1 Service Discovery based on Multicast DNS in IPv6 Mobile Ad-hoc Networks Jaehoon Jeong, ETRI VTC2003-Spring

2 Contents Introduction Related Work Ad-hoc Name Service System for IPv6 MANET (ANS) Name Service Service Discovery Conclusion

3 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

4 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 SenderLLMNR 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.

5 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 Autoconfiguration Technology IP Interface Configuration Name Service Service Discovery IP Multicast Address Allocation

6 Ad-hoc Name Service System for 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

7 ANS System (1/2) ANS Resolver Application Process Database Node Mobile Node A UNIX Datagram Socket ANS Responder ANS Zone DB Memory Read / Write ANS Resolver Application Mobile Node B ANS Responder ANS Zone DB Wireless Link

8 ANS System (2/2) Main-Thread DUR-Thread ANS Zone DB ANS Responder Process Thread Database Memeory Read / Write Internal Connection Main-Thread Resolv-Thread Timer-Thread ANS Cache ANS Resolver Process Thread Cache UNIX Datagram Socket Memeory Read / Write Internal Connection Application

9 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

10 Service Discovery $TTL 20 $ORIGIN ADHOC. PAUL FF-FE-9A-BC-DE.EUI-64 IN AAAA FEC0:0:0:0:3656:78FF:FE9A:BCDE PAUL-1 IN AAAA PAUL FF-FE-9A-BC-DE.EUI-64.ADHOC. ;; DNS SRV Resource Records ; Unicast Service : SERVICE-1 _SERVICE-1._TCP IN SRV PAUL-1.ADHOC. _SERVICE-1._UDP IN SRV PAUL-1.ADHOC. ; Multicast Service : SERVICE-2 _SERVICE-2._UDP IN SRV 0 1 Group IDFF Flags P=1, T=1 Scope Multicast Service Name 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-local Multicast Address Prefix IPv6 Site-local Multicast Address ANS Responder’s Zone File Multicast Address corresponding to Service Name

11 Scenario of Service Discovery MN-C MN-B MN-A DNS Query Message for Service Information DNS Query Message is sent in Multicast Receipt of DNS Query Message Request of Server Information Receipt and Process of DNS Query Message related to DNS SRV resource record DNS Response Message with Service Information Gain of Service Information MN-C tries to connect to the server on MN-A or MN-C joins the multicast group related to MN-A The server on MN-A accepts the request of the connection from MN-C or The multicast group comprises MN-A and MN-C DNS Query Message for Service Information

12 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