Frequently Asked Questions

Packet Tracer v3.2 Frequently Asked Questions (FAQ)

Q: Does Packet Tracer v3.2 support all of the features found in Cisco devices?
A: No. Packet Tracer supports a small subset of the features from Cisco devices. Specifics can be found in the help file.
Q: Can I learn CCNA just by using Packet Tracer v3.2?
A: No. Packet Tracer v3.2 is a tool to supplement the Cisco Networking Academy curriculum. Students can learn basic router and switch configuration and see how packets are processed by networking devices as they traverse the network.
Q: How do I put a device on the network. How do I use the panel?
A: Click on the icons in the panel once to use the item once. Double click to retain the selection. Then place the device in the network by clicking anywhere in the workspace.
Q: Can I create unlimited devices?
A: No, the number of devices is limited the amount of free memory on your computer.
Q: What router/switch/device model does Packet Tracer support?
A: Packet Tracer does not support a specific hardware platform. All devices are generic modular devices. Routers, switches, hubs, and clouds are generic devices with 10 modular slots. Ports on routers and switches use the slot/port notation to refer to an individual port. Since all ports are modular, they each represent a single slot with a single interface. The outputs were captured using 2621 routers and 2950 switches.
Q: What IOS version does the router/switch use?
A: The router IOS version is 12.2(13). The Catalyst switch version is 12.1.13.EA1.
Q: How do I specify a DCE or DTE interface for the devices?
A: If Simple Mode is on, the DCE or DTE is automatically set. If you wish to specify a device to be DTE or DCE, turn off Simple Mode and choose either Serial DCE or Serial DTE. The first device that you connect to will be the selected side of the cable. The DCE side of a serial cable is indicated by a small clock icon.
Q: Does the Simple Mode configuration allow me to configure all the features of the device?
A: No for switches and routers; yes for the other devices. For switches and routers, some features are only available through the terminal configuration interface and Packet Tracer’s simulated Cisco IOS. Use of IOS features are not necessary to create a working network, however they can be used to create a more sophisticated network (Access lists and IP NAT are two examples).
Q: How do I access the terminal?
A: There are several ways to access the terminal (only available for routers and switches).
Topology mode allows configuration and viewing of the configuration, no routing/switching information is available.
Simulation mode allows for viewing of the routing and switching information, but no device configuration is allowed.
1. If Simple Mode is on: connect a console cable from the router/switch to a PC. Bring up the configuration menu for the PC and click on the RS232 interface. Configure all of the terminal settings to match the settings on the router/switch's console port. (Note: default configurations from the router/switch and PC already match.) Click on the "Open Terminal" button to bring up the terminal. If all settings are configured properly, then inputs should be accepted by the router/switch. If your inputs are being ignored, click on the output field to make sure your selection is focussed on the terminal and try again. If it still fails, check your configuration.
2.If Simple Mode is off and Console Mode is off, click on the router/switch icon.
Note: If Console Mode is on, you can only access the terminal window through a PC.
Q: Why is the router not updating its routing tables?
A: Automatic routing is enabled by default when a router is created. This is equivalent to issuing the following command sequence:
router rip
version 2
network A.B.C.D
network F.G.H.I
If Simple Mode is on, users do not need to configure the routing configuration. All directly connected networks are automatically entered into the routing process. When users access the router through the terminal interface, this automatic configuration is disabled and the user will need to enter the specific networks into the routing process, or use simple mode to re-enable the automatic routing.
Q: Why is the routing table not showing up in Topology mode? Why can't I configure the device in Simulation mode or Realtime mode?
A: Routing/switching tables are created when Simulation Mode is initialized. Hence no tables are available when you are in Topology mode. When you are in Simulation mode, the network remains static, it may not be changed. This is to ensure consistent network behavior.
Q: Why do some links turn red when I switch from Topology to Simulation Mode?
A: When you switch from Topology to Simulation Mode, Packet Tracer initializes all of the devices in the network so they can function. The initialization process for hubs and repeaters is to eliminate Layer 1 loops. They remove these loops by disabling some ports in the loop. Thus some links would go down and the link lights would turn red. Switches and bridges use a similar process called the Spanning Tree Protocol (STP) to eliminate Layer 2 loops.
Q: Why do I receive an error about a script taking too long, and asking whether to stop or not?
A: This is a feature in Flash to stop infinite loops. On slow machines, large networks can take a long time to save/load/converge and Flash will complain. In these situations, you may choose "No" to let it finish. If you choose "Yes" to abort, the program will stop responding and you must manually end it.
Q: Why is Packet Tracer running so slow?
A: Does your system meet the minimum requirements? The minimum requirements allow for the basic usage of Packet Tracer in creating small to medium size networks. It is recommended that you use a faster machine with more memory to create large networks. Turn off animation and sounds, hide the ports, and turn off show packets to increase performance.
Q: Why does Packet Tracer crash upon startup?
A: You must update your Flash player to the newest version. The original Flash MX player has bugs that causes this crash.
Q: Why are the wireless frames different from what I read online?
A: WLANs use a 802.11 MAC frame, as opposed to an 802.3 frame. 802.11 wireless frames have 4 separate MAC addresses: Receiver; Transmitter; either the Ethernet source address, Ethernet destination address, or the BSSID; and an optional fourth address for Wireless Distribution System and Bridge to Bridge. The Receiver is the station that will receive the frame, but is not necessarily the destination (for example, the access point). The Transmitter is the station sending out the frame: again, not necessarily the source of the frame; again this could be the access point. The BSSID can be thought of as the MAC address of the antenna of the next device to send to, although different hardware vendors may use different schemes. The BSSID is a 48 bit identifier which distinguishes it from other BSSs in the network, and is not the same as an SSID or ESSID. The various fields are used to address the fact that multiple access points can be deployed in the same LAN, in which case, the addresses will be important in determining which access point you are sending your frames to. For simplicity, Packet Tracer will not use this detailed addressing scheme. In Packet Tracer, hosts can only associate with one access point. This essentially forces the Transmitter and Receiver MAC addresses to be that of the access point or the host, in which case, the Transmitter is the source device (or the access point) and the Receiver is the destination device (or the access point). The Ethernet source address, Ethernet destination address, and BSSID will not be important in this scenario and are thus ignored.. Aside from this, the main difference in Packet Tracer from that of a real access point is that Packet Tracer does not model any layer 2 information. So instead of seeing the MAC address of the access point in any of the address fields, the MAC address of the source or destination hop will be used instead. The extra wireless fields are transparently added and removed when a frame moves between wired and wireless interfaces. Once the frames leave the wireless portion of the network, the fields will be identical to that of the other frames.

Q: May I distribute Packet Tracer to my students?
A: Yes. Please distribute Packet Tracer to the students. If the distribution method is through a website, ensure that it is password protected.

Q: The Spanning Tree Protocol is incorrect, please fix it?
A: Packet Tracer does not use the standard Spanning Tree Protocol for performance reasons. It uses a simplified and more efficient method to achieve the same purpose (breaking up loops). However, the end result of the this method will not yield the same configuration as the true Spanning Tree Protocol. In future versions the actual STP algorithm will be more accurately modeled.

Q: I have a comment about Packet Tracer, where do I send it?
A: To report bugs or make suggestions, please use the Help -> Curriculum Quality Link on the Academy Connection. Packet Tracer discussion forums are available on the CCNA Instructor community website.

Q: Where is the "?" key?
A: Due to issues with the Flash player, the "?" key on certain keyboards will not be recognized. To solve this problem, install Microsoft Global Input Method Editors (IMEs), and use it to change your keyboard layout to the U.S. keyboard layout.

Q: I cannot access the tutorial files from Help.
A: Pop-up blockers can stop the tutorial files from running. Make sure you have these disabled when trying to view the tutorials.

Q: Some pictures do not show up in the Help files.
A: Some "pictures" are actually flash content (.swf) files. If you have recently installed the Windows XP SP2 update, or if Internet Explorer does not show flash files by default, you can change your internet settings to solve this problem. From the Internet Explorer tool bar, select Tools --> Internet options. Click the "Advanced" tab, and scroll down to the section on "Security", then check the box for "Allow active content to run in files on My Computer".