Re-feedback: freedom with accountability for causing congestion in a connectionless internetwork

This dissertation concerns adding resource accountability to a simplex internetwork such as the Internet, with only necessary but sufficient constraint on freedom. That is, both freedom for applications to evolve new innovative behaviours while still responding responsibly to congestion; and freedom for network providers to structure their pricing in any way, including flat pricing. The big idea on which the research is built is a novel feedback arrangement termed ‘re-feedback’. A general form is defined, as well as a specific proposal (re-ECN) to alter the Internet protocol so that self-contained datagrams carry a metric of expected downstream congestion. Congestion is chosen because of its central economic role as the marginal cost of network usage. The aim is to ensure Internet resource allocation can be controlled either by local policies or by market selection (or indeed local lack of any control). The current Internet architecture is designed to only reveal path congestion to end-points, not networks. The collective actions of self-interested consumers and providers should drive Internet resource allocations towards maximisation of total social welfare. But without visibility of a cost-metric, network operators are violating the architecture to improve their customer’s experience. The resulting fight against the architecture is destroying the Internet’s simplicity and ability to evolve. Although accountability with freedom is the goal, the focus is the congestion metric, and whether an incentive system is possible that assures its integrity as it is passed between parties around the system, despite proposed attacks motivated by self-interest and malice. This dissertation defines the protocol and canonical examples of accountability mechanisms. Designs are all derived from carefully motivated principles. The resulting system is evaluated by analysis and simulation against the constraints and principles originally set. The mechanisms are proven to be agnostic to specific transport behaviours, but they could not be made flow-ID-oblivious

Enforcing receiver-driven multicast congestion control using ECN-Nonce

Providing robust congestion control is essential prior to Internet-wide deployment of long-lived multicast flows. This thesis therefore reviews currently proposed techniques, and identifies key issues. It then proposes a new framework that enables the network to police and enforce correct congestion behaviour. Receiver-driven layer multicast congestion control is especially vulnerable to misbehaving receivers. Countering these problems demands a new paradigm to enforce correct receiver behaviour. A framework based on Explicit Congestion Notification (ECN)-nonce is proposed, which preserves the ability to work with system/network heterogeneity in the multicast tree, mandates layered multicast receivers to feedback nonce-reports in an arrayed form. Appropriate behaviour may be enforced in the new framework by introducing selected border routers in the multicast tree, known as enforcers. This also avoids practical limitations requiring an upgrade to all edge routers, and allows local service providers to protect their own network. The approach uses re-active policing. This can not prevent receivers joining under congestion, but reacts by preventing forwarding of specific groups within a reasonable delay. This approach eliminates the need for secure transfer of information from the sender to the enforcing routers and avoids a need to upgrade the IGMP and PIM protocols. The method is compatible with using ECN when Active Queue Management (AQM), which has benefit when using Forward Error Correction (FEC) based reliability. This framework was analysed using simulation. The thesis also analyses some important related performance issues for congestion-controlled multicast transport protocols, considering issues such as excessive overshoot and poor congestion response in delay-diversified networks using the IETF NACK-Oriented Reliable Multicast (NORM) framework and an unnecessary congestion response with heterogeneous receivers in Asynchronous Layered Coding (ALC) framework.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

LIPIcs, Volume 261, ICALP 2023, Complete Volume

LIPIcs, Volume 261, ICALP 2023, Complete Volum