Hierarchical and Hash-based Naming Scheme for ...

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Hierarchical and Hash-based Naming Scheme for Vehicular Information Centric Networks Safdar H. Bouka , Syed Hassan Ahmedb and Dongkyun Kimc School of Computer Science and Engineering, Kyungpook National University,Daegu, Korea. Email: {a bouk, b hassan}@monet.knu.ac.kr, c [email protected] Abstract—In this paper, we propose a hierarchical and hashbased naming scheme for Vehicular Information Centric Networks (VICNs). Our proposed naming scheme makes the best use of the features offered by hierarchical as well as hashbased naming schemes. The hierarchical part of the content name contains information about content owner or generator, content type, sub-types, and attributes of the digital content itself that is shared between vehicles. It serves two main purposes: first, it helps in minimizing the routing table by aggregating the names and simplifying the routing decisions. Second, it contains attributes, spatial, temporal and their range information to easily find and resolve the content. The hash part uniquely identifies the digital content required for VICN applications.

Prefix/Hierarchical Section Owner/Publisher

Content Info.


Vehicle Information CTRY= US, STT= CA , CTY= LA , OID= JOHN , VRP= CAL001 Contents Generated (1) TSQR.jpg “Times Square” “22 Apr 2014 9:30am” “800x600” (2) 42ST.avi “42 Street” “22 Apr 2014 9:30am ~ 01:00pm” .............. Scheme Prefix Signature vhn://us/ca/la/john/CAL001/image/jpg/40.75811,-73.98558/1398159000/ 800*600/TSQR AKgqS8BJInr7… Vhn://us/ca/la/john/CAL001/video/avi/40.7534,-73.9807~40.7492,-73.9708/1398159000~1398173400/E42ST PsLg6zOz1Bci…

Fig. 1.


Hash/Flat Section

Proposed Naming for DCs Generated by the Vehicle.


Vehicular Networks (VNs) with or without infrastructure support have been rigorously investigated in the recent past due to their vast variety of applications. These applications offer safety and comfort to the passengers and drivers. Vehicular applications mainly focus on the temporal, spatial and interestbased reliable information communication. The information requirement of the VN applications lies into two scopes: geographical and temporal scope. Some VN applications may require information about certain geographical region, e.g., city block, a region between two locations, highway section, street segment, etc. In addition to that, VN applications may also require temporal scope information, e.g., traffic of week, day, or a specific time range (between t1 and t2 ), weather, or incident information, etc. However, due to highly dynamic topology and scalability of VN, it is quite challenging to achieve the robust communication objectives of the applications. The Information Centric Networking (ICN) architectures have recently been investigated in the VNs [1]. The main concept of ICN is to smoothly distribute digital contents between the content originator and the requesting node without taking data originator’s location into account. The beauty of ICN is its simplest Request and Response (Interest–Data) type communication model. Along with the simple architecture, ICN has opened many research challenges and one of which is the content naming. In general, ICNs for the Future Internet, the digital content (DC) (e.g. text, video, audio, image, sensor data, blob, etc.) is assigned a name, called Content Name (CN), by the source or originator of the DC, which is a vehicle in this context. Each of the contents is uniquely identified by its CN. Multiple copies of the same DC cached at different vehicles in the VICN use the same CN. There exist different naming schemes that have been proposed for general quasi static ICN that are categorized as flat, hierarchical, and attribute based[2][3].

In this paper, we propose a hierarchical and hash based naming scheme for VICN that best uses the collective features of hierarchical and hash-based naming schemes. The hierarchical section provides detailed information about DC owner or generator and information or attributes of the DC. The DC information represents the generic attributes of the DC (e.g. file type, name, date, etc.) and its temporal and spatial range based information. On the whole, hierarchical part helps in name resolution, aggregation and simplification of route information in the routing engine, as well as satisfies the information requirements of the VICN applications. However, the name resolution and routing are out of the scope of this work. The hash or flat section of CN ensures contents integrity. II.


A vehicle that requires any DC (e.g. text, video, image, or any digital content) from the network, sends an interest message that contains either unique CN and/or different attributes that clearly define the content. Suppose a vehicle requires content item with attributes: image of an area or a site with specific name or coordinates, date and time when snapshot was taken, approximate resolution, etc. The vehicle first resolves the unique CN and then sends the interest message that includes that unique CN. In response to the interest packet, any vehicle that has originated or cached the requested content, reply with the Data message to the requesting node containing the inquired DC. This simplest communication model suits well to the dynamic topology of This research was supported by the MSIP(Ministry of Science, ICT & Future Planning), Korea, under the C-ITRC(Convergence Information Technology Research Center) support program (NIPA-2014-H0401-14-1004) supervised by the NIPA(National IT Industry Promotion Agency.) and also by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology(2012R1A1A4A01009954).

VNs. To adapt this communication model in VICN, we have proposed a hybrid naming scheme that uniquely identifies, aggregates and helps in routing the DCs generated by the vehicle. The proposed naming scheme divides CN into three parts as shown in Figure 1. The specification and effectiveness of each part is discussed below. 1) Scheme: The scheme part of CN is used to access and locate the content item within the VN. The value for this field can be vicn or vhn (Vehicular Hierarchical Naming), or vni (Vehicular Named Identifier). 2) Prefix / Hierarchical Section: This prefix or hierarchical part identifies content originating node, which is a vehicle, and the content item itself in a human–readable format. The information about content item and its owner has nothing to do with any physical location of vehicle. This hierarchical representation is adapted to easily provide name aggregation for optimized routing table and routing the Interest-Data messages in VICN. The content owner/publisher vehicle’s information in CN is represented in the following manner. •

• •

CTRY/STT/CTY represents the country, state and city or county name abbreviation, e.g., us/ca/la (USA/California/Los Angeles), ca/ab/cg (Canada/Alberta/Calgary) etc. OID is the owner identification that can be a person or company’s name or registration number. VRP is the vehicle registration plate number or license tag number.

One can argue that the OID and VRP are sufficient to uniquely identify a vehicle. However, there may be the case where some applications may require contents from the specific set of vehicles or vehicles registered with a company, state or region. Also, it will be difficult to aggregate CNs in the routing table for different types of DCs generated in a large-scale VN. That is why this hierarchical prefix format helps in aggregation to minimize the routing table size, as shown in Figure 2. The rest of the hierarchical section signifies the information about the DC itself that includes: • •

TYPE is the general type of DC produced or originated by the vehicle. This includes video, text, image, audio, etc. Sub-Type is the specific DC type under the category of Type. For example avi, mpeg, and mp4 lie under video category and gif, jpg, and png belong to the image category. SP/TEM are the SPatial and TEMporal attributes of the DC such as the image of a site/place (e.g. geolocation or name of the place) taken at time instance (time and date in UNIX format). SP/TEM also defines the range information during or for which the DC was created or related. For example, the movie recorded while driving from L1 (x1 , y1 ) to L2 (x2 , y2 ) and during t1 and t2 is represented as L1 ∼ L2 /t1 ∼ t2 . Attrs.(Attributes) part of CN shows the additional information about the DC. For example, an image in the jpg format with a resolution n*m, aperture a, focal length l, flash ON, name Times Square (TSQR) etc. are added in the name as .../image/jpg/L1/t1/m*n/a/l/ON/TSQR.


1 AKgqS8BJ7… PsLg6zOzi… …… vhn://us/nv/lv/smith/NVD001/ 2 uSwjkHZ… GGNzfm8… ……

Infrastructure Network


RSU-1 Vehicle (B)

Vehicle (A) US/CA/LA/John/CAL001/

Vehicle (C)

US/NV/LV/Smith/NVD001/ CA/AB/CG/Alvis/00A999/

Prefix Signature Scheme Prefix Signature Scheme vhn:// us/ca/la/john/CAL001/image/… AKgqS8BJ7… vhn:// us/nv/lv/smith/NVD0001/text/… uSwjkHZ… vhn:// us/ca/la/john/CAL001/video/… PsLg6zOzi… vhn:// us/nv/lv/smith/NVD0001/text/… GGNzfm8… … … … … … …

Fig. 2.

Example of CN Aggregation in VICN.

3) Hash/Flat Section: The Hash/Flat part of CN holds the full or partial value of the hash or signature that is either generated from the content item, its attributes, or public–key hash value of the content item or the information related to it. This information uniquely identifies the content item and is presented in base64 format. III.


The proposed naming scheme uniquely identifies each DC generated at every vehicle by combining the hierarchical and flat parts of the CN. The proposed CN also helps in aggregation and minimization of the routing table entries, as shown in Figure 2. It shows that the CNs produced by vehicles (A) and (B) can easily be aggregated at any Road Side Unit (RSU) or any vehicle (CNs aggregated at RSU-1 are shown in Figure 2). The comparison of hash value and/or prefix in the routing table as well as in the received interest packet will be easily routed by the RSU-1 further in the VICN via assigned face number. The hash value along with the aggregated hierarchical part of the CN also avoids the suffix hole problem. The temporal and spatial scopes as well as the range information satisfy the fundamental requirements of the VICN applications. The query can be sent by the application to find contents such as: vhn://us/ca/la?TYPE=image&TEM=12345, to get images captured at 12345 UNIX time–stamp style. IV.


We proposed a naming scheme for VICN that uniquely identifies the digital contents generated by the vehicles. The content aggregation and routing can easily be performed based on this scheme. In future, we want to analyze the routing and name resolution latency of the proposed scheme in different VICN environments. R EFERENCES [1] M. Amadeo, C. Campolo, and A. Molinaro, “Content-centric networking: is that a solution for upcoming vehicular networks?” In Proc. of 9th ACM International Workshop on Vehicular Inter-networking, Systems, and Applications (VANET ’12). New York, NY, USA, pp.99–102, 2012. [2] M. Amadeo, C. Campolo, and A. Molinaro, “Design and analysis of a transport-level solution for content-centric VANETs,” IEEE International Conference on Communications Workshops (ICC’13), 2013, pp.532–537, 9-13 June 2013. [3] H. Zhang, W. Quan, J. Guan, C. Xu, and F. Song “Uniform information with a hybrid naming (hn) scheme” ICNRG Internet draft, work in progress, April 5, 2014.

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