Stateless Core Research Articles

Scalable Flow Isolation With Work Conserving Stateless Core Fair Queuing for Deterministic Networking

Scalable Flow Isolation With Work Conserving Stateless Core Fair Queuing for Deterministic Networking

Keyflow: a prototype for evolving SDN toward core network fabrics

The large bulk of packets/flows in future core networks will require a highly efficient header processing in the switching elements. Simplifying lookup in core network switching elements is capital to transport data at high rates and with low latency. Flexible network hardware combined with agile network control is also an essential property for future software-defined networking. We argue that only further decoupling between the control and data planes will unlock the flexibility and agility in SDN for the design of new network solutions for core networks. This article proposes a new approach named KeyFlow to build a flexible network-fabricbased model. It replaces the table lookup in the forwarding engine by elementary operations relying on a residue number system. This provides us tools to design a stateless core network by still using OpenFlow centralized control. A proof of concept prototype is validated using the Mininet emulation environment and OpenFlow 1.0. The results indicate RTT reduction above 50 percent, especially for networks with densely populated flow tables. KeyFlow achieves above 30 percent reduction in keeping active flow state in the network.

Approximate fair bandwidth sharing in high-speed multimedia networks

Existing fair-queuing algorithms use complicated flow management mechanisms, thus making them expensive to deploy in current high-bandwidth networks. In this paper we propose a scalable SCORE (stateless core) approach to provide fair bandwidth sharing for a traffic environment composed of TCP and UDP flows. At an edge router, the arrival rates of each flow are estimated, each packet then being labelled with this estimate. The outgoing link's fair share at a router is estimated based on UDP traffic. Probabilistic dropping is used to regulate those flows that send more than the fair share. At a core router, all the functions performed by an edge router are repeated, excluding the flow rate estimation. The simulation results show that the degree of fairness achieved by the proposed solution is comparable to that of other algorithms, but with a lower implementation cost.

Adaptive CSFQ: determining the packet dropping probability adaptively for achieving fair bandwidth allocations in SCORE networks

In stateless core (SCORE) networks, edge routers maintain per-flow state while core routers do not. Core stateless fair queuing (CSFQ) has been proposed for approximating the operation of per-flow queuing techniques in SCORE networks. However, the packet dropping probability offered by CSFQ suits only UDP flows. Thus, CSFQ cannot achieve fair bandwidth allocation for TCP flows. This paper proposes adaptive CSFQ (ACSFQ). The packet dropping probability in ACSFQ is determined adaptively based on the flow arrival rate, the fair share rate, and the current queue length. It well supports TCP flows as well as UDP flows. We compare ACSFQ to CSFQ in terms of fair bandwidth allocation. This paper also proposes how to identify and penalize unresponsive flows without managing their flow state. The method is simple to realize because only the packet dropping probability is changed.

Theories and models for Internet quality of service

We survey advances in theories and models for Internet quality of service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also discussed. We then turn our attention to statistical performance guarantees and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some QoS differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support.