CONGESTION CONTROL IN CONTENT CENTRIC NETWORKS

PhD Thesis Proposal 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 to this cognitive mismatch between the service platform 
and the traffic it serves, several future Internet architectures have been 
proposed recently with the aim of re-engineering the Internet towards 
supporting content-oriented communication. Of all the proposed 
architectures Content-Centric Networking (CCN) and Named-Data Networking 
(NDN) are the two most promising proposals largely due to the significant 
attention they have drawn from networking researchers in the past few 
years. 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 are ill-suited for CCN due to data packet 
response delay volatility caused by in-network caching and 
one-source-many-receivers communication pattern caused by request 
aggregation. Clean-slate congestion control and traffic management 
mechanisms for CCN are needed.

In this work, 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. As such we strive to propose novel 
congestion control and traffic management mechanisms that take into 
account the PIT and buffer occupancies. Along this line, we make three 
contributions in this thesis:

First, we investigate the impact of losses and retransmission on the PIT 
occupancy. As such we characterize the PIT occupancy distribution using a 
2-dimensional continuous-time Markov chain model and use the 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 retransmits 
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, observed over a window of samples, 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. In our mechanism, the controller takes into 
account interest aggregation in upstream nodes to avoid excessive 
congestion window reduction.


Date:			Tuesday, 30 August 2016

Time:                  	2:00pm - 4:00pm

Venue:                  Room 2612A
                         (lifts 31/32)

Committee Members:	Dr. Brahim Bensaou (Supervisor)
  			Dr. Pan Hui (Chairperson)
 			Dr. Jogesh Muppala
  			Prof. Danny Tsang (ECE)


**** ALL are Welcome ****