# T-Move: A Light-Weight Protocol for Improved QoS in Content-Centric Networks with Producer Mobility
## 1 Introduction  
Recent advances in microelectronic and mechanical devices and wireless communication have given rise to large networks of mobile nodes for various purposes. These nodes may now be sensors, actuators, vehicles, and humans. Some of these are constrained in terms of energy, processing power, memory, etc. In addition, there has been a clear shift in interest towards data based on its content, rather than the host of the content. Gathering, processing, and communicating data in such large networks of mobile devices needs special architectures and protocols. In addition, service and device discovery and routing of data is a major challenge in applications with mobile nodes such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) networks. Solutions for service discovery and mobility that work in the Internet (such as DNS and Mobile IP) are not efficient enough in their current form for such networks because of the highly dynamic nature of content. For example, Mobile IP requires each device to have a unique IP address, which may not be possible in the case of many devices, whose life span may be very short. 6 LoWPAN (based on IPV6) makes this possible to some extent, but service/device discovery remains a problem. One way to solve the addressing and routing problem is information-centric networking (ICN). ICN is based on the fact that most users are interested in the data--not the address at which it is located. In the current Internet architecture, routing of the request for a resource (the Uniform Resource Identifier, URI) and the reply (e.g., the file named by the URI) is done solely based on the IP address of the source and destination computers. In ICN, the user requests the resource using a _name_ similar to the URI. Requests are routed using longest prefix-matching of the URI, and the content is routed tothe user on the reverse path. As devices do not have addresses, resolution of services to addresses is not necessary. MobilityFirst [1], which is another popular ICN architecture, uses both resource names and node addresses. The resource name is called the Global Unique IDentification(GUID) and is very similar to the URI. The difference between the GUID and the URI is that the GUID does not contain the address like the URI does. Hence, data can be routed based on the address or name. Routing schemes and tables in MobilityFirst are more complex than those in ICN. This paper proposes T-Move, based on Content-Centric Networking (CCN [2; 3]) and Named Data Networking (NDN [4]). CCN is a popular ICN architecture which makes use of in-network caching. NDN is derived from CCN and has the same core network elements and data structures. T-Move is built on just these basic network elements and data structures and hence can be used with both NDN and CCN implementations. Routers in CCN/NDN maintain a _content store_ (CS) to cache data and satisfy further interests for this data. In-network caching is an excellent mechanism to reduce the data retrieval time and network traffic. Both these are very important parameters in the context of many devices generating huge amounts of data. Hence, an information-centric approach has been proposed and evaluated successfully for several applications ([5; 6] etc.). However, the cache replacement policy [7] which decides what cache items are stored, plays a major role in the performance of caching. In the context of networks with mobile devices and low latency requirements, a cache replacement policy that can improve system performance is much more difficult to design. CCN/NDN inherently performs well even when consumers are mobile, as data objects are _pulled_ by consumers and follow a path set by the interest. producer mobility, on the other hand, is not easy to handle [8], as producers cannot be located with IP-like addresses in CCN/NDN. There are three main approaches to handle mobility in CCN/NDN--anchor-based, rendezvous-based, and anchorless. All these approaches are costly in terms of time and number of updates.