Transcript presented in IETF

Ad Hoc IP Address Autoconfiguration
draft-jeong-adhoc-ip-addr-autoconf-00.txt
Jaehoon Paul Jeong
ETRI
[email protected]
http://www.adhoc.6ants.net/~paul/
16th July 2003
57th IETF – Vienna, Austria
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Motivation of the Draft
• 4 basic MANET unicast routing protocols will be published as
experimental RFC soon.
– AODV, DSR, OLSR and TBRPF
• Next step?
– Addressing is as essential as Routing
• Automatic IP address configuration is necessary in MANET, which has
dynamic topology.
– Various approaches have been suggested in research domain
• Stateless vs. Stateful approaches
• Strong DAD vs. Weak DAD
• Active DAD vs. Passive DAD
• Therefore, it is time to develop MANET IP Address
Autoconfiguration in engineering mode.
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Framework of the Draft
1. IP Address Generation
2. Duplicate Address Detection
-
Hybid scheme considering MANET partition
•
•
Strong DAD
Weak DAD
3. Maintenance of Upper-layer Sessions
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IP Address Generation
• Selection of Random IP Address
– IPv4
• IPV4_MANET_PREFIX + 16-bit Random Number
– 169.254/16 is used as IPV4_MANET_PREFIX.
– IPv6
• IPV6_MANET_PREFIX + 64-bit Random Number
– fec0:0:0:ffff::/64 is used as IPV6_MANET_PREFIX.
» Because of the deprecation of IPv6 site-local address, a new
local prefix for local networks separated from the Internet is
necessary.
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Duplicate Address Detection
• Phase 1 : Strong DAD
– Time-based DAD
• For detecting IP address duplication in a connected MANET
partition within a finite bounded time interval
– Strong DAD is performed during the initiation of node’s
network interface.
• Phase 2 : Weak DAD
– Routing-based DAD
• For detecting IP address duplication during ad hoc routing
• It can handle the address duplication by MANET partition and
mergence.
• Key is used for the purpose of detecting duplicate IP addresses.
– Virtual IP Address = IP Address + Key
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Process of Duplicate Address
during Weak DAD
• Each node investigates the virtual IP address contained
in ad hoc routing control packet
– to see if there is the same address with different key in
routing table or cache.
• If there is the duplicate IP address,
– The node sends an AERR (Address Error) message to
another node using duplicate address that is associated with a
different key.
• The node, receiving the AERR message, autoconfigures a new IP address
– through Strong DAD
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Maintenance of Upper-layer Sessions
• Consequence of Address Replacement
– When address duplication happens and the duplicate
address is replaced with another, the sessions above
network layer can be broken.
• There should be a mechanism to guarantee the
survivability of upper-layer sessions
– Announcement of address change to peer-nodes is
needed.
• It is performed through AERR message.
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Data Delivery
after resolving Address Duplication
• Data Delivery through IP Tunneling
– After receiving the AERR message, the peer node sends its
data packets to the node, having announced address change,
through IP tunneling.
Data Packet
Peer Node
Announced Node
Address : IPpn
New Address : IPnew
Old Address : IPold
Outer IP Header
Inner IP Header
SRC Addr : IPpn
DEST Addr : IPnew
SRC Addr : IPpn
DEST Addr : IPold
Payload
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Discussion
• This draft can include Passive DAD (PDAD).
– PDAD does not need key unlike Weak DAD
• It is the work of Kilian Weniger.
• How about MANET wg draft?
– In order to develop a MANET IP Address
Autoconfiguration
• Any questions or comments?
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