Efficient IPv6 Neighbor Discovery in Wireless Environment

Abstract

As the address space of IPv4 is being depleted with the development of IoT (Internet
Of Things), there is an increasing need for permanent transition to the IPv6
protocol as soon as possible. Nowadays, many 3GPP (3rd Generation Partnership
Project) Networks have implemented or will implement IPv6 in the near future
for Internet access. These networks will also use NDP (Neighbor Discovery Protocol),
which is the IPv6 tailored version of ARP (Address Resolution Protocol).
The protocol is responsible for address auto-configuration, maintaining lists of all
neighbors connected to a network, verifying if they are still reachable, managing
prefixes and duplicate address detection.

The protocol is defined in RFC 4861 and although it works fine for wired connected
devices, it has been proven highly inefficient in terms of battery lifetime saving,
when wireless networks came to the market and its use increased tremendously.
This thesis work is a continuation of a previous master thesis and complements
the work done previously by showing how the solutions suggested in the new draft
can be implemented at the router and host side and practically confirms the previous
results of the theoretical analysis through simulation scenarios of sleep and
wake-up of the nodes, performed in OMNeT++. Subsequently, the scalability of
the system as a whole was analyzed with a simulation model containing a range of
hosts from 1 to 100, and shows it can operate efficiently on a larger scale, reducing
multicast messaging by almost 100%, presumably saving their battery power.

Popular Abstract

The introduction and rise of Internet of Things (IoT), and the use of more and more
wireless devices in the communication between users, has depleted the available
addresses of IPv4. The introduction of the new IPv6 protocol solves the address
depletion problem, but on the other hand, many of the existing protocols have to
be redesigned.

This thesis is based on RFC 4861’s NDP (Neighbor Discovery Protocol for IPv6
Networks, the equivalent protocol of ARP (Address Resolution Protocol) for IPv4
Networks. Like ARP, NDP is used in all Networks, wired or wireless, and it’s main
feature is to check and update periodically the state of the Network, provide L2
addresses to hosts in the same Network and verify their reachability.

While wired devices experience no issues regarding power supply, as they are constantly
hooked to a power source and rarely experience network failures, wireless
devices have limited power, as they rely on battery lifetime. This is also the case
of machines running NDP - the protocol relies on periodic exchange of multicast
ICMPv6 (Internet Control Message Protocol version 6) control messages, creating
unnecessary traffic overhead in the Network, as all hosts in a Network would receive
those messages, regardless if they are meant for them or not. As a general
working mode of a battery operated device, one enters predefined sleeping cycles
(stand-by), which are designed by each manufacturer in different ways. Therefore,
multicast signaling inside Networks disrupt those sleeping cycles, causing
increased battery consumption, as a result of more required processing power and
more consumed bandwidth.

RFC 6775, together with [3], propose updates to NDP, which would solve the
problems mentioned above. The major update is that each host can update the
router about its state, by sending unicast messages, without involving the other
hosts in the Network. The router, instead of sending periodic control messages to every host, it sends control messages to each host separately in specific time
intervals. Only when a major change occurs in the Network, for instance an
addition of a new host, or when a host leaves the Network, multicast messages
are sent to every host to update their state. Together with the establishment
of unicast signaling, a new method of address registration is introduced in the
documents cited above, called Address Registration Option. This registration
method is fully compatible with the two standard mechanism which provide the L3
addresses to hosts - Stateless Address Autoconfiguration (SLAAC) and Dynamic
Host Configuration Protocol (DHCP).

The previous thesis work took the first steps in implementing the proposed protocol
changes, by investigating functions inside RADVD - the Router Advertisement
Daemon, run on all routers and responsible for sending the multicast periodic
control messages to the hosts (Router Advertisements). A full implementation of
the proposed changes require covering both sides of the Network, i.e Host and
Router. While RADVD is handling the Router side, the implementation at the
Host side needs to be done inside the Linux Kernel. In this thesis work, the
RADVD implementation was completed and possible implementation methods
were shown inside the Linux Kernel. Due to the overall complexity of the Linux
Kernel, while the proposed code could cover most aspects from RFC 6775, it wasn’t
possible to test it, in order to conclude how much workload is left.

Simulations took place to compare the two protocols and verify, in what extend
these proposed changes can potentially improve battery lifetime. So, sleep and
wake up scenario was tested in same time intervals in order to observe Network
traffic. The goal was to have a decrease in control messages in the case where
the suggested changes were applied. Different number of hosts were selected to
see if these changes can be applied to larger network. In both cases, the best
case scenario was tested and parameters which would normally hinder network
performance were neglected. This decision was made to reduce the complexity
of the Network as well. The results of the simulations indicated that there could
be a decrease in control messages and the Network seems stable and scalable as
number of host increases.

• author: Neagoe, Dragos and Pateas, Antonios
• supervisor: Jens A Andersson; Stefan Höst; Jaume Rius i Riu
• organization: Department of Electrical and Information Technology
• course: EITM02 20161
• year: 2016
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: IPv6, Neighbor Discovery, 6LoWPAN, RFC 4861
• report number: LU/LHT-EIT 2016-550
• language: English
• id: 8895285
• date added to LUP: 2016-11-30 11:40:01
• date last changed: 2016-11-30 11:40:01