MANET Autoconfiguration (AUTOCONF) C. Bernardos
Internet-Draft M. Calderon
Intended status: Informational UC3M
Expires: October 10, 2008 H. Moustafa
France Telecom
April 8, 2008
Survey of IP address autoconfiguration mechanisms for MANETs
draft-bernardos-manet-autoconf-survey-03
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Abstract
This Internet Draft provides a detailed description of most of the
existing IP autoconfiguration solutions proposed so far. The main
aim of this document is to serve as a general reference for the
AUTOCONF solution space. We present most of the previously proposed
IP AUTOCONF mechanisms in MANETs, showing their key characteristics,
conforming to the AUTOCONF problem statement draft and the MANET
architecture draft. Furthermore, each solution is analysed based on
a number of evaluation considerations.
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Table of Contents
1. Introduction and motivation . . . . . . . . . . . . . . . . . 5
2. IP address auto-configuration protocols . . . . . . . . . . . 7
2.1. Solutions for Standalone MANET scenarios . . . . . . . . . 7
2.1.1. No merging support . . . . . . . . . . . . . . . . . . 7
2.1.1.1. IP address Autoconfiguration for Ad Hoc
Networks (Perkins et al.) . . . . . . . . . . . . 7
2.1.2. Merging support . . . . . . . . . . . . . . . . . . . 9
2.1.2.1. IPv6 Autoconfiguration in Large Scale Mobile
Ad-Hoc Networks (Weniger et al.) . . . . . . . . . 9
2.1.2.2. Ad Hoc IP Address Autoconfiguration (Jeong et
al.) . . . . . . . . . . . . . . . . . . . . . . . 10
2.1.2.3. IP Address Assignment in a Mobile Ad Hoc
Network (Mohsin et al.) . . . . . . . . . . . . . 12
2.1.2.4. An Address Assignment for the Automatic
Configuration of Mobile Ad Hoc Networks (Tayal
et al.) . . . . . . . . . . . . . . . . . . . . . 14
2.1.2.5. No Overhead Autoconfiguration OLSR (Mase et
al.) . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.2.6. PDAD-OLSR: Passive Duplicate Address Detection
for OLSR (Weniger et al.) . . . . . . . . . . . . 17
2.1.2.7. Passive Duplicate Address Detection for
On-demand Routing Protocols (Jeong et al.) . . . . 19
2.1.2.8. Prophet Address Allocation for Large Scale
MANETs (Zhou et al.) . . . . . . . . . . . . . . . 21
2.2. Solutions for Connected MANET scenarios . . . . . . . . . 23
2.2.1. No merging support . . . . . . . . . . . . . . . . . . 23
2.2.1.1. Automatic Configuration of IPv6 Addresses for
Nodes in a MANET with Multiple Gateways
(Ruffino et al.) . . . . . . . . . . . . . . . . . 23
2.2.1.2. Simple MANET Address Autoconfiguration
(Clausen et al.) . . . . . . . . . . . . . . . . . 24
2.2.1.3. Extensible MANET Auto-configuration Protocol
(EMAP) (Ros et al.) . . . . . . . . . . . . . . . 26
2.2.1.4. Global Connectivity for IPv6 Mobile Ad Hoc
Networks (Wakikawa et al.) . . . . . . . . . . . . 28
2.2.1.5. Multihop Radio Access Network (MRAN) Protocol
Specification (Hofmann) . . . . . . . . . . . . . 30
2.2.1.6. Automatic IP Address Configuration in VANETs
(Fazio et al.) . . . . . . . . . . . . . . . . . . 32
2.2.2. Merging support . . . . . . . . . . . . . . . . . . . 34
2.2.2.1. Address Autoconfiguration in Optimized Link
State Routing Protocol (Adjih et al.) . . . . . . 34
2.2.2.2. Extended Support for Global Connectivity for
IPv6 Mobile Ad Hoc Networks (Cha et al.) . . . . . 36
2.2.2.3. Gateway and Address Autoconfiguration for IPv6
Adhoc Networks (Jelger et al.) . . . . . . . . . . 38
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2.2.2.4. MANET Autoconfiguration using DHCP (Templin et
al.) . . . . . . . . . . . . . . . . . . . . . . . 39
3. Security Considerations . . . . . . . . . . . . . . . . . . . 43
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 45
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.1. Normative References . . . . . . . . . . . . . . . . . . . 46
6.2. Informative References . . . . . . . . . . . . . . . . . . 46
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 49
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 50
Intellectual Property and Copyright Statements . . . . . . . . . . 51
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1. Introduction and motivation
Multi-hop communication in ad hoc networks presents some interesting
advantages, where no permanent infrastructure is required. Also, the
coverage area of an existing infrastructure can be extended through
multi-hop ad hoc communication. Several MANET routing protocol
specifications have been developed by the IETF MANET WG. In order to
allow wide deployment of ad hoc networks, in which IP routing is the
most candidate approach, IP configuration of nodes is a strong
requirement that need to be satisfied. In this context, the AUTOCONF
WG is working towards standard specifications and solutions for IP
address autoconfiguration within different MANET environments.
Ad hoc networks present particular characteristics that should be
taken into account when designing address auto-configuration
protocols. Since existing solutions for IP infrastructure-based
networks (e.g., RFCs 4861, 4862, 3315 etc.) were designed for a
different scope that MANETs [1], there are several issues that need
to be tackled, mainly (but not only) the following: the lack of
multi-hop support, the lack of dynamic topology support, the lack of
network merging support and the lack of network partitioning support.
The main goal of the AUTOCONF WG is to develop solutions for IPv6
address auto-configuration (both MANET-local and global scoped). The
group has identified two possible scenarios of MANET where IP address
auto-configuration is required [1]:
o Standalone MANETs: these networks are not connected to any
external network. All traffic is generated by MANET nodes and
destined to nodes in the same MANET. Examples of these networks
are conference networks, battlefield networks, surveillance
networks, etc. In this scenario, nodes may join or leave
randomly. Besides, most likely no pre-established nor reliable
address or prefix allocation agency will be present in the
network.
o Connected MANETs. These networks have connectivity to one or more
external networks, typically the Internet, by means of one or more
gateways that are also known as MBRs (MANET Border Routers).
These networks may be connected to the Internet in permanent
fashion or in intermittent fashion.
This draft aims at providing a survey on most of the previously
proposed IP autoconfiguration solutions, trying to serve as a useful
reference for the AUTOCONF WG during the problem space analysis and
solution design phases.
In the following section, we provide a description of several
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existing AUTOCONF solution proposals, analysing them based on some
evaluation considerations proposed in [2]. In order to present the
analysed solutions in a structured way, two major classification
levels are used: i) standalone/connected, and ii) partitioning/
merging support.
The given analysis conforms to the AUTOCONF problem statement draft
[1] and the MANET architecture draft [3].
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2. IP address auto-configuration protocols
In this section we briefly describe some of the existing proposals
for IP address autoconfiguration, classifying them according to some
of the evaluation considerations introduced in [2].
2.1. Solutions for Standalone MANET scenarios
2.1.1. No merging support
2.1.1.1. IP address Autoconfiguration for Ad Hoc Networks (Perkins et
al.)
This address autoconfiguration mechanism -- proposed in [4] --
basically consists in choosing an address randomly from an address
pool (i.e., a network prefix) available to the MANET and then
performing a Duplicate Address Detection procedure within the MANET.
Assumptions: It is assumed that nodes performing this
autoconfiguration protocol obtain a non-link-local prefix (it cannot
be link-local, since the addresses have to be valid over a multiple-
hop distance) from which to configure an address. The method to
obtain a globally routable prefix is not specified in the solution
and, in case it is not possible to obtain any suitable one, a
reserved IPv6 prefix, called MANET_PREFIX, is used: fec0:0:0:
ffff::/64.
Approach description: This solution basically works as follows: a
node first selects a random address from the non-link-local prefix
that is deployed in the MANET and then performs a Non-unique Address
Detection procedure to check for its uniqueness across the MANET. To
perform this uniqueness check, the node sends an Address Request
(AREQ) message, including the randomly chosen tentative non-link-
local IP address. This message is broadcast to its neighbours, by
sending the message using the all-nodes multicast IPv6 address as
destination of the packet. The source address used by the node to
send the AREQ message is another temporary IP address, acquired only
for the purpose of sending these messages. This temporary IPv6
address belongs to a different non-overlapping prefix -- called
MANET_INITIAL_PREFIX -- so the probability of this address to be
duplicated in the network is very low, given its short lifetime (this
address is only used in this message exchange and discarded
thereafter). When a node receives an AREQ message, it creates a
reverse route entry for the temporary IPv6 address of the node. If
the tentative address contained in the AREQ message does not match
the address of the receiving node, it rebroadcasts the message to its
neighbours. If the IP address of the receiving node matches the
tentative address contained in the AREQ message it sends an Address
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Reply (AREP) message to the sender, indicating that the address is
already in use. The route created by the AREQ messages is used to
route the message back to the source node.
A node waits for a certain amount of time after sending an AREQ
message, for the reception of an AREP message. The process is
repeated if no answer is received, and if after a number of attempts
no AREP has been received, the node assumes that the tentatively
chosen IPv6 address is unique and starts using it. The values
configured for the involved timers and retry parameters have an
impact on the maximum size of the MANET where the solution would
properly work. Additionally, since the Non-unique Address Detection
procedure is performed only when the node initially chooses the
tentative IPv6 address to use, this mechanism does not support
merging of MANETs.
AREQ and AREP are a modification of the standard ICMPv6 Neighbour
Advertisement and Neighbour Solicitation messages, respectively.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets standalone MANETs, although
it considers the possibility of being applied to connected
scenarios in those cases in which nodes are provided with the non-
link-local prefix to be used in the MANET.
o Routing protocols' dependency: the solution is routing protocol
independent.
o Address uniqueness: the proposed solution makes use of Non-unique
Address Detection in the initial address assignment phase.
o Distributed/centralised approach: the solution does not make use
of any centralised server.
o Merging support: the solution does not support merging.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution requires additional message
flooding (AREQ messages) to verify if an IP address is being used
in the MANET.
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2.1.2. Merging support
2.1.2.1. IPv6 Autoconfiguration in Large Scale Mobile Ad-Hoc Networks
(Weniger et al.)
The solution described in [5] extends the Neighbour Discovery and
IPv6 Stateless Address Autoconfiguration mechanisms to work in multi-
hop wireless networks.
Assumptions: The solution assumes a hierarchical approach, where
there are two different types of participating nodes: those that
obtain IPv6 addresses by using a modified version of IPv6 Neighbour
Discovery, and special nodes -- called leader nodes --, that are
responsible for parts of the address configuration of other nodes.
Approach description: The solution basically extends IPv6 Neighbour
Discovery to provide nodes within a multi-hop environment with IPv6
address autoconfiguration capabilities. To do so, the following
modifications to the IPv6 Neighbour Discovery protocol are proposed:
o The Neighbour Solicitation message is modified to allow it to be
broadcast to a bounded area of radius r_s hops (instead of only a
single hop). In addition, a new option for Neighbour Discovery is
defined (called MANET option) which contains a Random Source ID
(RS-ID) field, that is used to distinguish different nodes. Nodes
use the all-nodes multicast address instead of the solicited-node
multicast address. This mechanism guarantees link-local addresses
to be unique within the scope (limited by r_s) of each node.
o To enable the configuration of unique site-local addresses, a
hierarchy is established by special nodes (called leader nodes)
that configure a group of nodes by issuing Router Advertisements
(RA) within their scope, containing the subnet ID (i.e., network
prefix) and its link-local address as source address. The subnet
ID has to be unique for each leader node, so Non-unique Address
Detection has to be performed between the leader nodes within the
entire Ad hoc network. An algorithm is provided for the election
of leader nodes.
It should be noted that because of the nature of the solution, it
would be possible to have multihomed nodes -- that is, nodes with
more than one IPv6 address -- if a node is within the scope of more
than one leader node.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets standalone MANETs, although
it could be possible to extend it to support the assignment of
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global IPv6 addresses.
o Routing protocols' dependency: the solution does not depend on any
particular ad-hoc routing protocol, but it may be advantageous the
routing protocol it follows a hierarchical structure. Besides, it
is also preferable that nodes move in logical groups. Otherwise,
the cost of maintaining the hierarchical structure may be
considerable.
o Address uniqueness: the proposed solution makes use of a periodic
Non-unique Address Detection for ensuring the address uniqueness
within the scope of the leader node. Since each leader node makes
use of a different Subnet ID, the uniqueness of the assigned
address within the entire MANET is ensured.
o Distributed/centralised approach: the solution does not make use
of any centralised server, but considers the existence of special
nodes (leader nodes) that participate in the mechanism in a
distributed fashion.
o Merging support: the solution support merging, by leader nodes
performing periodic Non-unique Address Detection that ensures the
uniqueness of Subnet IDs.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution requires additional message
flooding within a bounded area of radius r_s hops.
2.1.2.2. Ad Hoc IP Address Autoconfiguration (Jeong et al.)
The solution described in [6] proposes two Non-unique Address
Detection mechanisms. The first one -- called "strong DAD" -- is
done in the initial phase when the ad hoc node does not have an IP
address configured yet, it relates to the fact that before a randomly
generated address is assigned and used, it should be verified that it
will not create an address conflict. On the other hand the second
Non-unique Address Detection mechanism -- called "weak DAD" -- is
always executed by nodes taking part in ad hoc routing in order to
prevent any address conflicts due to mergers.
Assumptions: The solution assumes that initially a random address is
selected by ad hoc nodes using the reserved IPv6 prefix MANET_PREFIX.
Approach description: This approach includes two different Non-unique
Address Detection mechanisms:
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o Strong DAD: based on [4]. Strong DAD is done initially after an
ad hoc node has chosen randomly an IP address and it is trying to
find out whether there is a duplication conflict or not. AREQ
message for Strong DAD is broadcast in site-local scoped all node
multicast address, IPV6_MANET_BROADCAST_ADDRESS. The ad hoc node
waits for an AREP message -- indicating the selected address has
already been utilised -- until the timer for Strong DAD expires.
In the case an AREP message arrives it chooses a new address and
executes Strong DAD mechanism again. [6] describes the message
format, using ICMPv6 messages (new types are defined). [7]
describes the message format for AODV.
o Weak DAD: based on [8]. During ad hoc routing, weak DAD is used
to find out whether address duplication, due to merging has
occurred or not. The concept of ``Virtual IP address'', which is
the combination of an ''IP address'' and an ``Key'', is used,
which is selected to be unique by each mobile ad hoc node. This
''key'' is appended to control packets of ad hoc routing protocol,
such as route discovery messages or hello messages. Intermediate
routing points must store the ''key'' value for each address in
its routing table. Using these ''keys'', duplication conflicts
can be found out during ad hoc routing process. An AERR message
is sent during Weak DAD for the purpose of indicating that an
address duplication happened. The ad hoc node that receives an
AERR message should autoconfigure a new IPv6 address through
Strong DAD. The same AERR message is used to inform each peer
node that its address has been changed. In order to keep ongoing
sessions after an address duplication episode, data packets are
sent to the new address through IP tunnelling. The destination
address in outer IP header is the new IP address of the node that
announced duplicate address and the inner IP header contains the
duplicate IP address of the node, i.e. the old address of the
node. The match duplicate address and new address is done in an
Address Mapping Cache.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets standalone MANETs.
o Routing protocols' dependency: the solution does not depend on any
particular ad-hoc routing protocol.
o Address uniqueness: the proposed solution makes use of two
different Non-unique Address Detection mechanisms.
o Distributed/centralised approach: the solution is distributed. It
does not make use of either any centralised servers or special
nodes.
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o Merging support: the solution supports merging by looking for
duplicate addresses on an ongoing basis.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: The Strong DAD mechanism requires additional
message flooding (AREQ messages) to find out whether there is a
duplication conflict or not. The Weak DAD mechanism introduces
also some protocol overhead since the Key extension (20 bytes) is
appended to each control packet of the ad hoc routing protocol.
2.1.2.3. IP Address Assignment in a Mobile Ad Hoc Network (Mohsin et
al.)
This proposed solution [9] is based on a dynamic allocation of IP
addresses in MANETs using the concept of binary split. A proactive
approach is used, in the sense that each node can independently
assign a new IP address without consulting any other node in the
network. Partitioning and merging as well as nodes abrupt departures
are supported in this solution.
Assumptions: It is assumed that all nodes collectively perform the
DHCP functionality; where each node is capable of configuring a new
node and providing it with a new IP address. It is also assumed that
one MANET node have the entire pool of IP addresses at the beginning.
Approach description: In this proposed solution the concept of Buddy
Systems is used. This is a type of segregated lists used in memory
allocation and supports efficient splitting and coalescing. In the
context of the proposed solution, binary buddies are used, where all
buddy sizes are a power of two, and each size is divided into two
equal parts. Thus, every node has a disjoint set of IP addresses
that it can assign to a new node without consulting any other node in
the network. When a new unconfigured mobile node (B) joins the
network, it requests the nearest neighbour (A) an IP address. Node
(A) divides its IP address set into two, giving one half to the
requesting node (B). The new node assigns itself an IP address from
the acquired pool of addresses, storing the rest of addresses to
configure other nodes afterwards. The new node (B) is now configured
and is considered as the Buddy of node (A). The scheme of the IP
address assignment can be seen as a handshaking protocol between the
server and the client, where the node requesting the IP address is
considered as the client node and the node that actually assigns the
IP address is considered as the server node.
Nodes synchronise the IP blocks which they store to keep track of the
assigned IP addresses and detect any IP leakage, where every node
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keeps a record of all the IP address blocks in the network by
maintaining a corresponding table. Each node sends its IP address
pool to all other nodes in the network, and each node receiving an IP
pool from another node records the received information in its IP
address table. Through this approach, the network has among its
nodes the available IP addresses organised in the form of a binary
tree with a division of two identical blocks (Buddies) per level.
Two mechanisms are proposed for releasing the node's IP address pool
when the node leaves the network: i) graceful leave, in which the
leaving node gives its IP address pool to any nearby node. This
nearby node may keep the IP address pool for itself or may search in
its IP address table the Buddy of the leaving node and forward to it
the IP pool. ii) abrupt leave, in which the node leaves with its IP
address pool that leads to IP leakage. In such a case, a pool of IP
addresses that is not assigned to any node is not available. IP
leakage is detected from the IP address table stored at each node.
Each node scans from time to time its IP address table for the IP
pool of its Buddy node, if it does not find it, it concludes that the
node has left and it merges this missing IP block to itself.
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets standalone MANETs.
o Routing protocols' dependency: This proposed solution is
independent of the underlying routing protocol.
o Address uniqueness: The proposed solution does not use any Non-
unique Address Detection mechanism.
o Distributed/Centralised approach: Although this solution is based
on IP address pools assignment and splitting, it has a distributed
approach, where all nodes collectively perform the functionality
of a DHCP server.
o Merging support: Thanks to employing the buddy systems, the
proposed solution supports merging. In case of merging, the
process of buddies splitting allows the merging node to be
assigned an IP address and an IP pool.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution requires a kind of flooding so
that each node sends its IP address block to all other nodes in
the network. Furthermore, other control messages are required in
the form of request-reply messages to enable a new joining node to
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be assigned an IP address, or in the form of announcement in the
case of IP release.
2.1.2.4. An Address Assignment for the Automatic Configuration of
Mobile Ad Hoc Networks (Tayal et al.)
The solution described in [10] is very similar to the previous one
([9]), sharing the idea (also used by others) of nodes assignment of
half of their address pools to newly arrived nodes that request IP
addresses.
Assumptions: It is assumed that initially there is one node that
configures itself as initiator node (when there is no other node in
the network), configuring itself with a default IP address and
starting to manage a default address pool.
Approach description: The solution basically works as follows: when a
new node i (called requester node) is willing to join the MANET, it
has to contact an existing node j in the network. If node j has the
address pool, it divides it into two parts and allocates one part to
node i. The starting address of the allocated pool is the address of
node i. In case node j does not have the address pool, j starts
searching for nodes that might have an address pool, by broadcasting
a message (called SEARCH_ADDR). The search message is forwarded by
all the nodes which do not have an address pool. A node receiving
the search message, either replies with the address pool or with
negative ACK. If a node replies with its address pool, it marks half
of its addresses as under allocation and wait for a POOL_ACCEPTED
message from node j. Node j replies with POOL_ACCEPTED message to
the node whose address pool it received first, and allocates the
received address pool to node i.
This solution defines mechanisms to handle different scenarios, such
as network partitioning and merging, message loss, etc. More details
can be found in [10].
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets standalone
scenarios.
o Routing protocols' dependency: This proposed solution is
independent of the underlying routing protocol.
o Address uniqueness: The proposed solution does not use any Non-
unique Address Detection mechanism, since the uniqueness of the
solution is based on the split of the initially available IP
address pool.
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o Distributed/Centralised approach: the solution is based on IP
address pools assignment and splitting, where all nodes
collectively perform the functionality of assigning addresses to
newcomers.
o Merging support: the solution defines a mechanism to detect
merging, through redistributing information about assigned
addresses and pools. If an address collision is detected, then
the solution defines a mechanism to solve that, based on giving
up/shrinking the address pool used by one of the nodes detecting
the conflict.
o Prefix assignment support: Since the solution supports the
assignment of address pools, it can be possible to use it to
assign prefixes to nodes, although it is not explicitly covered by
the mechanism.
o Protocol overhead: the solution requires some message flooding to
search nodes that have an address pool available.
2.1.2.5. No Overhead Autoconfiguration OLSR (Mase et al.)
This solution [11] proposes some passive Non-unique Address Detection
techniques to be used in MANETs running the OLSR protocol. It
utilises the Passive Duplicate Address Detection concept [12], [13],
which enables nodes to passively detect duplicate addresses in the
network (e.g., occurring after network merging) by analysing received
routing protocol messages. The basic idea of PDAD is to exploit the
fact that some protocol events occur in case of duplicate address,
but (almost) never in case of a unique address. The proposed
techniques may be used to ensure uniqueness of an address when it is
initially generated before being assigned to an interface and the
solution also performs to ensure uniqueness of addresses which have
been assigned and used, and then a network merger happens.
This is one of the multiple drafts proposing the use of PDAD for OLSR
[14], [15].
Assumptions: The protocol assumes the existence of a Non-unique
Address Detection-based IP address generation mechanism.
Approach description: The solution proposes an ongoing duplicate
address detection mechanism, checking for inconsistencies in the
routing protocol messages to diagnose duplicate address detection.
The first kind of inconsistency is based on information included in
OLSR messages (such as HELLO messages and TC messages) and the second
kind of inconsistency is based on sequence numbers (when two nodes --
which selected the same IP address -- are present in a network, they
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would send control messages that will be inconsistent).
Different Non-unique Address Detection rules -- twelve in total --
are proposed to handle the cases where the distance between
conflicting nodes is one hop, two hops and, three hops or more. In
the two first cases the detection is done by means of HELLO messages
and in the last case -- three hops or more -- the detection is
fulfilled by using information inside TC messages. Also, an
additional case is taken into account: this is a specific multihop
address conflict case, where the address conflict results in
deficiencies in the MPR selection.
Each node has an "autoconfiguration state". This state is an
indicator of how long the node has been in the network. The central
idea, is that each time a node generates a tentative address, it
should enter the network gradually, running a restrained version of
the OLSR protocol. In this way, the node can detect which addresses
are being used, checking for duplicates of its own address, while
avoiding to disrupt the routing tables of the other nodes, in the
event that its address is actually found to be in conflict.
Based on [2], this solution has the following key features:
o MANET scenario: This Non-unique Address Detection technique is to
be used in standalone MANETs.
o Routing protocols' dependency: this mechanism depends on OLSR,
since the Non-unique Address Detection technique is designed for
MANETs running the OLSR protocol.
o Address uniqueness: The proposed mechanism assumes the existence
of a Non-unique Address Detection-based address assignment
mechanism.
o Distributed/centralised approach: the proposed solution follows a
distributed approach given that all nodes have the same
responsibility detecting address conflicts.
o Merging support: The proposed solution supports merging, enabling
nodes to continuously detect duplicate addresses by analysing
received routing protocol messages.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the proposed mechanism does not add any
additional messages but it checks for inconsistencies in the
routing protocol messages to diagnose duplicate address detection.
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2.1.2.6. PDAD-OLSR: Passive Duplicate Address Detection for OLSR
(Weniger et al.)
This solution [14] proposes a passive Non-unique Address Detection
mechanism for configured address uniqueness maintenance in MANETs
running the OLSR protocol.
Assumptions: The protocol assumes the existence of a Non-unique
Address Detection-based address generation mechanism.
Approach description: The proposed solution is made up of a set of
algorithms which specify how to detect duplicate addresses based on
incoming routing protocol messages. The algorithms utilise different
parameters in TC and HELLO messages such as link states (i.e.,
neighbour interface addresses), link codes, (message) sequence
numbers, and addresses in OLSR routing protocol messages as well as
addresses in the IP header. PDAD-OLSR allows the detection of
conflicts by intermediate nodes that have unique addresses.
Each node conceptually maintains two tables for PDAD: a Last received
Protocol Messages (LRM) table and a Neighbour History (NH) table.
LRM table contains information about the last TC and HELLO protocol
message received from a specific originator address (e.g., originator
address, message type, sequence number, neighbour interface
addresses, receive time). NH table contains the history of
neighbouring node addresses and is built from received HELLO messages
(e.g., neighbour interface address, last time the receiver has
selected this neighbour interface address as MPR, Last time the
receiver has been selected as MPR by this neighbour interface
address, reception time).
The solution proposes eight different algorithms for conflict
detection:
o PDAD-Source Address (SA). Whenever a node receives a TC or HELLO
message, it compares the source address in the IP header to its
own address (the IP source address is always the address of the
last forwarder). This mechanism (e.g., Both addresses coincide)
allows nodes to detect conflicts with its neighbouring nodes.
o PDAD-Sequence Numbers (SN): If a node receives a TC or HELLO
message, it compares the originator address with its own address.
If they are equal and the sequence number in the message is higher
than the receiver's sequence number, a conflict of the originator
address is detected. This mechanism allows to detect conflicts
between nodes that are any number of hops away from each other.
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o PDAD-Sequence Number Difference (SND): If a node receives a TC or
HELLO message, it compares the sequence number in the message with
the sequence number in the previously received message from the
same originator address and with the same message type (there is a
relation between the time a node has originated two TC messages
and the sequence number in those TC messages). This mechanism
allows to detect conflicts between nodes that are any number of
hops away from each other.
o PDAD-Sequence Numbers Equal (SNE): If an intermediate node
receives a TC or HELLO message, it searches its LRM table for a
message with the same type value and the same tuple < sequence
number, originator address > (the tuple < sequence number,
originator address > uniquely identifies messages originated by a
specific node. This mechanism allows to detect conflicts between
nodes that are any number of hops away from each other.
o PDAD-SNs Always Increment (SNI): If a node receives a HELLO
message, it compares the sequence number in the message with the
sequence number in the previous HELLO message from the same
originator address (HELLO messages sent by a specific node are
received in the order they are sent). This mechanism only allows
to detect conflicts between nodes that are at most two hops away
from each other.
o PDAD-Neighbourhood History (NH): If a node receives a TC message,
it checks whether its own address is part of the neighbour
interface addresses in the TC message. If this is the case and
the link code indicates a bi-directional link, the node searches
the originator address in its NH table (a TC message only contains
neighbours that have selected the originator address as MPRs and
that requires a bi-directional link). This mechanism allows to
detect conflicts between nodes that are any number of hops away
from each other.
o PDAD-Link States (LS): If a node receives a TC message with its
own address as originator address, it searches in its NH table for
each of the neighbour interface addresses (if the message has been
originated by the receiver, it must only contain addresses of
recent neighbour interfaces). This mechanism allows to conflicts
between nodes that are any number of hops away from each other.
o PDAD-extended Neighbourhood History (eNH): If a node receives a TC
message, it checks for each neighbour interface address in the
message if it is a neighbour. This algorithm is basically the
PAD-NH algorithm executed on behalf of a neighbouring node.
Minimal additional signalling is needed. This mechanism allows to
detect conflicts between nodes that are any number of hops away
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from each other.
For some of the above mechanisms it is crucial to detect a possible
sequence number wrap-around, so a mechanism to detect this kind of
events is proposed.
Based on [2], this solution has the following key features:
o MANET scenario: The solution targets standalone MANETs. Although
it proposes a Non-unique Address Detection mechanism suitable for
any kind of addresses exchanged in routing protocol messages, be
it MANET-local or globally routable addresses, the solution does
not address the issue of how to obtain global IPv6 addresses.
o Routing protocols' dependency: this solution requires OLSR, since
the set of proposed techniques are applicable to MANETs running
the OLSR protocol.
o Address uniqueness: The proposed mechanism assume the existence of
an address assignment mechanism which may assign duplicate
addresses.
o Distributed/centralised approach: The solution follows a
completely distributed approach, every node has the same
responsibility in detecting duplicate addresses and does the same
processing.
o Merging support: The proposed solution supports merging given that
it enables nodes to continuously detect duplicate addresses in the
network by analysing received routing protocol messages.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution enables nodes to passively detect
duplicate addresses in the network by analysing received routing
protocol messages and thus does not cause any overhead.
2.1.2.7. Passive Duplicate Address Detection for On-demand Routing
Protocols (Jeong et al.)
This solution [16] proposes a set of Non-unique Address Detection
techniques to be used jointly with an on-demand routing protocol. In
this proposal passive duplicate address detection is performed by
analysing incoming on-demand routing protocol packets.
Assumptions: The protocol assumes the existence of an on-demand
routing protocol and a Non-unique Address Detection-based IP address
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configuration mechanism.
Approach description: In this proposal passive duplicate address
detection is performed by analysing incoming on-demand routing
protocol packets. Additional information included in routing
protocol packets allows end-points of a communication -- source or
destination -- to detect that the other end-point is using an address
which is duplicated in the MANET.
This additional information is included into routing control packets
exchanged for route discovery and it may be: the node location when
it configured its IP address, the node's neighbour list when it
configured its IP address, or a sequence number in RREP packets
(increased whenever a destination node sends a new RREP packet).
The authors propose different mechanisms for detecting address
conflicts:
o PDAD-RREQ-with-Location-information Technique (RQL): This
technique includes location information in RREQ packets to
differentiate between RREQ packets which contain the same source
address but are generated by different nodes.
o PDAD-RREQ-with-Neighbour-knowledge Technique (RQN): This technique
includes a list of neighbour nodes (this list is captured and
recorded when the node's IP address is configured) in RREQ packets
to differentiate between RREQ packets which contain the same
source address but are generated by different nodes.
o PDAD-RREP-with-SEQ Technique (RPS) : This technique requires an
incremental PDAD-sequence number to be included in each RREP
packet transmitted by a destination node. Therefore, when a
source node receives more than one RREP packet with the same PDAD-
sequence number and the same destination address, the source node
can detect the address conflict of destination nodes.
o PDAD-RREP-with-Location-information Technique (RPL): This
technique includes location information into RREP packets to
differentiate between RREP packets which contain the same source
address (the source address of RREP packets is the destination
address of RREQ packets) but are generated by different nodes.
o PDAD-RREP-with-Neighbour-knowledge Technique (RPN): When a
destination node replies with an RREP packet, a list of neighbour
nodes of the destination node (this list is captured and recorded
when the node's IP address is configured) is included in the RREP
packet.
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The document does not include how to perform address conflict
resolution.
Based on [2], this solution has the following key features:
o MANET scenario: The solution targets standalone MANETs. Although
the proposed Non-unique Address Detection mechanism is suitable
for any kind of addresses exchanged in routing protocol messages,
be it MANET-local or globally routable addresses, it does not
define any mechanism to obtain global IPv6 addresses.
o Routing protocols' dependency: The set of proposed techniques
supposes the existence of an on-demand ad-hoc routing protocol.
o Address uniqueness: The proposed mechanism assumes the existence
of a Non-unique Address Detection-based address assignment
mechanism.
o Distributed/centralised approach: The solution follows a
completely distributed approach, every node has the same
responsibility in detecting duplicate addresses and does the same
processing.
o Merging support: The proposed solution supports merging given that
it enables nodes to continuously detect duplicate addresses in the
network by analysing received routing protocol messages.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution enables nodes to passively detect
duplicate addresses in the network by analysing received routing
protocol messages and thus does not cause any overhead.
2.1.2.8. Prophet Address Allocation for Large Scale MANETs (Zhou et
al.)
The mechanism defined in [17] is based on the use of a special type
of function to derive the IPv6 addresses of nodes, so the probability
of address duplication is very low, and therefore the use of a Non-
unique Address Detection mechanism can be avoided.
Assumptions: This solution is based on the use of a stateful function
f(n) (where the initial state of f(n) is the seed) that produces as
output an integer sequence of numbers. Different seeds lead to
different sequences, and the state of f(n) is updated. This function
can be used to generate IP addresses, since it satisfies the
following properties:
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o The interval between two occurrences of the same number in a
sequence is extremely long.
o The probability of more than one occurrence of the same number in
a limited number of different sequences initiated by different
seeds during some interval is extremely low.
These properties may be satisfied if the space of available addresses
is large, so it is relatively easy to achieve in IPv6.
Approach description: The mechanism basically work as follows: the
first node in the MANET chooses a random number as its IP address and
uses a random or default state value as the seed for its f(n). When
a different node approaches, the first node uses its f(n) to obtain a
different number and state. This number is used by the second node
as its IP address, and the state is used as the seed for its f(n).
After that both nodes are able to assign IP addresses to other nodes.
Authors of the mechanism propose different mechanisms to support
partitioning/merging, such as for example including the seed used in
the MANET in the messages of the routing protocol. By doing that,
nodes of different merging MANETs can easily detect the merge (if
different seeds are received, that would mean that a merge has
happened) and start checking if there are potential IP address
conflicts. Given the characteristics of the function f(n) if a MANET
gets partitioned and later merges, IP address conflicts are very
unlikely to occur.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets standalone MANETs.
o Routing protocols' dependency: the solution is routing protocol
independent.
o Address uniqueness: the proposed solution does not define any Non-
unique Address Detection mechanism. The address uniqueness is
ensured by using a "prophet" allocation with a very low
probability of collision.
o Distributed/centralised approach: the solution does not make use
of any centralised server.
o Merging support: the solution proposes different mechanisms to
support merging.
o Prefix assignment support: the solution supports the assignment of
IPv6 prefixes to nodes, by using the DHCP prefix delegation.
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o Protocol overhead: only few additional messages are required to
assign addresses to new nodes.
2.2. Solutions for Connected MANET scenarios
2.2.1. No merging support
2.2.1.1. Automatic Configuration of IPv6 Addresses for Nodes in a MANET
with Multiple Gateways (Ruffino et al.)
This proposed solution [18] describes a mechanism enabling nodes
belonging to a MANET connected to the infrastructure -- by means of
one or more gateways -- to obtain global IPv6 addresses that could be
used to communicate with external nodes.
Assumptions: This mechanism assumes the existence of one or more
gateways that provide MANET nodes with connectivity to external
networks (e.g., the Internet). It is also assumed that nodes running
this solution obtain at the bootstrapping phase a MANET local IPv6
address (which is the address that the node uses when it participates
in the routing protocol, which is assumed to be OLSR). The
uniqueness of the obtained address should be ensured by means of a
Non-unique Address Detection method. Neither the procedure followed
to obtain this address, nor the Non-unique Address Detection method
used to check its uniqueness, are defined in this solution.
Approach description: The mechanism basically works as follows: at
bootstrap, a node configures a Primary Address (PADD) that is MANET-
scoped and is used as main address in OLSR messages. The node then
is able to start participating to OLSR and receiving topology
information. Each of the gateways available at the MANET has a
global IPv6 prefix that is announced using a new OLSR message type,
called Prefix Advertisement (PA).
With the prefix information received in the PA messages, a node is
able to build a set of global IPv6 addresses (called Secondary
Addresses: SADDs). Among them, the node chooses the "best" prefix
and starts using the address formed from this prefix (called,
Designated Secondary Address: DSADD). The node introduces all (or a
subset) of the SADDs (including the DSADD) in OLSR messages and
starts broadcasting them, enabling these addresses to be routable and
reachable within the MANET. It should be noted, that this solution
does not define any new Non-unique Address Detection mechanism, while
it is suggested to use a generic MANET Non-unique Address Detection
procedure, such as [4], to verify the uniqueness of MANET-local and
global addresses.
Based on [2], this solution has the following key features:
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o MANET scenario: the solution targets connected MANETs.
o Routing protocols' dependency: the solution requires OLSR to be
run in the network.
o Address uniqueness: the proposed solution does not define any Non-
unique Address Detection mechanism, although requires some generic
one to be used to ensure the uniqueness of MANET-local and global
addresses.
o Distributed/centralised approach: the solution does not make use
of any centralised server, but requires gateways to announce the
global IPv6 prefixes that can be used by MANET nodes in the
configuration of their IPv6 addresses.
o Merging support: the solution partially supports merging, since
the scenario in which new gateways join the network as a result of
a merger is considered. However, since no Non-unique Address
Detection mechanism is defined, the solution does not describe how
to deal with IPv6 address duplication after merging of different
MANETs.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: the solution adds some overhead. since Gateways
broadcast prefix information.
2.2.1.2. Simple MANET Address Autoconfiguration (Clausen et al.)
This proposed solution [19] aims to provide a simple IP
autoconfiguration mechanism for mobile nodes joining an existing
MANET. This mechanism is designed for MANETs that act as an edge-
extension to the Internet, where mobile nodes need to maintain the
connections with each other and with the Internet.
Assumptions: It is assumed that at least one node in the network is
already configured with a permanent address. In the absence of a
configured node, it is assumed that an election mechanism is
undertaken allowing a selected node to be self-configured.
Approach description: In this proposed solution, only configured
nodes can participate in the MANET and are considered as MANET nodes.
These nodes are also considered as "configuring nodes" aiding the new
joining nodes to acquire an IP address. Actually, each new joining
node is firstly assigned a temporary local address then a permanent
global address. The configuring nodes emit periodical ADDR_BEACON
messages to their neighbours in order to signal their existence to
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new nodes. A new node joining the network selects a configuring node
from its neighbours, then sends an Address Request (AREQ) to this
selected configuring node and waits for a reply. The process of
sending AREQ may be repeated for a number of trials until either
receiving a reply or selecting a new configuring node. The
configuring node replies by an Addr-Config message, containing a
local temporary address, and keeps track of the link existence with
the new joining node through local routing messages exchange on this
link. If this link disappears then the configuring node gives up,
otherwise the configuring node assigns a global address to the new
joining node.
The process of obtaining a temporary address consists of having an
address space, where each MANET node independently selects an address
sequence from this space and signals it to its neighbours (through
beacons). Each MANET node records the address sequence received from
is neighbours to avoid conflicts in the chosen addresses. If a
conflict is detected between two nodes, the node with the lowest ID
should select a new sequence if both nodes are not configuring nodes
(MANET nodes that are not yet engaged in configuring a new node).
Otherwise, if one or more configuring nodes are involved in the
conflict, each configuring node should narrow its sequence of
addresses to contain only the address that is currently assigned (in
order to keep on the configuring session). On the other hand two
options exist for global addresses allocation. One option is that
the configuring node acts as a modified DHCP proxy and transmits a
request to a DHCP server to acquire a global address for each new
node it configures. Another option is that the configuring node
consults the nodes' topology tables (containing destinations and thus
network addresses), and then picks up an unused address. It then
sends an advertisement to all MANET nodes to be sure that this
address is not used. If a node detects that its address is being
used, it can signal the conflict to the originator of the
advertisement.
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets connected MANET
scenarios.
o Routing protocols' dependency: This proposed solution uses OLSR,
typically extending OLSR messages, however it is not dependent on
the routing protocol. Although the proposed solution is open to
any routing protocol, the fact that periodical beacons are used
requires a proactive routing protocol.
o Address uniqueness: The proposed solution uses a Non-unique
Address Detection mechanism to avoid conflicts in IP address
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assignment. In global address allocation, using a Non-unique
Address Detection mechanism is an option but the proposed solution
can function without a Non-unique Address Detection mechanism if
the modified DHCP proxy approach is followed. While in temporary
address allocation, a limited Non-unique Address Detection
mechanism is used with the neighbourhood to resolve any conflict
when assigning temporary addresses sequences to MANET nodes.
o Distributed/Centralised approach: The proposed solution is
distributed in the sense that it can employ a decentralised DHCP
server using the concept of proxy DHCP to reach the server.
o Merging support: This proposed solution has no merging support.
o Prefix assignment support: The proposed solution allows prefix
assignment through using DHCP.
o Protocol overhead: the solution requires a considerable number of
signalling. This is mainly during the advertisement messages for
global addresses flooded to all nodes in the network for verifying
the global address uniqueness, the periodical ADDR_BEACON messages
that are transmitted by each configuring nodes to its neighbours,
and the Beacon messages signalling the selected address space by
each configuring node during the process of temporary address
assignment. Furthermore, AREQ messages are used by each new
joining node while communicating a neighbour configuring node,
which in turn replies by an Addr-config message.
2.2.1.3. Extensible MANET Auto-configuration Protocol (EMAP) (Ros et
al.)
The Extensible MANET Auto-configuration Protocol (EMAP) [20] provides
an autoconfiguration solution for isolated as well as hybrid MANETs.
EMAP is envisioned to be integrated within unicast routing protocols
as DYMO or OLSRv2. The notion of intermediate proxies is used in the
autoconfiguration process. The general EMAP framework may be used as
a service discovery protocol for MANETs, however the approach is
extensible to other services. An optional feature in EMAP includes
DNS discovery, where nodes can discover DNS servers reachable from
the MANET, and this feature can be extended to services like SIP,
proxies, and authentication entities.
Assumptions: It is assumed that at least one element must act as a
gateway between the MANET and the fixed network. This element is
called an Internet Gateway (IGW).
Approach description: EMAP allows MANET nodes to configure unique IP
local addresses and globally routable IP addresses. The local
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configuration allows a MANET node to communicate with other nodes in
the same MANET. To configure a local address, the MANET node picks
an IP address and asks the network if it is already being used, thus
avoiding address duplication. In this process, a node generates a
pair of IP addresses: temporary and tentative ones. The temporary
address is used as the originator-address, where it can be a mobile
IP home address or another sort of highly likely unique address.
While the tentative address is the one which is being requested and
is used as the requested address in the DAD_REQ messages and the
originator-address in DAD_REP messages. Thanks to the proxy
functionality, intermediate nodes can also answer with a DAD_REP
message if they do not own the requested address but they do know
that it is being used by another node. If the MANET node sending the
DAD_REQ receives no DAD_REP messages, then it understands that there
is no address conflict and it considers that the tentative address is
its local address.
On the other hand, global configuration takes place through using the
Internet Gateway (IGW), which may be a fixed element belonging to
each network, or a mobile one which detects the presence of an
attachment point to the Internet (e.g. a wireless router). The
mobile node requesting a global address either waits for
advertisements sent by the IGW (mainly advertising its prefix) to
configure its global address or floods a global configuration request
(GC_REQ) message. When an IGW receives a GC_REQ message, it sends a
global configuration reply message (GC_REP) to the originator-address
through unicast. Thus, the originating node is able to auto-
configure a global address by substituting the first bits of the
requested local address by the prefix advertised by the IGW. When
there are multiple IGWs announcing their own information, the MANET
node selects one, and the selection rules are implementation-
dependent.
A given option in EMAP allows a MANET node to issue a query to find
DNS Server Advertisers, which provide IP addresses of available DNS
servers. This feature may be quite useful in situations where a high
degree of auto-configuration is desired.
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution is designed for standalone
MANETs and connected MANETs.
o Routing protocols' dependency: Although EMAP is envisioned to be
integrated with unicast routing protocols like DYMO or OLSRv2, it
may be implemented as a standalone daemon.
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o Address uniqueness: The proposed solution uses a Non-unique
Address Detection mechanism during the autoconfiguration of MANET
local addresses.
o Distributed/Centralised approach: The proposed solution is a
distributed solution in the sense of not being based on any DHCP
servers.
o Merging support: No special merging mechanisms are explained in
this solution. However, no in-service Non-unique Address
Detection is used which makes the merging support not feasible.
o Prefix assignment support: This solution employs IPv6 prefixes,
where gateway nodes are responsible for advertising their
prefixes.
o Protocol overhead: the solution adds certain overhead, depending
on the network size, the number of IGWs, and the applied option in
global address configuration. The resulting overhead in this
solution mainly concerns: flooding of the local address selected
by each joining node to verify its uniqueness through the DAD_REQ
messages, prefix advertisement by IGWs during global address
configuration (this has more impact on the overhead when the
number of IGWs increases), and flooding of GC_REQ messages by the
node requesting a global address (in case that no prefix
advertisement is taking place by the IGWs) where in this case
GC_REP messages are sent by IGWs through unicast. Furthermore,
DAD_REPLY messages could take place in case of address conflicts
detection.
2.2.1.4. Global Connectivity for IPv6 Mobile Ad Hoc Networks (Wakikawa
et al.)
The solution described in [21] proposes how to provide Internet
connectivity with mobile ad hoc networks. It describes how to obtain
a globally routable IPv6 address from an Internet gateway. The
Internet access method is not dependent on a particular MANET routing
protocol, however there is still a need to a protocol.
Assumptions: The solution assumes that before configuring a global
IPv6 address, the node has configured a routable address (i.e.
MANET-local address or a Mobile IPv6 home address). The routable
address is used for initial configuration when a node boots up and
joins the MANET.
Approach description: This mechanism [21] is similar to [22] from the
point of view of how IPv6 addresses are configured. Global prefix
information is obtained from Internet gateways. Two methods are
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proposed for the Internet gateway discovery: one method periodically
disseminates gateway advertisements to all nodes in the MANET; the
other method utilises solicitation and advertisement signalling
between a MANET node and the gateway. Extended router solicitation
and advertisements of the Neighbour Discovery Protocol (NDP) or
extended control message of each MANET routing protocol can be used
for this signalling. The proposed methods target all MANET protocols
regardless of whether they are reactive or proactive. Internet
gateways supply their own global prefix information and IPv6 global
address to MANET nodes somehow, either proactively or reactively. In
this way, the reactive and proactive route discovery features of each
MANET routing protocol are not disturbed. An advertisement from the
Internet gateway provides prefix information -- IP routing prefix and
prefix length -- and lifetime.
After accepting an advertisement from the Internet gateway inserts
the Internet gateway address as an Internet route and the MANET node
configures a global address from the prefix of the Internet gateway.
It uses the 64-bit interface ID in order to construct a valid address
with the acquired prefix. It is assumed that before configuring a
global IPv6 address, the node has configured a routable local address
(i.e. MANET-local address), and a Non-unique Address Detection
mechanism has been performed for that routable local address (e.g.
using the mechanism defined in [4] and [23]), so it is assumed that
the global address would be also unique. If not, the node may
perform another Non-unique Address Detection mechanism for this
global address.
If the destination of a packet is inside the MANET even though a
global routable address is used as destination address, the gateway
prevents this packet from being forwarded to the Internet. It
returns the packet back to the MANET if it has a MANET route for the
destination. The source node receives an ICMP Redirect message from
the Internet Gateway warning that it should use a host route (MANET-
local address) instead of a default route (Internet route). To do
so, each Internet gateway may manage a list of IP addresses of all
the associated MANET nodes (mainly if a reactive ad hoc routing
protocol is being used). So, each MANET node must contact the
Internet gateway at least once it establishes an Internet route
through the Internet Gateway in order to communicate its global
routable address to the Internet Gateway.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets connected MANETs.
o Routing protocols' dependency: Not restricted to any particular ad
hoc routing solution, and it is designed to work properly with
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both proactive and reactive protocols.
o Address uniqueness: It is assumed that the global address would be
also unique. If not, the node may perform a Non-unique Address
Detection mechanism for this global address. In any case the Non-
unique Address Detection mechanism is considered out of scope.
o Distributed/centralised approach: The proposed solution uses a
distributed approach where nodes do not solicit any centralised
server for IP address assignment.
o Merging support: No special merging mechanisms are discussed in
this solution. Also, no in-service Non-unique Address Detection
is used which makes the merging support not feasible.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
o Protocol overhead: depends on the approach utilised. If extended
control messages of the MANET routing protocol -- including global
prefix information -_ are used the solution introduces low
overhead, but if gateway advertisement messages are periodically
flooded (with the hop limit field set to an appropriate value in
the MANET) then the solution introduces high overhead.
2.2.1.5. Multihop Radio Access Network (MRAN) Protocol Specification
(Hofmann)
This proposed solution [24] presents the Multihop Radio Access
Network (MRAN) protocol, which is an IPv6-based protocol for the
interconnection of ad hoc networks and the Internet. MRAN proposes
an approach that enables mobile ad hoc nodes to communicate with
correspondent nodes on the Internet. The application scenario of
this protocol is mainly when multiple gateways are available and
mobile nodes are frequently changing these gateways. The gateways
are supposed to be fixed and advertising different prefixes. MRAN
treats the gateways discovery and selection, the autoconfiguration of
global addresses, and the packet forwarding to/from the fixed
network.
Assumptions: It is assumed that mobile nodes (MNs) and Gateways (GWs)
use local addresses for communication within the MANET and that
routing is performed by a MANET routing protocol. It is also assumed
that a flooding protocol is used for broadcasting certain MRAN
control messages, where the flooding functionality may be provided by
the routing protocol.
Approach description: The operation of MRAN involves several
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functions: GW discovery, GW selection, address autoconfiguration,
registration with the GW, packet forwarding and multi-hop handovers.
Three modes of GW discovery are proposed and the choice between them
depends on the application scenario. In proactive GW discovery, all
GWs periodically broadcast advertisement messages "GW_ADV", where MNs
in proactive mode requiring Internet access waits until they receive
such a message. The reactive mode discovery allows MNs to discover
the available GWs when needed through broadcasting a GW solicitation
message. A GW receiving such a message replies by unicast solicited
GW advertisement message "sol_GW_ADV" to the MN. Hybrid GW discovery
mode is a combination of both proactive and reactive discovery, where
the GW is in proactive mode and the MN is in reactive one. All GW
advertisement messages contain the GW globally valid prefix of 64
bits length. The GW selection process allows each MN to select the
closet GW with respect to the number of hops. Other additional
metrics may be included in the selection process. After the GW
selection, the MN uses the selected GW's prefix and its own EUI-64 to
autoconfigure the global address. It may subsequently perform a Non-
unique Address Detection. Registration with the selected GW should
take place, where the MN sends a registration request message
"MN_REG" to the selected GW. A GW receiving this message replies by
a registration acknowledgement message "MN_REG_ACK" indicating the
successful registration. The MN then periodically repeats the
registration process and the registration may be used for other
purposes as well (for instance the AAA). To assure appropriate
packet forwarding between each MN and its selected GW, payload
packets are tunnelled between MNs and GWs in both directions. The
tunnelling approach uses IP-in-IP encapsulation thus allowing using
local addresses for intra-MANET communication. In the tunnel from
the GW to the MN, the destination address of the inner IP header is
the MN global address and the destination address of the outer header
is the local address of the MN. On the other hand, in the tunnel
from the MN to the GW, the destination address of the inner IP header
is the CN global address, whereas the destination address of the
outer header is the local address of the GW. In the case of MN's
disconnection from its current GW while communicating with a CN in
the Internet, multihop handover takes place. Thus, the MN has to
discover, select and register with another GW. This is called a
"forced multihop handover". For optimisation reasons, the MN may
also select a new GW that could be more close than the current GW.
In this case, the MN performs the registration with the new GW while
it is connected to the current one. This is known as "optimised
multihop handover", and is much faster than the forced one.
Maintenance takes place through creating two tables: i) GW table, and
ii) MN table. MNs maintain a GW table storing information about the
available GWs (local address, prefix, expiration time, registration
expiration). A table entry is created when the MN receives a GW_ADV
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or Sol_GW_ADV messages. On the other hand, GWs maintain MN tables
storing information about mobile nodes having a valid registration,
where each entry in this table stores the following information on
MNs (local address, global address, registration expiration time).
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets connected MANET
scenarios enabling mobile nodes to communicate with correspondent
nodes in the Internet.
o Routing protocols' dependency: This proposed solution works
independent of the MANET routing protocol.
o Address uniqueness: The proposed solution may use a Non-unique
Address Detection mechanism.
o Distributed/Centralised approach: The proposed solution uses a
distributed approach, where it does not solicit any centralised
server for IP address assignment.
o Merging support: No special merging mechanisms are discussed in
this solution. Also, no in-service Non-unique Address Detection
is used which makes the merging support not feasible.
o Prefix assignment support: This proposed solution supports
prefixes assignment, where the different gateways are responsible
for IPv6 prefixes advertisements.
o Protocol overhead: the solution integrates several mechanisms and
there is a number of flooding used to achieve the proper
mechanisms' functioning. The overhead in this solution mainly
lies in the assumption of an existing flooding protocol for
broadcasting certain MRAN control messages, and GWs periodical
broadcast of GW_ADV messages (containing the GW prefix) when
proactive GW discovery is applied. Also, GW_Solicitation messages
are broadcast on-demand when reactive GWs discovery is applied,
and periodical MN_REG messages are sent to the selected GWs by
each node requesting an IP address which is acknowledged by a
MN_REG_ACK by the selected GW. Furthermore, additional messages
are used for maintenance.
2.2.1.6. Automatic IP Address Configuration in VANETs (Fazio et al.)
Automatic IP address configuration is a challenging and still
unexplored issue in vehicular ad hoc networks (VANETs) environments,
where the vehicles' high mobility and variant density impede the
direct utilisation of traditional networking techniques and
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protocols. Aiming at integrating VANETs within the Internet and
providing passengers with any kind of Internet applications, the IP
address represents the natural identifier in the system. This work
[25] proposes an IP autoconfiguration solution in VANETs environment,
exploiting the VANETs topology and an enhanced DHCP service with
dynamically elected leaders to provide a fast and reliable IP address
configuration.
Assumptions: It is assumed that the network topology is linear and
that a group of nodes move following a track with an internal
mobility with respect to each other. It is also assumed that the
relative speed between nodes is low.
Approach description: This work proposes a novel automatic IP address
configuration protocol named Vehicular Address Autoconfiguration
(VAC), that is characterised by a low configuration time. VAC
represents the first protocol for IP address configuration in VANETs.
It exploits the VANET topology and a distributed dynamic host
configuration protocol (DHCP) runs by dynamically elected leader
vehicles to quickly provide unique identifiers and reduce the
frequency of IP address re-configurations due to mobility. VAC
organises leaders in a connected chain such that every node (vehicle)
lies in the communication range of at least one leader. This
hierarchical organisation allows limiting the signal overhead for the
address management tasks. Only leaders communicate with each others
to maintain updated information on configured addresses in the
network. Leaders act as servers of a distributed DHCP protocol and
normal nodes ask leaders for a valid IP address whenever they need to
be configured.
VAC guarantees unique IP addresses within a defined SCOPE around the
leader, where the SCOPE of the leader A is the set of leaders whose
distance from A is less or equal to SCOPE hops. Considering the
normal node Y that received the IPy address from A, IPy will be
unique as long as Y moves within the SCOPE of A. If Y goes out of the
SCOPE of A, in order to still ensure the address uniqueness, Y has to
ask the new leader for another address. Considering that the
relative speed between the nodes is low, changes in the address
configuration due to having left the own leader's SCOPE are not
frequent.
Based on [2], this solution has the following key features:
o MANET scenario: The proposed solution targets connected MANET
scenarios, enabling mobile nodes (vehicles) to communicate with
correspondent nodes on the Internet.
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o Routing protocols' dependency: Apparently VAC does not depend on a
special routing protocol. However no clear definition is given on
how and what control messages are exchanged in order to configure
each node requiring an IP address.
o Address uniqueness: The proposed solution does not employ any Non-
unique Address Detection mechanisms, however it guarantees address
uniqueness for each configured node.
o Distributed/Centralised approach: The proposed solution employs a
partially distributed approach, where distributed DHCP run by some
mobile nodes (vehicles)that are elected in a dynamic manner to
assign IP addresses to the requesting nodes.
o Merging support: No special merging mechanisms are explained in
this proposed solution, however it could support merging. The
SCOPE principle together with the distributed DHCP permit the
nodes to join/leave different SCOPES while acquiring a new address
from the SCOPE leader.
o Prefix assignment support: This proposed solution does not employ
any IPv6 prefix assignment to nodes.
o Protocol overhead: the hierarchical organisation in this solution
limits the signalling overhead and avoids flooding. The overhead
in this solution mainly concerns: the signalling messages for
communication between leaders nodes, the request messages sent by
mobile nodes requesting an IP address from their leaders (this
takes place in a limited scope), and the reply messages from the
leaders to the requesting mobile nodes for assigning IP addresses
(this also takes place in a limited scope). It is noticed that
this solution does not use Non-unique Address Detection mechanisms
due to the distributed DHCP functionality among leader nodes,
which helps in limiting the signalling overhead.
2.2.2. Merging support
2.2.2.1. Address Autoconfiguration in Optimized Link State Routing
Protocol (Adjih et al.)
This proposed solution [26] is based on the concept of conflict
detection. Each node periodically sends its address and an
identifier. The node identifier is a sequence of bits, of fixed
length (L), that is randomly generated. An address conflict is
detected when the identifier mismatches. This proposed solution is
suitable for OLSR routing protocol with a light increase of control
message overhead, however, it might be used with any MANET protocol.
Two issues are addressed in this solution, an IPv6 stateless
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autoconfiguration mechanism and a mechanism promoting address
uniqueness in the situation where different ad hoc networks merge.
Assumptions: Two assumptions are mainly considered in this proposed
solution. Firstly, it is assumed that the identifier of each node is
globally unique in the network. Secondly, it is assumed that a MANET
may be isolated.
Approach description: In this proposed solution, a new mobile node
joining the network is assigned an IP address then it carries out a
conflict detection procedure through running a Non-unique Address
Detection mechanism. If another node is detected to have the same
address, the new joining node selects a new address. The address
assignment process takes place as follows: i)consulting a neighbour
node that should configure an address for the new node. The
neighbour node then selects an IP address and sends it to the new
node. This takes place by control messages exchange. ii) picking up
a random address inside a given subnet with MANET_prefix either from
a pool of allocated addresses or through a set of addresses
advertised by each MANET node and are believed not used. In case of
address pool existence, this pool could be reserved by the IANA for
local use only (i.e. not forwarded outside MANET). In addition, in
case of MANETs connected to the Internet, nodes acting as gateways
diffuse IPv6 router advertisement messages. In this case each
address in the pool would be a global address that can be seen from
the outside.
The Non-unique Address Detection algorithm uses a single special
control message to perform conflict detection. Each node
periodically diffuses to the entire network a special message called
MAD (Multiple Address Declaration). This message contains the node
address and a unique identifier for the node. Several mechanisms are
proposed for MAD messages propagation. When using OLSR, propagation
of MAD messages mainly relies on the MPR flooding, where a number of
MPR selection rules are explained, presenting different options. If
another routing protocol is used, default pure flooding is used for
MAD messages propagation. In case of IP conflict discovery, this is
resolved by the node with the smaller identifier in each conflicting
pair. This node should change its IP, selecting a new IP at random
(that is believed to be free) following the same approach of IP
address assignment.
When OLSR routing protocol is used, an additional proposed option is
using Passive Duplicate Detection. In this case, the topological
information diffused by the OLSR routing protocol is sufficient to
detect address conflict. However, some MPR selection mechanisms are
used to ensure that the control messages are properly propagated.
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Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets both standalone and
connected MANETs scenarios.
o Routing protocols' dependency: This proposed solution depends on
the underlying routing protocol.
o Address uniqueness: the proposed solution comprises a Non-unique
Address Detection mechanism. The notion of passive duplicate
detection is also used, where the solution makes use of the
routing protocol messages propagation to detect the address
conflicts.
o Distributed/Centralised approach: The proposed solution uses a
distributed approach in the sense of not communicating with a
centralised DHCP server to acquire IP addresses.
o Merging support: This proposed solution has a merging support,
since the conflict detection process is periodically carried out
by mobile nodes. Thus, this solution assures address uniqueness
in case of ad hoc networks merge.
o Prefix assignment support: This solution does not support IPv6
prefix assignment to nodes.
o Protocol overhead: the solution adds low protocol overhead, since
this solution benefits from the OLSR routing protocol signalling
and MPRs concept to verify the address conflicts. The signalling
in this solution is limited to a single control message (MAD
message) to perform conflicts detection. If passive duplicate
detection option is applied with OLSR, the overhead is almost
none, as the topological information diffused by OLSR is
sufficient to detect address conflict. However, if another
routing protocol is used (which is an option), the MAD messages
have to be flooded resulting in a 'medium' overhead since the
flooding is limited to only one message in this case.
2.2.2.2. Extended Support for Global Connectivity for IPv6 Mobile Ad
Hoc Networks (Cha et al.)
The solution described in [27] proposes a stateful global IP
autoconfiguration for MANETs with the goal of providing enhanced
Internet connectivity to mobile ad-hoc networks. This stateful
autoconfiguration is performed through the exchange of extended
control messages of MANET routing protocols. The protocol is devised
as an extension to AODV, but the concept may be applicable to
proactive routing protocols.
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Assumptions: The solution assumes that each node has a
local_IP_address configured.
Approach description: The protocol basically consists in nodes
requesting global addresses to a gateway, which assigns a non-used
address to the requesting node. When an ad hoc node needs a global
IP address it sends an Internet-gateway solicitation message (GW_SOL
message). The Gateway uses an Internet-gateway advertisement(GW_ADV
message)to assign the solicited global IP address to the ad hoc node.
Given the event that an ad hoc node which has a Global IP address
(e.g., G-A1) assigned by a gateway (e.g., GW1) cannot reach GW1
anymore due to a partition in the MANET but this ad hoc node has
Internet connectivity through a different gateway (e.g.. GW2), the
ad hoc node gets another global IP address from GW2 (e.g., G-A2) and
it performs a Locator Registration Procedure with GW1. This locator
registration procedure is similar to Binding Updates in Mobile IPv6.
Using this procedure the ad hoc node registers G-A2 as CoA -- Care of
Address in Mobile IPv6 terminology -- of G-A1, so that ongoing
communications are kept.
More details can be found in [27].
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets connected MANETs.
o Routing protocols' dependency: although the protocol is devised as
an extension to AODV, it could be applicable to proactive routing
protocols.
o Address uniqueness: since non-duplicate addresses are assigned to
ad hoc nodes, the proposed solution is Non-unique Address
Detection-free.
o Distributed/centralised approach: the solution makes use of
centralised servers (gateways) in order to assign IP global
addresses.
o Merging support: given that the proposed solution assigns global
IP addresses avoiding duplicates, merging is supported. On the
other hand it supports partitions through the Locator Registration
Procedure.
o Prefix assignment support: the solution does not support the
assignment of IPv6 prefixes to nodes.
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o Protocol overhead: the solution adds certain protocol overhead,
since the mechanism appends some fields to AODV routing protocol
(RREQ message) to ask for a global IP address and gateway
information, and the replay (GW-ADV message) is unicast to the
originator MANET node. The solution includes the possibility of
gratuitous GW_ADV broadcast periodically.
2.2.2.3. Gateway and Address Autoconfiguration for IPv6 Adhoc Networks
(Jelger et al.)
This proposed solution [22] allows nodes in an ad hoc network to
proactively discover a gateway/prefix pair to be used in building an
IPv6 global address and to maintain a default route towards the
Internet. The core element of this proposed solution is the concept
of "Prefix Continuity". With prefix continuity, any node A that
selected a given prefix P has at least one neighbour with prefix P on
its path to the selected gateway G, thus assuring that each node on
the path between node A and the Gateway G uses the same prefix P.
Assumptions: It is assumed that each node can find a Gateway to
connect with and that each node can be assigned a global address
through this gateway. It is also assumed that one (or possibly more)
nodes of the ad hoc network should provide connectivity to the
Internet, thus acting as Gateways to other nodes.
Approach description: In this proposed solution, each Gateway (GW)
periodically sends a GW_INFO message notifying nodes in the ad hoc
network about its existence as well as the prefix it uses. Some
information in the GW_INFO message allows nodes to select the more
appropriate GW when more than one GW exist. Other information
contained in this message concerns: the GW global address, the length
of the prefix part of the address, and the distance to the gateway as
perceived by the node sending the message. The node receiving the
GW_INFO message forwards it to its 1-hop neighbourhood, where the
forwarder node is considered as the upstream node for each node that
receives the message. Among the transmitted GW-Info messages, each
mobile node selects (through a selection algorithm) only one
neighbour as its upstream neighbour and receives the GW_INFO messages
from this neighbour (i.e. consider this upstream as an intermediate
node to the gateway), then it forwards the message. A node must not
forward a GW_INFO message sent by a node that is not its upstream
neighbour. The destination address of the IPv6 header of the packet
containing the GW_INFO message must be FF02::1 (all nodes), while the
source address of such a packet must be the link local address of the
sender. Thanks to the prefix continuity, the routing via the GW can
be achieved without the need of an IPv6 routing header. Each mobile
node creates its IPv6 global address as follows: {Extended Unique
Identifier (EUI) of the interface from which the GW_INFO message is
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received + prefix contained in the message}. No Non-unique Address
Detection mechanism is needed in this approach, as there is a very
little probability of address duplication when EUI is used.
Based on [2], this solution has the following key features:
o MANET scenario: This proposed solution targets connected MANETs
scenarios.
o Routing protocols' dependency: This proposed solution is
independent (in terms of message semantics) of the underlying
routing protocol. Thus, it can be integrated in the operation of
the routing protocol or it can run as standalone daemon.
o Address uniqueness: The proposed solution does not depend on a
Non-unique Address Detection procedure or mechanism.
o Distributed/Centralised approach: The proposed solution is
distributed in the sense of not employing any centralised DHCP
server.
o Merging support: Although no Non-unique Address Detection
mechanism is used, this proposed solution supports networking
partitioning and merging as it is based on generating an IPv6
address for each node based on the prefix advertisements.
o Prefix assignment support: This proposed solution is based on the
prefix continuity and is thus supporting prefix assignment. Each
gateway advertises the IPv6 prefix that it uses.
o Protocol overhead: depends on the network size and the number of
GWs. The main signalling in this solution mainly concerns the
GW_INFO messages that are periodically sent by each GW notifying
its existence as well as its prefix. Since no Non-unique Address
Detection mechanism is needed in this solution, this helps in
limiting the signalling and hence the overhead.
2.2.2.4. MANET Autoconfiguration using DHCP (Templin et al.)
This draft [28] discusses about possible solution architectures to
provide MANET nodes with IP address autoconfiguration capabilities.
Basically, the solution proposes to connect nodes within a MANET by
means of virtual ethernets, which are imaginary shared links that
connects the MANET nodes. The nodes attach to the virtual ethernet
via an interface configured over underlying MANET interface(s).
Using this virtual ethernet, MANET nodes can configure global IPv6
addresses using for example DHCPv6.
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Assumptions: It is assumed that a MANET Router (MR) embodies a router
entity linked to one or more host entities by virtual point-to-point
interfaces. It is also assumed that the router entity also connects
to an imaginary shared link (i.e., a "virtual ethernet") that
connects all MRs in the MANET.
MANETs are connected to other networks by means of MANET Border
Routers (MBRs). MBRs are assumed to have configured a DHCP relay
and/or a DHCP server.
Approach description: The proposed solution considers that MANET
Routers are attached to an imaginary shared link (called "virtual
ethernet") that connects all the MRs in the MANET. Two different
types of "virtual ethernets" are defined:
o An "enhanced" view of this virtual ethernet sees the MANET as a
fully-connected shared link that connects all MRs. With this
approach, the MR encapsulates each IP packet in an outer IP header
and then sends it on an underlying MANET interface such that the
HOP Limit in the inner IP header is not decremented as the packet
traverses the MANET. Therefore, with this view, all MRs are
neighbours and standard Neighbour Discovery works as-normal. In
[29], this particular approach is separately documented.
o An "unenhanced" view sees the MANET as a multilink site. With
this approach, the MR sends each IP packet on an underlying MANET
interface without further encapsulation, and therefore the Hop
Limit may be decremented as the packet traverses the MANET. With
this view, since there are multiple hops between MRs, a "site-
scoped" equivalent of ND is defined (called Extended Neighbour
Discovery, END). In [30], this particular approach is separately
documented.
The MANET Router autoconfiguration procedure works as follows: first,
each MR configures MANET Local Addresses (MLAs) on each MANET
interface. These MLAs should be unique within the MANET and are used
as an identifier for operating the routing protocol (can also be used
as a locator for packets forwarded within the scope of the MANET).
In IPv6, MLAs are typically generated using Unique Local Addresses
with interface identifiers that are either managed for uniqueness or
self-generated using a suitable random interface identifier
generation mechanism that is compatible with EUI-64 format.
In a second step, the MR engages in the routing protocol over its
MANET interfaces and discovers the list(s) of MBRs that identify the
MANET(s). There are multiple approaches that can be used to perform
this MBR discovery, such as the use of information contained in the
routing protocol, a DHCP option, etc.
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For each MANET to which the MR attaches, it also configures a virtual
ethernet interface over the underlying MANET interfaces connected to
the MANET. After the MR configures the virtual ethernet interface,
it can verify the reachability of MBRs and discover prefixes
associated with the MANET's virtual ethernet. This is done by using
Router Solicitation/Router Advertisement exchanges, either using
normal IPv6 Neighbour Discovery -- in the case of "enhanced" view --
or Extended Neighbour Discovery -- for the "unenhanced" view. It is
also possible to use information conveyed in the routing protocol
itself, or through some other means associated with the particular
link technology.
After the MR discovers MBRs, it can configure addresses/prefixes
according to either DHCPv6 or IPv6 Stateless Address
AutoConfiguration (SLAAC). When the former method is used, the MR
sends a DHCPv6 request to the MBR(s) to get global address/prefix
delegations and then assigns addresses/prefixes to internal virtual
interfaces and/or downstream- attached physical interfaces. Once the
MR has obtained a global IPv6 address/prefix, it can send packets
with global source addresses using RFC4191 [31] router selection.
It should be noted that for the global addresses/prefixes [32]
obtained through DHCPv6, a Non-unique Address Detection mechanism is
not needed, since DHCPv6 ensures the uniqueness of the delegated
addresses/prefixes. However, the MLAs assigned to MANET interfaces
should be statistically unique so MANET-wide pre-service Non-unique
Address Detection mechanism is not needed. Alternatively, passive
in-service Non-unique Address Detection mechanisms can be used to
detect other MRs potentially using the same MLA.
Based on [2], this solution has the following key features:
o MANET scenario: the solution targets connected MANETs.
o Routing protocols' dependency: the solution is routing protocol
independent.
o Address uniqueness: the proposed solution does not define any Non-
unique Address Detection mechanism. the uniqueness of MANET Local
Addresses assigned to MANET interfaces should be statistically
ensured so MANET-wide pre-service Non-unique Address Detection is
not needed. If this cannot be achieved, passive in-service Non-
unique Address Detection mechanisms can be used to detect other
MRs potentially using the same MLA. The uniqueness of the global
IPv6 assigned addresses/prefixes is ensured by DHCPv6.
o Distributed/centralised approach: the solution makes use of the
available DHCPv6 servers to assign global IPv6 addresses/prefixes,
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although some hints about the use of IPv6 StateLess Address
AutoConfiguration (SLAAC) are also provided in Appendix B of [28].
o Merging support: the solution supports merging. Different
mechanisms are proposed to deal with different defined
partitioning/merging scenarios.
o Prefix assignment support: the solution supports the assignment of
IPv6 prefixes to nodes.
o Protocol overhead: depending on the virtual ethernet approach
followed, it can add overhead -- for the 'enhanced' view, where
normal IPv6 SLAAC or DHCPv6 can be used --, or medium overhead --
for the 'unenhanced' view, where an Extended Neighbour Discovery
mechanism (that makes use of site-scoped message flooding) is
required.
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3. Security Considerations
Due to the open wireless environment of ad hoc networks, IP
autoconfiguration mechanisms are susceptible to a number of attacks.
The autoconfiguration problem statement draft [1] states some
security issues that worth consideration.
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4. IANA Considerations
This document has no actions for IANA.
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5. Acknowledgements
We would like to thank all the AUTOCONF ML people that provided
comments to the previous version of the I-D. We would also like to
thank Kilian Weniger for his useful review of this draft, and Thomas
Clausen for his review and support on the continuity of this draft in
another shape.
The work of Carlos J. Bernardos and Maria Calderon has been partly
supported by the Spanish Government under the POSEIDON (TSI2006-
12507-C03-01) project.
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6. References
6.1. Normative References
[1] Baccelli, E., Mase, K., Ruffino, S., and S. Singh, "Address
Autoconfiguration for MANET: Terminology and Problem
Statement", draft-ietf-autoconf-statement-04 (work in
progress), February 2008.
[2] Moustafa, H., Bernardos, C., and M. Calderon, "Evaluation
Considerations for IP Autoconfiguration Mechanisms in MANETs",
draft-bernardos-autoconf-evaluation-considerations-01 (work in
progress), October 2007.
[3] Chakeres, I., Macker, J., and T. Clausen, "Mobile Ad hoc
Network Architecture", draft-ietf-autoconf-manetarch-07 (work
in progress), November 2007.
6.2. Informative References
[4] Perkins, C., "IP Address Autoconfiguration for Ad Hoc
Networks", draft-perkins-manet-autoconf-01 (work in progress),
November 2001.
[5] Weniger, K. and M. Zitterbart, "IPv6 Autoconfiguration in Large
Scale Mobile Ad-Hoc Networks", European Wireless 2002 , 2002.
[6] Jeong, J., "Ad Hoc IP Address Autoconfiguration",
draft-jeong-adhoc-ip-addr-autoconf-06 (work in progress),
January 2006.
[7] Jeong, J., "Ad Hoc IP Address Autoconfiguration for AODV",
draft-jeong-manet-aodv-addr-autoconf-01 (work in progress),
July 2004.
[8] Vaidya, N., "Weak Duplicate Address Detection in Mobile Ad Hoc
Networks", MOBIHOC'02 , 2002.
[9] Mohsin, M. and R. Prakash, "IP Address Assignment in a Mobile
Ad Hoc Network", MILCOM 2002 , 2002.
[10] Tayal, A. and L. Patnaik, "An address assignment for the
automatic configuration of mobile ad hoc networks", Personal
Ubiquitous Computing , 2004.
[11] Mase, K. and C. Adjih, "No Overhead Autoconfiguration OLSR",
draft-mase-manet-autoconf-noaolsr-01 (work in progress),
April 2006.
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[12] Weniger, K., "Passive Duplicate Address Detection in Mobile Ad
hoc Networks", IEEE Wireless Communications and Networking
Conference (WCNC) , 2003.
[13] Weniger, K., "PACMAN: Passive autoconfiguration for mobile ad
hoc networks", IEEE Journal on Selected Areas in
Communications, vol. 23, no. 3, Mar 2005 pp. 507-519 , 2005.
[14] Mase, K. and K. Weniger, "PDAD-OLSR: Passive Duplicate Address
Detection for OLSR", draft-weniger-autoconf-pdad-olsr-01 (work
in progress), June 2006.
[15] Baccelli, E., "OLSR Passive Duplicate Address Detection",
draft-clausen-olsr-passive-dad-00 (work in progress),
July 2005.
[16] Jeong, H., "Passive Duplicate Address Detection for On-demand
Routing Protocols", draft-jeong-autoconf-pdad-on-demand-01
(work in progress), April 2007.
[17] Zhou, H., Ni, L., and M. Mutka, "Prophet Address Allocation for
Large Scale MANETs", Proceedings of INFOCOM 2003 , 2003.
[18] Ruffino, S. and P. Stupar, "Automatic configuration of IPv6
addresses for MANET with multiple gateways (AMG)",
draft-ruffino-manet-autoconf-multigw-03 (work in progress),
June 2006.
[19] Clausen, T. and E. Baccelli, "Simple MANET Address
Autoconfiguration", draft-clausen-manet-address-autoconf-00
(work in progress), February 2005.
[20] Ruiz, P. and F. Ros, "Extensible MANET Auto-configuration
Protocol (EMAP)", draft-ros-autoconf-emap-02 (work in
progress), March 2006.
[21] Wakikawa, R., "Global connectivity for IPv6 Mobile Ad Hoc
Networks", draft-wakikawa-manet-globalv6-05 (work in progress),
March 2006.
[22] Jelger, C., "Gateway and address autoconfiguration for IPv6
adhoc networks", draft-jelger-manet-gateway-autoconf-v6-02
(work in progress), April 2004.
[23] Suan, Y., Belding-Royer, E., and C. Perkins, "Internet
Connectivity for Ad hoc Mobile Networks", International Journal
of Wireless Information Networks special issue on 'Mobile Ad
Hoc Networks (MANETs): Standards, Research, Applications' ,
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2002.
[24] Hofmann, P., "Multihop Radio Access Network (MRAN) Protocol
Specification", draft-hofmann-autoconf-mran-00 (work in
progress), March 2006.
[25] Fazio, F., Palazzi, C., Das, S., and M. Gerla, "Automatic IP
Address Configuration in VANETs", ACM VANET 2006 Workshop co-
located with Mobicom 2006 , 2006.
[26] Laouiti, A., "Address autoconfiguration in Optimized Link State
Routing Protocol", draft-laouiti-manet-olsr-address-autoconf-01
(work in progress), July 2005.
[27] Cha, H., Park, J., and H. Kim, "Extended Support for Global
Connectivity for IPv6 Mobile Ad Hoc Networks",
draft-cha-manet-extended-support-globalv6-00 (work in
progress), October 2003.
[28] Templin, F., Russert, S., and S. Yi, "The MANET Virtual
Ethernet (VET) Abstraction", draft-templin-autoconf-dhcp-14
(work in progress), April 2008.
[29] Templin, F., "MANET Autoconfiguration over Virtual Ethernets",
draft-templin-autoconf-virtual-00 (work in progress),
February 2007.
[30] Templin, F., "MANET Autoconfiguration over Multilink Sites",
draft-templin-autoconf-multilink-00 (work in progress),
February 2007.
[31] Draves, R. and D. Thaler, "Default Router Preferences and More-
Specific Routes", RFC 4191, November 2005.
[32] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host
Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
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Appendix A. Change Log
Changes from -02 to -03:
o New release to keep the document alive.
o Update of some references.
Changes from -01 to -02:
o The classification criteria section has been removed, since it is
now part of the evaluation considerations in [2]. Solutions are
now analysed conforming to some of these evaluation considerations
in [2].
o The Conclusions section has been removed.
o The Terminology section has been removed.
o The term "DAD" has been removed in the document (when possible),
using Non-unique Address Detection instead.
o Many editorial changes.
Changes from -00 to -01:
o The structure of the I-D has modified, classifying the analysed
solutions according to a number of useful criteria, conforming to
the AUTOCONF problem statement draft and the MANET architecture
draft.
o More solutions have been added to the I-D.
o Adding of a security consideration section.
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Authors' Addresses
Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
Maria Calderon
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 8780
Email: maria@it.uc3m.es
Hassnaa Moustafa
France Telecom
38-40 rue du General Leclerc
Issy Les Moulineaux 92794 Cedex 9
France
Phone: +33 145296389
Email: hassnaa.moustafa@orange-ftgroup.com
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