|  | PRouter | Physical router represents a real testbed machine. |
### Network Nodes
These nodes are mostly used to create a Linux bridge that serves the
purpose described below.
| Icon | Name | Description |
|---|---|---|
|  | Hub | Ethernet hub forwards incoming packets to every connected node. |
|  | Switch | Ethernet switch intelligently forwards incoming packets to attached hosts using an Ethernet address hash table. |
|  | Wireless LAN | When routers are connected to this WLAN node, they join a wireless network and an antenna is drawn instead of a connecting line; the WLAN node typically controls connectivity between attached wireless nodes based on the distance between them. |
|  | RJ45 | RJ45 Physical Interface Tool, emulated nodes can be linked to real physical interfaces; using this tool, real networks and devices can be physically connected to the live-running emulation. |
|  | Tunnel | Tool allows connecting together more than one CORE emulation using GRE tunnels. |
### Annotation Tools
| Icon | Name | Description |
|---|---|---|
|  | Marker | For drawing marks on the canvas. |
|  | Oval | For drawing circles on the canvas that appear in the background. |
|  | Rectangle | For drawing rectangles on the canvas that appear in the background. |
|  | Text | For placing text captions on the canvas. |
### Execution Toolbar
When the Start button is pressed, CORE switches to Execute mode, and the Edit
toolbar on the left of the CORE window is replaced with the Execution toolbar
Below are the items on this toolbar, starting from the top.
| Icon | Name | Description |
|---|---|---|
|  | Stop Button | Stops Execute mode, terminates the emulation, returns CORE to edit mode. |
|  | Selection Tool | In Execute mode, the Selection Tool can be used for moving nodes around the canvas, and double-clicking on a node will open a shell window for that node; right-clicking on a node invokes a pop-up menu of run-time options for that node. |
|  | Marker | For drawing freehand lines on the canvas, useful during demonstrations; markings are not saved. |
|  | Run Tool | This tool allows easily running a command on all or a subset of all nodes. A list box allows selecting any of the nodes. A text entry box allows entering any command. The command should return immediately, otherwise the display will block awaiting response. The *ping* command, for example, with no parameters, is not a good idea. The result of each command is displayed in a results box. The first occurrence of the special text "NODE" will be replaced with the node name. The command will not be attempted to run on nodes that are not routers, PCs, or hosts, even if they are selected. |
## Menu
The menubar runs along the top of the CORE GUI window and provides access to a
variety of features. Some of the menus are detachable, such as the *Widgets*
menu, by clicking the dashed line at the top.
### File Menu
The File menu contains options for manipulating the **.imn** Configuration
Files. Generally, these menu items should not be used in Execute mode.
| Option | Description |
|---|---|
| New Session | This starts a new session with an empty canvas. |
| Save | Saves the current topology. If you have not yet specified a file name, the Save As dialog box is invoked. |
| Save As | Invokes the Save As dialog box for selecting a new **.xml** file for saving the current configuration in the XML file. |
| Open | Invokes the File Open dialog box for selecting a new XML file to open. |
| Recently used files | Above the Quit menu command is a list of recently use files, if any have been opened. You can clear this list in the Preferences dialog box. You can specify the number of files to keep in this list from the Preferences dialog. Click on one of the file names listed to open that configuration file. |
| Execute Python Script | Invokes a File Open dialog box for selecting a Python script to run and automatically connect to. After a selection is made, a Python Script Options dialog box is invoked to allow for command-line options to be added. The Python script must create a new CORE Session and add this session to the daemon's list of sessions in order for this to work. |
| Quit | The Quit command should be used to exit the CORE GUI. CORE may prompt for termination if you are currently in Execute mode. Preferences and the recently-used files list are saved. |
### Edit Menu
| Option | Description |
|---|---|
| Preferences | Invokes the Preferences dialog box. |
| Undo | (Disabled) Attempts to undo the last edit in edit mode. |
| Redo | (Disabled) Attempts to redo an edit that has been undone. |
| Cut, Copy, Paste, Delete | Used to cut, copy, paste, and delete a selection. When nodes are pasted, their node numbers are automatically incremented, and existing links are preserved with new IP addresses assigned. Services and their customizations are copied to the new node, but care should be taken as node IP addresses have changed with possibly old addresses remaining in any custom service configurations. Annotations may also be copied and pasted.
### Canvas Menu
The canvas menu provides commands related to the editing canvas.
| Option | Description |
|---|---|
| Size/scale | Invokes a Canvas Size and Scale dialog that allows configuring the canvas size, scale, and geographic reference point. The size controls allow changing the width and height of the current canvas, in pixels or meters. The scale allows specifying how many meters are equivalent to 100 pixels. The reference point controls specify the latitude, longitude, and altitude reference point used to convert between geographic and Cartesian coordinate systems. By clicking the *Save as default* option, all new canvases will be created with these properties. The default canvas size can also be changed in the Preferences dialog box.
| Wallpaper | Used for setting the canvas background image. |
### View Menu
The View menu features items for toggling on and off their display on the canvas.
| Option | Description |
|---|---|
| Interface Names | Display interface names on links. |
| IPv4 Addresses | Display IPv4 addresses on links. |
| IPv6 Addresses | Display IPv6 addresses on links. |
| Node Labels | Display node names. |
| Link Labels | Display link labels. |
| Annotations | Display annotations. |
| Canvas Grid | Display the canvas grid. |
### Tools Menu
The tools menu lists different utility functions.
| Option | Description |
|---|---|
| Find | Display find dialog used for highlighting a node on the canvas. |
| Auto Grid | Automatically layout nodes in a grid. |
| IP addresses | Invokes the IP Addresses dialog box for configuring which IPv4/IPv6 prefixes are used when automatically addressing new interfaces. |
| MAC addresses | Invokes the MAC Addresses dialog box for configuring the starting number used as the lowest byte when generating each interface MAC address. This value should be changed when tunneling between CORE emulations to prevent MAC address conflicts. |
### Widgets Menu
Widgets are GUI elements that allow interaction with a running emulation.
Widgets typically automate the running of commands on emulated nodes to report
status information of some type and display this on screen.
#### Periodic Widgets
These Widgets are those available from the main *Widgets* menu. More than one
of these Widgets may be run concurrently. An event loop fires once every second
that the emulation is running. If one of these Widgets is enabled, its periodic
routine will be invoked at this time. Each Widget may have a configuration
dialog box which is also accessible from the *Widgets* menu.
Here are some standard widgets:
* **Adjacency** - displays router adjacency states for Quagga's OSPFv2 and OSPFv3
routing protocols. A line is drawn from each router halfway to the router ID
of an adjacent router. The color of the line is based on the OSPF adjacency
state such as Two-way or Full. To learn about the different colors, see the
*Configure Adjacency...* menu item. The **vtysh** command is used to
dump OSPF neighbor information.
Only half of the line is drawn because each
router may be in a different adjacency state with respect to the other.
* **Throughput** - displays the kilobits-per-second throughput above each link,
using statistics gathered from the ng_pipe Netgraph node that implements each
link. If the throughput exceeds a certain threshold, the link will become
highlighted. For wireless nodes which broadcast data to all nodes in range,
the throughput rate is displayed next to the node and the node will become
circled if the threshold is exceeded.
#### Observer Widgets
These Widgets are available from the **Observer Widgets** submenu of the
**Widgets** menu, and from the Widgets Tool on the toolbar. Only one Observer Widget may
be used at a time. Mouse over a node while the session is running to pop up
an informational display about that node.
Available Observer Widgets include IPv4 and IPv6 routing tables, socket
information, list of running processes, and OSPFv2/v3 neighbor information.
Observer Widgets may be edited by the user and rearranged. Choosing
**Widgets->Observer Widgets->Edit Observers** from the Observer Widget menu will
invoke the Observer Widgets dialog. A list of Observer Widgets is displayed along
with up and down arrows for rearranging the list. Controls are available for
renaming each widget, for changing the command that is run during mouse over, and
for adding and deleting items from the list. Note that specified commands should
return immediately to avoid delays in the GUI display. Changes are saved to a
**config.yaml** file in the CORE configuration directory.
### Session Menu
The Session Menu has entries for starting, stopping, and managing sessions,
in addition to global options such as node types, comments, hooks, servers,
and options.
| Option | Description |
|---|---|
| Sessions | Invokes the CORE Sessions dialog box containing a list of active CORE sessions in the daemon. Basic session information such as name, node count, start time, and a thumbnail are displayed. This dialog allows connecting to different sessions, shutting them down, or starting a new session. |
| Servers | Invokes the CORE emulation servers dialog for configuring. |
| Options | Presents per-session options, such as the IPv4 prefix to be used, if any, for a control network the ability to preserve the session directory; and an on/off switch for SDT3D support. |
| Hooks | Invokes the CORE Session Hooks window where scripts may be configured for a particular session state. The session states are defined in the [table](#session-states) below. The top of the window has a list of configured hooks, and buttons on the bottom left allow adding, editing, and removing hook scripts. The new or edit button will open a hook script editing window. A hook script is a shell script invoked on the host (not within a virtual node). |
#### Session States
| State | Description |
|---|---|
| Definition | Used by the GUI to tell the backend to clear any state. |
| Configuration | When the user presses the *Start* button, node, link, and other configuration data is sent to the backend. This state is also reached when the user customizes a service. |
| Instantiation | After configuration data has been sent, just before the nodes are created. |
| Runtime | All nodes and networks have been built and are running. (This is the same state at which the previously-named *global experiment script* was run.)
| Datacollect | The user has pressed the *Stop* button, but before services have been stopped and nodes have been shut down. This is a good time to collect log files and other data from the nodes. |
| Shutdown | All nodes and networks have been shut down and destroyed. |
### Help Menu
| Option | Description |
|---|---|
| CORE Github (www) | Link to the CORE GitHub page. |
| CORE Documentation (www) | Lnk to the CORE Documentation page. |
| About | Invokes the About dialog box for viewing version information. |
## Connecting with Physical Networks
CORE's emulated networks run in real time, so they can be connected to live
physical networks. The RJ45 tool and the Tunnel tool help with connecting to
the real world. These tools are available from the **Link-layer nodes** menu.
When connecting two or more CORE emulations together, MAC address collisions
should be avoided. CORE automatically assigns MAC addresses to interfaces when
the emulation is started, starting with **00:00:00:aa:00:00** and incrementing
the bottom byte. The starting byte should be changed on the second CORE machine
using the **Tools->MAC Addresses** option the menu.
### RJ45 Tool
The RJ45 node in CORE represents a physical interface on the real CORE machine.
Any real-world network device can be connected to the interface and communicate
with the CORE nodes in real time.
The main drawback is that one physical interface is required for each
connection. When the physical interface is assigned to CORE, it may not be used
for anything else. Another consideration is that the computer or network that
you are connecting to must be co-located with the CORE machine.
To place an RJ45 connection, click on the **Link-layer nodes** toolbar and select
the **RJ45 Tool** from the submenu. Click on the canvas near the node you want to
connect to. This could be a router, hub, switch, or WLAN, for example. Now
click on the *Link Tool* and draw a link between the RJ45 and the other node.
The RJ45 node will display "UNASSIGNED". Double-click the RJ45 node to assign a
physical interface. A list of available interfaces will be shown, and one may
be selected by double-clicking its name in the list, or an interface name may
be entered into the text box.
> **NOTE:** When you press the Start button to instantiate your topology, the
interface assigned to the RJ45 will be connected to the CORE topology. The
|Basic|on/off|Linux|Low|Ethernet bridging with ebtables|
|EMANE|Plug-in|Linux|High|TAP device connected to EMANE emulator with pluggable MAC and PHY radio types|
To quickly build a wireless network, you can first place several router nodes
onto the canvas. If you have the
Quagga MDR software installed, it is
recommended that you use the **mdr** node type for reduced routing overhead. Next
choose the **WLAN** from the **Link-layer nodes** submenu. First set the
desired WLAN parameters by double-clicking the cloud icon. Then you can link
all selected right-clicking on the WLAN and choosing **Link to Selected**.
Linking a router to the WLAN causes a small antenna to appear, but no red link
line is drawn. Routers can have multiple wireless links and both wireless and
wired links (however, you will need to manually configure route
redistribution.) The mdr node type will generate a routing configuration that
enables OSPFv3 with MANET extensions. This is a Boeing-developed extension to
Quagga's OSPFv3 that reduces flooding overhead and optimizes the flooding
procedure for mobile ad-hoc (MANET) networks.
The default configuration of the WLAN is set to use the basic range model. Having this model
selected causes **core-daemon** to calculate the distance between nodes based
on screen pixels. A numeric range in screen pixels is set for the wireless
network using the **Range** slider. When two wireless nodes are within range of
each other, a green line is drawn between them and they are linked. Two
wireless nodes that are farther than the range pixels apart are not linked.
During Execute mode, users may move wireless nodes around by clicking and
dragging them, and wireless links will be dynamically made or broken.
The **EMANE Nodes** leverage available EMANE models to use for wireless networking.
See the [EMANE](emane.md) chapter for details on using EMANE.
### Mobility Scripting
CORE has a few ways to script mobility.
| Option | Description |
|---|---|
| ns-2 script | The script specifies either absolute positions or waypoints with a velocity. Locations are given with Cartesian coordinates. |
| CORE API | An external entity can move nodes by sending CORE API Node messages with updated X,Y coordinates; the **coresendmsg** utility allows a shell script to generate these messages. |
| EMANE events | See [EMANE](emane.md) for details on using EMANE scripts to move nodes around. Location information is typically given as latitude, longitude, and altitude. |
For the first method, you can create a mobility script using a text
editor, or using a tool such as [BonnMotion](http://net.cs.uni-bonn.de/wg/cs/applications/bonnmotion/), and associate the script with one of the wireless
using the WLAN configuration dialog box. Click the *ns-2 mobility script...*
button, and set the *mobility script file* field in the resulting *ns2script*
configuration dialog.
Here is an example for creating a BonnMotion script for 10 nodes:
