OTN nodes are either modular or integrated units.
Each modular node is mounted in a 19" rack and is equipped with network cards, interface cards and one or more power supply modules. The network cards provide communication between the optical rings and the interface cards.

The node design is largely hardware based, requiring little or no upgrades. In the event an upgrade is needed, this can be done centrally, without the need to go onsite. Critical components, such as power supplies or common logic cards (BORA) can be protected by a redundant unit.

More info about the N50/N70 series.

N22 node
Modular node
8 interface slots
Height: 6 HU
N215 node
Modular node
4 interface slots
Height: 3 HU
N42C node
Modular node
8 interface slots
Height: 6 HU
N415 node
Modular node
4 interface slots
Height: 3 HU
N2021 node
Interfaces integrated on board
Height: 1 HU
N50/N70 node
ETS
N50/N70 node