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last change: December 29, 2021

Frequently Asked Questions (FAQs)


What is the Vienna Internet eXchange?

The Vienna Internet eXchange (VIX) is a neutral peering infrastructure for National Research and Education Networks (NRENs), Internet Service Providers (ISPs), Content Delivery Networks (CDNs), and Content Providers in Austria and the Central and Eastern European region. The VIX is used by its participants to exchange Internet traffic at the national and international level. The University of Vienna provides and operates the redundant VIX infrastructure at three sites in Vienna, ensuring a neutral, robust, high-performance peering environment for all participants. more information

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Who is connected to VIX?

In addition to national and international Internet Service Providers and Research and Education Networks, Content Providers and Content Delivery Networks are also welcome at VIX (see the List of Participants).

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Does VIX support IPv6?

Yes, IPv6 is productive at VIX. This means that your connection agreement is as valid for IPv6 traffic as it is for IPv4. If your router is IPv6-enabled, you can use a special syntax to generate your IPv6 address in order to enable IPv6 peerings on your VIX interface. This syntax is described in detail on the IPv6 page.

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Do I have a 10 Gbps connection to the Internet when I connect to VIX with 10 Gbps?

A 10 Gbps port on the VIX does not mean that you have a 10 Gbps Internet connection. The amount of Internet traffic that you can handle through VIX depends primarily on the type and number of your peering agreements with other VIX participants.

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What are the costs of a VIX participation?

There is a non-recurring setup fee of 1000 EUR (as of 06/2021) once per contract. The monthly port costs depend on the number and speed of the requested ports. Participants with connections at two VIX sites (including VIX1) may, under certain conditions, receive a discount. All details about costs are specified in the Cost Overview.

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Will the setup fee be charged again if I order an additional or more powerful connection to VIX?

No, the setup fee is charged only once per contract.

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Can I buy upstream via the VIX?

VIX, as a neutral Internet Exchange Point, provides a complementary peering infrastructure. Commercial agreements between participants - including physical VIX infrastructure - are not prohibited, but are not supported by VIX.

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When will a particular network that is important to me finally be connected to the VIX?

In our experience, this decision depends on several circumstances, including: Does the potential participant already have infrastructure at a VIX location? If not, how expensive is it to set up a connection? Is it economically reasonable? Does the potential participant follow a policy that states, for example, that there are only private interconnects to non-Tier 1 networks?

Sometimes a decision to participate in VIX is also triggered by expressions of interest from existing participants. Therefore, it may be useful to communicate such considerations to the appropriate peering contact of the desired network. Usually these contacts can be found in the Peering Database. We gladly accept suggestions for connecting a specific network to the VIX, but ask for your understanding that we cannot make any statements or even promises in this regard.

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What are the requirements for a VIX participation?

The essential precondition for a connection to VIX is a unique AS (Autonomous System) Number with an already established global Internet connectivity. Participants are expected to use their VIX connection as a complementary tool for optimizing regional Internet traffic flows. The only permitted routing protocol on the VIX infrastructure is BGP4. For more information, see Requirements.

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I do not have my own AS number. Can I participate anyway?

Unfortunately, no. As with any other Internet Exchange Point, a unique AS Number is a technical necessity for peering on the VIX. The reason is that VIX uses the Border Gateway Protocol (BGP) as a routing protocol, and BGP requires distinct AS numbers.

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What is BGP?

The Border Gateway Protocol (BGP) is the default routing protocol used by Internet Service Providers to exchange routes and routing information between Autonomous Systems. At VIX, BGP is the technical basis for bilateral peering agreements between participants. more information

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Why do I have to configure my router with BGP if I want to connect to VIX?

Only the BGP routing protocol allows you to exchange routing information (and thus also IP traffic) with other VIX participants.

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Can I participate in VIX without placing my router directly in a VIX location?

Yes, via "Remote Peering". This means that a carrier of your choice provides a connection via a transparent Layer 2 Ethernet Service which allows you to connect your peering router to the VIX, even over long distances. You are the contractual partner of the carrier and the VIX, and thus accountable to the VIX for the quality of your remote connection. We reserve the right to turn off an unstable remote line if it compromises the stability or operation of the exchange point.

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The lowest bandwidth offered is 3 Gbps - but I don't need 3 Gbps. Why are there no Gigabit interfaces anymore?

The current VIX hardware platform is built for physical bandwidths of 10 and 100 Gbps. Each bandwidth transition contains conflict potential in terms of queuing, buffering, etc. Lower connection bandwidths are probably offered by a reseller who handles these transitions - adapted to the circumstances - in his own network.

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What is a VIX reseller?

It's an organization that has made a separate agreement with VIX to divide its physical connection into several logical connections with agreed individual bandwidths. These logical connections are then freely offered to other suitable subscribers - generally uplink and connection as a package. The contractual relationship is concluded between the participant and the reseller. Participants who are connected to VIX via a reseller will of course (to an adapted extent) also receive appropriate support from the VIX NOC.

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What do I have to do if I want to become a VIX participant?

To become a VIX participant, please read the General Terms and Conditions and then complete the VIX Connection Agreement. After submitting the completed web form you will receive your Connection Agreement by e-mail. Please send the digitally signed PDF form by e-mail to admin(at)vix.at (your signature must be verifiable by RTR's signature verification service). Alternatively, you can also send us the printed form with your original signature by post. In both cases we will return the digitally countersigned document by e-mail.

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What happens after I've sent the Connection Agreement to VIX?

The VIX team will process your Connection Agreement and contact you within 5 working days. If you are planning to connect at Interxion or NTT, you can already initiate the required patch in the meantime (see next two items).

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How do I order a VIX patch at Interxion?

When establishing your connection, please tell us your patch coordinates at Interxion and send us a suitable LOA (Letter of Authorization). For remote peerings with a carrier connection, we need this from your carrier. The patch is ordered from Interxion by the VIX NOC and is included in the participation fee (as of 02/2019).

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How do I order a VIX patch at NTT?

Please order the patch directly from NTT, with CC to noc(at)vix.at. Simply indicate "Vienna Internet eXchange" as destination point and pass on the data about device and port number given by us.

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How do I peer then?

At VIX, two variants have been established which can be used independently by each participant:

a) VIX route servers:
If you use the route servers, every other participant has the possibility to view your respective peering policy with them, from non-participation to default peering for all. You don't have to use the route servers - however, we recommend it because the administration effort decreases drastically and traffic can be exchanged quickly with other participants. Besides, we recommend setting up additional bilateral peerings to those VIX participants that appear to be particularly important for your own network.

b) Bilateral peerings:
Direct peering between participant routers, freely agreed between two participants. Try to contact the peering team of the desired participant in order to conclude a (mostly informal) agreement.

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How is the accounting done?

Basically by PDF to the specified billing contact. The invoice contains VAT, which (if applicable) can be claimed as input tax. Please ensure that your payment is received free of charge. Any deducted bank charges will be offset against the next invoice run.

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I need a tax form (Certificate of Residence, US W-8, etc.) from VIX - how do I get that?

Please contact buchhaltung(at)vix.at.

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Web Portal

What features does the web portal offer?

The User Profile shows your own data. The web interfaces for the Route Servers allow you to configure peerings with just a few mouse clicks. The Network Status section includes statistics, peering traffic analyses, and a Layer2 view. more information

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Is there a list of IP addresses and MAC addresses of participants' routers?

Yes, the web portal provides such a list (menu item "Network Status / Layer2 View"), which is updated automatically every 2 minutes.

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Can I find out how much traffic I am exchanging with my peering partners?

Yes, that is also visible in the web portal (menu item "Network Status / Peering Traffic").

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Why is my interface first put into a quarantine setup?

In the course of this standard procedure, it is checked whether a connection complies with the guidelines/BCPs and whether the BGP announcements are within reasonable limits. So this is a contribution to operational safety. After adjusting the self-selected MD5 secret, you may continue to use the quarantine settings for using the route servers in the Peering LAN - the IP numbers there are identical.

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How do I establish a BGP test connection in the quarantine setup?

There are three route servers in the quarantine setup that simulate the ACOnet routers in the Peering LAN. Once you have successfully established a BGP connection to these route servers, we will test your announcements and filter settings. When we subsequently move you into the Peering LAN, these test peerings automatically become true peerings with the ACOnet networks.

The three test devices are to be configured as follows:

AS Number IP Address MD5 Password
1853 ACOnet Backbone will be advised
1853 ACOnet Backbone will be advised
1120 ACOnet/VIX Service will be advised

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What are site-specific BGP communities?

Site-specific BGP communities serve to optimize traffic flows between VIX participants. more information

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Why is it not allowed to use the Spanning Tree Protocol (or other)?

The Spanning Tree Protocol is designed to prevent Ethernet loops within an organization, but not on Internet Exchange Points. We use other techniques to ensure that no loops can affect the IXP infrastructure. more information

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Why can't I have more than one MAC address on VIX ?

At an Internet Exchange Point, each participant port is designed to connect exactly one peering router. If a VIX participant is sending data packets from more than one MAC address this usually indicates a misconfiguration. In many of these cases, a loop occurs that could theoretically paralyze the operation of the Exchange Point. We prevent this by ignoring traffic from unregistered MAC addresses for security reasons.

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What should I consider when I replace the router hardware at my VIX port?

If the MAC address changes, please make sure you give us the new address! In emergency situations this can also be done via telephone or outside office hours via voicemail message (see "How can I contact the VIX NOC?").

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Why can't I set up a peering with the VIX route servers?

One reason may be that the route servers are not activated in the web portal. Someone in your organization whose VIX portal account is qualified as "Route Server Admin" must enable the route servers there. An MD5 secret is obligatory.
If the route servers are enabled and still no peering occurs, the reason is probably the TTL. Please make sure that the TTL of the peering session is 1 or 255.
On some platforms, a known issue with "bgp enforce-first-as" also leads to a termination of the peering session - please check and correct if necessary! If that doesn't help, please contact the VIX NOC.

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Why are all routes offered by the route server invalid?

Some router manufacturers have the default setting in their software to compare the first AS of the received route with the AS of the peer. If these are not identical, the route is marked as invalid. The route server has its own AS, but does not add it to the path. Please configure your router accordingly, e.g. "no bgp enforce-first-as".

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Why doesn't the route server send me prefixes from a specific AS?

The most common reasons for this behavior are:
a) The participant does not use the route servers, or has a peering policy that prevents any exchange with your AS. This can be seen in the configuration of the route servers in the web portal.
b) The prefixes are not, or not properly, registered in the RIPE database (inetnum with matching route-object). Please contact the peering team of the other AS. If it is a network from another RIR, you can also change the peer in the route server configuration so that you get all the prefixes from this AS - whether documented or not.

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Why am I missing prefixes from an AS that I get via my transit?

This occurs especially with Content Delivery Networks (CDNs). It is then part of the CDN's load sharing concept not to announce everything on every POP.

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Help, my prefix is announced by someone else!

There is often a configuration error behind it, but sometimes it is malicious intent. Please check your documentation in the RIR first. The VIX route servers shouldn't pass on such announcements if the receiving participants have activated the RIPE filter option. However, you'll have to contact the source of the misannouncements and ask them to stop. The VIX NOC can help to find the contact, but we don't have any authorization whatsoever to request changes, especially if it is not a VIX participant.

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Help, my VIX port is saturated!

First, try to find out if it's a volume attack or legitimate traffic. The identification of the source peer in the VIX web portal can help with this distinction. In the case of legitimate traffic, traffic engineering (i.e. the processing of traffic via other routes) might provide a short-term remedy. In the medium term you should consider an upgrade of your VIX connection. In the event of an attack, all that remains is other mitigation (e.g. in the transit network) or a shutdown of the source(s) - but this can be quite laborious or practically infeasible. In any case, all these measures are beyond the control of the VIX.

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Help, I am attacked by an IaaS/CDN provider with UDP from individual IP numbers!

This is most likely a download via QUIC and not an attack (see https://en.wikipedia.org/wiki/QUIC).

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How can I contact the VIX Network Operations Center (NOC)?

Either by e-mail to noc(at)vix.at or during office hours (Mon-Fri 7:00 am - 3:00 pm UTC) by calling the phone number +43 1 4277-14030. Outside our office hours, we request that you leave a message on this number only in emergencies. In sufficiently urgent cases we will call back as soon as possible. more information

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For technically advanced end users of a network connected to VIX

I try to determine my accessibility on the Internet, among other things by means of an ICMP echo request (ping) to an interface at VIX, but the answer is sometimes lacking. Is there an error?

In most router types, an answer to ICMP echo requests is given by the control plane - this is the part of a router that is busy, among other things, exchanging information with other routers about available paths on the Internet and making decisions about paths it uses itself. In its role as the central point of a router, this control plane is normally protected against load that does not directly serve the operational purpose. In other words, a participant router has enough other things to do than answer pings from somewhere - so sometimes, depending on the situation, it just doesn't answer.

Because of this behavior, echo requests (or replies) do not allow any conclusions about a connection problem or the performance of the network - only the participant's NOC can clarify this. If you suspect connection problems, please contact your ISP. If necessary, the ISP can contact the other participants involved in order to locate a possible problem.

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My traceroute to a VIX participant shows asterisks or something else starting from a VIX interface, but no response times. Is there an error?

Traceroutes are bundles of IP packets with ascending TTL that are supposed to cause the corresponding routers in the path to generate ICMP unreachables of the type "TTL expired" and send them back to the sender of the IP packets (i.e. the initiator of the traceroute). These unreachables, evaluated by the traceroute software, give hints on a chosen (outward) path through the Internet.

Please note, however, that asymmetries in the outward and return routes can only be assumed or are not recognizable at all, and that the return path can partly run over completely different routes. Moreover, due to protection considerations for their own network some ISPs do not allow their routers to respond to such requests, or they only answer a certain total number of requests per time unit. Beyond that, the same applies as for ICMP Echo Requests.

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