CESNET 3 network

The basic element of the entire e-infrastructure is the high-speed computer network CESNET3, whose backbone connects the circuits with high transmission speeds to the largest university cities of the Czech Republic and other areas. In addition to the standard Internet connection and large transmission capacities for scientific and research purposes, it offers its users other modern services such as video conferencing, the MetaCentre supercomputer, IP telephony, etc.

Key features

• Cutting-edge specifications of network infrastructure (high bandwidth – typically 10-400 Gb/s, high redundancy, multi-layer connection). A comprehensive optical backbone network solution enables connected organisations to use even very demanding applications such as multimedia transmissions, sharing of data resources, computing resources or experimental equipment.
• Specific connections at the user request (end-to-end services) connect a limited number of devices over a dedicated link. They enable extraordinary amounts of data to be transmitted, for example, when unique instruments are used remotely. Their operation is completely isolated from the rest of the network and they do not have to share the available capacity with normal traffic. In addition, we are also able to provide these services abroad.
• Virtual private networks (VPN) – they enable a secure connection of defined points, the communication between which is separate from the remaining network traffic. Unlike end-to-end services, they do not have dedicated communication channels, but share transmission capacity with others. They can especially be used for securing sensitive data flows.

High reliability levels are guaranteed by the combination of backbone infrastructure redundancy (each backbone node has at least two independent connections) and continuous monitoring of the network status. Backup connections are usually sized at the basic connection level, which is not common in other networks. Users can fully rely on the availability of quality services.

CESNET3 network topology

At the core of the network is a rich DWDM infrastructure with dozens of transmission channels at speeds of 400, 100, 40, 10 and 1 Gbps. We started building it in 2005, when we put the first DWDM route between Prague and Brno into operation. In 2013, the backbone infrastructure was upgraded to a transmission capacity of 100 Gb/s. We continuously expand the number of connected nodes as well as the number and capacity of channels as needed. In 2022 and 2023, the network core is being upgraded to 400 Gbps.

Other CESNET3 backbone circuits use 100-gigabit, 10-gigabit and 1-gigabit Ethernet. Routes to smaller nodes offer speeds of 10 Gbps as a rule. Their capacity is also continuously increased in accordance with the needs and actual operation of specific nodes.

The network topology consists of circles passing through a limited number of cities (ideally up to four cities per circle). The goal is a redundant network backbone with not very long paths and therefore with little delay incurred in the active network elements.

CESNET3 network topology

At the network layer level, we support both IPv4 and IPv6. We can also offer transmission services in lower layers in the form of dedicated circuits (end-to-end services) Dedicated circuits and networks, Lambda services and Photonic services).

Connectivity

CESNET3 has rich connections with foreign countries:

• The key is the connection to the European GÉANT network, whose node is located directly on the CESNET premises. The link has a capacity of redundant 200 Gb/s and primarily carries traffic between academic institutions.
• We communicate with the regular (commercial) Internet via the Tier2 line of the Telecom Italia operator (redundant 20 Gb/s).
• Individually, we are connected to three national research and education networks in neighbouring countries. The networks are SANET (Slovakia, 100 Gbps), ACONET (Austria, 100 Gbps) and PIONIER (Poland, 10 Gbps).
• We also have a separate connection to the Google network (40 Gb/s).

The external transmission capacity of CESNET3 is further enhanced by the connection to peering centres:

• 2x 100 Gb/s to NIX.CZ, mainly for peering with home Internet providers. Within NIX.CZ we are involved in the FENIX security project.
• 2x 10 Gb/s to AMS-IX for peering with selected foreign providers.

Information on transmitted traffic is provided by a map of the current load on the backbone network.