MultiNext: Measuring Concurrent Multipath Transmissions in an Experimental Facility
Today, data transport is achieved mainly by the IP (Internet Protocol) protocol. Its routing feature is used to accomplish scalability in the connection of local subnets and end systems. The IP protocol assumes that the interconnecting nodes (i.e. the routers) and the actual transport resources (i.e. the links) are stable and change only in case of faults. The Future Internet will also consist of interconnected subnets and interconnecting nodes. However, the availability of these resources is expected to be provided for a certain lifetime and their capabilities are highly variable. Networks that are based on the model of temporal leasing of variable resources are referred to as federated networks and technologies that enable the save sharing of such network resources are denoted as Network Virtualization (NV) mechanisms.
A major task when creating federated networks for data transport is the selection of resources. The selection has to consider the temporal availability of the resources. Therefore, a measurement-based scheme for selecting the resources is needed. The scheme should adapt the federated transport network to the variable demand for resources as well as to the currently available resources. In addition, the scheme has to scale sufficiently such that it can be applied in large networks.
The concept of Transport Virtualization (TV) enhances the capabilities of future networks. TV can be considered as an alternative mode of Network Virtualization. While NV typically facilitates the sharing of resources, TV creates virtual network based on the aggregation of resources. The simplest form of TV is achieved by collecting multiple transport resources (even from different virtual networks or providers) and selecting the best resources for exclusive or concurrent use. However, the selection and application of concurrent paths (also known as Concurrent Multipath, CMP) is complex and its impact on the transmission is non-intuitive. Path length diversity of different concurrent paths inevitably introduces out-of-order packet delivery. In order to understand the fundamental behavior of resource selection in TV in CMP environments, it is necessary define, verify, and investigate mathematical models for the analysis of packet re-ordering in CMP.
An architecture to enable concurrent multipath transmissions for TV, the so called SORA architecture, was presented by Lane and Nakao. The use of concurrent multipath (CMP) transmissions will bring exceptional advantages to networks, such as higher throughput and increased resilience. However, CMP will introduce additional complexity which has to be understood. First, CMP transmission will inevitably introduce out-of-order packets due to different stochastic packet delay characteristics on the paths. The re-ordering has to be compensated by buffering at the destination, possibly leading to increased e2e delay. Second, the different stochastic delay processes on the paths can amend each other in their negative effects on out-of-order packets. Third, the strength and occurrences of these combination effects are highly non-intuitive.
The importance of multipath transmissions for the Future Internet is reflected also by current research efforts in the IETF and other FP7 projects. Currently the LEDBAT WG within the IETF investigates multi-path TCP. It should be noted that at the last IETF meeting in Stockholm preparations a BoF on multipath TCP was successfully organised. This BoF builds on results obtained within the TRILOGY FP7 project showing that performance between end hosts can be improved by using different paths in parallel.
The aim of the proposed specific EuroNF project is threefold:
- To determine how measurements (e.g. one way delay, throughput, etc.) can be conducted within experimental facilites
- To perform measurements on the relevant parameters within the SORA Architecture
- To link theoretical mathematical models with the obtained measurements
- February 5th 11-12am, Kick-off call, organizational matters
- March 9th 1pm - 2pm, Use of experimental facilities, measurement tools
- April 21st 11-12am, Measurement setup
- May 20th 11.30-12.30am, Preparation of Kick-off Meeting
- June 16th 11.30-12.30am, Discussion of suitable measurement enhancements
- July 22nd 11.30-12.30am, Discussion of the first measurements and how to proceed with the measurements
- September 28th 11.30-12.30am, Discussion measurements, discussion of possible submissions / suitable conferences/workshops
- November 11th, Discussion FIA Book Chapter
Kick-Off meeting, Juni 2nd, 2010, co-located with Euro-NF NGI2010 in Paris
Internal project meeting, August 2nd, 2010, during Euroview 2010 in Wuerzburg
Artikel in einem Journal, einer Zeitung oder einem Magazin
Hoßfeld, T., Liers, F., Schatz, R., Staehle, B., Staehle, D., Volkert, T., Wamser, F.: Quality of Experience Management for YouTube: Clouds, FoG and the AquareYoum. PIK - Praxis der Informationverarbeitung und -kommunikation (PIK). (2012).