CONGESTION CONTROL IN CONTENT CENTRIC NETWORKS

The Hong Kong University of Science and Technology
Department of Computer Science and Engineering


PhD Thesis Defence


Title: "CONGESTION CONTROL IN CONTENT CENTRIC NETWORKS"

By

Mr. Amuda James ABU


Abstract

Today’s Internet is no longer fit for the user traffic patterns that it is 
serving. To remedy this cognitive mismatch between the service platform 
and the traffic it serves, several future Internet architectures such as 
Content-Centric Networking (CCN) have been proposed recently with the aim 
of re-engineering the Internet towards supporting content-oriented 
communication. With the mechanisms to transform the Internet from being 
host-centric to becoming content-centric well spelt-out in the CCN 
standard, the problem of how to manage congestion and control traffic 
flows in CCN is still left open. Existing congestion control mechanisms 
for the current Internet have been shown to be ill-suited for CCN making 
the case for a clean-slate design of congestion control and traffic 
management mechanisms for CCN.

In this thesis, we identify that congestion in CCN can take place not only 
in the transmission buffer but also in the pending interest table (PIT), a 
data structure that keeps track of all requests received from downstream 
nodes and forwarded to upstream nodes. Keeping this in mind, we make three 
contributions in this thesis: First, we characterize the PIT occupancy 
distribution using a 2- dimensional continuous-time Markov chain model to 
study the impact of PIT entry timeout and interest retransmission on the 
interest blocking probability. Second, given the dependence of the PIT 
occupancy on the PIT entry timeout and interest retransmission, we 
investigate the performance of two types of routers in lossy networks: 
no-rtx routers that do not retransmit pending interests upon timeout, and 
rtx routers that do retransmit pending interests periodically. Based on 
this, we further introduce a novel adaptive method to estimate the PIT 
entry timer that relies on the data chunk response delays to replace the 
currently used fixed-value method introduced in CCN. Finally, identifying 
that content requesters should be responsible for retransmitting timeout 
requests and that estimates of the retransmission timeout should reflect 
the network load conditions, we propose a novel congestion control 
mechanism for CCN that takes into account both the PIT and the transmit 
buffer. Using the PIT occupancy as a good estimator for the data flight 
size to arrive to the node in the near future, we design a congestion 
avoidance mechanism that adjusts the request rate based on anticipated 
congestion.


Date:			Thursday, 24 November 2016

Time:			10:30am - 12:30pm

Venue:			Room 4472
  			Lifts 25/26

Chairman:		Prof. Jiang Xu (ECE)

Committee Members:	Prof. Brahim Bensaou (Supervisor)
  			Prof. Pan Hui
  			Prof. Jogesh Muppala
  			Prof. Danny Tsang (ECE)
  			Prof. Salil Kanhere (U of NSW)


**** ALL are Welcome ****