1. IPv6 integration with the ATN Tony Whyman Helios Information Services Ltd

2. Current Status The ATN SARPs specify the OSI Protocol Suite CLNP, TP4, ES-IS, IDRP Mandatory for Government Procurements in early 1990s Aeronautical Industry working with IP protocol suite For Airline Passenger Services Possibly some Operational Services AEEC Project 664 Aircraft Data Networks (ADN)

3. What is the Issue? OSI Standards no longer being developed IP Ground Networks “cheap” and available APC Services to use IP Protocols IPv6 becoming available Considerable Industry investment in the ATN Specification

4. Need for Change ATN must accommodate ground IP networks X.25 ceasing to be supported IPv4 in short term IPv6 in medium to long term ATN should be able to co-exist with airborne ADN IP systems Long Term Strategy needed Otherwise issue will keep reappearing

5. IP vs OSI Internet Protocol (IP) Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Routing Protocols ARP, RIP, OSPF, BGP-4 Addressing Interface based 4 byte addresses (IPv4) 16 byte addresses (IPv6) Connectionless Network Protocol (CLNP) Transport Protocol (TP4) Connectionless Transport Protocol (CLTP) Routing Protocols ES-IS, IS-IS, IDRP Addressing 20 byte System Addresses

6. Key Differences Protocols are not mutually intelligible Information is encoded differently CLNP has a much bigger address space Transport connection semantics are different TCP has a graceful release option TP4 is both message and stream oriented

7. Options for Convergence (1) Replace OSI ATN with IP ATN Community investment lost Delays introduction of datalink services Invalidates current operational services Use IP as an ATN Subnetwork Ground Only at present An Encapsulation Strategy (CLNP inside of IP) Permits use of IP Networks as part of ATN Does not affect existing Avionics Or Ground End Systems

8. Options for Convergence (2) IP to CLNP Protocol Conversion Permits a gradual replacement of CLNP with IP Independent of end-to-end communications (implies TP4 over IP) Full migration requires Application Change Transport Relays TCP to TP4 not possible in general ATN Dialogue Service TCP/TP4 gateway possible Single Point of Failure Issues

9. The Ground Environment ATC Centre CLNP IPv4 or IPv6 Internet CLNP ATC Centre IPv4 or IPv6 Internet ATC Centre CLNP in End System

10. The IP SNDCF CLNP IP SNDCF IP Network Other IP Service Users e.g. TCP/UDP Data Link Services e.g. Ethernet, PPP, etc. Other SNDCFs ES-IS

11. IP SNDCF Benefits Simple to implement Can support both IPv4 and IPv6 No impact on rest of ATN Allows COTS IP Networks to be part of the ATN Gives maximum benefit for least investment Specification being presented to ATNP Eurocontrol and STNA validating specification

12. Air/Ground Environment Expensively produced avionics DO178B Level C Software Development Certified for Operational Use Long in service lifetime Support for Aircraft Mobility needed Security Requirements Include Separation from Passenger Systems Resistent to external threats

13. Mobility Scenarios Aircraft only uses a single A/G Service Provider No network roaming requirement Aircraft serially uses multiple A/G Service Providers Strategy Required to manage transition Aircraft concurrently uses multiple A/G Service Providers Strategy required to manage use and route traffic according to policy and application requirements

14. Current ATN Mobility Extends standard Routing Protocols Adds information on route QoS and A/G networks Meets all Scenarios Needs a big address space - mobility at top of addressing hierarchy Security Leverages off existing “web of trust” routing model

15. Mobile IP

16. Mobile IP and ATN Supports only serial use of multiple A/G Service Providers Security Complex dynamic three way trust model Requires a network wide Public Key Infrastructure Potential for single point of failure Rejected by ATNP as a model for ATN Mobility

17. Airborne Convergence Options (1) No Change Retains strong separation between ATC and passenger communications Compatible with use of IP Ground Networks Make use of ADN IP networks where appropriate Extend use of IP SNDCF Respects differences in equipment lifecycles Firewalls can maintain strong separation

18. Airborne Convergence Options (2) Replace CLNP with IPv6 in new systems Requires new SARPs development Assumes Ground Systems Migration Translation of ATN Mobile Routing to IP Requires development of new certified systems Requires more complex firewalls Compatibility with passenger systems potentially limited by product lifecycle differences Currently not under consideration

19. Conclusion ATN will include IP Networks in its scope IP SNDCF is first step Meets most of the real requirement Co-existence with ADN IP Systems Currently under consideration Long Term Strategy to follow