Netnod’s IXP Architecture

This page explains the technical setup at Netnod IXes and provides important connection details for customers.

Technical overview

Netnod’s Internet exchange points are built on Ethernet technology. They are a layer 2 service with no routing facilities existing within the exchange points.

For customers connecting to Netnod at a data centre, one cross connect is needed per port. If you order a redundant connection in Stockholm, Copenhagen or Helsinki (see below), you will need two cross connects. In that case, you will be guaranteed diverse paths to ensure redundancy.

Redundant ports vs single port 

At the Netnod IXes in Stockholm, Copenhagen and Helsinki, the IX has two redundant peering LANs located in separate, secure sites. There are also a number of co-location sites with switches and DWDM equipment to backhaul traffic to the two main sites. The switch fabric in these metros uses a dedicated fibre path for each switch to ensure multiple, redundant paths.

Customers at the IXes in Stockholm, Copenhagen and Helsinki can buy a redundant connection which gives them two ports connected to separate switches on the Internet Exchange. These switches are labelled “Green” and “Blue”.

As can be seen in the picture below Customer A has redundant connections and connects to the Blue network with one port and to the Green network with a second port. Customers B and C use a single connection over a single port and connect to the Blue AND Green Networks via a single port.

Netnod IX redundant ports vs single port

The Netnod IXes in Gothenburg, Sundsvall, and Luleå do not currently have physical redundancy as an option. However, if there is customer demand, Netnod will add redundant switches to any of our IXes. 

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 needs to be notified at least one full working day in advance.

IP addresses

All Netnod IXes 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 each peering LAN is configured with either 1 or 2 VLANs per peering LAN according to the two types shown above.

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.

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


*Customers who need local redundancy in Helsinki are advised to connect to HE7


Setup in Stockholm:

VLAN setup Stockholm

Setup in Copenhagen:

VLAN setup Copenhagen


Setup in Helsinki:



Setup in Gothenburg:

VLAN setup Gothenburg

Setup in Sundsvall:

VLAN setup Sundsvall

Setup in Luleå:

VLAN Setup Lulea


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.
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This page summarises the usage and connection policy at the Netnod Internet Exchange.
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Connected networks at Netnod IX