WindowTree: Explicit congestion notification and route labeling for congestion control in content centric networks

Content Centric Networking has gained in popularity in recent years as a novel networking paradigm based on the idea of named content. Individual chunks of data are given routable names and can be cached throughout the network by intermediate nodes. In contrast with today's internet, where two hosts establish a connection before sharing data, a content centric network allows any network node that possess requested content to provide it directly to the requesting client. This creates an inherently multipath environment, where requested data can arrive over any path at any time. Congestion control protocols are necessary to ensure maximal fairness, reliability, and efficiency of these data transfers. Several proposals have been made for protocols to provide congestion control in the content centric context, however many of these protocols fail to fully adapt to the multipath nature of content centric networks (CCNs).;We propose a novel congestion control protocol, WindowTree, that adapts existing congestion control concepts found in TCP New Reno to the receiver driven content centric context. WindowTree also includes an Explicit Congestion Notification (ECN) mechanism by which the network can deliver early information about increasing congestion to the receiver, allowing the receiver to adjust accordingly to provide more efficient transfers. The protocol utilizes information about the network topology delivered through the use of route labeling, in which individual network nodes identify themselves and their relative layouts to the receiver. The WindowTree protocol maintains a tree of congestion windows derived from this topology information that enables it to adapt its behavior in response to network changes that affect each individual network source. Route labeling and shared congestion windows, combined with ECN marking, allows WindowTree to drastically reduce loss and more fully fulfill the requirements of a network dominated by the multipath data flows that exist in a CCN.