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RIPE Atlas FAQs

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General questions
Concepts
Technical details
Privacy
Troubleshooting
Data collection
User interface

General questions

Q: What is RIPE Atlas?
A: It is the next generation active Internet measurement system from the RIPE NCC. It is currently in the prototype stage. It will scale up to thousands of measurement nodes ("probes") distributed around the globe. You can read much more about all aspects of RIPE Atlas on RIPE Labs.

Q: Is this a new RIPE NCC service?
A: At the moment it is a prototype service. This means it is not a full service with guaranteed service levels yet and we give no guarantee that it will ever be offered as a full service. On the other hand, the prototye is substantial with hundreds of probes and we are doing our best to keep the system stable and alive. During the prototype phase we will frequently add new functionality.

Q: Why the name "RIPE Atlas"?
A: We believe that this system will produce measurement data about the Internet on a new scale. We'd like to derive different kinds of maps from this data - latency maps, reachability maps, etc. An atlas is a collection of maps.

Q: Where can I find more information?
A: More information is available on this website and on RIPE Labs. If you still have questions that are not answered yet, feel free to contact us at atlas@ripe.net.

Q: Is there a mailing list?
A: Yes! Please subscribe to the RIPE Atlas mailing list for announcements about RIPE Atlas and discussions with other members of the RIPE Atlas community.

Concepts

Q: What's a probe?
A: A probe is a tiny hardware device that runs measurements in the RIPE Atlas system and reports these measurements to the data collection components.

Q: What's a host?
A: A host is someone who hosts a probe for RIPE Atlas; that is, someone who takes a measurement probe, connects it to their network and leaves it running. More information is available in this RIPE Labs article.

Q: Why would I want to host a probe?
A: Because it benefits the measurement community. It's also beneficial for you, since you'll also get your own measurement results from the system.

Q: How can I join as a host?
A: You need a probe before you can host. Fill in the pre-registration form to request a probe.

Q: Can I transfer a probe to a new host?
A: If you are hosting a probe and would like to transfer it to a new host (for instance if you are leaving a company but the probe will remain, and a co-worker will take over responsibility for it), send a mail to atlas@ripe.net with the number or MAC address of the probe, and the contact details of the new host.

Q: What's a sponsor?
A: A sponsor is someone who is willing to support the system by paying for a number of probes. In exchange, the sponsor gets all the benefits that the hosts have -- for all the probes they sponsored. More information is available on our sponsors page.

Q: Can I join as a sponsor?
A: Sure! Please check our sponsors page for more details.

Q: How do you measure probe uptime?
A: A probe is "up" when it has a working Internet connection and it is connected to our infrastructure. This means that if the probe has a working Internet connection, but it cannot connect to the central infrastructure (because it's firewalled or such) then it shows up as "down" in the UI. This is also the reason why one can see more connect/disconnect events than expected: even though the local network was working fine, there may have been a connection reset on the probe's connection to its controller.

Q: What does it mean when a probe is listed as "down" in the "My Probes" list?
A: When a probe is listed as "down," it means that the probe is not able to connect to RIPE NCC's Atlas servers. In a situation where the probe still has network access, it will continue to collect measurements until its memory is exhausted (about 3.5 days) for later delivery.

Technical details

Q: How are the probes powered?
A: You'll need to supply some electricity to the probe through its USB cable. Any USB port capable of supplying 500mA should be fine; it could be a free USB port on your home router, or you can use a USB power adapter. Note that devices that go into sleep mode (monitors with built-in USB hubs, laptops, etc.) are not good enough as they usually stop supplying power over USB when they go into sleep mode.

Q: How does the probe connect to the Internet?
A: The probe has an RJ-45 (wired) Ethernet interface. It doesn't have WiFi capabilities. This means that you have to connect it to a physical Ethernet port. Once this is done, the probe acquires an IP address and DNS resolver information using DHCP and then tries to look up the controlling infrastructure using DNS and connects to it over outgoing TCP port 443 (HTTPS) connections.
If you want to configure a DHCP server, you can use the following example dhcpd.conf snippet, kindly contributed by Alan Barrett: 

ddns-update-style none;
subnet <<my subnet>> netmask <<my netmask>> {
    option subnet-mask <<my netmask>>;
    option routers <<address of default gateway>>;
    option domain-name-servers <<address of open resolver>>;
}
host <<hostname assigned to probe>> {
    hardware ethernet <<MAC address of probe>>;
    fixed-address <<IP address assigned to probe>>;
}

Q: So which services exactly do I need for my probe to work?
A: The absolute minimum set is DHCP, DNS and outgoing TCP port 443 (HTTPS), in order to allow the probe to connect to the network. However, this in itself is not enough to do measurements, which is the whole point, so you should also allow ICMP for the time being. HTTP(S), SSL and other measurments are planned, but not activated yet.

Q: Does the probe work behind a NAT? I just want to plug it in at home and not configure anything.
A: Yes. The probe works fine behind a NAT box. So in most cases, one can just plug it in and it should "just work".

Q: I have an IPv6-only network. Will the probe work on it?
A: Although the probe itself is IPv6-ready in general, some of the off-the-shelf software components on it are not (yet). In particular, current firmware does not support DHCPv6 (RFC3345) or DNS resolver option in RA (RFC6106) and thus there is no way of dynamically acquiring the necessary DNS information. With a static configuration it should be possible for the probe to function on an IPv6-only network.

We hope that this will be resolved soon, but until then the probe needs IPv4 to communicate with our infrastructure, unless full IPv6 configuration is performed manually. The measurements themselves can run on IPv6.

Q: I connected the probe. Now what?
A: The probe immediately starts connecting to our infrastructure and performing predefined measurements.

Q: How much bandwidth will the probe consume?
A: That depends on the number of measurements running on the probe. Our estimate is that it will initially not use more than a few kilobits per second, except for occasional firmware updates. We plan to allow hosts to specify the maximum bandwidth their probe can use.

Q: Can I access the data that is collected by my probe?
A: Yes. First, you have to register as a RIPE Atlas user, which will allow you to register your probe. By doing so you'll be able to access more information about your probe, including the measurements carried out by your probe. We will frequently add new functionality in this area.

Q: Can I deploy a probe on someone else's network, such as my company's, for instance?
A: That's your decision, but in our opinion you must ask permission first.

Q: Can I disconnect my probe?
A: Sure you can. But we'd like to ask you not to if you don't have to. If you want to shut it down for good, then please return it to us so we can redistribute it to someone else.

Q: I'm going on vacation. Can I disconnect the probe for that time?
A: Again, we'd like to ask you not to.

Q: Can I disassemble my probe to see what's inside?
A: No. You are not allowed to disassemble, reverse engineer, hack or otherwise harm your probe. We're happy to tell you what's inside and how it works - please look around on the RIPE Atlas website and in RIPE Labs articles about the topic. If you still have questions, let us know.

Q: What hardware device are you using? What's the software?
A: The hardware of the first generation probe is a Lantronix XPort Pro module with custom powering and housing built around it. The probe is not a powerful device on its own, but it's small and attractive. The software on the device is developed by the RIPE NCC (it's a real challenge, given the resource constraints). The probes are connected to a hierarchical control and data collection service, which is also built by us.

Q: Why did you choose a hardware solution instead of software?
A: With a pure software solution, distribution costs are low and the number of potential hosts is very large. However, there are several significant downsides to a pure software approach. First, host machines may not run continuously over long periods, which affects our ability to gather round-the-clock measurements. Second, measurements can be influenced by sharing systems and network resources with other applications on the host computer. Third, it is often not possible to install software like this in a corporate or computer centre environment. Fourth, it is easier to tamper with the results. Because of these drawbacks, we opted to develop the Atlas probe as a stand-alone piece of hardware.

We have chosen not to release a software version in tandem with the hardware solution for the fourth reason: we cannot trust the results.

Q: Can I assign static IP addresses to my probe?
A: Yes. Please check the static network configuration documentation for details.

Q: How secure is the system? Can someone take it over?
A: We've built in many safeguards to prevent anyone from taking over the system as such. Of course we cannot be absolutely sure that this cannot be done. We believe that the limited capabilities and the exoticness of the individual probes make the system an unattractive target, and that the current protection mechanisms are adequate against less concentrated attacks.

Privacy

Q: Does the probe listen to my local, private traffic?
A: No, it doesn't. It only talks to our central infrastructure and executes active measurement commands towards the public Internet.

Q: I'm still concerned about the probe being able to snoop on my traffic.
A: You should install the probe on a switch port (the home router often has this already), where it cannot hear any other traffic. Even better, you can put it behind a firewall, as long as that firewall does not prevent the probe from talking to the outside world.

Q: Will my IP address show up in measurements done by my probe?
A: Yes, it very likely will. We're thinking about what level of detail we can share with members of this measurement community in general. For example, you certainly won't have a problem seeing your IP address in your own measurements. Once we start sharing measurements with others, we'll start thinking about how freely we can do that. If sharing original data becomes an issue, we can introduce aggregation or anonymisation of the data.

Q: Do you accept any liability for incorrect operation, disputed actions or damages caused by the probe?
A: Sorry, we can't do that.

Troubleshooting

Q: The probe doesn't have any lights on. Is it dead?
A: Once you connect the probe on both connections (Ethernet and USB), it should come alive quickly. The green "link" LED should come on when the Ethernet link is established. The orange "data" LED will blink as the probe sends and receives packets. If this is not the case then please make sure that both connections are fine (for example, the USB really gives power, the Ethernet port is active, etc.). If the probe still looks dead, please contact us.

Q: I just connected my probe and the lights are up, but it is still listed as "down" in the "My Probes" list. What is happening?
A: It can take up to 10 minutes before enough data is collected and the probe is listed as up.

Q: The lights are on but I still cannot register my probe, or the system says my probe is not connected ("never seen"). What can I do?
A: Please double check that your probe received an IP address and DNS information through DHCP, and that there's no firewall rule or MAC address filtering blocking its access to the Internet.

Q: I want to share my Internet connection of my Mac (Mini, iMac, MacBook, etc.) and run the probe on that, but it doesn't seem to work. What can I do?
A: Some Atlas users who use "Internet Sharing" of OS X (10.4 and 10.5) have reported these issues. A workaround, that seems to work in all cases that we know of, is to change reply_threshold_seconds to 0. See these links for more details:

Q: I see 100% packet loss on all my probes to labs.ripe.net. Is this expected?
A: Since early 2012, ICMP rate limiting has been enforced near RIPE Labs, leading to these ping results. We will remove this server from the list of default measurements soon.

Data collection

Q: What kind of measurements does my probe do? What data does it collect?
A: Initially, every probe collects built-in measurements, such as:

  • Its own network configuration information
  • Current uptime, uptime history and total uptime
  • RTT (round trip time) measurements to the first and second hops (think about the first two lines in your outgoing traceroutes)
  • RTT measurements to a number of predetermined destinations
  • traceroute measurements to a number of predetermined destinations
  • DNS queries to root DNS servers (an later on to others)
Later we'll allow hosts to define their own measurements, thereby harnessing the power of multiple probes hosted by others.

User Interface

Q: I only host a probe or two, but I can see a lot of probes in the list. Why?
A: In early January we enabled a feature where hosts can "open up" their probe, meaning that any registered user can look at the state and measurement results of this probe. You can see these probes in the "Public Probes" list, with the role "Viewer". In the "My Probes" list you should only see the probes you host (or sponsored).

Q: Is there and API or such? Can I tweak my graphs?
A: See the documentation page about this.


The FAQ was last updated on 16 May 2012.