Node Caching for Content Distribution in Mobile Delaytolerant Network
Junli She, Xiangyu Bai
*
, Qi Liu
College of Computer Science–College of Software Engineering
Inner Mongolia University
Hohhot, China
e-mail: 1014725411@qq.com, bxy@imu.edu.cn, snowliuqi@163.com
Abstract—Different countries in the world all have different
degrees of communication underdeveloped areas, how to
reduce "digital gap" between urban and rural effectively is one
of the problems need to be solved. This phenomenon provides
ample space for the development of mobile delay tolerant
network because the "storage-carry-forward" communication
mode in MDTN does not need the support of the network
infrastructure, and MDTN can effectively compensate for the
shortage of operator's network coverage. At the same time, the
requirement of storage capacity of nodes in MDTN is
increasing quickly. How to manage the limited cache space
efficiently is the focus of the study. At present, many cache
strategies have achieved some results, but the “user interest” is
often easily overlooked by the researchers. Based on this
phenomenon, we believe that the user interest is one of the
factors that cannot be ignored in the design of caching
strategies. Considering the lack of communication in remote
areas, this paper combined MDTN and content center network
and proposed a new node cache technology named IBCS for
this hybrid network. In IBCS, we consider the user interest as
the main metric to decide whether or not to cache a content.
Finally, the cache technology is implemented on the ONE
simulation platform. Through the experiment analysis and
comparison under the real data set and the whole simulation
data set, we found that the IBCS (Interest Based Cache
Strategy) proposed in this paper is the best in all aspects of
network performance under the same network environment.
Keywords-mm obile delay tolerant network; content center
network; caching technology; user interest
I. INTRODUCTION
The initial concept of Delay Tolerant Networks (DTN) [1]
is derived from DARPA (Defense Advanced Research
Projects Agency) [2]. The DTN adds a “Bundle layer"
between the transport layer and the application layer, and it
using the "storage-carry-forward" communication mode.
When data is sent, the message (called the bundle) is
transferred from one node to another along the path. This
method isolates the delay, thus supporting intermittent
communication between nodes [3].
In recognition of the host-centric Internet architecture
cannot meet the needs of a large number of content, Teresa
Lant (Teresa Lunt) show a special network environment
designed for the new network technology in 2013 named
Content-Centric Network (CCN) [4], which also known as
the Information Center Network (Information-Centric
Network, ICN). This network is centered on content and is
designed for data distribution rather than communication.
One of the key principles in CCN [5] is using dynamic
content caching to maximize bandwidth utilization, enabling
fast, reliable, and scalable content delivery to avoid
congestion. The main research problems of content center
network includes naming scheme [6], content addressing and
forwarding [7], routing and transmission [8], cache
mechanism [9]. In this paper, we will improve the
performance of mobile delay tolerant network (MDTN) [10-
13] by considering the network caching technology, content
popularity [14-20], node activity [21-22] and user interest
[23-26].
Cache management is a very important research, a well-
designed caching strategy can reduce the occupation of
network bandwidth resources, reduce the time that a user
obtains the resources, and reduce the burden of resource
publishing server [27]. Because of the limited cache space,
when a node stores a large number of outdated content items
or the remaining cache space is insufficient, the node needs
to discard some of the secondary content items in order to
free up cache space for the useful content items. So, an
effective cache replacement strategy needs to be designed to
make the choice of how to cached content. At present, most
of the research results in the mobile delay tolerant network
are mainly focused on cooperative cache technology [25-34].
Above all, based on the traditional DTN cache
mechanisms, we combined them with CCN technology and
took into account of the social attributes, content
requirements, node center degree, user interest and other
factors, to design a complete caching strategy according to
the needs of the application scenario. The main contributions
of this paper are:
• (1) Take the user interest as the main factor to
decide whether to cache a content or not, and applied it to the
design of the cache strategy.
• (2) Each content item of the network is named by
hierarchical naming scheme, the format of the resource list
and the interest list are given. If the system distributes new
resources, the resource list will be updated. The interest list
is updated according to the user's interest. According to the
number of messages exchanged with other nodes, the nodes
are divided into high activity nodes and low activity nodes.
Different kinds of nodes adopt different cache replacement
policies.
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2017 17th IEEE International Conference on Communication Technology
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