How efficient is Efficient NDP?

Abstract

In the following years we will experience a transition towards Internet Protocol version 6 (IPv6). The reason is the depletion of IPv4 address space due to the rapid increasing numbers of Internet of Things (IoT) devices connection. This transition however poses a problem, since the majority of these devices mostly are mobile and not connected to power source.
Neighbor Discovery Protocol (NDP) defined in RFC 4861 is used in IPv6 networks, to manage the address configuration as well as the network prefix and maintain lists of all the neighbors connected to that network. However, this protocol does not work as good in wireless connected devices as in wired. The messages exchange in the network disrupts the sleep mode of the nodes resulting in lower battery time. Hence the energy efficiency of these devices is now something we should consider. To solve this problem, the Efficient NDP draft was introduced as one of the optimized methods.
This thesis takes the previous theses of analysis and simulations of IPv6 Neighbor Discovery for wireless networks further, to explore the ND protocol in RFC 4861 (legacy NDP), and compare it to the Efficient NDP draft in terms of energy efficiency for the devices mentioned above. Several dynamic network cases are taken into analysis, and simulation scenarios for these cases are tested in OMNeT++. These simulation models follow the implementation process introduced in the protocols with consideration of network scalability, and present the result that the Efficient NDP has large improvement in saving multicast messages in ND process.

Popular Abstract

In the real world, people need addresses to identify their locations. Similar to this, devices also need to have network labels which called IP addresses for identification and locating when they connect to the Internet. Internet Protocol version 4 (IPv4) is a protocol which introduces a 32-bits IP address format and popularly used in today’s networks. However, the increased number of devices connecting to the Internet has led to the depletion of available IPv4 addresses. IPv6 was introduced with more address space to solve IPv4 address exhaustion problem. But on the other hand, many existing protocols used in IPv4 have to be extended or redesigned to fit IPv6 networks.
A network always contains many nodes (routers and hosts). A node recognizes other nodes in its located network as its neighbors. Discovering neighbor locations, gathering neighbor information and defining the communication methods between neighbors are the contents in IPv6 Neighbor Discovery Protocol (NDP). The legacy NDP was announced 10 years ago in RFC 4861. It relies on periodical multicast Internet Control Message Protocol version 6 (ICMPv6) control messages to maintain relationship between neighbors. Which means that these control messages are sent to all the members in a group. Although these messages are only relevant to a specific member in this group at most of time, other members also have to receive and process them.
As we known, receiving and processing messages require power consumption. It is inefficient for nodes to handle these unnecessary messages frequently, especially for wireless devices. As wireless devices are always not connected to power supplies, power saving becomes an important point for their battery life.
To solve the high power consumption problem in legacy NDP, a more efficient protocol the Efficient NDP was announced. This protocol introduces a registration mechanism for hosts with a router. In this mechanism, the router does not need to send periodical control messages to the hosts for asking their updates, but give a registration timer to each host. A host only has to wake up and send messages to the router when the timer is reached, and can keep in sleep mode for a long time. This can significantly reduce the power consumption. On the other hand, as the router functions as a registration point in the network, it has the knowledge of each node address information, so it can help hosts for handling address related issues with their neighbors.
From analysis, we have already known that the Efficient NDP provides a good solution in power saving, comparing with the legacy NDP. But how efficient it can achieve? To answer this question, an evaluation is required. As today’s networks are always dynamic networks, nodes are able to enter, leave and change their locations in networks at any time, it is worth for us to analyze the performance of these two protocols in this environments. However, as implementing a real dynamic network environment is too complex, simulation becomes an ideal method for evaluation.
Two scenarios were taken into analysis and simulations in this thesis, one is nodes entering and leaving a network scenario, and another is nodes losing connection to a network case in movement scenario. As network scalability is an important parameter for evaluation, simulation models were designed with different network sizes. The obtained results indicate that in both of these scenarios, the Efficient NDP can achieve very high messages saving percentages in large networks. On the other word, it provides a great power saving solution.

• author: Xu, Tian and Kalomoiris, Dimitris
• supervisor: Jens A Andersson; Stefan Höst
• organization: Department of Electrical and Information Technology
• course: EITM02 20171
• year: 2017
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Simulations, Neighbor Discovery, Efficient NDP, RFC 4861, Dynamic wireless networks.
• report number: LU/LTH-EIT 2017-604
• language: English
• id: 8927565
• date added to LUP: 2017-10-23 13:18:42
• date last changed: 2017-10-23 13:18:42