Autoconfiguration Technologies in IPv6 Mobile Ad Hoc Networks
description
Transcript of Autoconfiguration Technologies in IPv6 Mobile Ad Hoc Networks
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Autoconfiguration Technologies in IPv6 Mobile Ad Hoc Networks
Jaehoon Jeong, [email protected]
http://www.adhoc.6ants.net/~paul
APANAPAN20032003
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Contents
Introduction Unicast Address Autoconfiguration Multicast Address Allocation Multicast DNS Service Discovery Protocol Stack supporting MANET
Autoconfiguration Conclusion References
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Introduction
Mobile Ad Hoc Network (MANET) MANET has dynamically changing network topology.
MANET partition and mergence may happen. In MANET, there are many points to consider unlike the Internet.
There is no network administrator. The current Internet services, such as address autoconfi
gation and DNS, are difficult to adopt.
So, Auto-configuration is necessary in MANET!!
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MANET Auto-configuration
Unicast Address Autoconfiguration Multicast Address Allocation Multicast DNS Service Discovery
MANETAutoconfiguration
Mu
ltic
as
t D
NS
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Multicast Address Allocation
Unicast Address Autoconfiguration
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Unicast Address Autoconfiguration
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Introduction Configuration of Unicast Address in Network Interface
Precedent step for IP networking Methods of IP address configuration in network interface
Manual configuration Automatic configuration
Consideration of IP address configuration A unique address should be assigned. Automatic configuration is needed for user’s convenience.
Addressing in MANET Each mobile node is necessary to autoconfigure its IP address t
hrough DAD. A arbitrary address is selected. The uniqueness of the address is verified though Duplicate Addre
ss Detection (DAD).
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Strong DAD
Definition Ai(t) : Address assigned to node i at time t. For each address a != undefined,
Sa(t) = {j | Aj(t) = a}.
Condition of Strong DAD Within a finite bounded time interval after t,
at least one node in Sa(t) will detect that |Sa(t)| > 1.
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Host A
Router
Host B
Wireless Link
NS message NA message
Host C
Where NS : Neighbor Solicitation, NA : Neighbor Advertisement
MAC & IPv6 Address of Host C MAC Address – a9:bb:cc:dd:ee:ff IPv6 Address - fec0:0:0:ffff:abbb:ccff:fedd:eeff
1st Try of Host A MAC Address - a9:bb:cc:dd:ee:ff IPv6 Address - fec0:0:0:ffff:abbb:ccff:fedd:eeff
MANET Prefix
EUI-64
2nd Try of Host A 64-bit Random Number – 1111:2222:3333:4444 IPv6 Address - fec0:0:0:ffff:1111:2222:3333:4444
Random Number
Example of Strong DAD
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Generation of Tentative address with MANET_PREFIX and 64-bit Number
Generation of 64-bitRandom Number
Was any extended NA message received from any other node?
YES NO
Reconfiguration of Unicast address in NIC
Transmission of Extended NS message
MANET_INIT_PREFIX
fec0:0:0:ffff::/96
MANET_PREFIX
fec0:0:0:ffff::/64
Generation of 32-bit Random Numberand 64-bit Random Number
Generation of Temporary address withMANET_INIT_PREFIX and 32-bit Number
Procedure of Strong DAD
This iteration is This iteration is performed by performed by
predefined predefined retry-number.retry-number.
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Problem of Strong DAD - 1/2
AA
CC
EE
DD
BB
FF
GG
HH
KK
IP address = aIP address = a
IP address = aIP address = a
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Problem of Strong DAD – 2/2
AA
CC
EE
DD
BB
FF
GG
HH
KK
IP address = aIP address = a
IP address = aIP address = a
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Conclusion for Strong DAD
Simple Observation If partitions can occur for unbounded
intervals of time, then strong DAD is impossible.
Limitation of Charles E. Perkins’s DAD When partitions merge, addresses of all
nodes must be checked for duplicates. This DAD does not indicate how merging of
partitions should be detected. This does not suggest how the congestion
caused by DAD messages may be reduced.
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Weak DAD
Requirements Correct Delivery
Packets meant for one node must not be routed to another node, even if the two nodes have chosen the same address.
Relaxed DAD It does not require detection of all duplicate
addresses. The duplication of addresses can not be
detected in partitioned networks.
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Definition
Assumption A packet sent by node X at time t to
destination address a be delivered to node Y that has chosen address a.
Condition After time t, packets from node X with
destination address a are not delivered to any node other than node Y.
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Design Goals Address size cannot be made arbitrarily large.
MAC address cannot be embedded in the IP address.
IP header format should not be modified. It is wanted to add new options to the IP header.
Contents of routing-related control packets may be modified to include information pertinent to DAD. E.g., Link state updates, Route request / reply.
No assumptions should be made about protocol layers above the network layer.
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Main Idea Key is used for the purpose of detecting
duplicate IP addresses. The key is not embedded in the IP address itself.
Generation of Key MAC Address
When MAC address of an interface is guaranteed to be unique.
Random Number A sufficiently large number of bits of making the
probability of key conflict acceptably small Number derived from some other information
E.g., Manufacture’s name and device serial number
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Link State Routing with Strong DAD
AA
CC
EE
DD
BB
Dest Next Hop
IP_B IP_B
IP_C IP_E
IP_A IP_B
IP_E IP_E
Routing table at node DRouting table at node D
From To Cost
IP_D IP_E 2
IP_D IP_B 10
Link state packet transmitted by DLink state packet transmitted by D
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Link State Routing with Weak DAD
Dest DestKey
Next Hop
IP_B K_B IP_B
IP_C K_C IP_E
IP_A K_A IP_B
IP_E K_E IP_E
Routing table at node DRouting table at node D
From FromKey
To ToKey
Cost
IP_D K_D IP_E K_E 2
IP_D K_D IP_B K_B 10
Link state packet transmitted by DLink state packet transmitted by D
AA
CC
EE
DD
BB
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Resolution of Address Conflict by Weak DAD
AA
CC
EE
DD
BB
FF
GG
HH
KK
(IP address, Key) = (a, K_A)(IP address, Key) = (a, K_A)
(IP address, Key) = (a, K_K)(IP address, Key) = (a, K_K)
(IP address, Key) = (b, K_K)(IP address, Key) = (b, K_K)E detects the duplication E detects the duplication
of address of address aa with key with key information information
DuplicationDuplicationAdvertisementAdvertisement
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Hybid DAD Hybid DAD
Combination of Strong DAD and (Enhanced) Weak DAD Strong DAD detects duplicate address within a single conn
ected partition. Weak DAD processes the address conflict by MANET’s part
ition and mergence.
Hybrid DAD Scheme It may detect some duplicate addresses sooner than using
weak DAD alone. The use of weak DAD makes it robust to partitions and larg
e message delays in Strong DAD.
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Phases of Hybid DAD 1st Phase
By Strong DAD Time-based DAD
It is performed in the stage for IPv6 address to be configured in network interface.
2nd Phase By Weak DAD It is performed during the routing process.
Router discovery in reactive Ad Hoc routing protocols, such as DSR and AODV.
Routing information exchange in proactive Ad Hoc routing protocols, such as OLSR and TBRPF.
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Conclusion for Unicast Address Autoconfiguration
Requirements of Ad Hoc DAD Correct Delivery
Packets meant for one node must not be routed to another node, even if the two nodes have chosen the same address.
Relaxed DAD It does not require detection of all duplicate
addresses. The duplication of addresses can not be detected in
partitioned networks.
Guarantee of Upper-layer session Under the address change by DAD, the upper-layer
session, such as TCP session, should be guaranteed to continue.
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Multicast Address Allocation
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Multicast Address Allocation
Network prefix Interface ID
Interface IDFF Group ID
(a)
(b)
64-bit 64-bit
64-bit 32-bit8-bit
4-bit 4-bit
Flags Scope
0 A P T 0 1 0 1
8-bit
reserved
16-bit
Role It allocates a unique IPv6 multicast address to a session
without address allocation server.
Address Format IPv6 multicast (a) is generated on the basis of Interface ID
of IPv6 unicast address (b).
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Procedure of Multicast Address Allocation
Generation of Unused Group ID
Generation of a Multicast Address
Delivery of the Multicast Address
Request ofMulticast Address Allocation
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Service of Multicast Application: Allocation of a unique Multicast Address for a new Session
B C DEA
A B C D E
1
2 3
456
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1 1 1 1
Step
Action
1 Unicast Address Autoconfiguration
2 Run of Video-conferencing Tool (e.g., SDR) and Creation of a new Session-> Multicast Address Allocation
3 Advertisement of Session Information
4 MN A’s join to the new Session
5 MN E’s join to the new Session
6 Transmission of Video/Audio Data by MN A
7 Transmission of Video/Audio Data by MN E
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Multicast DNS
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Introduction
Name Service in 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: 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 1?
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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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
ANSResolver
ApplicationApplication
ANSResponder
ANSZone DB
ANSResolver
ApplicationApplication
ANSResponder
ANSZone DB
Mobile Node C
ANSResponder
ANSResolver
ApplicationApplicationApplicationApplicationANS
Zone DB
DNS Query
DNS Response
DNS Message
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ANS System (2/2)
Main-Thread
DUR-Thread
ANSZone DB
ANS Responder
Process
Thread
Database
Memeory Read / Write
Internal Connection
UNIX Datagram Socket
Main-Thread
Resolv-ThreadTimer-Thread
ANS Cache
ANS Resolver
Process
Thread
Cache
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
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Conclusion for Multicast DNS
ANS is a new name service scheme in MANET.
Name service of ANS Automatic name generation Automatic zone file generation Name-to-address translation
Future work ANS will be enhanced to provide secure name service.
Authentication of DNS response message through Pre-shared group key and IPsec ESP’s null-transform
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Service Discovery
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Service Discovery Definition
Discovery of the location (IP address, Transport-layer protocol, Port number) of server that provides some service.
Methods Multicast DNS based Service Discovery
Service discovery through Multicast DNS and DNS SRV
resource record, which indicates the location of server or the multicast address of the service
SLP based Service Discovery Service discovery through IETF Service Location
Protocol (SLP) RFC 2165, RFC 2608, RFC 3111
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Considerations for Service Discovery
Limitations of Existing Schemes Most of current schemes are concerned with
service location for the Internet. Such protocols have not taken into account the
mobility, packet loss issues and latency.
Considerations Some devices are small and have limited
computation, memory, and storage capability. They can only act as clients, not servers.
Power constraints Service discovery should not incur excessive
messaging over wireless interface.
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$TTL 20$ORIGIN ADHOC.PAUL-1 IN AAAA FEC0:0:0:FFFF:3656:78FF:FE9A:BCDE
;; 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 @.1.5.
Service Discovery based on Multicast DNS
Group IDFF
FlagsP=0, T=1
Scope5
8 4 1124
Multicast Service Name
+
128-bit Digest
MD5 Hash Function
Group ID=Low-order 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 File
IPv6 Multicast Address corresponding to Service Name
Generation of IPv6 Multicast Address
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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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Protocol Stack supporting
MANET Autoconfiguration
NetworkInterface
IPv6 MLDICMPv6
TCP/UDP
Wireless Link
Link
Network
Transport
ApplicationUnicast Address
AutoconfigurationMulticast Address
AllocationMulticast
DNSService
Discovery
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Conclusion MANET Autoconfiguration
Unicast Address Autoconfiguration Multicast Address Allocation Multicast DNS Service Discovery
Autoconfiguration Technologies in MANET They can provide Ad Hoc users with auto-
networking. They should be default functions for the deployment
of MANET. Also, security in MANET is important issue and is
considered together in auto-networking in MANET.
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References[1] Jaehoon Jeong, Hyunwook Cha, Jungsoo Park and Hyoungjun Kim, “Ad Hoc IP Address
Autoconfiguration”, draft-jeong-adhoc-ip-addr-autoconf-00.txt, May 2003.[2] Nitin H. Vaidya, “Weak Duplicate Address Detection in Mobile Ad Hoc Networks”, Mobi
Hoc2002, June 2002.[3] Charles E. Perkins et al., “IP Address Autoconfiguration for Ad Hoc Networks”, draft-ietf
-manet-autoconf-01.txt, November 2001.[4] Jaehoon Jeong and Jungsoo Park, “Autoconfiguration Technologies for IPv6 Multicast S
ervice in Mobile Ad-hoc Networks”, 10th IEEE International Conference on Networks, August 2002.
[5] Jung-Soo Park and Myung-Ki Shin, “Link Scoped IPv6 Multicast Addresses”, draft-ietf-ipv6-link-scoped-mcast-02.txt, July 2002.
[6] Jaehoon Jeong, Jungsoo Park, Hyoungjun Kim and Kishik Park, “Name Service in IPv6 Mobile Ad-hoc Network”, ICOIN2003, February 2003.
[7] Gulbrandsen, P. Vixie and L. Esibov, “A DNS RR for specifying the location of services (DNS SRV)”, RFC2782, February 2000.
[8] Jaehoon Jeong, Jungsoo Park, and Hyoungjun Kim, “Service Discovery based on Multicast DNS in IPv6 Mobile Ad-hoc Networks”, VTC2003 Spring, April 2003.