Neutral Internet eXchange
NIX.CZ allows you to connect, interact and share in whole new ways.

Network Topology

Topology NIXSK

Using our extensive experience with the Prague Peering Exchange, we have selected Cisco Nexus 7010 for the launch of the NIX.SK node. With this hardware profile the switches are located in two detached locations and are configured to be fully redundant. The interconnection of the switches is ensured by two independent routes each with double the desired capacity, so that failure of one of the routes does not affect the operation of the connection node.


SITELPOP2, Kopčianska 18, Bratislava

SITELPOP1, Kopčianska 20, Bratislava

DIGITALIS, Trnavská cesta 110/B, Bratislava
Single-Mode optical Fiber (SMF)


Route Servers

Two route servers at NIX.SK1 and NIX.SK2 simplify the system of peering sessions between members and customers, where there is no need of individual BGP sessions. These route servers also simplify the process of new member’s and customer’s admission to the Association. The service is provided free of charge to members and customers and peering is supported in both IPv4 and IPv6 protocols. Due to the requirements for higher stability, the route servers were divided into two servers with different operating system and both are running at routing daemon Bird. Promoting peer prefixes over route servers can be managed through BGP communities.


IPv6 protocol

IPv6 protocol is a successor to the IPv4 protocol, which is currently widely used on the Internet. Its specifications were developed in the 1990's. One of the reasons for the development of IPv6 was a thread of IPv4 address space exhaustion. Besides the bigger address pool, the new IPv6 protocol comes with support for QoS, implementation of security mechanisms and support for mobile devices or automatic device configuration.


With the IPv6 protocol the bit- length of the address is increased fourfold; instead of the original 232 (4294967296), there are now 2128 (340282366920938463463374607431768211456) addresses available. IPv6 address space is divided into several groups and global addresses are assigned from the 2000::/3 pool. According to the published hypotheses, the IPv4 address space exhaustion was expected in July 2012 but NIX.CZ has allowed IPv6 peerings for its members and customers since 2003. At the moment, 86 of 117 connected networks to NIX.CZ are using this option.


Please note that this page allows you to check whether your computer is connected via IPv6 protocol, or not. It is also possible to use IPv6 protocol parallel to the IPv4 protocol.

32bit AS numbers

Beside the IPv4 address pool exhaustion there was also a need to solve a similar problem for numbers of autonomous systems used for BGP router identification, as autonomous system numbers are being exhausted too. The original pool contained 216 (65536) autonomous system numbers, and by the new specification it was boosted to 232 (4294967296). This enlargement is still compatible with routers, which do not support 32bit autonomous system numbers. The exhaustion of the current 16bit pool was expected in June 2011 but the RIPE registry has been providing 32bit autonomous system numbers for new requests since the beginning of 2009.