Netnod’s IXP Architecture

Swedish national Internet exchange points are built on Ethernet technology. They are a layer 2 service with no routing facilities existing within the exchange points. The connected customer’s routers are responsible for the routing of packets through the exchange points. Netnod provides IX connections at sites in Stockholm, Copenhagen/Malmö, Gothenburg, Sundsvall/Gävle, Luleå, Oslo (powered by NIX) and Helsinki.

Technical overview

In Stockholm the exchange point consists of two redundant peering LANs located in two main safe facilities operated by Netnod. There are also a couple of co-location sites where Netnod has switches and DWDM-equipment to backhaul traffic to the two main sites.

All of the installed infrastructure equipment has redundancy to protect from electrical breakdown for high reliability demands. The two peering networks are labelled “Green” and “Blue”. Netnod has two core sites in Stockholm where the switches and other common equipment are physically protected according to current rules and recommendations from the Swedish regulator (PTS). The exact locations of these sites are not published.
For customers connecting to Netnod at a data centre, one or two local cross-connects are needed to connect. One for single-port and two for a redundant connection. If a redundant connection is ordered Netnod will ensure that the paths will be diverse.

In Gothenburg, Malmö, Sundsvall and Luleå the exchange point consists of one peering network located in a safe facility operated by Netnod. All installed infrastructure equipment has redundancy from electrical breakdown for high reliability demands.

The two sites in Copenhagen that, together with VG4 and NNB, form Netnod IX Copenhagen are located at data centres. These sites also have a high degree of physical access-safety, redundant power and fire suppression.

Technical description

In Gothenburg, Sundsvall and Luleå the exchange points are single, standalone, non-interconnected switches.
In Stockholm and Copenhagen the exchange points are built in a redundant manner providing the possibility of connecting to both the “Green” and “Blue” peering networks (Netnod IX Redundant). There is also the possibility of connecting to both peering networks over a single port (Netnod IX Single Port). The networks will then be provided in tagged VLANs on the same physical customer port.

Network connections in Stockholm

There are two ways to connect to the peering LANs in Stockholm:Netnod on-net locations
If the customer is present at an on-net location where Netnod has an established presence, the customer only needs to order a cross-connect.Netnod off-net locations
If the customer wants to connect from an off-net location, the cost for the access fibre will be added.

MAC addresses

The ports on the peering LAN will be configured to allow only the connected customers' interface-MAC-addresses. The MAC addresses of the customer's interfaces need to be provided to Netnod in advance.  In case of a change in the customer's hardware, Netnod need to be notified at least one full working day in advance.

IP addresses

All Netnod exchange points support IPv4 and IPv6. Each VLAN connection should always have one of each.

The amount of IP addresses needed for each customer depends on two things: if the exchange is Redundant and the MTU/VLAN setup on the peering LAN.
Netnod will assign and distribute IP addresses to the connected customers.

MTU/VLAN setup

Currently there are 2 standard setups:


  1. MTU 9000 only peering VLAN per peering LAN (1 IPv4  + 1 IPv6)

  2. MTU 1500 + MTU 4470 peering VLANs per peering LAN ( 2 IPv4 + 2 IPv6)

If the exchange is Redundant (as in Stockholm and Copenhagen) each peering LAN is configured with either 1 or 2 VLANs per peering LAN according to the two types shown above.

Summary of MTU/VLAN setup at Netnod IXes

Exchange Location Available VLANs MTU-size(s) Redundancy
Stockholm BLUE


Copenhagen BLUE


Helsinki BLUE


Gothenburg BLUE 1500+4470


Sundsvall BLUE 1500+4470


Luleå BLUE 1500+4470



*You need to connect to two sites for full redundancy

Setup in Stockholm:

VLAN setup Stockholm

Setup in Copenhagen:

VLAN setup Copenhagen

Setup in Gothenburg:

VLAN setup Gothenburg

Setup in Sundsvall:

VLAN setup Sundsvall

Setup in Luleå:VLAN Setup Lulea

The VLANs are implemented according to IEEE802.1Q. As there is no connection within the exchange points between the different VLANs, a customer that communicates with parties using different MTU-sizes needs to have a connection to each VLAN they want to exchange traffic on.

Redundant Ports vs Single Port

In the exchange points that have both a Blue and a Green Network, a fully redundant setup is possible (currently Stockholm and Copenhagen). As can be seen in the picture below Customer A has redundant connections and connects to the Blue network with one physical link/interface and to the Green network with a second physical link/interface. Customer B and C use single connections and will connect to the Blue AND Green Networks via a single physical link/interface.

Netnod IX technical information

Unicast traffic

Peering between a customer’s routers through the exchange point will be done via BGP4. Any kind of tunneling is explicitly forbidden.

Multicast traffic

Multicast traffic is supported over the exchange points.

A route server facilitates the administration of peering arrangements for networks present at an exchange point. By connecting to the route server, you can replace some or all of your separate BGP sessions to your peers, with one single session towards the route server.
Here are example configurations that illustrates a router connected to both of the VLANs on the STH-B switch. The VLAN ids will be different for other Netnod IX's. The examples are only examples and will most likely need to be adopted to your environment and platform.
Transport network suppliers and fibre suppliers for connecting in Göteborg, Malmö and Sundsvall.
Here we answer some of the most common questions about peering, IXPs and Netnod IX.
Educational resources
Peering allows multiple networks to connect and exchange traffic. Find out how peering helps cut costs and increase the resilience, speed and performance of networks. This peering overview explains the different types of peering arrangements and what you need to do to get started.
Educational resources
Any company doing digital business needs an IT strategy that ensures network security, reach and performance. Interconnection plays a key role here. The right interconnection strategy grows your network, saves costs and provides the flexibility to scale and guarantee high-performing services.
Connected networks at Netnod IX