Curtis David
Professor Jain
Mobility First Report
August, 30, 2014
In today’s society, everything that we do revolves around the Internet, from our money
transactions to all forms of entertainment. Like everything else in the universe the current design
of the Internet architecture is not perfect. The current design has many flaws which could be
detrimental to the future of the network. Why not redesign its current architecture such that it
stays in sync with today’s society? The current architecture follows the narrow waist model
where IP is at the waist. Today with the high demand for data, users are interested “what” the
data is and not “where" the data is located. This is where Named Data Network (NDN) takes
over by getting the “what” not the “where”. This report discusses NDN and its architecture and
also content security.
The rise of social media and multimedia changed the entire design of the network from a
communication system to a distribution system. Examples of such distribution systems would be
YouTube, Facebook, and Instagram. People searching for videos (movies, snippets, clips) are
interested in what the video entails rather than where it is located. The current IP structure
contains source and destination addresses, while NDN on the other hand contains names which
would then return the data. There are two types of NDN packets (Interest and Data) which both
contain names. The distinction between the two is that the data packet contains a digital signature
which securely binds the name to the data. A user sends out interest packet in the form of data
names without giving the location of the data. Each NDN router contains a Forwarding Interest
Base (FIB), Pending Interest Table (PIT) and a cache of temporary data. The PIT maintains the
names of the interest packets, the incoming interface as well as the outgoing interface. The FIB
on the other hand forwards the interest onto the next router.
To simply put it, when a request (interest) is received, it is checked in the cache. If it is
already in the cache then it is returned, else the PIT checks if there was a previous entry. If there
was a previous entry then the incoming interface is added to the PIT. If the PIT does not have an
entry for the interest, the interest is added to the PIT and then forwarded. If at any time there is
no interest found in the PIT, the NDN node sends out a NACK which contains an error code
stating that the interest was not found. NDN has a unique way unlike IP of handling Traffic
congestion. Whenever there is congestion on a NDN router from any neighbor the given router
slows down or stops sending interest packets to that neighbor. This is called one-to-one flow
balance. Congestion is at a minimum because the data and interest packets don’t loop primarily
due to the fact that they follow the reverse path when transmitting. Furthermore, there are two
important aspects of the NDN network. They are routing and recognition. Routing finds what the
data entails and recognition identifies the data. Just like the current architecture NDN face many
challenges which include Scalability routing on names, signature efficiency, trust models for data
centric networks and privacy protection of content.
Privacy is a necessity today, especially on the Internet. Many individuals maliciously attack
networks to show how weak a system is, while others purposely attack a network to steal
personal information which could later sell on the black market. The NDN structure has a theory
which prevents content poisoning along the network. Content security at the application layer
should be able to deal with poisoned content by demanding an “interest packet to reflect the
public key of the producer” (Ghali, 4). This is known as Interest Key Binding Rule. The public
key could contain common prefixes. Having a common prefix as a form of trust management is
all up to the application. In theory this appears to be a working solution but in reality there are
implications. The biggest implication is client software.
To combat this implication a globally unique NDN key name can be assigned to special
interest packets. Assigning a unique public key to special interest packets only minimize content
poisoning to a certain extent. NDN offers no means to ask routers to flush fake content from
their cache. Research is still being done to eliminate point content from entering the network.
Data in the NDN network is multi-path which allows consumers to discover more than one data
path as well as make their selections. Another issue NDN faces but tries to eliminate is content
provider mobility. The provider should be able to move around the network without facing any
issues. Whenever the network wants to discover content it uses name as a label to route. This
becomes problematic when the content provider moves. A locator (contains access points and the
address of the provider) is added to interest packets. To ensure that routers get the locator of an
interest packet, a mapping system is implemented. A mapping system basically maps a name to a
locator. In addition a mapping system records updates after a content provider moves to a new
access point₁. Providers in this case have both a home and access AS, which most times are the
same. Whenever providers move they send an update to the previous access mapping system of
its new location. Providers notify home mapping systems to update their record. This maintains
mobility throughout the network. If an interest is sent out the NDN stack searches the mapping
system to get the locator of the desired packet. After the interest packet locator area is filled. This
process is repeated until the original data is found. NDN is a unique network structure because it
creates solution to the loop holes of the current Internet architecture. This research topic which
would in the soon to the near future redesigns the entire IP thin waist model. The current network
continues to grow exponentially due to the rise of mobiles and tables. The demand is no longer
the source and destination addresses; instead consumers are more concerned about the content.
Works Cited
₁Jun Bi †, Pingping Lin, You Wang, Xiaoke Jiang, Zhaogeng, “A Content Provider Mobility
Solution of Named Data Networking”.
Muhammad Tahir, Zain ul Abidin Jaffri, Zeeshan Ahmad, “Named Data Networking (NDN),
New Approach to Future Internet Architecture Design: A Survey“ College of
Communication Engineering, Chongqing University, P.R.Chin School of Software
Engineering, Chongqing University, P.R.China. Nov 30th, 2013.
Cesar Ghali, Ersin Uzun, Gene Tsudik, “Elements of Trust in Named-Data Networking”
University of California, Irvine University of California, Irvine Palo Alto Research Center.