Strategies For Detecting Network Attachment in Wireless IPv6 Networks Greg Daley - Research Fellow Monash University Centre for Telecommunications and Information Engineering

Overview: Tomorrow’s Wireless Internet Strategies for Detecting Network Attachment in IPv6 DNA Working Group Progress Future Challenges

Tomorrow’s Wireless Internet

Wireless Data Communications Used for wide purposes –Mobile Data –Wire replacement Telco to SoHo –Management, Planning, Security Same convergence as wired networks –Merging of Internet and Telephony –Data services providing voice, voice networks with data

Wireless Data Communications

Towards All IPv6 Wireless Internet Similar applications in Wireless to fixed New Applications –Peer-to-peer hampered by NAT IPv6 well positioned for wireless –Basic IPv6 capabilities support dynamism

NAT and Applications

Maintaining Internet Connectivity Cell to cell transitions can cause address changes Addresses are used for routing and Session Identification (TCP/UDP) Hide/Prevent Address changes –Tunnel, Link-Layer switching, Mobility Agents Manage Address changes –Addressing update, requires peer support

Maintaining Internet Connectivity OLD CELL NEW CELL Address Range: 2001:388:608c::/64 Address Range: 3ffe:12:388:fc:/64

Maintaining Internet Connectivity Internet A P P S A P P S M I P 6 M I P 6 I P V 6 I P V 6

Strategies for Detecting Network Attachment in IPv6

Change Management in Wireless IPv6 Detect which change will occur (hard?) –Allows predictive repair Detect when link-layer changes Detect when change has occurred React to change –Configuration of addresses, local routers Signal to proxies and peers –Path restoration after change

Change Management in Wireless IPv6 Internet M I P v 6 D N A v 6 Peer RS RA BU BAck

Detecting Network Attachment Avoid reconfiguration if possible –Addresses, Multicast Joins, Mobility Signalling Detect if configuration change is required –Trade off test cost against config cost Query the network to detect if change has occurred Relies upon network information services Single Message Pair exchange

Detecting Network Attachment RA RS OLD LINK NEW LINK

Key DNA Tasks Address uncertainty management Response without induced delays Immediate Change Detection Authoritative Responses

Key Task: Address Management Host unaware of address conflicts at attachment point Link-Local address collision may have occurred, upon link change Optimistic Duplicate Address Detection is used in sending DNA messages New RS Tentative-Source Link-Layer Address Option: Optimistic DAD safe solicitations (GD,EN,NM)

Key Task: Address Management FE80::FEOF

Key Task: Fast Router Advertisement Existing RFCs have random delay timing FastRA Schemes reduce delay Original FastRA – manual config (MK,JK,BP) Deterministic – Automated config (GD,BP) Probabilistic – Small random delays (SN,GD) Hash – Speed of Det, less config (BP,EN)

RFC 2461 RS/RA Timing Router2 Router1 Router3Host Solicitation Advertisement Time (s) T T+.5

Fast Router Advertisement (RA) Router2 Router1 Router3Host Solicitation Advertisement Time (s) T T+.5

Deterministic FastRA Router2 Router1 Router3 Host Solicitation Advertisement Time (s) T T+.5 T+.05 T+.1

Probabilistic Fast RA Router2 Router1 Router3 Host Solicitation Advertisement Time (s) T T+.5 T+.02 T+.04 T+.06

Hash ordered Fast RA Router2 Router1 Router3 Host Solicitation Advertisement Time (s) T T+.5 T+.02 T+.04

Key Task: Link Identification Early work centred on numeric link- identifiers placed in each RA packet (BP,EN,GD,JHC). Current schemes use queries: “Is prefix aaaa::/64 on link? (BP,EN,SN)” Augment Prefix advertisements with learnt information (CompleteRA, Prefix LinkID ) Message Order Independence analysis (GD,AS,BP)

Link Identification: Identifiers LINK-A LINK-B

Link Identification: CompleteRA P1 P3 P2 P3

Link Identification: Landmarks P1 P2 P1 here? NO P1:

Key Task: Message Authorization RA message authorization is built into SEND Separate timers for RS/RA Certificate Chain Solicit/Advert Last Hop certification Certificate solicitation in RS Place certificate in RA if it fits (Modified format – GD)

Key Task: Message Authorization CCA CA CCS CERT

DNA Working Group Progress

Detecting Network Attachment Working Group Documents DNA Goals Link Information DNA with unmodified routers DNA For IPv6 Hosts DNA For IPv6 Routers DNA Solution protocol (under discussion)

Interactions with Existing Protocols Link Information –Hints to start DNA from L2 Complete Prefix Lists –Inferring Link Change with unmodified routers Host Operations –Initiation/After DNA Router management –Address Prefix and Advertisement Config

New DNA protocol modifications Builds on IPv6 Router Discovery New ND message formats, timers Provide single message pair exchange Fast Unicast RA delivery and configuration RA augmented for Link Identification Automatic Bootstrapping

Future Challenges

IPv4/IPv6 change detection Dual Stack hosts accessing the Internet –Protocol Specific Mobility: MIPv4/MIPv6 –Protocol Agnostic Mobility: Mobike/HIP –Transition Gateway detection Detecting IPv4 or IPv6 Network Services –Local Link/Subnet services –More remote services –Getting access to remote resources.

Generic Link-Layer Interfaces IEEE Handoff Direct input of indications to DNA Other information Will generally available Link-Layer information change: –L3 Change Detection? –Mobility/Movement Management

Interface Policy interaction DNA is run per interface Limited direction for ‘Inactive’ interfaces DNA is Mobility Protocol Independent –Is multiple interface management? –Reasoning about local information, like DNA

DNA indications Path Change Indications End-to-End interactions Multiple Interfaces/Multiple Paths.

Change Detection without Neighbour Discovery Ad-hoc network topologies –Many Wireless Edge Links –Fat Link-Layer Shims Router Properties in ad-hoc hosts –DNA supports autoconf hosts only