
 406                 <br>Select the target host by clicking it.
 407                 <br>A successful selection will result in marking the host with a green rectangle.
 408                 <br><img src="18.jpg">
 409                 <br>
 410                 <br>When finishing selecting the target host, click "<i><b>Done</b></i>" at the bar at the head of the panel.
 411                 <br>
 412                 <br></ul>
 413         <li><a name="Setting a datagram's length"></a><u>Set a datagram's length</u>
 414         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 415                 <ul type="disc">
 416                 <br>Right clicking on a datagram will cause a menu to pop up.
 417                 <br>Choose "<i><b>Edit Datagram</b></i>". A window with the datagram properties will be opened.
 418                 <br><img src="14.jpg">
 419                 <br>
 420                 <br>Double-clicking on a datagram will also open the same window.
 421                 <br>
 422                 <br>In that window you can select the datagram's length at the appropriate field.
 423                 <br><img src="11.jpg">
 424                 <br>
 425                 <br></ul>
 426         <li><a name="Setting a datagram's TTL"></a><u>Set a datagram's TTL</u>
 427         <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 428                 <ul type="disc">
 429                 <br>Right clicking on a datagram will cause a menu to pop up.
 430                 <br>Choose "<i><b>Edit Datagram</b></i>". A window with the datagram properties will be opened.
 431                 <br><img src="14.jpg">
 432                 <br>
 433                 <br>Double-clicking on a datagram will also open the same window.
 434                 <br>
 435                 <br>In that window you can select the datagram's TTL at the appropriate field.
 436                 <br><img src="12.jpg">
 437                 <br>
 438                 <br></ul>
 439         </ul>
 440 <li><a name="Sending a datagram"></a><u>Send a datagram</u>
 441 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 442         <ul type="disc">
 443         <br>Right clicking on a datagram will cause a menu to pop up.
 444         <br>Choose "<i><b>Send Datagram</b></i>" and the datagram will be sent.
 445         <br><img src="31.jpg">
 446         <br>
 447         <br>While sending a datagram a bar appears at the head of the main panel.
 448         <br>This bar gives information concerning the datagram traveling through the network.
 449         <br><img src="38.jpg">
 450         <br>
 451         <br>The "<b><i>Stop Simulation</i></b>" button will stop the simulation a short time after pressing it.
 452         <br>
 453         <br>When arriving a network, the bar will show the network's MTU:
 454         <br><img src="39.jpg">
 455         <br>
 456         <br>When arriving a router, the bar will show the entry in the router routing table that was chosen:
 457         <br><img src="40.jpg">
 458         <br>
 459         <br>The bar is also used for error reporting in the sending process.
 460         <br>For example:
 461         <br><img src="41.jpg">
 462         <br><img src="42.jpg">
 463         <br>And more...
 464         <br>
 465         <br><u>Datagram Fragmentation</u>
 466         <br>In case the datagram has to be fragmented, the datagram icon will be changed from &nbsp; <img src="10.gif"> &nbsp; to &nbsp;<img src="44.gif">.
 467         <br>Also, the number of fragments will be shown in the brackets, next to the fragmented datagram icon:
 468         <br><img src="45.jpg">
 469         <br>
 470         <br>More information concerning the number of fragments, and the length of each fragment can be found
 471         <br>in the bar at the head of the main panel:
 472         <br><img src="46.jpg">
 473         <br>
 474         <br><a href="#Why can't I send a datagram?"><b>FAQ</b></a> - "<i><b>Send Datagram</b></i>" is disabled. Why can't I send my datagram?
 475         <br>
 476         <br></ul>
 477 <li><a name="Removing a datagram"></a><u>Remove a datagram</u>
 478 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#Datagram">Datagram</a></font></li>
 479         <ul type="disc">
 480         <br>Right clicking on a datagram will cause a menu to pop up.
 481         <br>Choose "<i><b>Remove Datagram</b></i>". The datagram will be removed from the main panel.
 482         <br><img src="25.jpg">
 483         <br>
 484         <br></ul>
 485 </ul>
 486
 487 <br><br>---------------------------------------------------------------------------<br><br>
 488
 489
 490 <b>FAQ</b> <ul type="disc">
 491 <li><a name="PlaceNetworks"></a><u>What is the purpose of "<b><i>Place Networks</i></b>"?</u>
 492 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#FAQ">FAQ</a></font></li>
 493         <ul type="disc">
 494         <br>"<b><i>Place Networks</i></b>" menu item allows you to use predefined networks.
 495         <br>These networks are built-in in the applet.
 496         <br>After placing them on the panel, you may edit them as you like.
 497         <br><img src="23.jpg">
 498         <br>
 499         <br>Three networks are available in the "<b><i>Place Networks</i></b>" menu:
 500         <br>
 501         <br>
 502         <ol type="i" start="1">
 503                 <li><b>Star</b> - This network is constructed of three main networks connected using
 504                 <br>a router to each other. Each of these main networks is connected to another two
 505                 <br>"sub-networks".
 506                 <br>Hosts are allocated only in the "sub-networks".
 507                 <br>All routers are already configured to transfer datagrams between the hosts.
 508                 <br>Determine datagram's source and target, and send it.
 509                 <br>
 510                 <br>
 511                 </li>
 512                 <li><b>Loop</b> - This network simulates an error in the configuration of the routers.
 513                 <br>The source and the target of the datagram are already determined.
 514                 <br>Simply send the datagram and watch what happens.
 515                 <br>
 516                 <br>
 517                 </li>
 518                 <li><b>Long</b> - This network is constructed of a list of routers and networks.
 519                 <br>Routers are not configured.
 520                 <br>You may add networks, hosts, routers, datagrams and configure them as you like.
 521                 <br>
 522                 <br>
 523                 </li>
 524         </ol>
 525 </ul>
 526 <li><a name="Why can't I add a host to a network?"></a><u>Why can't I add a host to a network?</u>
 527 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#FAQ">FAQ</a></font></li>
 528         <ul type="disc">
 529         <br>First <a href="#IPPoolDefine">define an IP address for your network</a>.
 530         <br>Then, you will be able to add hosts to your network.
 531         <br>
 532         <br></ul>
 533 <li><a name="RemoveAll"></a><u>How can I remove all objects from main panel?</u>
 534 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#FAQ">FAQ</a></font></li>
 535         <ul type="disc">
 536         <br>A right click on the main panel will open a pop-up menu.
 537         <br>Select "<i><b>Remove All</b></i>" and the main panel will be cleaned of objects.
 538         <br><img src="24.jpg">
 539         <br>
 540 <br></ul>
 541 <li><a name="Why can't I send a datagram?"></a><u>Why can't I send a datagram?</u>
 542 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#FAQ">FAQ</a></font></li>
 543         <ul type="disc">
 544         <br>First <a href="#Setting a datagram's source & target hosts">define the datagram's source and target</a>.
 545         <br>Then, you will be able to send the datagram.
 546         <br>
 547         <br></ul>
 548 <li><a name="How does a host gets its IP address?"></a><u>How does a host get its IP address?</u>
 549 <br><font color="black" size="2" face="arial">Back to: <a href="#Top">Top</a> | <a href="#Questions">Questions</a> | <a href="#FAQ">FAQ</a></font></li>
 550         <ul type="disc">
 551         <br> After the user has defined an IP address for a network, the network is responsible for allocating IP
 552         <br> addresses for any peripherals (hosts and routers) that are connected to it. The pool of addresses
 553         <br> is defined by network address. When creating a new host or connecting a router to the network, a free
 554         <br> address from the pool is allocated. When a host is being removed or a router is being disconnected
 555         <br> from a network, its IP address is deallocated and returned to pool.
 556         <br>
 557         <br> Please note that allocation of addresses is not necessarily successive (e.g. for class C network
 558         <br> 192.168.2.0 allocation of addresses for 2 hosts might return 192.168.2.1 and 192.168.2.3).
 559         </ul>
 560 </ul>
 561
 562 </font>
 563
 564 </BODY>
 565 </HTML>