# An Efficient Probe-Based Routing for Content-Centric Networking  
[PERSON]  
1 Institute of Manufacturing Information and Systems, National Cheng Kung University,  
Tainan City 701, Taiwan 1  
[PERSON]  
2 Department of Computer Science and Information Engineering, National Cheng Kung University,  
Tainan City 701, Taiwan 2  
[PERSON]  
2 Department of Computer Science and Information Engineering, National Cheng Kung University,  
Tainan City 701, Taiwan 2  
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(TCP/IP) communication protocol, CCN is more flexible and scalable by allowing data to be cached in routers and using interest with content name, which is the name of the required data, as the query packet [8]. The response time of interest can be significantly reduced by utilizing efficient routing and in-network caching [9]. The traditional TCP/IP routing protocol is a single-source to a single-destination transmission that only considers one server as the content provider and uses the shortest length or lowest cost as the path planning goal function. In this paper, the content provider is defined as the server or router that owns the content that the user requires. However, with the increasing number of IoT applications, TCP/IP networks face an insufficient number of IP addresses or require a longer IP address to handle numerous amounts of devices, putting a strain on the router. Furthermore, TCP/IP networks cannot satisfy more and more Quality of Service (QoS) criteria, such as real-time traffic (such as video conferencing) and best-effort traffic (such as file transfer protocol (FTP)) [10]. Different from the TCP/IP protocol that uses IP to identify a single content provider, CCN uses the properties of in-network caching that scatters contents over routers to consider all routers in the network as potential content providers. CCN relies on two tables for routing: Forwarding Information Base (FIB) and Pending Interest Table (PIT). The outgoing interface of packet forwarding is determined by routers using FIB. Therefore, FIB is designed to keep track of potential content providers. PIT is used by routers to track the forwarded path of an unsatisfied interest so that data can be sent back along that path, as well as to prevent duplicate forwarding of interests requesting the same content. However, Basic CCN's planning routing is inefficient [3]. Because of insufficient FIB space or out-of-date FIB entries, basic CCN experiences frequent retransmission and network congestion. As a result, many studies propose exploring the distribution of cached content to improve the CCN. Based on how to obtain cache information, they are categorized into content share [5; 11; 12; 13] and content query [3; 4]. Content share is that the router periodically shares cache information with other routers. Content query is that the router asks for other routers' cache information. However, according to our observations or surveys, their common shortcoming is extra-packets for exploring the distribution of cached content which significantly increases network traffic overhead. To tackle this issue, this paper presents an efficient _probe_-based routing approach for CCN. So long as the router's FIB is correct and up-to-date, it is possible to choose the best content provider. Therefore, our approach focuses on the FIB updating algorithm. A path planning table is also added in our approach for determining the content provider. Instead of the outgoing interface, FIB is modified to record the candidate content providers. The shortest path to content providers is stored in the path planning table. Many TCP/IP routing algorithms can be used [14; 15]. Our approach adds a new field called _probe_ to the interest and data packets to allow for cache content exploration.