Strategies For Detecting Network Attachment in Wireless IPv6

NetworksGreg Daley - Research Fellow

Monash UniversityCentre 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

TELCOTELCO

TELCOTELCO

TELCO

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

NATNAT

Internet

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

APPS

APPS

MIP6

MIP6

IPV6

IPV6

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

MIPv6

DNAv6

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

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

FE80::FEOF

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 TimingRouter2Router1 Router3 Host

Solicitation

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Time (s)

T

T+.5

Fast Router Advertisement (RA)Router2Router1 Router3 Host

Solicitation

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Time (s)

T

T+.5

Deterministic FastRARouter2Router1 Router3 Host

Solicitation

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Time (s)

T

T+.5

T+.05

T+.1

Probabilistic Fast RARouter2Router1 Router3 Host

Solicitation

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Time (s)

T

T+.5

T+.02T+.04T+.06

Hash ordered Fast RARouter2Router1 Router3 Host

Solicitation

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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-B

Link Identification: CompleteRA

P1

P3

P2

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

CCSCERT

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 802.21 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