This section explains the topology of the network, Figure 12-1 presents the topology as it was in February 2003 for the 6NET core and NREN PoPs.

Figure 12-1 The 6NET Core and NREN PoPs

The 6NET network consisted of a set of international POS STM1/OC3 backbone circuits and a set of access circuits which mostly were native connections plus some tunnelled connections to 6NET partners. The 6NET core is represented by orange routers whilst blue routers represents the access
routers of the NRENs.

In total, there were 16 partners directly connected to the 6NET core. POL34 was connected via a manual IPv4-to-IPv6 tunnel to the Swedish router. It also had a backup manual tunnel connection to the German Router. GRnet was connected to 6NET via a CCC/MPLS connection to the German router.

Previously, manual IPv4-to-IPv6 tunnels were configured for connecting HUNGARNET and CESNET. From January 2003 they were changed to STM1/OC3-155Mbps native connections. The rest of the access links were STM1/OC3-155Mbps, except NORDUnet with STM16/OC48-2.5Gbps, SURFnet with a 2xGE (2x1Gbps) access links and NTT with an E1 link to the UK router (2Mbps).