How are the IFE Server, Floor Disconnect Box (FDB), Seat Electronic Box (SEB) and Seat Display Unit (SDU) connected to each other?
Airbus IFE system



All data sources and servers are concentrated in the IFE Center which delivers them to the cabin LAN using Ethernet. The LAN itself is Ethernet.

Some data are received by the IFE Center from the Cabin Intercommunication Data System which is itself connected to AFDX (Ethernet, ARINC 664) ADCN network. 

The cabin network then distributes data and power to overhead displays and seat IFE units.

Schematic:


Source, page 15

Architecture:


Source, page 15



IFE System for the A350



The IFEC rack is the source for all data sent to the passengers IFE units and the flight attendants panels. It contains files and media servers, is linked to external cameras (ETACS), landscape cameras and SATCOM.


IFE: In Flight Entertainment
IFEC: In Flight Entertainment Center. A system with redundant sources and redundant outputs.
ETACS: External and Taxiing Aid Camera System
SATCOM: Satellite Communications


The IFEC is also interfaced with the CIDS which supply it with data from systems like CDAU and ADIRS and other aircraft systems using AFDX, engine data from PCS, or discrete signals like cabin systems (oxygen) or public address.


CIDS: Cabin Intercommunication Data System, the main way for attendants to control the cabin systems other than IFE.
CDAU: Centralized Data Acquisition Unit
ADIRS: Air Data/Inertial Reference System
AFDX: Avionics Full Duplex Switched Ethernet (ARINC 664)
ADCN: Avionics Data Communication Network 
PCS: Propulsion Control system


IFE power is supplied by some SPDB.


SPDB: Secondary Power Distribution Box


The IFEC and SPDB are controlled by ICPs, FAPs, CWSs and RCCs.


ICP: Integrated Control Panel (in cockpit)
FAP: Flight Attendant Panel
CWS: Cabin Work Station
RCC: Remote Control Center


The IFEC delivers data (audio, video, other data) as Ethernet frames to FDBs using a switch. There are actually two or more IFEC switches, each one feeds some FBDs. 

FBDs also receive power from the SPDB. Ethernet frames and power are distributed by FDBs to overhead displays and IFE units.


FDB: Floor Disconnect Box. Used as a switch to create the network. FDB ensure network redundancy: Each FDB receives data from one IFEC switch, but as FDB share the same network, IFEC is still available when one of its switch is failed.


Each seat gets its IFE unit which is connected using a SEB. The IFE unit encompasses the SDU, the PCU and headset.


SEB: Seat Electronic Box. A network interface card, with power management.
SDU: Seat Display Unit (touch screen in front of the passenger)
PCU: Passenger Control Unit (interface)


The big picture:


Source



Security aspects



Your question was motivated by the security aspects of the cabin network vs. the other aircraft domains (e.g. avionics or cabin systems).

For Airbus, the cabin IFE network is only a layer 2 LAN with multiple Ethernet segments linked by Ethernet switches. There is no possibility to route malicious packets to other domains, since there is no routable (layer 3) protocol.

The interconnection between IFE and other systems is made through the CIDS, which is based on a redundant "director" which controls data destination. Without other elements, the assumption is security is primarily at CIDS level.

More information in this presentation (some pages are in German, most are in English).