<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!--Converted with LaTeX2HTML 2017.2 (Released Jan 23, 2017) --> <HTML> <HEAD> <TITLE>4. Quick Intro</TITLE> <META NAME="description" CONTENT="4. 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User Interface Layout</A> <BR> <BR></DIV> <!--End of Navigation Panel--> <!--Table of Child-Links--> <A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A> <UL CLASS="ChildLinks"> <LI><A NAME="tex2html270" HREF="node4.html#SECTION00410000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN> Simple Network Scenario</A> <UL> <LI><A NAME="tex2html271" HREF="node4.html#SECTION00411000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Building a simple network</A> <UL> <LI><A NAME="tex2html272" HREF="node4.html#SECTION00411100000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Adding and deleting network elements</A> <LI><A NAME="tex2html273" HREF="node4.html#SECTION00411200000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Rearranging network elements</A> </UL> <LI><A NAME="tex2html274" HREF="node4.html#SECTION00412000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Configuring a simple network</A> <UL> <LI><A NAME="tex2html275" HREF="node4.html#SECTION00412100000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Hub/LAN switch configuration window</A> <LI><A NAME="tex2html276" HREF="node4.html#SECTION00412200000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> PC/Host/Click router configuration window</A> <UL> <LI><A NAME="tex2html277" HREF="node4.html#SECTION00412210000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> <SPAN CLASS="textit">Static routes</SPAN></A> </UL> <LI><A NAME="tex2html278" HREF="node4.html#SECTION00412300000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">3</SPAN> Router configuration window</A> <UL> <LI><A NAME="tex2html279" HREF="node4.html#SECTION00412310000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">1</SPAN> <SPAN CLASS="textit">Routing models and protocols</SPAN></A> </UL> <LI><A NAME="tex2html280" HREF="node4.html#SECTION00412400000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">4</SPAN> Link configuration window</A> <LI><A NAME="tex2html281" HREF="node4.html#SECTION00412500000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">5</SPAN> Configured network topology</A> </UL> <LI><A NAME="tex2html282" HREF="node4.html#SECTION00413000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN> Simulating a simple network</A> <UL> <LI><A NAME="tex2html283" HREF="node4.html#SECTION00413100000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">1</SPAN> Starting an experiment</A> <LI><A NAME="tex2html284" HREF="node4.html#SECTION00413200000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">2</SPAN> Options from the node and the link menu</A> <LI><A NAME="tex2html285" HREF="node4.html#SECTION00413300000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">3</SPAN> Terminating an experiment</A> </UL> </UL> <BR> <LI><A NAME="tex2html286" HREF="node4.html#SECTION00420000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN> Configuration files management</A> <UL> <LI><A NAME="tex2html287" HREF="node4.html#SECTION00421000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Saving a virtual network configuration</A> <LI><A NAME="tex2html288" HREF="node4.html#SECTION00422000000000000000"><SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> Opening a virtual network configuration</A> </UL></UL> <!--End of Table of Child-Links--> <HR> <H1><A NAME="SECTION00400000000000000000"> <SPAN CLASS="arabic">4</SPAN>. Quick Intro</A> </H1> <P> <H1><A NAME="SECTION00410000000000000000"></A> <A NAME="sec:SimpleNetworkScenario"></A> <BR> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN> Simple Network Scenario </H1> In this section we will show how to build, configure and simulate the following simple network topology: <P> Personal computers (<SPAN CLASS="textit">office-pc1</SPAN> and <SPAN CLASS="textit">office-pc2</SPAN>) from the network 192.168.1.0/24 are connected to the LAN switch (<SPAN CLASS="textit">office-switch</SPAN>) which is connected to the router (<SPAN CLASS="textit">office-router</SPAN>). The server (<SPAN CLASS="textit">office-host</SPAN>) from the network 192.168.2.0/24 is directly connected to the router (<SPAN CLASS="textit">office-router</SPAN>). Personal computers from the first network have route only to the network 192.168.2.0/24. The server from the second network has the default route. Quagga routing is enabled on the router in order to be able to serve and receive dynamic route updates. <P> <H2><A NAME="SECTION00411000000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Building a simple network</A> </H2> After running IMUNES on FreeBSD with some kind of X11 window manager (see Section <A HREF="node3.html#sec:UserInterfaceLayout">3</A>), we will build previously described network using tools from the toolbox (see Section <A HREF="node3.html#sec:toolbox">3.1</A>). <P> <H3><A NAME="SECTION00411100000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Adding and deleting network elements</A> </H3> To draw a node click on the corresponding node tool and then click on the workspace to place it. To connect nodes click on the <SPAN CLASS="textit">Link tool</SPAN>, then click and hold on the source node and go to the destination node. <P> Now draw a router, a host, a LAN switch and two PCs. Using the <SPAN CLASS="textit">Link tool</SPAN> connect the LAN switch to the router and then connect each PC to the LAN switch. Connect the host directly to the router. The created network topology should look like the one in Figure <A HREF="#fig:simple_topology">4.1</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:simple_topology"></A><A NAME="780"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.1:</STRONG> <SPAN CLASS="textit">Simple network topology</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="1022" HEIGHT="778" ALIGN="BOTTOM" BORDER="0" SRC="./simple_topology.png" ALT="Image simple_topology"></TD></TR> </TABLE> </DIV> <P> When nodes are connected with the <SPAN CLASS="textit">Link tool</SPAN> (the direction does not matter), the source node, the destination node and the link automatically get preconfigured parameters. When a mouse pointer is above a node or a link, some of the configured parameters are shown on the left side of the statusbar placed at the bottom of the window (Figure <A HREF="#fig:statusbar_node">4.2</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:statusbar_node"></A><A NAME="781"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.2:</STRONG> <SPAN CLASS="textit">Node parameters in the statusbar</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="749" HEIGHT="19" ALIGN="BOTTOM" BORDER="0" SRC="./statusbar1.png" ALT="Image statusbar1"></TD></TR> </TABLE> </DIV> <P> Some of the parameters can be visible on the canvas: interface names (link layer: e0, e1, e2 and network layer: eth0, eth1), IPv4/IPv6 addresses of network layer elements (PC, host, router), node names (router1, host1, switch1, pc1, pc2) and link labels (Bandwidth, Delay, BER or Duplicate if their values are not default). <P> You can manipulate with the visibility of nodes and links parameters from the View menu (Figure <A HREF="#fig:view_menu1">4.3</A>). In this simple scenario we do not want for IPv6 addresses to be visible, so we will turn the <SPAN CLASS="textit">Show IPv6 Addresses</SPAN> option off. <P> <DIV ALIGN="CENTER"><A NAME="fig:view_menu1"></A><A NAME="782"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.3:</STRONG> <SPAN CLASS="textit">Show or hide nodes and links parameters</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="208" HEIGHT="209" ALIGN="BOTTOM" BORDER="0" SRC="./view_menu1.png" ALT="Image view_menu1"></TD></TR> </TABLE> </DIV> <P> To delete the network element select it using the <SPAN CLASS="textit">Select tool</SPAN> and then use the <SPAN CLASS="textit">Delete</SPAN> keyboard button. You can also delete it by right clicking on it and clicking on the <SPAN CLASS="textit">Delete</SPAN> label in the popped up menu. The node deletion is automatically followed by the deletion of associated links. <P> <H3><A NAME="SECTION00411200000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Rearranging network elements</A> </H3> You can change position of the network element (node or link) and/or the node name. To move both the network element and its name select the network element with the <SPAN CLASS="textit">Select tool</SPAN> and drag it to the designated position. To move only the node name select it with the <SPAN CLASS="textit">Select tool</SPAN> and drag it to the designated position. <P> Using the <SPAN CLASS="textit">Select tool</SPAN> you can also move around a group of connected nodes which can be selected using the <SPAN CLASS="textit">Ctrl</SPAN> keyboard button in addition to the left click. To select the whole network topology use <SPAN CLASS="textit">Select All</SPAN> option from the <SPAN CLASS="textit">Edit</SPAN> menu. <P> For automatic rearranging of all network elements or rearranging the selected group of network elements use <SPAN CLASS="textit">Rearrange</SPAN> and <SPAN CLASS="textit">Rearrange All</SPAN> options from the <SPAN CLASS="textit">Tools</SPAN> menu. To stop the rearranging process click with the <SPAN CLASS="textit">Select tool</SPAN>. <P> <H2><A NAME="SECTION00412000000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Configuring a simple network</A> </H2> <P> Although preconfigured parameters of network elements are usually sufficient to start a simulation (automatically provided IPv4/IPv6 addresses, the default static route on the PC and the host and routing model and protocols parameters on the router as well), in this scenario we will set up our own parameters. <P> To open the network element configuration window: <UL> <LI>right click on the network element and select the <SPAN CLASS="textit">Configure</SPAN> label from the popped up menu (Figure <A HREF="#fig:configure_label">4.4</A>) <P> or <P> </LI> <LI>double click on the network element. </LI> </UL> <P> <DIV ALIGN="CENTER"><A NAME="fig:configure_label"></A><A NAME="783"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.4:</STRONG> <SPAN CLASS="textit">Configure a network element</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="183" HEIGHT="240" ALIGN="BOTTOM" BORDER="0" SRC="./configure_label.png" ALT="Image configure_label"></TD></TR> </TABLE> </DIV> <P> Network elements configuration parameters can be also changed through the topology tree. To show the topology tree turn on the <SPAN CLASS="textit">Show Topology Tree</SPAN> option from the <SPAN CLASS="textit">View</SPAN> menu. The tree with a list of network topology elements (nodes and links) will be shown on the right side of the window (Figure <A HREF="#fig:topology_tree">4.5</A>). To open the network element configuration window double click or use the <SPAN CLASS="textit">Enter</SPAN> keyboard button on node, interface or link label in the topology tree. <P> <DIV ALIGN="CENTER"><A NAME="fig:topology_tree"></A><A NAME="784"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.5:</STRONG> <SPAN CLASS="textit">Changing configuration parameters through the topology tree</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="1022" HEIGHT="778" ALIGN="BOTTOM" BORDER="0" SRC="./topology_tree.png" ALT="Image topology_tree"></TD></TR> </TABLE> </DIV> <P> Depending on the type of a network element in our topology, there are 4 types of configuration windows: <P> <UL> <LI><SPAN CLASS="textit">Hub/LAN switch configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">PC/Host/Click router configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">Router configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">Link configuration</SPAN> window </LI> </UL> <P> There are also other types of configuration windows which are explained in other sections: <P> <UL> <LI><SPAN CLASS="textit">External interface configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">External connection configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">NAT64 configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">RSTP switch configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">Filter node configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">Packet generator configuration</SPAN> window </LI> <LI><SPAN CLASS="textit">Click switch configuration</SPAN> window </LI> </UL> <P> <H3><A NAME="SECTION00412100000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Hub/LAN switch configuration window</A> </H3> The <SPAN CLASS="textit">hub/LAN switch configuration</SPAN> window, as well as the configuration windows of other node types, contains a node name field. Besides that it contains only link layer interface parameters. <P> We will change the LAN switch name and data packet scheduling method (from preconfigured First In First Out (FIFO) data packet scheduling method to Weighted Fair Queuing (WFQ) method). <P> Change the node name to <SPAN CLASS="textit">office-switch</SPAN>. To change data packet scheduling method select the link layer interface <SPAN CLASS="textit">e0</SPAN> from the list of interfaces, choose <SPAN CLASS="textit">WFQ</SPAN> option from the <SPAN CLASS="textit">Queue</SPAN> menu and click on the <SPAN CLASS="textit">Apply</SPAN> button (Figure <A HREF="#fig:LANswitch_config">4.6</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:LANswitch_config"></A><A NAME="785"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.6:</STRONG> <SPAN CLASS="textit">LAN switch configuration window</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="454" HEIGHT="326" ALIGN="BOTTOM" BORDER="0" SRC="./LANswitch_config.png" ALT="Image LANswitch_config"></TD></TR> </TABLE> </DIV> <P> Packet scheduling method is now applied and you can see new queuing discipline for interface <SPAN CLASS="textit">e0</SPAN> in the column <SPAN CLASS="textit">Queue disc</SPAN> (Figure <A HREF="#fig:LANswitch_config_applied">4.7</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:LANswitch_config_applied"></A><A NAME="786"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.7:</STRONG> <SPAN CLASS="textit">LAN switch configuration window with applied changes</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="454" HEIGHT="326" ALIGN="BOTTOM" BORDER="0" SRC="./LANswitch_config_applied.png" ALT="Image LANswitch_config_applied"></TD></TR> </TABLE> </DIV> <P> Repeat the same procedure for the other link layer interfaces. Changed configuration is already applied so you can close the configuration window with the <SPAN CLASS="textit">Cancel</SPAN> button but you can also use the <SPAN CLASS="textit">Apply and Close</SPAN> button. <P> <H3><A NAME="SECTION00412200000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> PC/Host/Click router configuration window</A> </H3> The <SPAN CLASS="textit">PC/Host/Click router configuration</SPAN> window consists of two subwindows. Each of them is associated with one of the following tabs: <SPAN CLASS="textit">Configuration</SPAN> and <SPAN CLASS="textit">Interfaces</SPAN> (Figure <A HREF="#fig:pc_config_tabs">4.8</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_config_tabs"></A><A NAME="787"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.8:</STRONG> <SPAN CLASS="textit">Tabs in the PC/Host/Click router configuration window</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="517" HEIGHT="103" ALIGN="BOTTOM" BORDER="0" SRC="./pc_config_tabs.png" ALT="Image pc_config_tabs"></TD></TR> </TABLE> </DIV> <P> Besides a node name field, <SPAN CLASS="textit">PC/Host/Click router configuration</SPAN> window contains startup services, routing parameters and custom configuration parameters (in the window associated with the <SPAN CLASS="textit">Configuration</SPAN> tab) and network interface parameters (in the window associated with the <SPAN CLASS="textit">Interfaces</SPAN> tab). <P> We will change the node name, network interface parameters and routing parameters. <P> Change the host node name to <SPAN CLASS="textit">office-host</SPAN> and PC node names to <SPAN CLASS="textit">office-pc1</SPAN> and <SPAN CLASS="textit">office-pc2</SPAN>. To change IPv4 address left click on the <SPAN CLASS="textit">Interfaces</SPAN> tab, select interface <SPAN CLASS="textit">eth0</SPAN> from the list of interfaces, change the IPv4 address field and click on the <SPAN CLASS="textit">Apply</SPAN> button (Figure <A HREF="#fig:pc_config_ipv4">4.9</A>). We will change the host IPv4 address field to 192.168.2.5/24 (now it belongs to 192.168.2.0/24) and PC IPv4 address fields to 192.168.1.5/24 and 192.168.1.7/24 (now they belong to network 192.168.1.0/24). IP address fields require the CIDR notation, so the IPv4 address is followed by a slash and a network length. <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_config_ipv4"></A><A NAME="788"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.9:</STRONG> <SPAN CLASS="textit">Changing IPv4 address</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="517" HEIGHT="513" ALIGN="BOTTOM" BORDER="0" SRC="./pc_config_ipv4.png" ALT="Image pc_config_ipv4"></TD></TR> </TABLE> </DIV> <P> <H4><A NAME="SECTION00412210000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> <SPAN CLASS="textit">Static routes</SPAN></A> </H4> <P> PCs and Hosts both use static routing. The preconfigured routing table contains only the default route. Every static route, as well as the default route, consists of: <OL> <LI>the destination network: an IP address which is followed by a slash and a network prefix and </LI> <LI>the next hop network interface IP address (which is an IP address without a slash and without a network prefix). </LI> </OL> <P> If the route syntax is wrong, that route will be silently ignored. <P> We will add the static route on <SPAN CLASS="textit">office-pc1</SPAN> and <SPAN CLASS="textit">office-pc2</SPAN> for the network 192.168.2.0/24 through the gateway 192.168.1.1 (Figure <A HREF="#fig:pc_config_staticroutes">4.10</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_config_staticroutes"></A><A NAME="790"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.10:</STRONG> <SPAN CLASS="textit">Adding the static route on the PC</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="109" ALIGN="BOTTOM" BORDER="0" SRC="./pc_config_staticroutes.png" ALT="Image pc_config_staticroutes"></TD></TR> </TABLE> </DIV> <P> On <SPAN CLASS="textit">office-host</SPAN> we will change default gateway address to 192.168.2.1 (Figure <A HREF="#fig:host_config_staticroutes">4.11</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:host_config_staticroutes"></A><A NAME="791"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.11:</STRONG> <SPAN CLASS="textit">Adding the static route on the PC</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="109" ALIGN="BOTTOM" BORDER="0" SRC="./host_config_staticroutes.png" ALT="Image host_config_staticroutes"></TD></TR> </TABLE> </DIV> <P> IPv6 addresses and default routes (placed below IPv4 addresses and routes) can be deleted. <P> To apply the changed configuration and close the configuration window click on the <SPAN CLASS="textit">Apply and Close</SPAN> button. <P> <H3><A NAME="SECTION00412300000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">3</SPAN> Router configuration window</A> </H3> The <SPAN CLASS="textit">router configuration window</SPAN>, in addition to fields from <SPAN CLASS="textit">PC/Host/Click router configuration</SPAN> window, contains the part for choosing the routing model and protocols, as well as an <SPAN CLASS="textit">IPsec</SPAN> tab with IPsec parameters (See IPsec Section TODO). <P> We will only change the node name and network interface parameters. <P> Change the node name to <SPAN CLASS="textit">office-router</SPAN> and IPv4 addresses on both network interfaces: 192.168.1.1/24 on the network interface <SPAN CLASS="textit">eth0</SPAN> and 192.168.2.1/24 on the network interface <SPAN CLASS="textit">eth1</SPAN>. <P> <H4><A NAME="SECTION00412310000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">1</SPAN> <SPAN CLASS="textit">Routing models and protocols</SPAN></A> </H4> <P> There are three possible routing models: <OL> <LI>the quagga model </LI> <LI>the xorp model (eXtensible Open Router Platform) </LI> <LI>the static model </LI> </OL> <P> In the case of quagga and xorp routing models, there are options for enabling/disabling RIP, RIPng, OSPFv2 and OSPFv3. By default, all new quagga or xorp router instances will have both RIPv2 and RIPng enabled. The defaults can be changed with the <SPAN CLASS="textit">Tools <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Routing protocol defaults</SPAN> option from the menubar, which will be applied to all selected routers (if any) at the time of change, as well as to all the subsequentially created ones (see Section <A HREF="node5.html#sec:RoutingProtocolDefaults">5.3.5</A>). In the case of static routing model, the router uses routes from the static routes field that has the same syntax as the static routes field in the <SPAN CLASS="textit">PC/Host/Click router configuration</SPAN> window. <P> We will leave the default router model - quagga with RIP and RIPng protocols enabled, and OSPFv2 and OSPFv3 protocols disabled (Figure <A HREF="#fig:router_config_routingmodels">4.12</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:router_config_routingmodels"></A><A NAME="793"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.12:</STRONG> <SPAN CLASS="textit">Routing models and protocols</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="517" HEIGHT="155" ALIGN="BOTTOM" BORDER="0" SRC="./router_config_routingmodels.png" ALT="Image router_config_routingmodels"></TD></TR> </TABLE> </DIV> <P> <H3><A NAME="SECTION00412400000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">4</SPAN> Link configuration window</A> </H3> The <SPAN CLASS="textit">link configuration</SPAN> window offers the possibility to configure the link bandwidth (between 0 and 10<SUP>9</SUP> bps), the propagation delay (between 0 and 10<SUP>7</SUP> <SPAN CLASS="MATH"><IMG WIDTH="13" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img2.png" ALT="$\mu$"></SPAN>s), the bit error rate (between 0 and 10<SUP>12</SUP>) and the probability of package duplication (between 0 and 50%). There are also display properties: the link width (line thickness between 1 and 8) and the link color (red, green, blue, yellow, magenta, cyan or black). <P> <DIV ALIGN="CENTER"><A NAME="fig:link_config"></A><A NAME="794"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.13:</STRONG> <SPAN CLASS="textit">Link configuration window</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="251" HEIGHT="293" ALIGN="BOTTOM" BORDER="0" SRC="./link_config.png" ALT="Image link_config"></TD></TR> </TABLE> </DIV> <P> Default values are as follows: the link which transmits packets without errors and without any possibility for the packet duplication with the unlimited link bandwidth and the zero propagation delay. The link width is set to value 2 and the link color is red. <P> We will leave default values on all links except on the link between <SPAN CLASS="textit">office-switch</SPAN> and <SPAN CLASS="textit">office-router</SPAN> (Figure <A HREF="#fig:configured_topology">4.14</A>). On that link we will set up the delay of 30000 <SPAN CLASS="MATH"><IMG WIDTH="13" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img2.png" ALT="$\mu$"></SPAN>s. Delay will be tested during the network simulation with the <SPAN CLASS="textit">traceroute</SPAN> tool (see Section <A HREF="#sec:NodeandLinkMenuOptions">4.1.3</A>). <P> <H3><A NAME="SECTION00412500000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">5</SPAN> Configured network topology</A> </H3> Configured network topology should look like the one in Figure <A HREF="#fig:configured_topology">4.14</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:configured_topology"></A><A NAME="795"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.14:</STRONG> <SPAN CLASS="textit">Configured network topology</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="843" HEIGHT="707" ALIGN="BOTTOM" BORDER="0" SRC="./simple_topology_configured.png" ALT="Image simple_topology_configured"></TD></TR> </TABLE> </DIV> <P> <H2><A NAME="SECTION00413000000000000000"></A> <A NAME="sec:simulating_a_simple_network"></A> <BR> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN> Simulating a simple network </H2> <P> <H3><A NAME="SECTION00413100000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">1</SPAN> Starting an experiment</A> </H3> After the network topology is completely built and properly configured, we will start an experiment with the <SPAN CLASS="textit">Experiment <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Execute</SPAN> option from the menubar and IMUNES will switch from the edit mode to the execute mode. In the process of starting an experiment, IMUNES creates and configures the virtual network. That will take a few seconds and all events during that process will be shown in the statusbar placed at the bottom of the window. <P> <SPAN CLASS="textbf">NOTE:</SPAN> Although you can draw network topology on any system that supports Tcl/Tk (Linux, FreeBSD, Windows, Mac OS X, Solaris), an experiment can only be started on FreeBSD and Linux operating systems with root permissions (Figure <A HREF="#fig:execute_windows">4.15</A> and Figure <A HREF="#fig:execute_not_root">4.16</A>)! <P> <DIV ALIGN="CENTER"><A NAME="fig:execute_windows"></A><A NAME="796"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.15:</STRONG> <SPAN CLASS="textit">Starting an experiment in Windows</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="412" HEIGHT="113" ALIGN="BOTTOM" BORDER="0" SRC="./execute_windows.png" ALT="Image execute_windows"></TD></TR> </TABLE> </DIV> <P> <DIV ALIGN="CENTER"><A NAME="fig:execute_not_root"></A><A NAME="797"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.16:</STRONG> <SPAN CLASS="textit">Starting an experiment in FreeBSD without root permissions</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV><IMG WIDTH="380" HEIGHT="137" ALIGN="BOTTOM" BORDER="0" SRC="./execute_not_root.png" ALT="Image execute_not_root"></TD></TR> </TABLE> </DIV> <P> In addition to configured parameters, each node will be set with the loopback interface, a router will have the kernel forwarding enabled, and a host node will have portmap and inetd started. <P> Information about the time spent instantiating the network topology is shown in the statusbar (Figure <A HREF="#fig:statusbar_execute">4.17</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:statusbar_execute"></A><A NAME="798"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.17:</STRONG> <SPAN CLASS="textit">Message about the instantiation of the network topology</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="869" HEIGHT="19" ALIGN="BOTTOM" BORDER="0" SRC="./statusbar3.png" ALT="Image statusbar3"></TD></TR> </TABLE> </DIV> <P> In the right corner of the statusbar you can also see that IMUNES now works in the execute mode, as well as experiment unique identifier. <P> <H3><A NAME="SECTION00413200000000000000"></A> <A NAME="sec:NodeandLinkMenuOptions"></A> <BR> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">2</SPAN> Options from the node and the link menu </H3> To open the node menu in the execute mode right click on the node. Note that the menu in the execute mode is different from the menu in the edit mode. It offers the possibility to select the node connected to this node (<SPAN CLASS="textit">Select adjacent</SPAN>), to see the current configuration (<SPAN CLASS="textit">Configure</SPAN>), to <SPAN CLASS="textit">Start / Stop / Restart</SPAN> the network element, to start / stop / restart any of the possible <SPAN CLASS="textit">Services</SPAN> or to <SPAN CLASS="textit">Import Running Configuration</SPAN> from the <SPAN CLASS="textit">Settings</SPAN> menu. The <SPAN CLASS="textit">Import Running Configuration</SPAN> option copies the current MTU value and IPv4/IPv6 addresses from the running node to its configuration. It is also possible to open the <SPAN CLASS="textit">Shell window</SPAN> (X terminal with a Unix shell), <SPAN CLASS="textit">Wireshark</SPAN> or <SPAN CLASS="textit">tcpdump</SPAN> network sniffers on any of the interfaces, <SPAN CLASS="textit">Firefox</SPAN> <SPAN CLASS="textit">Web Browser</SPAN> or a <SPAN CLASS="textit">Mail client</SPAN>. <P> <DIV ALIGN="CENTER"><A NAME="fig:execute_menu"></A><A NAME="799"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.18:</STRONG> <SPAN CLASS="textit">Network-layer node menu in the execute mode</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="178" HEIGHT="303" ALIGN="BOTTOM" BORDER="0" SRC="./execute_menu.png" ALT="Image execute_menu"></TD></TR> </TABLE> </DIV> <P> Note that both the node and the link menu in the execute menu offer the possibility to open the configuration window (<SPAN CLASS="textit">Configure</SPAN> label). <P> From the node configuration window in the execute mode it is possible to change only the node name. Other node parameters such as link layer interface parameters, network interface parameters and routing parameters can be changed from the shell window on each node. To change those parameters from the node configuration window, stop the node (using the <SPAN CLASS="textit">Stop</SPAN> label), change parameters and then start the node agin (using the <SPAN CLASS="textit">Start</SPAN> label). <P> On the other side, from the link configuration window in the execute mode it is possible to change the following link parameters: link bandwidth, the propagation delay, the bit error rate and the probability of package duplication. It is also possible to change display properties: the link width and the link color. <P> We will now check if the virtual network topology is properly configured. Open the shell window (e.g. <SPAN CLASS="textit">Shell window</SPAN> <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> <SPAN CLASS="textit">csh</SPAN> or simply double click on the node) on the network element (e.g. <SPAN CLASS="textit">office-pc1</SPAN>). <UL> <LI>To check the network interface eth0 parameters type the following command: <TT>ifconfig eth0</TT>. The result is shown in Figure <A HREF="#fig:pc_ifconfig">4.19</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_ifconfig"></A><A NAME="800"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.19:</STRONG> <SPAN CLASS="textit">Shell window on office-pc1, network interface parameters</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="166" ALIGN="BOTTOM" BORDER="0" SRC="./pc_ifconfig.png" ALT="Image pc_ifconfig"></TD></TR> </TABLE> </DIV> <P> </LI> <LI>To check static routes type the following command: <TT>netstat -nrf inet</TT>. The result is shown in Figure <A HREF="#fig:pc_netstat">4.20</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_netstat"></A><A NAME="801"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.20:</STRONG> <SPAN CLASS="textit">Shell window on office-pc1, static routes</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="166" ALIGN="BOTTOM" BORDER="0" SRC="./pc_netstat.png" ALT="Image pc_netstat"></TD></TR> </TABLE> </DIV> <P> </LI> <LI>To test if a particular network element is reachable (e.g <SPAN CLASS="textit">office-host</SPAN>) type the following command: <TT>ping 192.168.2.5</TT>. The result is shown in Figure <A HREF="#fig:pc_ping">4.21</A>. To stop transmitting packets press <SPAN CLASS="textit">Control-C</SPAN> keyboard button. <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_ping"></A><A NAME="802"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.21:</STRONG> <SPAN CLASS="textit">Shell window on office-pc1, pinging office-host</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="166" ALIGN="BOTTOM" BORDER="0" SRC="./pc_ping.png" ALT="Image pc_ping"></TD></TR> </TABLE> </DIV> <P> </LI> </UL> <P> We will test delay on the link between <SPAN CLASS="textit">office-switch</SPAN> and <SPAN CLASS="textit">office-router</SPAN>, which is set to 30000 <SPAN CLASS="MATH"><IMG WIDTH="13" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img2.png" ALT="$\mu$"></SPAN>s (30 ms), by using the <SPAN CLASS="textit">traceroute</SPAN> tool: <UL> <LI>In the shell window on <SPAN CLASS="textit">office-pc1</SPAN> type the following command: <BR><TT>traceroute 192.168.1.1</TT>. The result is shown in Figure <A HREF="#fig:pc_traceroute">4.22</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:pc_traceroute"></A><A NAME="803"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.22:</STRONG> <SPAN CLASS="textit">Shell window on office-pc1, traceroute to office-router</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="90" ALIGN="BOTTOM" BORDER="0" SRC="./pc_traceroute.png" ALT="Image pc_traceroute"></TD></TR> </TABLE> </DIV> <P> </LI> <LI>In the shell window on <SPAN CLASS="textit">office-host</SPAN> type the following command: <BR><TT>traceroute 192.168.2.1</TT>. The result is shown in Figure <A HREF="#fig:host_traceroute">4.23</A>. <P> <DIV ALIGN="CENTER"><A NAME="fig:host_traceroute"></A><A NAME="804"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.23:</STRONG> <SPAN CLASS="textit">Shell window on office-host, traceroute to office-router</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="505" HEIGHT="90" ALIGN="BOTTOM" BORDER="0" SRC="./host_traceroute.png" ALT="Image host_traceroute"></TD></TR> </TABLE> </DIV> <P> </LI> </UL> <P> <H3><A NAME="SECTION00413300000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN>.<SPAN CLASS="arabic">3</SPAN> Terminating an experiment</A> </H3> To terminate an experiment and switch from the execute mode to the edit mode use the <SPAN CLASS="textit">Experiment <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Execute</SPAN> option from the menubar. During the termination process, IMUNES will terminate active services on each node and shut down all network elements (links and nodes with both virtual and physical interfaces). The termination is finished when the message about the successful cleanup shows up in the statusbar (Figure <A HREF="#fig:statusbar4">4.24</A>). <P> <DIV ALIGN="CENTER"><A NAME="fig:statusbar4"></A><A NAME="805"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.24:</STRONG> <SPAN CLASS="textit">Message about the successful cleanup</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="771" HEIGHT="19" ALIGN="BOTTOM" BORDER="0" SRC="./statusbar4.png" ALT="Image statusbar4"></TD></TR> </TABLE> </DIV> <P> <H1><A NAME="SECTION00420000000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN> Configuration files management</A> </H1> <P> <H2><A NAME="SECTION00421000000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Saving a virtual network configuration</A> </H2> <P> After the virtual network is successfully built, configured and tested, it can be saved with <SPAN CLASS="textit">File <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Save</SPAN> or <SPAN CLASS="textit">File <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Save As</SPAN> options from the menubar. The virtual network topology is saved in IMUNES network configuration file format (.imn). <P> <DIV ALIGN="CENTER"><A NAME="fig:file_save"></A><A NAME="806"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.25:</STRONG> <SPAN CLASS="textit">File Save dialog</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="441" HEIGHT="286" ALIGN="BOTTOM" BORDER="0" SRC="./file_save.png" ALT="Image file_save"></TD></TR> </TABLE> </DIV> <P> The structure of the configuration file is simple and suitable for changing with a text editor (see Appendix <A HREF="node8.html#sec:IMUNESNetworkConfigurationFile">8</A>). <P> <H2><A NAME="SECTION00422000000000000000"> <SPAN CLASS="arabic">4</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> Opening a virtual network configuration</A> </H2> To open an existing IMUNES network configuration file use the <SPAN CLASS="textit">File <SPAN CLASS="MATH"><IMG WIDTH="20" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img1.png" ALT="$\to$"></SPAN> Open</SPAN> option from the menubar and select it from the invoked <SPAN CLASS="textit">File Open</SPAN> dialog. <P> <DIV ALIGN="CENTER"><A NAME="fig:file_open"></A><A NAME="807"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 4.26:</STRONG> <SPAN CLASS="textit">File Open dialog</SPAN></CAPTION> <TR><TD> <DIV ALIGN="CENTER"> </DIV> <BR> <BR> <IMG WIDTH="441" HEIGHT="286" ALIGN="BOTTOM" BORDER="0" SRC="./file_open.png" ALT="Image file_open"></TD></TR> </TABLE> </DIV> <P> The other way to open an imn file is to start IMUNES with that file as an argument: <TT>imunes simple-topology.imn</TT> <DIV CLASS="navigation"><HR> <!--Navigation Panel--> <A NAME="tex2html268" HREF="node5.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html266" HREF="html_document.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html260" HREF="node3.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <BR> <B> Next:</B> <A NAME="tex2html269" HREF="node5.html">5. 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