Frequently asked questions


  1. What is the Croatian Internet eXchange?
    University Computing Centre is providing hosting to Croatian point for common exchange of Internet traffic - Croatian Internet eXchange (CIX), and is responsible for reliable and stable functioning of CIX. CIX users are commercial providers of Internet services (ISPs) in Croatia, non-commercial and private networks.
  2. Who is connected to CIX?
    Besides national and international Internet Service Providers and Education and Research Networks also Content Providers and Content Delivery Networks are welcome to CIX. More Details are shown in the participants list.
  3. What are the costs of a CIX participance?
    There is a non-recurring set-up fee of 3000,00 HRK once per contract. The monthly port cost depend on number and speed of the ports. For every second and each subsequent 10G connection participants can get a 50% discount. These and more details about the costs are specified in the price list.
  4. If I order an additional connection at CIX, will the setup-fee be charged again?
    No, the setup-fee is charged only once per contract.
  5. Does the CIX support IPv6?
    Sure, IPv6 at CIX has production status, ie. the agreement applies to IPv6 traffic as it does to IPv4 traffic.


  1. Which requirements shall I fulfill to participate at CIX?
    The only requirement for a connection to CIX is an unique Autonomous System (AS) Number with already properly esablished global Internet connectivity. Participants are expected to use their CIX connection as a complementary tool for optimization of regional Internet traffic flows. The only routing protocol which may be used across the CIX infrastructure is BGP4.
  2. I do not have an own AS-Number, can I participate at CIX anyway?
    Unfortunatly not. At CIX (like at any other Internet Exchange Point) an own AS-number is a technical prerequisite to peer. CIX uses the Border Gateway Protocol (BGP) as routing protocol and this requires an own Autonomous System Number (ASN).
  3. What is BGP?
    The Border Gateway Protocol (BGP) is the standard routing protocol used by internet providers. With this protocol routes and routing information are exchanged between autonomous systems. BGP is the technical basis at CIX for bilateral peering agreements between CIX participants.
  4. Why do I have to configure my Router with BGP, if I want to connect at CIX?
    Without BGP you cannot exchange any routing information or IP-traffic with other CIX participants.
  5. Is it possible to participate at CIX, without hosting my router at one of the CIX locations directly?
    Yes, this is possible. That option implies that a remote provider of your choice establishes a connection through a transparent layer 2 ethernet service to the CIX. In this case your company signs a contract with CIX and with the Carrier, therefore you are responsible for the quality of your remote connection. We reserve the right to disconnect an instable remote connection, if it compromises the stability or operation of the exchange point.
  6. Can I buy upstream over the CIX?
    The CIX, as a neutral Internet Exchange Point, provides a complementary peering infrastructure. Commercial agreements between participants including the physical CIX infrastructure is not forbidden but it is also not supported by CIX.
  7. Do I have a direct 10 Gbit connection to the Internet, if I connect to CIX with 10 Gbit?
    You can connect to CIX with 10 Gbit but this does not imply that you can exchange 10 Gbit per second of traffic to the Internet. The amount of Internet-traffic that really flows depends on the number and kind of your peering agreements with other CIX participants.


  1. What shall I do, if I want to participate at CIX?
    To become a CIX participant, please read "CIX Policy" and ''CIX Agreement'' and then contact us via email cix [at] We will prepare Agreement, and send four printed and signed copies by (snail) mail to you. You need to send by (snail) mail two sidned copy back.
  2. How do I physically connect to CIX switch?
    For the purpose of connecting to CIX switch at CIX1 location CIX member provides adequate cable; the cable will connect employees of Srce. Connecting to CIX switch at CIX2 location is carried out according to the procedures of Altus IT.
  3. How can I access my equipment?
    The procedure of access to the CIX member's equipment is described in the internal web,

The procedure for connecting to CIX

  1. Which is the procedure for connecting to CIX?
  • To become a CIX member please fill out the application form at or contact us at cix [at]
  • To prepare the contract template we need the following information:
    • Legal entity name
    • VAT/TAX number
    • Street and street number
    • Location and zip code
    • Country
    • Address for submission of documentation (if different from the address in the contract)
    • Legal representative
    • E-mail address for official communication (alias)
    • AS number
  • The contract template will be sent to you for a review and we will sign it, if you agree with the text of the proposal.
  • We will send four printed and signed copies of Agreement by (snail) mail to you. You need to send by (snail) mail two sidned copy back.
  • After signing the contract, you will get access to the IXP Manager application where you will enter your data and track traffic (peer to peer).
  • For the realization of physical connection to CIX it is necessary to choose the desired medium ( to ensure the appropriate SFP.
  • After the physical connection is realized you will get IPv4 and IPv6 addresses and passwords for the route server.
  • On CIX public website we will announce that you have joined CIX and we will notify current CIX members by e-mail. You can start peering negotiation with those members that do not have open peering on route servers.

Access to equipment owned by CIX member

  1. Entering at the CIX1 location (Srce, J. Marohnica 5)

    Access to equipment owned by CIX member located at the CIX1 location must be announced by e-mail at cix [at] in advance. The e-mail should contain information about the person or persons arriving, including the names and time of arrival, and a brief description of the reason for arrival and the time required to perform the work. Note: Persons must be appointed through CIX internal portal. 

  • Access to equipment and standard operations during working hours (Mon-Fri, 8:00 am - 4:00 pm) should be announced 24 hours in advance.
  • Access to equipment and standard operations outside working hours should be announced 48 hours in advance.
  • For urgent work an e-mail can be sent just before the intervention. In this case, it is important that the subject of the e-mail begins with "EMERGENCY INTERVENTION".
  1. Importing and removing equipment at the CIX1 location.

    Importing or removing of equipment should be announced via e-mail; e-mail must include a list and serial numbers of the equipment.

    User equipment can be removed from the CIX1 loacation only with a record signed by an authorized technical person.

    In case of emergency work outside working hours equipment can be taken out the next business day with signed records.

  2. Recommendations for access to equipment located at CIX1 location related to coronavirus.

Avoid getting to the CIX1 location. Check first that the works can be performed by the Srce staff, without your arrival at the site. If arrival cannot be avoided, be sure to follow all behavioral guidance by Srce staff and / or the porter as well as positive guidance from the Civil Protection Crisis Staff and coronavirus prevention. Users without a protective mask and gloves will not be allowed to enter the CIX1.

  1. Entering at the CIX2 location (Altus Information Technology Ltd, Selska cesta 93)

Access to equipment must be agreed with the Altus Information Technology Data Center.

Technical details

  1. What are the technical details that are important when connecting to CIX switch?
    Important technical details you can find here.

Peering matrix

  1. What is a peering matrix and how is it obtained?
    The Peering Matrix displays information about which CIX members are open to exchange traffic through CIX. Peering matrix is ​​based on technical data automatically collected from CIX members.
  1. How to "read" a peering matrix?
    In the rows of the peering matrix for each member we can see with which other members it wants to exchange the traffic - on the intersection of the row of the member with the other member's column there is a green box.

    The traffic is exchanged bilaterally, so both members want to exchange the traffic, in which case both members have in each row a green box to the other member.

    If only one member has a green box in its row to another member, it means that it is ready for exchange, but the other member is not and therefore there is no traffic exchange until the other member agrees.

  1. Peering matrix and open peering policy
    Open peering policy means that a member is willing to exchange traffic with all other members. In principle, such members are recognized as those with green boxes according to most other members, although this is not a sufficient condition to claim this with absolute certainty.
  1. What can you learn from the peering matrix?
    You can see with some likelihood who are your potential peering partners, but we advise that if certain members are important to you, check with them directly to see if they are interested in exchanging traffic with you.