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Service Discovery based on Multicast DNS in IPv6 Mobile Ad-

hoc Networks

Jaehoon Jeong, ETRIpaul@etri.re.kr

VTC2003-Spring

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Contents

Introduction Related Work Ad-hoc Name Service System for IPv6

MANET(ANS)

Name Service Service Discovery Conclusion

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Introduction

Name Service in Mobile Ad-hoc Network(MANET) MANET has dynamic network topology

Current DNS can not be adopted in MANET! Because it needs a fixed and well-known name server

Idea of Name Service in MANET All the mobile nodes take part in name service

Every mobile node administers its own name information It responds to the other node’s DNS query related to its

domain name and IP address

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Related Work (1/2): Link-Local Multicast Name Resolution (LLMNR)

DNS service based on IP multicast in link-local scoped network

Each node performs the role of DNS name server for its own domain name.

LLMNR Sender LLMNR Responder

LLMNR query message (What is IPv6 address of “host.private.local”?) - It is sent in link-local multicast

LLMNR response message (IPv6 address of “host.private.local”) - It is sent in link-local unicast

Verification of LLMNR response - Does the value of the response conform to the addressing requirements? - Is hop-limit of IPv6 header 255?

If the result is valid, then the Sender caches and passes the response to the application that initiated DNS query.

else the Sender ignores the response and continues to wait for other responses.

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Related Work (2/2): Autoconfiguration Technology IP interface configuration Name service

Translation between host name and IP address Generation of unique domain name

IP multicast address allocation Service discovery

Unicast Service Multicast Service

AutoconfigurationTechnology

IP Interface Configuration

Nam

e S

erv

ice

Ser

vic

e D

isc

ov

ery

IP Multicast Address Allocation

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Ad-hoc Name Service Systemfor IPv6 MANET (ANS)

ANS provides Name Service in MANET

Architecture of ANS System ANS Responder

It performs the role of DNS Name Server ANS Resolver

It performs the role of DNS Resolver

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ANS System (1/2)

ANSResolver

ApplicationApplication

Process

Database

Node

Mobile Node A

UNIX Datagram Socket

ANSResponder

ANSZone DB

Memory Read / Write

ANSResolver

ApplicationApplication

Mobile Node B

ANSResponder

ANSZone DB

Wireless Link

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ANS System (2/2)

Main-Thread

DUR-Thread

ANSZone DB

ANS Responder

Process

Thread

Database

Memeory Read / Write

Internal Connection

Main-Thread

Resolv-ThreadTimer-Thread

ANS Cache

ANS Resolver

Process

Thread

Cache

UNIX Datagram Socket

Memeory Read / Write

Internal Connection

Application

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Name Service in ANS Name Generation

generates a unique domain name based on the network device identifier

Zone File Generation generates ANS zone file with the unique domain

name and corresponding IPv6 address Name Resolution

performs the name-to-address translation Service Discovery

performs the service discovery through DNS SRV resource record, which indicates the location of server or the multicast address of the service

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Service Discovery$TTL 20$ORIGIN ADHOC.

PAUL-1.36-56-78-FF-FE-9A-BC-DE.EUI-64 IN AAAA FEC0:0:0:0:3656:78FF:FE9A:BCDEPAUL-1 IN AAAA PAUL-1.36-56-78-FF-FE-9A-BC-DE.EUI-64.ADHOC.

;; DNS SRV Resource Records; Unicast Service : SERVICE-1_SERVICE-1._TCP IN SRV 0 1 3000 PAUL-1.ADHOC._SERVICE-1._UDP IN SRV 0 1 3000 PAUL-1.ADHOC.

; Multicast Service : SERVICE-2_SERVICE-2._UDP IN SRV 0 1 4000 @.3.5.

Group IDFF

FlagsP=1, T=1

Scope5

8 4 1124

Multicast Service Name

+

128-bit Digest

MD5 Hash Function

Group ID = Lower 112 bits of Digest

DNS SRV Resource Record for Multicast Service

Flags label & Scope label

Parsing Function

16-bit IPv6 Site-localMulticast Address Prefix

IPv6 Site-local Multicast Address

ANS Responder’s Zone FileMulticast Address corresponding to Service Name

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Scenario of Service Discovery

MN-C MN-B MN-A

DNS Query Messagefor Service Information

DNS Query Messageis sent in Multicast Receipt of

DNS Query Message

Request ofServer Information

Receipt and Processof DNS Query Message

related toDNS SRV resource recordDNS Response Message

with Service Information

Gain ofService Information

MN-C tries to connect to the server on MN-A

orMN-C joins the multicast group

related to MN-A

The server on MN-A accepts the request of the connection from MN-C

orThe multicast group comprises

MN-A and MN-C

DNS Query Messagefor Service Information

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Conclusion ANS is a new name service scheme in IPv6 mobile ad-hoc network

(MANET).

Name service of ANS Automatic name generation Automatic zone file generation Name-to-address translation Service discovery

Future work We will enhance ANS to provide secure name service.

Secure ANS (SANS) Authentication of DNS response message through

Pre-shared group key and IPsec ESP’s null-transform