Simulate the Topology

Simulate the Topology Overview

The simulation phase is when you run the simulation of your topology design. The Simulation perspective provides a set of views that support the simulation phase. By comparison, the design and build activities occur in the Design perspective, which provides a set of views that support the design activity. Some views in the Simulation perspective can also be viewed in the Design perspective.

Simulation Perspectives and Views

The main areas of focus within the Simulation perspective are the Simulations view and the Console view. The following figure highlights the Simulations and Console views for a running simulation.

Figure 1. Simulation Perspective Initial Display



From the View menu, you can open additional views in the perspective and arrange the open views by dragging them within the perspective workspace. See the online help and the section Customize Perspectives for more information.

Note
To reset your current perspective to its original configuration when the workbench was first opened, right-click the perspective button and select Reset.

Node Limits

In Cisco Modeling Labs, the number of nodes you can run is limited by the resources available on the server and the number of licenses available. Currently, the design limit is 1,000 nodes.

Launch a Simulation

To launch a simulation, complete the following steps.

Before You Begin

  • Complete the topology design.

  • Complete the task of building the nodes and interfaces.

  • (Optional) Generate the configuration using AutoNetkit.

    Caution
    When you manually make changes to a node configuration and bypass AutoNetkit autogeneration, those changes do not appear in the topology view of the Design perspective or Simulation perspective. For example, if you use the hostname command to change the host name from iosv-1 to Router-1 in the configuration, the node name in the topology view and in other related views remains as iosv-1.

  • Open the desired topology.


    Note
    The topology should be open and visible in the Topology Editor. If you have multiple topologies open in the Topology Editor, simulation will launch for the currently active view.
    Step 1   From the toolbar, click the Launch Simulation button. The simulation launches and provides a unique identifier, which means that multiple instances of the topology can be launched and each will have a unique name.
    Step 2   In the Launching Simulation dialog box, select any of the following actions:

    1. Check the Always run in the background check box. All future node start requests, stop requests, and simulation launch requests run in the background and do not display dialog boxes.
      Note    To control the background setting, choose File > Preferences > General.
    2. Click Run in Background. The dialog box closes when the node simulation starts.
    3. Click Cancel to return to the Design view.
    4. Take no action, and the node simulation launches momentarily.
      Tip    When you click Run in Background, the status bar displays a progress icon. Click the icon to display a compact view of the activity progress. If the background activity encounters an error, the icon shows a red X. Click the error icon to display the error dialog.
    Step 3   In the Simulation launched dialog box, click OK.

    Step 4   When prompted to switch to the Simulation perspective, click Yes.

    Note    We recommend that you switch to the Simulation perspective to view the running simulation and to connect to node consoles.

    The Cisco Modeling Labs client tracks the state of the simulations. All launched simulations appear in the Simulations view. Status messages are displayed in the Console view. After the Cisco Modeling Labs server has started the simulation launch, a confirmation dialog box appears with an identifier assigned to the simulation by the Cisco Modeling Labs server.
    When the nodes are running on the Cisco Modeling Labs server, they are displayed in the Simulations view with the status [ACTIVE], as shown in the following figure.
    Figure 2. Simulation Launched in Simulations View



    Jumphost Virtual Machine (VM)

    The jumphost VM is the default method for accessing the management network of a running simulation. The jumphost node runs in a separate simulation named ~jumphost and has two interfaces, eth0 in the project/user management network and eth1 in the FLAT network.

    The purpose of the jumphost is to provide an access point into a simulated network that remains fixed, in that there is a single external IP address or port that the user can access. A user can access the jumphost and then access all the nodes inside the simulation.

    Cisco Modeling Labs provides two implementations of jumphost:

    • A VM: Based on the server VM image type.

    • A Linux container: A lighter weight form of a jumphost. See Linux Container (LXC) for more information.

    The VM implementation is costly in terms of the memory and CPU used when a jumphost is instantiated. However, since it is a full-blown server VM, there is value to it, in that you can install and run any application on it.

    To select a jumphost VM, in the Cisco Modeling Labs client, choose Properties > Topology > Management Network > Private project network or Shared flat network.
    Figure 3. Setting the Jumphost Option



    The jumphost VM is per user; a user can create multiple simulations, but only one corresponding jumphost is created. Therefore, depending on the type of simulation you are running, you can choose between the two implementations.

    Linux Container (LXC)

    An LXC provides a means of accessing a topology rather than having to create a full Linux server VM. All nodes in the network are connected to a hidden OOB management network that uses the first interface on each of the nodes.

    In the Cisco Modeling Labs client, it is enabled by selecting the management network type Private simulation network for your topology. The LXC is automatically connected into this hidden OOB management network to which all VMs in your simulation are connected. This enables you to connect into each VM via its management Ethernet port, removing the need to use the console port connection method.
    Figure 4. Setting the LXC Option



    The LXC is operational when your simulation is active and terminates when your simulation stops. LXC uses a significantly smaller memory footprint than the Linux server VM. The LXC automatically gets an IP address on the FLAT network.
    Figure 5. LXC on the FLAT Network



    LXC facilitates SSH access to the VMs; it provides direct SSH access to each VM running inside the simulation. Telnet is not supported. As shown below, LXC is accessed by right-clicking the ~mgmt_lxc [ACTIVE] node and selecting SSH from the list.
    Figure 6. Accessing LXC



    The LXC is automatically spun up and provides a jumphost point for access into the network. Connecting to the LXC means you can see the interfaces to the outside world and to the OOB network inside your simulation.

    A connection is opened from the Cisco Modeling Labs client to a port on the Cisco Modeling Labs server and is forwarded to the LXC. The LXC, in turn, opens a connection to the Management Interface (Gi0/0) of the VM inside the simulation to the node instance.

    Static Port Assignment to the LXC

    When the management network property Private simulation network is set, Cisco Modeling Labs assigns a random port for SSH port access to the LXC. However, you can statically define this by setting an extension on your topology.

    To set an extension for your topology, complete the following steps.

      Step 1   Click on the canvas to open the Topology tab in the Properties view.
      Step 2   Click the Extensions tab.

      Step 3   Click the Add new extension icon. The Edit Extension dialog box appears.
      Step 4   Enter the following values:
      • Key: lxc.host.tcp_port
      • Value: 30799
      • Type: String (from the drop-down list)
      Figure 7. Add a New Extension



      Step 5   Click OK to add the new extension. When the LXC starts, it will be bound to the TCP port specified in the new extension.

      Launch a Phased Simulation

      On occasions, you may need to start your simulation in phases rather than having all nodes launched at the same time. This functionality is facilitated by the Exclude node from simulation launch check box, which allows you to pick and choose which nodes to start.

      To launch a phased simulation, complete the following steps.

        Step 1   With the applicable topology open, click on the canvas and move the selection area over the nodes to be excluded from the running simulation. (Alternatively, you can double-click a specific node, hold down the Shift key, and select the remaining nodes.) The Properties > Node view opens.
        Step 2   In the Properties > Node view, check the Exclude node from simulation launch check box.
        Figure 8. Nodes Excluded from Simulation Start



        Step 3   Save your topology using Ctrl-S.
        Note   

        You can set this property for each individual node, if you prefer. Select the node on the canvas, and select the Exclude node from simulation launch check box in the Properties > Node view.

        Step 4   From the toolbar, click the Build Initial Configurations button to build the node configurations.
        Step 5   From the toolbar, click the Launch Simulation button. The simulation launches.
        When the nodes are running on the Cisco Modeling Labs server, they are displayed in the Simulations view with the status as [ACTIVE].
        Note    In the Console view, you can see the message Node '<node name>' is excluded from automatic start for the excluded nodes, and in the Simulations view, you can see that the excluded nodes have the state [ABSENT].
        Figure 9. Phased Simulation Launched



        Launch a Time-Limited Simulation

        In circumstances where you need to run a simulation for a specified time, complete the following steps.

          Step 1   From the toolbar, click the down arrow to the right of the Launch Simulation button.
          Step 2   Click Launch Simulation (with time limit).
          Figure 10. Launch Simulation with Time Limit Option



          The Launch Time-limited Simulation dialog box is displayed.
          Figure 11. Launch a Time-Limited Simulation



          Step 3   Set a time duration for the simulation by entering details for Days, Hours, and Minutes by using either the up and down arrows or entering the values directly. Click OK to apply your time limit to the simulation. The simulation launches.
          Note    An expiration warning is displayed ten minutes (or less) before your simulation is due to expire.
          Figure 12. Simulation Expiration Warning



          We recommend that you extract configurations for your simulation before it expires.
          Note    You can reset the time limit for a running simulation in the User Workspace Management interface. See Reset the Time Limit on a Running Simulation for more information.

          Reset the Time Limit on a Running Simulation

          You can extend or reduce the time limit set for a running simulation in the User Workspace Management interface. To do this, complete the following steps.

            Step 1   Log in to the User Workspace Management interface. On the Overview page, information on running simulations is displayed. Move to the applicable simulation under the Session heading. If your simulation is due to expire in ten minutes or less, the simulation name is displayed in red.
            Step 2   Under the Options column, click the down arrow and click Set expiration.
            Figure 13. Soon to Expire Simulation



            Step 3   The Set expiration for session page is displayed. In the date and time field, enter either a new expiration date and time, a date only, or a time only for the simulation.
            Figure 14. Set Expiration for Session Page



            Step 4   Click Set expiration to save the changes. The time limit for the simulation is updated.

            Control Interface States

            In a running simulation, you are able to change the state of the network interface by bringing it up or down.

            Note
            This changes the state of the underlying communication infrastructure, not the interface state of the virtual machine.

            To control the state of an interface, complete the following steps.

              Step 1   Log in to the User Workspace Management interface.
              Note    You must log in as a user other than the uwmadmin user, for example, guest.
              Step 2   On the Overview page, under Sessions, choose the applicable running session. A list of active virtual machines and interfaces is displayed.
              Step 3   Scroll down to the Interfaces section and choose the applicable virtual machine.
              Step 4   From the applicable Options drop-down list, click Update admin state.
              Figure 15. Interface State Control Option



              Depending on the current state of the interface, either a Bring Down or Bring Up page is displayed. In this case, the Bring Down page is displayed.
              Figure 16. Bring Down the Applicable Interface



              Step 5   Click Bring down to bring down the network interface. A message is displayed indicating that the interface has been brought down.
              Figure 17. Interface Successfully Brought Down



              Step 6   To bring up the interface at a later stage, click Update admin state again. The Bring up page displayed.
              Figure 18. Bring Up the Applicable Interface



              Step 7   Click Bring up to bring up the network interface. A message is displayed indicating that the interface has been brought up.
              Figure 19. Interface Successfully Brought Up



              Connect to a Simulation Node Console

              Cisco Modeling Labs provides the capability for you to connect to your nodes via SSH and Telnet. You can start an SSH session, which connects into the node via the LXC, as described in Linux Container (LXC).

              This access method makes use of SSH to the LXC and then Telnet from the LXC to the nodes running inside the simulation. This does not use the console port of the nodes and is more reliable and faster to use.

              Connect to a Simulation Node Console via SSH

              To connect to a simulation node console, complete the following steps.

              Before You Begin

              • Launch a simulation.

              • Ensure that the Simulation perspective is active.

              • Ensure that the Simulations view and Console view are displayed.

                Step 1   To connect to a console for a specific node, right-click the node in the Simulations view and choose SSH > to its Management (via LXC) port.

                Figure 20. Connecting to a Node Console via SSH



                A new Terminal view opens.

                Figure 21. Terminal View



                Step 2   To disconnect a terminal from the simulation, click Disconnect in the Terminal view toolbar or click the Close icon in the Terminal view.
                Note    When you disconnect or close a Terminal view, all text in the view is discarded.
                Tip    When you disconnect a terminal but do not close the Terminal window, you can press Enter to reconnect the terminal.

                Connect to Multiple Simulation Node Consoles

                To connect to all consoles for all nodes in a running simulation, complete the following steps.

                  Step 1   Right-click the simulation in the Simulations view and choose Telnet > to all <number> available Console ports.

                  Figure 22. Connect to Multiple Node Consoles



                  A new Terminal view opens for all console ports.

                  Figure 23. Terminal View



                  Step 2   To disconnect a terminal from the simulation, click Disconnect in the Terminal view toolbar or click the Close icon in the Terminal view.
                  Note    When you disconnect or close a Terminal view, all text in the view is discarded.
                  Tip    When you disconnect a terminal but do not close the Terminal window, you can press Enter to reconnect the terminal.

                  Terminal Multiplexer Functionality

                  A terminal multiplexer is available for use with the Cisco Modeling Labs client. It permits a number of terminals to be accessed and controlled from a single terminal. Terminals can be detached to run in the background and then reattached later.

                  The terminal multiplexer is available from Window > Show View > Other > General > Terminal Multiplexer.

                  When the terminal multiplexer starts up, a status line at the bottom of the terminal displays information on the current session and is used to enter interactive commands. It lists all of the active console sessions. You can select console sessions individually or all together from the View Menu drop-down list. Keyboard commands entered in the command-line text box are broadcast to the selected sessions.
                  Figure 24. Terminal Multiplexer



                  The terminal multiplexer also provides a command-line history, which you can access using Ctrl-Space.
                  Figure 25. Accessing the Command-Line History



                  Start a Single Node

                  To start a single node, complete the following steps.

                    Step 1   Right-click a stopped node. When a node is stopped, its status is shown as [ABSENT].
                    Step 2   Click Start this node.
                    Figure 26. Start a Single Node



                    The Requesting start dialog box appears.
                    Figure 27. Requesting Start Dialog Box



                    Step 3   Choose one or more of the following actions:
                    1. Check the Always run in the background check box. All future node start requests, stop requests, and simulation launch requests run in the background and do not display dialog boxes.
                      Note    To control the background setting, choose File > Preferences > General.
                    2. Click Run in Background.

                      The dialog box closes while the node simulation stops.

                    3. Click Cancel to return to the Simulations view.
                    4. Take no action and the node simulation restarts momentarily.
                    Tip    When you click Run in Background, the status bar displays a progress icon. Click the icon to display a compact view of the progress. If an error is encountered, the icon displays a red X. Click the error icon to display the error dialog box.

                    Start a Node in a Running Simulation

                    In cases where a phased simulation is running, you can later start those nodes not started with the initial simulation. To start a node in a running simulation, complete the following steps.

                      Step 1   In the Simulations view, right-click the node.
                      Note    A node not yet started has the status [ABSENT].
                      Step 2   Click Start this node.
                      Figure 28. Start This Node Option



                      The Requesting start dialog box appears.

                      Figure 29. Requesting Start Dialog Box



                      Note    The status of the selected node is changed from [ABSENT] to [ACTIVE], indicating that the node is up and running.

                      Start Multiple Nodes in a Running Simulation

                      In cases where a phased simulation is running, you can later start those nodes not started with the initial simulation. To start multiple nodes, complete the following steps.

                        Step 1   In the Simulations view, click the first node in the list to be started.
                        Step 2   Hold down the Shift key and select the remaining nodes.
                        Step 3   Right-click the selected nodes.
                        Step 4   Click Start nodes.
                        Figure 30. Start Nodes Option



                        The Requesting start dialog box appears.

                        Figure 31. Requesting Start Dialog Box



                        Note   

                        The status of the selected nodes changes from [ABSENT] to [ACTIVE], indicating that the nodes are up and running.

                        Figure 32. Multiple Nodes Started



                        Stop a Simulation

                        There are several ways to stop a simulation. In addition, you can stop multiple simulations at the same time. These are discussed in the following sections.

                        Stop a Simulation from the Toolbar

                        To stop a simulation from the toolbar, complete the following steps.

                          Step 1   In the toolbar, click the Stop Simulations button. A Stop Simulation(s) dialog box appears.
                          Figure 33. Stop Simulation(s) Dialog Box



                          Step 2   In the Simulation column, click once to highlight the simulation to stop.
                          Step 3   (Optional) To save the configurations, click the adjacent setting in the Extract Configurations? column until the prompt changes to Yes.
                          Note    Configurations for server nodes are not extracted.
                          Step 4   (Optional) To close the internal terminals associated with the simulation, click the adjacent setting in the Close Terminals? column until the prompt changes to Yes.
                          Note    External terminal connections are not stopped as part of this operation and must be closed manually.
                          Step 5   To stop the simulation, click the adjacent setting in the Stop Simulation? column until the prompt changes to Yes.
                          Step 6   Click OK to stop the simulation, or click Cancel to leave the simulation running.

                          On OS X, you update the values for Extract Configurations?, Stop Simulation?, and Close Terminals? in the columns directly. You do not need to select the name of the simulation.

                          Stop a Simulation from the Simulations View

                          To stop a simulation, complete the following steps.

                            Step 1   In the Simulations view, right-click the simulation name and select Stop Simulation.
                            Figure 34. Stop a Simulation



                            The Stop Simulation Confirmation dialog box appears.

                            Figure 35. Stop Simulation Confirmation Dialog Box



                            • (Optional) Check the Extract Configurations before Stopping the Simulation check box to save the current configurations.

                            • (Optional) Check the Close Associated Terminal Views check box to close all the open internal terminals associated with the specific simulation. External terminals are not closed.

                            Step 2   Click OK to stop the simulation. Once selected, all nodes in the simulation start shutting down. It may take a few minutes for the simulation to shut down completely and to disappear from the Simulations view.
                            Note    For instances where a user account expires, all running simulations for that user continue to run. Since the user account can no longer log in to stop them, they will remain active until the next system reboot or until the system administrator explicitly stops them.

                            Stop Multiple Simulations from the Simulations View

                            To stop multiple simulations, complete the following steps.

                              Step 1   In the Simulations view, click the first simulation in the list to stop.
                              Step 2   Hold down the Shift key and select the remaining simulations.
                              Step 3   Right-click the selected simulations and select Stop Simulations.
                              Figure 36. Stop Multiple Simulations



                              The Stop Simulations Confirmation dialog box appears.

                              Figure 37. Stop Simulations Confirmation Dialog Box



                              • (Optional) Check the Extract Configurations before Stopping the Simulation check box to save the current configurations.

                              • (Optional) Check the Close Associated Terminal Views check box to close all the open internal terminals associated with the specific simulation. External terminals are not closed.

                              Step 4   Click OK to stop the simulations. Once selected, all nodes in the simulations start shutting down. It may take a few minutes for the simulations to shut down completely and to disappear from the Simulations view.
                              Note    For instances where a user account expires, all running simulations for that user continue to run. Since the user account can no longer log in to stop them, they will remain active until the next system reboot or until the system administrator explicitly stops them.

                              Stop a Single Node

                              To stop a single node in a simulation, complete the following steps.

                                Step 1   In the Simulations view, right-click the node to stop and select Stop this Node.

                                Figure 38. Stop a Single Node



                                The Are you sure? dialog box appears.

                                Step 2   Click OK to stop the node. Alternatively, click Cancel to abandon the operation and return to the simulation.
                                Note    When you click OK, the node stops without saving any changes to the configuration.
                                When a node is stopped, its status changes to [ABSENT].

                                Stop Multiple Nodes

                                To stop multiple nodes in a running simulation, complete the following steps.

                                  Step 1   In the Simulations view, click the first node in the list to stop.
                                  Step 2   Hold down the Shift key and select the remaining nodes.
                                  Step 3   Right-click the selected nodes.
                                  Step 4   Click Stop Nodes.

                                  Figure 39. Stop Multiple Nodes



                                  The Are you sure? dialog box appears.

                                  Step 5   Click OK to stop the nodes. Alternatively, click Cancel to abandon the operation and return to the simulation.
                                  Note    When you click OK, the nodes stop without saving any changes to the configuration.
                                  When the nodes are stopped, their status changes to [ABSENT].
                                  Figure 40. Multiple Nodes Stopped



                                  Modify a Node Configuration in the Simulation

                                  You can modify node configurations in a running simulation. To do this, the type of connection available, either SSH or Telnet depends on the option set for the topology property Management Network.

                                  • When Management Network is set to Private simulation network, SSH and Telnet are available.

                                  • When Management Network is set to Shared flat network, Private project network, or not specified, only Telnet is available.

                                  Modify a Node Configuration in the Simulation via SSH

                                  To modify a node configuration in a running simulation via SSH, complete the following steps.

                                    Step 1   Right-click the node in the Simulations view and choose SSH > to its Management (via LXC) port.

                                    Figure 41. Connecting to a Node Console



                                    A new Terminal view opens.

                                    Figure 42. Terminal View



                                    Step 2   If no banner or router prompt is visible, press Enter. You are now working with the operating system running on the node, for example, Cisco IOSv virtual software.
                                    Step 3   Use the operating system commands to view or modify the node configuration.
                                    Note    Changes you make to the configuration do not appear in the canvas of the Topology Editor.

                                    Modify a Node Configuration in the Simulation via Telnet

                                    To modify a node configuration in a running simulation via Telnet, complete the following steps.

                                      Step 1   Right-click the node in the Simulations view and choose Telnet > to its Console port.

                                      Figure 43. Connecting to a Node Console



                                      A new Terminal view opens.

                                      Figure 44. Terminal View



                                      Step 2   If no banner or router prompt is visible, press Enter. You are now working with the operating system running on the node, for example, Cisco IOSv virtual software.
                                      Step 3   Use the operating system commands to view or modify the node configuration.
                                      Note    Changes you make to the configuration do not appear in the canvas of the Topology Editor.

                                      Modify Multiple Node Configurations in the Simulation

                                      To modify multiple node configurations in a running simulation, complete the following steps.

                                        Step 1   Right-click the topology in the Simulations view and choose Telnet > to all <number> available Console ports.

                                        Figure 45. Connect to Multiple Node Consoles



                                        A new Terminal view opens for each of the consoles.
                                        Figure 46. Terminal Views



                                        Step 2   If no banner or router prompt is visible, press Enter. You are now working with the operating system running on the node, for example, Cisco IOSv virtual software.
                                        Step 3   Use the operating system commands to view or modify the node configuration.
                                        Note    Changes you make to the configuration do not appear in the canvas of the Topology Editor.

                                        Extract and Save Modified Configurations

                                        To extract and save modified configurations, complete the following steps.

                                        Before You Begin

                                        • You have modified a configuration within one or more nodes running within the simulation and want to save the changes.

                                        • Ensure that all routers in the simulation are operational before attempting to extract their configurations.

                                          Step 1   In the Simulations view, right-click the topology name, making sure not to click the node name, and select Extract Configurations.

                                          Figure 47. Simulations View Context Menu



                                          A confirmation dialog box appears.
                                          Step 2   Ensure that all external Telnet connections to the simulation are closed before proceeding.
                                          Note    You must close all external Telnet connections to the simulation before you can proceed.

                                          Figure 48. Extract Configurations Dialog Box



                                          Step 3   Click OK.

                                          The Extracting Configurations dialog box appears indication that the extraction is in process.

                                          When the extraction is complete, a message is displayed.

                                          Figure 49. Extraction Complete Message



                                          Note    The configuration information is extracted and saved in the filename.virl file that corresponds to the topology. For example, the file New_Topology that is running as a New_Topology-dkIFaW simulation has its configuration extracted to the file New_Topology.virl.
                                          Step 4   Click OK.

                                          Partial Configuration Extraction

                                          During a configuration extraction, if the process encounters issues or fails for a particular node, the problem node is identified and reported.

                                          The extraction process then continues for all other nodes in the simulation and returns collected configurations to you.

                                          Linux Server Snapshot Support

                                          When a Linux server is present in a running simulation, you can use the User Workspace Management interface to take a snapshot of the disk content of the server. This newly created user-specific disk image can be used in other simulated sessions.

                                          To take a snapshot of the server's disk contents, complete the following steps.
                                            Step 1   Log in to the User Workspace Management interface.
                                            Note    You must log in as a user other than the uwmadmin user, for example, guest.
                                            Step 2   On the Overview page, under Sessions, select the applicable running simulation.
                                            Figure 50. Running Simulation Listed



                                            A list of active VMs is displayed.
                                            Figure 51. Active VMs



                                            Step 3   Select the applicable Linux server, and from the Options drop-down menu, click Create snapshot.

                                            Figure 52. Create Snapshot Option



                                            Project details for the newly created snapshot are displayed.
                                            Figure 53. Newly Created Disk Image



                                            Reuse the Image Snapshot

                                            To reuse the image snapshot, complete the following steps.

                                              Step 1   Create a new topology or open an existing topology.
                                              Step 2   On the canvas, add a node to the topology.
                                              Step 3   Select the node on the canvas. The sample topology opens in the Topology Editor canvas.
                                              Step 4   In the Properties > Node view, click Browse beside the VM Image field. The Select VM Image dialog box appears.
                                              Step 5   Select the applicable image snapshot and click OK.
                                              Figure 54. Select the Image Snapshot to Use



                                              Details for the image snapshot are visible in the VM Image field under Properties > Node view.
                                              Figure 55. Image Snapshot Selected