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Emulab FAQ

Emulab FAQ

Getting Started

  1. Is there a help forum? Yes, join Emulab Users.
  2. Who is eligible to use Emulab.Net?
  3. How do I start a project?
  4. I'm a project leader and someone applied to join my project, but they are not on the list to be approved
  5. How do I join a project?
  6. Will Emulab send me email messages?
  7. I have an Emulab account. Now what?
  8. Can I be in more than one project?
  9. Can I change my Emulab password?
  10. I'm a project leader. Can I designate TAs?
  11. How do I report a specific problem?
  12. Where do I get more help?
  13. Forgot your password? Resetting does not work!
  14. How do I change my email address?

Using the Testbed

  1. Is there a tutorial?
  2. Do you have a GUI to help me create experiments?
  3. Are there any constraints on my topology?
  4. How many nodes can I ask for?
  5. How long can I keep using my nodes?
  6. I only need a couple of nodes but none are free, should I just keep trying?
  7. What if I need more nodes than are free?
  8. Do I get root access on my nodes?
  9. Do my nodes have consoles I can look at?
  10. How do I connect directly to node consoles, without going through users?
  11. Can I reboot (power cycle) my nodes?
  12. I've clobbered my disk! Now what?
  13. Where do I store files needed by my experiment?
  14. My experiment needs access to multi-gigabyte data sets, how do I do that?
  15. Are my files on the "users" server backed up (filesaved)?
  16. Are the nodes in my experiment backed up (filesaved)?
  17. What is Swapping?
  18. How can I get switch statistics (such as packet counts) for my experiment?
  19. What names should I use to refer to the nodes in my experiment?
  20. Can I modify my experiment after creating it?
  21. Are there Linux and/or FreeBSD sources and packages available locally?
  22. How can I login to the "users" server or a node in my experiment without providing my password?
  23. How much permanent disk is available for my files?
  24. Can I specify specific network interfaces on the nodes for the links in my topology?
  25. So you want to teach a class using Emulab?
  26. What topology generators work with Emulab?
  27. Why can't I swap in my N node experiment, when there are more than N nodes free?
  28. Available network topological data
  29. Is there a Web Service interface for common emulab tasks?
  30. Can I specify the switches to use for my links?

Hardware Setup

  1. What kind of computers are used for my nodes?
  2. How many nodes are there?
  3. How many ethernet cards are on each node?
  4. How do I ask for specific hardware?
  5. How many nodes are currently available (free)?
  6. Can I do traffic shaping on my links?
  7. Can I modify the traffic shaping parameters on my links?
  8. Are there other traffic shaping parameters besides latency,bandwidth, and packet loss rate?
  9. Do any Emulab nodes have wifi (802.11) interfaces?
  10. What kind of wifi cards are used in Emulab?
  11. What is the current arrangement of switches and nodes?
  12. What is the control net and how do I identify it on a node?
  13. What are the limits for link shaping?
  14. Can I make a simplex link instead of a duplex link in an experiment?

Customizing your experiment

  1. How do I build a custom Linux kernel?


  1. Citing Emulab in papers that use Emulab

Security Issues

  1. Is Emulab Firewalled?
  2. Do nodes have root passwords?

Software Setup

  1. What OS do the nodes run?
  2. How do I select which OS to run on each node?
  3. Is Windows 2000 supported as well as Windows XP?
  4. Can I load my own software (RPMs/Tarballs) on my nodes?
  5. Can I schedule programs to run automatically when a node boots?
  6. How can I turn on routing or set up routes automatically on my nodes?
  7. How does my software determine when other nodes in my experiment are ready?
  8. Can I run my own Operating System?
  9. Can I share a disk image between two projects?
  10. What if I need more disk space on my nodes?
  11. Are there testbed-specific daemons that could interfere with my experiment?
  12. Does Emulab support IP Multicast?
  13. Why does my image not boot on node type Y?
  14. What FreeBSD kernels are available and what features do they include?
  15. Locking complaints during compilation
  16. What device drivers do I need in my operating system to run in Emulab?
  17. How is experiment idle monitoring done?
  18. Can I enable ALTQ on FreeBSD for strict priority and class-based queuing?
  19. How do I create an image of second hard drive?


  1. My experiment setup failed, what did I do wrong?
  2. My experiment is set up, but I cannot send packets between some of the nodes. Why?
  3. I asked for traffic shaping, but everything seems to be going at full LAN speeds
  4. I set a non-zero packet-loss (or delay) but 'ping' shows no packet-loss (or delay)
  5. I set a non-zero packet-loss (or delay) but 'ping' shows a different packet-loss (or delay)
  6. In general, how can I make sure my traffic is doing the right thing?
  7. I decreased the bandwidth on a link and now the ping time between the nodes has increased
  8. I wrote a small TCP application to test the bandwidth of a link/LAN, but I do not observe the bandwidth that I asked for.
  9. I wrote a small UDP application to test the bandwidth of a link/LAN, but I do not observe the bandwidth that I asked for.
  10. I am running a routing daemon in my topology but the daemon claims that all my nodes are directly connected!
  11. My custom Linux kernel won't boot, why?
  12. Why is the per-packet latency so high (variable) on the pc3000 nodes?
  13. Why isn't my multicast traffic being correctly shaped?
  14. Why does my NS file not parse correctly anymore?
  15. I got an error in my swapin that says 'Temporary Resource Shortage' - what does it mean?
  16. I am running into errors while working in my home and/or project directory (or subdirectories). What's going on?
  17. What does the warning message 'due to delay implementation, odd delay value N for LAN may be rounded up' mean?
  18. My program agent command did not execute, why not?
  19. I get a WARNING message from linktest, what does it mean?
  20. How does Windows XP start up in Emulab?

Setting Up a New Emulab

  1. I've added new nodes to the testbed but I cannot ping them, what is wrong?
  2. Event system: elvin or pubsub?

Collaboration Tools

  1. Who is the administrator of per-project mailing lists?