Projects
TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet

The Internet as we know it today has been optimised to transmit large amounts of data or “greedy streams” - the type of transmission involved in downloading large files or watching online TV. Up to recently, Internet research has primarily focused on speeding up transmission by increasing bandwidth so that more data can be transferred at a given time. The most common Internet protocol for transmitting data, TCP, works by apportioning available bandwidth among the users present at any given time. The downside is that this can cause latency, or delay, in data transmissions. For time-dependant applications such as Internet telephony and online gaming, time lags as short as a few hundred milliseconds can create big problems.
In real-time gaming against other players online, data is transmitted only when an action such as moving around or shooting at someone is performed. The same principle applies for stock market programs when placing orders or requesting share prices, for example, via the trading systems in use the Norwegian Stock Exchange. In such cases it is essential to avoid any delay.
Applications like these often generate what are called thin data streams. With thin streams only small amounts of data are transmitted at a time and there can be extended periods between data packages. Such thin streams cannot compete with greedy traffic for bandwidth. Thin streams almost invariably come up short against greedy traffic and users are left to cope with the resulting lag. We want a more balanced Internet where thin streams don’t always lose out. This can be achieved by adding speed to the mix, instead of only thinking about maximising throughput.
Final goal:
Locate the sources of increased delay and loss rates for thin streams along the entire path of a data packet. Develop mechanisms that reduce the latency for time-dependent thin-stream applications without having to change current Internet infrastructure.
Funding source:
The Research Council of Norway
All partners:
- Coop. Assoc. for Internet Data Analysis (CAIDA)
- FUNCOM OSLO AS
- Universitetet i Oslo
- Karlstads Universitet
- UNINETT AS
- University of Kaiserslautern
- CISCO SYSTEMS NORWAY AS
Publications for TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet
Technical reports
Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Architecture
Internet Engineering Task Force, 2017.Status: Submitted
Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Architecture
This document describes the L4S architecture for the provision of a new service that the Internet could provide to eventually replace best efforts for all traffic: Low Latency, Low Loss, Scalable throughput (L4S). It is becoming common for all (or most) applications being run by a user at any one time to require low latency. However, the only solution the IETF can offer for ultra-low queuing delay is Diffserv, which only favours a minority of packets at the expense of others. In extensive testing the new L4S service keeps average queuing delay under a millisecond for all applications even under very heavy load, without sacrificing utilization; and it keeps congestion loss to zero. It is becoming widely recognized that adding more access capacity gives diminishing returns, because latency is becoming the critical problem. Even with a high capacity broadband access, the reduced latency of L4S remarkably and consistently improves performance under load for applications such as interactive video, conversational video, voice, Web, gaming, instant messaging, remote desktop and cloud-based apps (even when all being used at once over the same access link). The insight is that the root cause of queuing delay is in TCP, not in the queue. By fixing the sending TCP (and other transports) queuing latency becomes so much better than today that operators will want to deploy the network part of L4S to enable new products and services. Further, the network part is simple to deploy - incrementally with zero-config. Both parts, sender and network, ensure coexistence with other legacy traffic. At the same time L4S solves the long-recognized problem with the future scalability of TCP throughput.
This document describes the L4S architecture, briefly describing the different components and how the work together to provide the aforementioned enhanced Internet service.
Afilliation | Communication Systems |
Project(s) | TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2017 |
Number | draft-briscoe-tsvwg-l4s-arch-01 |
Date Published | 03/2017 |
Publisher | Internet Engineering Task Force |
Keywords | Algorithms, Analysis, AQM, Congestion Avoidance, congestion control, Data Communication, Design, Evaluation, Internet, latency, networks, Performance, QoS, Scaling, tcp |
Notes | (Work in Progress) |
URL | https://tools.ietf.org/html/draft-briscoe-tsvwg-l4s-arch |
Adding Explicit Congestion Notification (ECN) to TCP Control Packets
Internet Engineering Task Force, 2017.Status: Submitted
Adding Explicit Congestion Notification (ECN) to TCP Control Packets
This documents explores the possibility of adding ECN support to TCP control packets.
Afilliation | Communication Systems |
Project(s) | TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2017 |
Number | draft-bagnulo-tcpm-generalized-ecn-00 |
Date Published | 04/2017 |
Publisher | Internet Engineering Task Force |
Keywords | congestion control, Data Communication, Internet, latency, networks, Protocols, QoS, Quality of Service, Rate Control, Security, Signalling, Standards |
Notes | (Work in Progress) |
URL | https://tools.ietf.org/html/draft-bagnulo-tcpm-generalized-ecn |
TRILL: ECN (Explicit Congestion Notification) Support
Internet Engineering Task Force, 2017.Status: Accepted
TRILL: ECN (Explicit Congestion Notification) Support
Explicit congestion notification (ECN) allows a forwarding element to notify downstream devices, including the destination, of the onset of congestion without having to drop packets. This document extends this capability to TRILL switches, including integration with IP ECN.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2017 |
Number | draft-ietf-trill-ecn-support-02 |
Date Published | 03/2017 |
Publisher | Internet Engineering Task Force |
Keywords | Architecture, congestion, Control, Data Communication, Encapsulation, Explicit Notification, Incremental Deployment, Internet, Layering, networks, Protocol Engineering, QoS, Tunnels |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-ietf-trill-ecn-support |
Proceedings, refereed
PI2 : A Linearized AQM for both Classic and Scalable TCP
In Proc. ACM CoNEXT 2016. New York, NY, USA: ACM, 2016.Status: Published
PI2 : A Linearized AQM for both Classic and Scalable TCP
This paper concerns the use of Active Queue Management (AQM) to reduce queuing delay. It offers insight into why it has proved hard for a Proportional Integral (PI) controller to remain both responsive and stable while controlling `Classic' TCP flows, such as TCP Reno and Cubic. Due to their non-linearity, the controller's adjustments have to be smaller when the target drop probability is lower. The PI Enhanced (PIE) algorithm attempts to solve this problem by scaling down the adjustments of the controller using a look-up table. Instead, we control an internal variable that is by definition linearly proportional to the load, then post-process it into the required Classic drop probability---in fact we show that the output simply needs to be squared. This allows tighter control, giving responsiveness and stability better or no worse than PIE achieves, but without all its corrective heuristics.
With suitable packet classification, it becomes simple to extend this PI2 AQM to support coexistence between Classic and Scalable congestion controls in the public Internet. A Scalable congestion control ensures sufficient feedback at any flow rate, an example being Data Centre TCP (DCTCP). A Scalable control is linear, so we can use the internal variable directly without any squaring, by omitting the post-processing stage.
We implemented PI2 as a Linux qdisc to extensively test our claims using Classic and Scalable TCPs.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2016 |
Conference Name | Proc. ACM CoNEXT 2016 |
Pagination | 105-119 |
Date Published | 12/2016 |
Publisher | ACM |
Place Published | New York, NY, USA |
ISBN Number | 978-1-4503-4297-1 |
Keywords | Algorithms, Analysis, AQM, Congestion Avoidance, congestion control, Data Communication, Design, Evaluation, Internet, latency, networks, Performance, QoS, Scaling, tcp |
URL | http://dl.acm.org/citation.cfm?doid=2999572.2999578 |
DOI | 10.1145/2999572.2999578 |
Technical reports
Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Problem Statement
Internet Engineering Task Force, 2016.Status: Submitted
Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Problem Statement
This document motivates a new service that the Internet could provide to eventually replace best efforts for all traffic: Low Latency, Low Loss, Scalable throughput (L4S). It is becoming common for all (or most) applications being run by a user at any one time to require low latency. However, the only solution the IETF can offer for ultra-low queuing delay is Diffserv, which only favours a minority of packets at the expense of others. In extensive testing the new L4S service keeps average queuing delay under a millisecond for all applications even under very heavy load, without sacrificing utilization; and it keeps congestion loss to zero. It is becoming widely recognized that adding more access capacity gives diminishing returns, because latency is becoming the critical problem. Even with a high capacity broadband access, the reduced latency of L4S remarkably and consistently improves performance under load for applications such as interactive video, conversational video, voice, Web, gaming, instant messaging, remote desktop and cloud-based apps (even when all being used at once over the same access link). The insight is that the root cause of queuing delay is in TCP, not in the queue. By fixing the sending TCP (and other transports) queuing latency becomes so much better than today that operators will want to deploy the network part of L4S to enable new products and services. Further, the network part is simple to deploy - incrementally with zero-config. Both parts, sender and network, ensure coexistence with other legacy traffic. At the same time L4S solves the long-recognized problem with the future scalability of TCP throughput.
This document explains the underlying problems that have been preventing the Internet from enjoying such performance improvements. It then outlines the parts necessary for a solution and the steps that will be needed.
Afilliation | Communication Systems |
Project(s) | TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2016 |
Number | draft-briscoe-tsvwg-aqm-tcpm-rmcat-l4s-problem-02 |
Date Published | 07/2016 |
Publisher | Internet Engineering Task Force |
Keywords | Algorithms, Analysis, AQM, Congestion Avoidance, congestion control, Data Communication, Design, Evaluation, Internet, latency, networks, Performance, QoS, Scaling, tcp |
Notes | (Work in Progress) |
URL | https://tools.ietf.org/html/draft-briscoe-tsvwg-aqm-tcpm-rmcat-l4s-problem |
Propagating Explicit Congestion Notification Across IP Tunnel Headers Separated by a Shim
Internet Engineering Task Force, 2016.Status: Accepted
Propagating Explicit Congestion Notification Across IP Tunnel Headers Separated by a Shim
RFC 6040 on "Tunnelling of Explicit Congestion Notification" made the rules for propagation of ECN consistent for all forms of IP in IP tunnel. This specification extends the scope of RFC 6040 to include tunnels where two IP headers are separated by a shim header that cannot stand alone.
Afilliation | Communication Systems |
Project(s) | TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2016 |
Number | g-rfc6040update-shim-00 |
Date Published | 11/2016 |
Publisher | Internet Engineering Task Force |
Keywords | Architecture, congestion, Control, Data Communication, Encapsulation, Explicit Notification, Internet, Layering, Management, Monitoring, networks, Protocol Engineering, QoS, Tunnels |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-briscoe-tsvwg-rfc6040update-shim |
More Accurate ECN Feedback in TCP
Internet Engineering Task Force, 2016.Status: Accepted
More Accurate ECN Feedback in TCP
Explicit Congestion Notification (ECN) is a mechanism where network nodes can mark IP packets instead of dropping them to indicate incipient congestion to the end-points. Receivers with an ECN-capable transport protocol feed back this information to the sender. ECN is specified for TCP in such a way that only one feedback signal can be transmitted per Round-Trip Time (RTT). Recently, new TCP mechanisms like Congestion Exposure (ConEx) or Data Center TCP (DCTCP) need more accurate ECN feedback information whenever more than one marking is received in one RTT. This document specifies an experimental scheme to provide more than one feedback signal per RTT in the TCP header. Given TCP header space is scarce, it overloads the three existing ECN-related flags in the TCP header and provides additional information in a new TCP option.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2016 |
Number | draft-ietf-tcpm-accurate-ecn-02 |
Date Published | 10/2016 |
Publisher | Internet Engineering Task Force |
Keywords | Architecture, congestion control, Data Communication, Internet, networks, Protocols, QoS, Quality of Service, Rate Control, Security, Signalling, Standards |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn |
DualQ Coupled AQM for Low Latency, Low Loss and Scalable Throughput
Internet Engineering Task Force, 2016.Status: Submitted
DualQ Coupled AQM for Low Latency, Low Loss and Scalable Throughput
Data Centre TCP (DCTCP) was designed to provide predictably low queuing latency, near-zero loss, and throughput scalability using explicit congestion notification (ECN) and an extremely simple marking behaviour on switches. However, DCTCP does not co-exist with existing TCP traffic---throughput starves. So, until now, DCTCP could only be deployed where a clean-slate environment could be arranged, such as in private data centres. This specification defines `DualQ Coupled Active Queue Management (AQM)' to allow scalable congestion controls like DCTCP to safely co-exist with classic Internet traffic. The Coupled AQM ensures that a flow runs at about the same rate whether it uses DCTCP or TCP Reno/Cubic, but without inspecting transport layer flow identifiers. When tested in a residential broadband setting, DCTCP achieved sub-millisecond average queuing delay and zero congestion loss under a wide range of mixes of DCTCP and `Classic' broadband Internet traffic, without compromising the performance of the Classic traffic. The solution also reduces network complexity and eliminates network configuration.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2016 |
Number | draft-briscoe-tsvwg-aqm-dualq-coupled-00 |
Date Published | 10/2016 |
Publisher | Internet Engineering Task Force |
Keywords | Algorithms, Analysis, AQM, Congestion Avoidance, congestion control, Data Communication, Design, Evaluation, Internet, latency, networks, Performance, QoS, Scaling, tcp |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-briscoe-tsvwg-aqm-dualq-coupled |
RITE: Reducing Internet Transport Latency

RITE proposes to remove the root causes of unnecessary latency over the Internet. Whilst time-of-flight delay is inevitable, greater delays can result from interactions between transport protocols and buffers. It is this that RITE are tackling.
In RITE we aim to explore and develop changes to the existing infrastructure, so that the changes can be deployed without having to redesign the Internet. Latency can arise from a myriad of different reasons. As an example, setting up all connections for loading a dynamic web page, including DNS and background database connections, may delay the loading of the page with several extra RTTs. This will, unnecessarily, reduce the load speed. In RITE we analyse network traces and investigate network components and operating systems to locate the bottlenecks. RITE researchers use what we learn from this investigation to develop mechanisms that can be deployed in the existing infrastructure to improve the latency for generic Internet use, as well as for our chosen use-cases.
RITE has a strong focus on standardisation, and works through the IETF to transform the results of the project into standards. The partners also aim to contribute new code to the Linux kernel, making the improvements available to the public.
The project is driven by three specific use-cases: Financial applications, networked games and interactive video. These are applications with very different characteristics, but all have strict latency requirements. The industry partners will benefit from reduced Internet latency in a wide range of applications that they either provide infrastructure or hardware for, ultimately benefitting their customers.
Reducing latency may pave the way for new, exiting uses of the Internet. Applications that to this point have been unthinkable may be realised with consistent low-latency service. Also, lower latency for our time-dependent use-cases will improve the experience for the users drastically, giving our industry partners a competitive benefit.
Final goal:
The ultimate goal of RITE is to bring stable, low-latency services to Internet users and businesses, and lay the groundwork for consistent low latency in Internet communication.
Starting by better understanding how latency is traded off for throughput and what generates latency in the Internet, we will investigate the Internet systems to find the latency-inducing bottlenecks, both in the end-systems and in the network. Finally we will design mechanisms that can be integrated with the existing infrastructure to improve the experienced latency.
Funding source:
- The European Commission
- Funding scheme: STREP Total Cost: € 4,910,044.00 EC Contribution: € 3,569,000.00 Contract Number: CNECT-ICT-317700
All partners:
- Simula Research Laboratory (NO)
- British Telecommunications (UK)
- Alcatel-Lucent Bell (BE)
- Megapop Games (NO)
- University of Oslo (NO)
- Karlstad University (SE)
- Institut Mines-Telecom (FR)
- The University Court of the University of Aberdeen (UK)
Publications for RITE: Reducing Internet Transport Latency
Journal Article
Online Identification of Groups of Flows Sharing a Network Bottleneck
IEEE/ACM Transactions on Networking 28 (2020): 2229-2242.Status: Published
Online Identification of Groups of Flows Sharing a Network Bottleneck
Abstract—Most Internet hosts today support multiple access technologies and network interfaces. Multipath transport protocols, like MPTCP, are being deployed (e.g., in smartphones), allowing transparent simultaneous use of multiple links. Besides providing increased resilience to link failures, multipath trans- ports may better exploit available (aggregate) capacity across all interfaces. The safest way to ensure fairness is to assume that any subflows of a multipath end-to-end connection may share bottleneck links, but knowledge of non-shared bottlenecks could allow multipath senders to exploit more capacity without being unfair to other flows. The problem of reliably detecting the existence of (non)-shared bottlenecks is not trivial and is compounded by the fact that bottlenecks may change due to traffic dynamics. In this paper we focus on practical methods to reliably group flows that share, possibly dynamic, bottlenecks online and in a passive manner (i.e., without injecting measurement traffic). We introduce a novel dynamic clustering algorithm that we apply to update our previous shared bottleneck flow grouping (SBFG) method standardized by the IETF, based on delay statistics. We also adapt an offline SBFG method based on wavelet filters to enable it for online operation. These SBFG methods are evaluated by a simple testbed, rigorous simulation and real-world Internet experiments in a testbed comprised of multihomed hosts. Our results suggest that there is no clear winner, and selection of the “best” SBFG method will have to consider tradeoffs regarding accuracy, lag, and application requirements.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, Department of Mobile Systems and Analytics, The Center for Resilient Networks and Applications |
Publication Type | Journal Article |
Year of Publication | 2020 |
Journal | IEEE/ACM Transactions on Networking |
Volume | 28 |
Number | 5 |
Pagination | 2229--2242 |
Publisher | IEEE/ACM |
ISSN | Print ISSN: 1063-6692, Electronic ISSN: 1558-2566 |
Keywords | dynamic clustering, Internet congestion control, multipath congestion control., shared bottleneck detection |
Notes | Published in the Early Access area on IEEE Xplore. The content is final as presented with the exception of pagination and |
DOI | 10.1109/TNET.2020.3007346 |
Miscellaneous
Shared Bottleneck Detection for Coupled Congestion Control for RTP Media
In RFC 8382. Internet Requests for Comments ed. RFC Editor, 2018.Status: Published
Shared Bottleneck Detection for Coupled Congestion Control for RTP Media
This document describes a mechanism to detect whether end-to-end data flows share a common bottleneck. This mechanism relies on summary statistics that are calculated based on continuous measurements and used as input to a grouping algorithm that runs wherever the knowledge is needed
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Miscellaneous |
Year of Publication | 2018 |
Publisher | RFC Editor |
Notes | Internet Engineering Task Force (IETF) Request for Comments: 8382 Category: Experimental ISSN: 2070-1721 |
URL | https://www.rfc-editor.org/info/rfc8382 |
DOI | 10.17487/RFC8382 |
TR-Number | 8382 |
Journal Article
Operating ranges, tunability and performance of CoDel and PIE
Computer Communications 103 (2017): 74-82.Status: Published
Operating ranges, tunability and performance of CoDel and PIE
Bufferbloat is excessive delay due to the accumulation of packets in a router’s oversized queues. CoDel and PIE are two recent Active Queue Management (AQM) algorithms that have been proposed to address bufferbloat by reducing the queuing delay while trying to maintain a high bottleneck utilization. This paper fills a gap by outlining what are the operating ranges, that is the network characteristics (in terms of round-trip times and bottleneck capacity), for which these algorithms achieve their design goals. This new approach to the problem lets us identify deployment scenarios where both AQM schemes result in poor performance when used with default parameters. Because PIE and CoDel have been proposed with RED’s deployment issues in mind, it was essential to evaluate to what extent we can tune them to achieve various trade-offs and let them control the queuing delay outside their default operating range. We find that, by appropriate tuning (1) the amount of buffering can easily be controlled with PIE, (2) the Round Trip Time (RTT) sensitivity of CoDel can be reduced. Also, we observe there is more correlation between the congestion level, the achieved queuing delay and the targeted delay with CoDel than with PIE. This paper therefore concludes there is no single overall best AQM scheme, as each scheme proposes a specific trade-off.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Journal Article |
Year of Publication | 2017 |
Journal | Computer Communications |
Volume | 103 |
Pagination | 74-82 |
Date Published | 05/2017 |
Publisher | Elsevier |
Keywords | AQM, Bufferbloat, CoDel, congestion control, PIE |
DOI | 10.1016/j.comcom.2016.07.013 |
Proceedings, refereed
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
In IFIP Networking. IFIP, 2017.Status: Published
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
A number of recently proposed Active Queue Management (AQM) mechanisms instantiate shallow buffers with burst tolerance to minimise the time that packets spend enqueued at a bottleneck. However, shallow buffering causes noticeable TCP performance degradation as a path’s underlying round trip time (RTT) heads above typical intra-country levels. Using less-aggressive multiplicative backoffs in TCP can compensate for shallow bottleneck buffering. AQM mechanisms may either drop packets or mark them using Explicit Congestion Notification (ECN), depending on whether the sender marked packets as ECN-capable. While a drop may therefore stem from any type of queue, an ECN-mark indicates that an AQM mechanism has done its job, and therefore the queue is likely to be shallow. We propose ABE: “Alternative Backoff with ECN”, which consists of enabling ECN and letting individual TCP senders back off less aggressively in reaction to ECN-marks from AQM-enabled bottlenecks. Using controlled testbed experiments with standard NewReno and CUBIC flows, we show significant performance gains in lightly-multiplexed scenarios, without losing the delay-reduction benefits of deploying AQM. ABE is a sender-side-only modification that can be deployed across networks incrementally (requiring no flag-day) and offers a compelling reason to deploy and enable ECN across the Internet.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | IFIP Networking |
Publisher | IFIP |
Keywords | AQM, congestion control, ECN, low latency, tcp |
Notes | Best Paper Award |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570335770.pdf |
Talks, invited
Multi-Path Transport with OMNeT++ and the INET Framework
In Albacete, Castilla-La Mancha, Spain. Albacete, Castilla-La Mancha, Spain, 2017.Status: Published
Multi-Path Transport with OMNeT++ and the INET Framework
In order to evaluate the performance of multi-path transport protocols, a straightforward initial step is to perform simulations. OMNeT++, together with the INET Framework, provide a powerful Open Source platform for running network simulations. This talk provides an overview of simulating multi-path transport with OMNeT++ and the INET Framework. Particular focus is on the Concurrent Multipath Transfer extension for the Stream Control Transmission Protocol (SCTP). Furthermore, useful additions like the NetPerfMeter application model, the extended network auto-configurator as well as the Simulation Processing Tool-Chain (SimProcTC) are explained.
Afilliation | Communication Systems |
Project(s) | NorNet, RITE: Reducing Internet Transport Latency |
Publication Type | Talks, invited |
Year of Publication | 2017 |
Location of Talk | Albacete, Castilla-La Mancha, Spain |
Place Published | Albacete, Castilla-La Mancha, Spain |
Keywords | CMT, CMT-SCTP, Concurrent Multipath Transfer, INET Framework, Multi-Path Transport, NetPerfMeter, OMNeT++, SCTP, SimProcTC, Stream Control Transmission Protocol |
Technical reports
TRILL: ECN (Explicit Congestion Notification) Support
Internet Engineering Task Force, 2017.Status: Accepted
TRILL: ECN (Explicit Congestion Notification) Support
Explicit congestion notification (ECN) allows a forwarding element to notify downstream devices, including the destination, of the onset of congestion without having to drop packets. This document extends this capability to TRILL switches, including integration with IP ECN.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Technical reports |
Year of Publication | 2017 |
Number | draft-ietf-trill-ecn-support-02 |
Date Published | 03/2017 |
Publisher | Internet Engineering Task Force |
Keywords | Architecture, congestion, Control, Data Communication, Encapsulation, Explicit Notification, Incremental Deployment, Internet, Layering, networks, Protocol Engineering, QoS, Tunnels |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-ietf-trill-ecn-support |
Guidelines for Adding Congestion Notification to Protocols that Encapsulate IP
IETF, 2017.Status: Accepted
Guidelines for Adding Congestion Notification to Protocols that Encapsulate IP
Afilliation | Communication Systems |
Project(s) | The Center for Resilient Networks and Applications, RITE: Reducing Internet Transport Latency |
Publication Type | Technical reports |
Year of Publication | 2017 |
Number | draft-ietf-tsvwg-ecn-encap-guidelines-08 |
Publisher | IETF |
Keywords | Architecture, congestion, Control, Data Communication, Encapsulation, Explicit Notification, Internet, Layering, Management, Monitoring, networks, Protocol Engineering, QoS, Tunnels |
Notes | (Work in Progress) |
URL | http://tools.ietf.org/html/draft-ietf-tsvwg-ecn-encap-guidelines |
Journal Article
Is Multi-Path Transport Suitable for Latency Sensitive Traffic?
Computer Networks (COMNET) 105 (2016): 1-21.Status: Published
Is Multi-Path Transport Suitable for Latency Sensitive Traffic?
This paper assesses whether multi-path communication can help latency-sensitive applications to satisfy the requirements of their users. We consider Concurrent Multi-path Transfer for SCTP (CMT-SCTP) and Multi-path TCP (MPTCP) and evaluate their proficiency in transporting video, gaming, and web traffic over combinations of WLAN and 3G interfaces. To ensure the validity of our evaluation, several experimental approaches were used including simulation, emulation and live experiments. When paths are symmetric in terms of capacity, delay and loss rate, we find that the experienced latency is significantly reduced, compared to using a single path. Using multiple asymmetric paths does not affect latency -- applications do not experience any increase or decrease, but might benefit from other advantages of multi-path communication. In the light of our conclusions, multi-path transport is suitable for latency-sensitive traffic and mature enough to be widely deployed.
Afilliation | , Communication Systems, Communication Systems |
Project(s) | NorNet, RITE: Reducing Internet Transport Latency, The Center for Resilient Networks and Applications |
Publication Type | Journal Article |
Year of Publication | 2016 |
Journal | Computer Networks (COMNET) |
Volume | 105 |
Pagination | 1-21 |
Date Published | 08/2016 |
Publisher | Elsevier |
Keywords | CMT-SCTP, Internet, latency, MPTCP, Multi-Path Communication, transport protocols |
DOI | 10.1016/j.comnet.2016.05.008 |
Proceedings, refereed
Managing real-time media flows through a flow state exchange
In NOMS 2016 IEEE/IFIP Network Operations and Management Symposium, 2016.Status: Published
Managing real-time media flows through a flow state exchange
When multiple congestion controlled flows traverse the same network path, their resulting rate is usually an outcome of their competition at the bottleneck. The WebRTC / RTCWeb suite of standards for inter-browser communication is required to allow prioritization. This is addressed by our previously presented mechanism for coupled congestion control, called the Flow State Exchange (FSE). Here, we present our first simulation results using two mechanisms that have been proposed for IETF standardization: Google Congestion Control (GCC) and Network-Assisted Dynamic Adaptation (NADA). These two mechanisms exhibit aspects that allow us to use a simpler “passive” algorithm in our FSE. Passive coupling allows a less time-constrained request-response style of signaling between congestion control mechanisms and the FSE, which enables the FSE to run as a stand-alone management tool.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Proceedings, refereed |
Year of Publication | 2016 |
Conference Name | NOMS 2016 IEEE/IFIP Network Operations and Management Symposium |
Pagination | 112--120 |
Date Published | 04/2016 |
DOI | 10.1109/NOMS.2016.7502803 |
PI2 : A Linearized AQM for both Classic and Scalable TCP
In Proc. ACM CoNEXT 2016. New York, NY, USA: ACM, 2016.Status: Published
PI2 : A Linearized AQM for both Classic and Scalable TCP
This paper concerns the use of Active Queue Management (AQM) to reduce queuing delay. It offers insight into why it has proved hard for a Proportional Integral (PI) controller to remain both responsive and stable while controlling `Classic' TCP flows, such as TCP Reno and Cubic. Due to their non-linearity, the controller's adjustments have to be smaller when the target drop probability is lower. The PI Enhanced (PIE) algorithm attempts to solve this problem by scaling down the adjustments of the controller using a look-up table. Instead, we control an internal variable that is by definition linearly proportional to the load, then post-process it into the required Classic drop probability---in fact we show that the output simply needs to be squared. This allows tighter control, giving responsiveness and stability better or no worse than PIE achieves, but without all its corrective heuristics.
With suitable packet classification, it becomes simple to extend this PI2 AQM to support coexistence between Classic and Scalable congestion controls in the public Internet. A Scalable congestion control ensures sufficient feedback at any flow rate, an example being Data Centre TCP (DCTCP). A Scalable control is linear, so we can use the internal variable directly without any squaring, by omitting the post-processing stage.
We implemented PI2 as a Linux qdisc to extensively test our claims using Classic and Scalable TCPs.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, TimeIn: Traffic behaviour of interactive time-dependent thin streams on the modern Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2016 |
Conference Name | Proc. ACM CoNEXT 2016 |
Pagination | 105-119 |
Date Published | 12/2016 |
Publisher | ACM |
Place Published | New York, NY, USA |
ISBN Number | 978-1-4503-4297-1 |
Keywords | Algorithms, Analysis, AQM, Congestion Avoidance, congestion control, Data Communication, Design, Evaluation, Internet, latency, networks, Performance, QoS, Scaling, tcp |
URL | http://dl.acm.org/citation.cfm?doid=2999572.2999578 |
DOI | 10.1145/2999572.2999578 |
NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet

The NEAT project wants to achieve a complete redesign of the way in which Internet applications interact with the network. Our goal is to allow network "services" offered to applications – such as reliability, low-delay communication or security – to be dynamically tailored based on application demands, current network conditions, hardware capabilities or local policies, and also to support the integration of new network functionality in an evolutionary fashion, without applications having to be rewritten. This architectural change will make the Internet truly “enhanceable”, by allowing applications to seamlessly and more easily take advantage of new network features as they evolve.
Funding source

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 644334. (ICT-05-2014: Smart Networks and novel Internet Architectures)
All partners:
- Simula Research Laboratory (Norway)
- Celerway (Norway)
- Cisco Europe (France)
- EMC (Ireland)
- Mozilla Denmark (Denmark)
- Fachhochschule Münster (Germany)
- Karlstad University (Sweden)
- University of Aberdeen (United Kingdom)
- University of Oslo (Norway)
Project leader
David Ros, Simula Research Laboratory (Norway)
Online presence
Publications for NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet
Journal Article
On the Usability of Transport Protocols other than TCP: A Home Gateway and Internet Path Traversal Study
Computer Networks 173 (2020).Status: Published
On the Usability of Transport Protocols other than TCP: A Home Gateway and Internet Path Traversal Study
Network APIs are moving towards protocol agility, where applications express their needs but not a static protocol binding, and it is up to the layer below the API to choose a suitable protocol. The IETF Transport Services (TAPS) Working Group is standardizing a protocol-independent transport API and offering guidance to implementers. Apple’s recent “Network.framework” is specifically designed to allow such late and dynamic binding of protocols. When the network stack autonomously chooses and configures a protocol, it must first test which protocols are locally available and which work end-to-end (“protocol racing”). For this, it is important to know the set of available options, and which protocols should be tried first: Does it make sense to offer unchecked payload delivery, as with UDP-Lite? Is a UDP-based protocol like QUIC always a better choice, or should native SCTP be tried? This paper develops answers to such questions via (i) a NAT study in a local testbed, (ii) bidirectional Internet tests, (iii) a large scale Internet measurement campaign. The examined protocols are: SCTP, DCCP, UDP-Lite, UDP with a zero checksum and three different UDP encapsulations.
Afilliation | Communication Systems |
Project(s) | NorNet, The Center for Resilient Networks and Applications, NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Journal Article |
Year of Publication | 2020 |
Journal | Computer Networks |
Volume | 173 |
Date Published | 05/2020 |
Publisher | Elsevier |
ISSN | 1389-1286 |
Keywords | DCCP, Internet, NAT, Protocol Testing, SCTP, UDP-Lite |
DOI | 10.1016/j.comnet.2020.107211 |
Journal Article
On the Utility of Unregulated IP DiffServ Code Point (DSCP) Usage by End Systems
Performance Evaluation 135 (2019): 102036.Status: Published
On the Utility of Unregulated IP DiffServ Code Point (DSCP) Usage by End Systems
DiffServ was designed to implement service provider quality of service (QoS) policies, where routers change and react upon the DiffServ Code Point (DSCP) in the IP header. However, nowadays, applications are beginning to directly set the DSCP themselves, in the hope that this will yield a more appropriate service for their respective video, audio and data streams. WebRTC is a prime example of such an application. We present measurements, for both IPv4 and IPv6, of what happens to DSCP values along Internet paths after an end system has set them without any prior agreement between a customer and a service provider. We find that the DSCP is often changed or zeroed along the path, but detrimental effects from using the DSCP are extremely rare; moreover, DSCP values sometimes remain intact (potentially having an effect on traffic) for several AS hops. This positive result motivates an analysis of the potential latency impact from such DSCP usage, for which we present the first measurement results. We find that routers at approximately 3% of more than 100,000 links differentiate between the WebRTC DSCP values (EF, AF42 and CS1) and consistently reduce delay in comparison with probes carrying a zero value (CS0) under congestion. In contrast, routers at around 2% of these links increase the delay by a comparable amount under congestion, uniformly for EF, AF42 and CS1.
Afilliation | Communication Systems |
Project(s) | NorNet, The Center for Resilient Networks and Applications, Simula Metropolitan Center for Digital Engineering, NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet, MELODIC: Multi-cloud Execution-ware for Large-scale Optimised Data-Intensive Computing |
Publication Type | Journal Article |
Year of Publication | 2019 |
Journal | Performance Evaluation |
Volume | 135 |
Pagination | 102036 |
Date Published | 08/2019 |
Publisher | Elsevier |
ISSN | 0166-5316 |
Keywords | DiffServ, DiffServ Code Point, latency, QoS, WebRTC |
URL | https://doi.org/10.1016/j.peva.2019.102036 |
DOI | 10.1016/j.peva.2019.102036 |
Proceedings, refereed
ctrlTCP: Reducing Latency through Coupled, Heterogeneous Multi-Flow TCP Congestion Control
In 21st IEEE Global Internet Symposium (GI 2018). Honolulu, HI, USA: IEEE, 2018.Status: Published
ctrlTCP: Reducing Latency through Coupled, Heterogeneous Multi-Flow TCP Congestion Control
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2018 |
Conference Name | 21st IEEE Global Internet Symposium (GI 2018) |
Date Published | 04/2018 |
Publisher | IEEE |
Place Published | Honolulu, HI, USA |
Notes | In conjunction with IEEE INFOCOM, Honolulu, HI, USA |
URL | https://www.duo.uio.no/handle/10852/71297 |
DOI | 10.1109/INFCOMW.2018.8406887 |
Journal Article
NEAT: A Platform- and Protocol-Independent Internet Transport API
IEEE Communications Magazine 55, no. 6 (2017): 46-54.Status: Published
NEAT: A Platform- and Protocol-Independent Internet Transport API
The sockets Applications Programming Interface (API) has become the standard way that applications access the transport services offered by the Internet Protocol stack. This paper presents NEAT, a user-space library that can provide an alternate transport API. NEAT allows applications to request the service they need using a new design that is agnostic to the specific choice of transport protocol underneath. This not only allows applications to take advantage of common protocol machinery, but also eases introduction of new network mechanisms and transport protocols. The paper describes the components of the NEAT library and illustrates the important benefits that can be gained from this new approach. NEAT is a software platform for developing advanced network applications that was designed in accordance with the standardization efforts on Transport Services (TAPS) in the Internet Engineering Task Force (IETF), but its features exceed the envisioned functionality of a TAPS system.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Journal Article |
Year of Publication | 2017 |
Journal | IEEE Communications Magazine |
Volume | 55 |
Issue | 6 |
Pagination | 46-54 |
Date Published | 06/2017 |
Publisher | IEEE |
ISSN | 0163-6804 |
DOI | 10.1109/MCOM.2017.1601052 |
Research Notes | https://www.neat-project.org/publications/#papers |
Proceedings, refereed
fling: A Flexible Ping for Middlebox Measurements
In 2017 29th International Teletraffic Congress (ITC 29). Vol. 1. IEEE, 2017.Status: Published
fling: A Flexible Ping for Middlebox Measurements
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | 2017 29th International Teletraffic Congress (ITC 29) |
Volume | 1 |
Pagination | 134–142 |
Publisher | IEEE |
A NEAT Way to Browse the Web
In Proceedings of the Applied Networking Research Workshop (ANRW). Praha/Czech Republic: IEEE, 2017.Status: Published
A NEAT Way to Browse the Web
There is a growing concern that the Internet transport layer has become ossified in the face of emerging novel applications, and that further evolution has become very difficult. The NEAT system is a novel and evolvable transport system that decouples applications from the underlying transport layer and network services. In so doing, it facilitates dynamic transport selection. This demo shows how the NEAT system is able to dynamically select the most appropriate transport solution for the Mozilla Firefox web browser.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet, NorNet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | Proceedings of the Applied Networking Research Workshop (ANRW) |
Date Published | 07/15/2017 |
Publisher | IEEE |
Place Published | Praha/Czech Republic |
Keywords | NEAT, ossification, SCTP, tcp, Transport Selection, Transport Service |
Notes | Demo Presentation |
URL | https://irtf.org/anrw/2017/anrw17-final13.pdf |
Evaluating CAIA Delay Gradient as a Candidate for Deadline-Aware Less-than-Best-Effort Transport
In Workshop on Future of Internet Transport (FIT 2017). IFIP, 2017.Status: Published
Evaluating CAIA Delay Gradient as a Candidate for Deadline-Aware Less-than-Best-Effort Transport
Less-than-best-effort (LBE) congestion control offers a low-priority service for applications tolerant to high latency and low throughput, like peer-to-peer file transfers or automatic software updates. There are, however, situations where it would be beneficial for the application to specify a soft deadline for task completion. Examples of such situations could be completion of backup tasks or synchronisation between CDN data centres. Since network conditions change over time, a deadline-aware LBE (DA-LBE) congestion control would need the ability to dynamically adapt how aggressively it competes for capacity to meet the soft deadline, trading low-priority behaviour for timeliness. One candidate that shows promise as a LBE congestion control is CAIA Delay Gradient (CDG). CDG uses changes in measured end-to-end delay to control the congestion window. CDG has several parameters that might help tune its “aggressiveness” in a way that might help achieve the goal of DA-LBE congestion control. We have evaluated CDG in order to establish how it can be tuned to exhibit different degrees of LBE behaviour under varying network conditions. Our results show that it is possible to control CDG to vary its aggressiveness in a consistent way, making it a prime candidate to implement a DA-LBE congestion control system.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | Workshop on Future of Internet Transport (FIT 2017) |
Publisher | IFIP |
ISBN Number | 978-3-901882-94-4 |
Keywords | congestion control, deadline-aware congestion control, Less-than-Best-Effort Service, scavenger service |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570350870.pdf |
DOI | 10.23919/IFIPNetworking.2017.8264882 |
A Framework for Less than Best Effort Congestion Control with Soft Deadlines
In 2017 IFIP Networking Conference (IFIP Networking) and Workshops. IEEE, 2017.Status: Published
A Framework for Less than Best Effort Congestion Control with Soft Deadlines
Applications like inter data-centre synchronisation or client-to-cloud backups require a reliable end-to-end data transfer, however, they typically do not have strong capacity or latency constraints, just a loose delivery deadline. Besides, their potential to disrupt more quality-constrained flows should be kept to a minimum. These applications could be well served by a transport protocol providing a less-than-best-effort (LBE) or scavenger service rather than TCP but, neither TCP nor standard LBE methods like LEDBAT consider any notion of deadline or completion time. TCP simply tries to maximise the use of available capacity, while LEDBAT tries to enforce an LBE behaviour regardless of any timeliness requirements.
This paper introduces a framework for adding both LBE behaviour and awareness of “soft” delivery deadlines to any congestion control (CC) algorithm, whether loss-based, delay-based or explicit signaling-based. This effectively allows it to turn an arbitrary CC protocol into a scavenger protocol that dynamically adapts its sending rate to network conditions and remaining time before the deadline, to balance timeliness and transmission aggressiveness. Network utility maximization (NUM) theory provides a solid foundation for the proposal. The effectiveness of the approach is validated by numerical and simulation experiments, with TCP Cubic and Vegas used as examples.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | 2017 IFIP Networking Conference (IFIP Networking) and Workshops |
Publisher | IEEE |
ISBN Number | 978-3-901882-94-4 |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570334752.pdf |
DOI | 10.23919/IFIPNetworking.2017.8264853 |
Talks, invited
NEAT Tutorial at Hainan University: Getting Started with NEAT
In Haikou, Hainan, People's Republic of China. Haikou, Hainan/People's Republic of China, 2017.Status: Published
NEAT Tutorial at Hainan University: Getting Started with NEAT
The goal of NEAT (A New, Evolutive API and Transport-Layer Architecture for the Internet) is to allow network "services" offered to applications – such as reliability, low-delay communication or security – to be dynamically tailored based on application demands, current network conditions, hardware capabilities or local policies, and also to support the integration of new network functionality in an evolutionary fashion, without applications having to be rewritten. This talk gives a practical introduction to NEAT from a developer's perspective: after an introduction to NEAT, the APIs and in particular the NEAT Sockets API are explained. This is followed by pseudo-code examples and finally running-code examples. These running-code examples particularly also show how to use NEAT in NorNet Core.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet, NorNet |
Publication Type | Talks, invited |
Year of Publication | 2017 |
Location of Talk | Haikou, Hainan, People's Republic of China |
Place Published | Haikou, Hainan/People's Republic of China |
Type of Talk | Tutorial |
Keywords | Client, Examples, NEAT, NEAT Sockets API, NorNet Core, programming, Server |
A Practical Introduction to NEAT at Hainan University
In Haikou, Hainan, People's Republic of China. Haikou, Hainan, People's Republic of China, 2017.Status: Published
A Practical Introduction to NEAT at Hainan University
The goal of NEAT (A New, Evolutive API and Transport-Layer Architecture for the Internet) is to allow network "services" offered to applications – such as reliability, low-delay communication or security – to be dynamically tailored based on application demands, current network conditions, hardware capabilities or local policies, and also to support the integration of new network functionality in an evolutionary fashion, without applications having to be rewritten. This talk gives a practical introduction to NEAT from a developer's perspective: after an introduction to NEAT, the APIs and in particular the NEAT Sockets API are explained. This is followed by pseudo-code examples and finally running-code examples. These running-code examples particularly also show how to use NEAT in NorNet Core
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet, NorNet |
Publication Type | Talks, invited |
Year of Publication | 2017 |
Location of Talk | Haikou, Hainan, People's Republic of China |
Place Published | Haikou, Hainan, People's Republic of China |
Type of Talk | Invited Talk |
Keywords | Client, Examples, NEAT, NEAT Sockets API, NorNet Core, programming, Server |
MAMI: Measurement and Architecture for a Middleboxed Internet

A central tussle in today’s Internet is that between the desire for privacy, which requires strong encryption to protect, and the need to efficiently manage network traffic. Current approaches to traffic management typically require access to plaintext and application payload, which is fundamentally incompatible with the privacy goal.
The MAMI project aims to rearchitect the Internet to allow explicit cooperation between endpoints and middleboxes, restoring the promise and innovation potential of the original end-to-end architecture of the Internet while enabling appropriate in-network services to ease management and scalability of ever more demanding applications. To ensure the applicability of the protocol, it will develop it on a background of middlebox behaviour models, derived from large-scale measurements of middleboxes in the public Internet conducted on top of the MONROE testbed. After evaluating the fitness of proposed MCP by assessing its applicability to a set of real-world use cases for transport layer evolution, it will focus on incremental deployability in the presence of both cooperative and uncooperative middleboxes by experimentation in the Internet utilising the facilities provided by MONROE.
Final goals
The MAMI project has three main goals:
1. Large-scale measurements of deployed middleboxes
The MAMI project will perform Internet measurements using existing large-scale measurement platforms such as RIPE ATLAS, CAIDA Ark and the MONROE FIRE+ testbed, as well as design and develop measurement techniques and tools to detect and monitor middlebox behavior. Further, MAMI will implement of a measurement observatory to collect measurement results and make them accessible to others.
2. An architecture for middlebox cooperation
Based on understanding derived from analysing middlebox characteristics, MAMI will develop an architecture providing a shim layer that contains the Middlebox Cooperation Protocol (MCP), which allows transport and application protocols to selectively expose semantic information to middleboxes while maintaining protocol level details inside an encrypted encapsulation protocol. Further, MAMI will investigate approaches to maintain connectivity even if the MCP is not supported on a certain path as well as the integration of encryption or partial encryption methods into the proposed architecture. Together with the MCP, this will provide a flexible transport framework that can be used by emerging applications.
3. Experimental evaluation of use case applicability and deployability
MAMI will develop a classification scheme and models of middlebox behavior as detected by Internet measurement. This analysis of the middlebox behavior not only be used to improve measurement techniques but will also provide the basic for performance evaluation of and experimentation with the proposed MAMI architecture and respective protocol mechanisms.
Funding source

This project is receiving funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 688421. (ICT-12-2015 - Integrating experiments and facilities in FIRE+)
All partners
- ETH Zürich (Switzerland)
- Simula (Norway)
- Telefonica I+D (Spain)
- Université de Liège (Belgium)
- University of Aberdeen (United Kingdom)
- Zurich University of Applied Sciences/ZHAW (Switzerland)
- Alcatel-Lucent (United Kingdom)
Project leader
ETH Zürich (Switzerland)
Media presence
Publications for MAMI: Measurement and Architecture for a Middleboxed Internet
Proceedings, refereed
On the importance of TCP splitting proxies for future 5G mmWave communications
In IEEE Local Computer Networks (LCN) Symposium on Emerging Topics in Networking. IEEE, 2019.Status: Published
On the importance of TCP splitting proxies for future 5G mmWave communications
Abstract—5G mmWave technology promises capacities 10 to 100 times that of 4G. However, mmWave links are very sensitive to having direct line of sight between sender and receiver, with dramatically fluctuating capacities due to transient blocking and shadow fading, which can substantially degrade TCP performance. TCP-splitting proxies (SPEPs) are often used to improve TCP performance over wireless links. We investigate current operator SPEPs (used in 4G LTE networks) under mmWave-like dynamics using the MONROE testbed. We introduce a mmWave emulation model for an urban canyon scenario, and use it to evaluate how current operational SPEPs impact the performance. Our results from experiments including four operators and three countries, indicate that SPEPs will be even more important for 5G mmWave than they are in LTE. Current 4G SPEPs provide significant, though not optimal, benefits under mmWave-like conditions, allowing them to be utilized as the network transitions to 5G technology.
Afilliation | Communication Systems |
Project(s) | MAMI: Measurement and Architecture for a Middleboxed Internet, MONROE: Measuring Mobile Broadband Networks in Europe , Department of Mobile Systems and Analytics, The Center for Resilient Networks and Applications |
Publication Type | Proceedings, refereed |
Year of Publication | 2019 |
Conference Name | IEEE Local Computer Networks (LCN) Symposium on Emerging Topics in Networking |
Pagination | 108--116 |
Date Published | 10/2019 |
Publisher | IEEE |
ISBN Number | 978-1-7281-2561-9 |
URL | http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9000661&isnumber... |
DOI | 10.1109/LCNSymposium47956.2019.9000661 |
Publications
Journal Article
Proxy Path Scheduling and Erasure Reconstruction for Low Delay mmWave Communication
IEEE Communications Letters 27, no. 6 (2023): 1649-1653.Status: Published
Proxy Path Scheduling and Erasure Reconstruction for Low Delay mmWave Communication
Afilliation | Communication Systems |
Project(s) | The Center for Resilient Networks and Applications, Information Theory Section |
Publication Type | Journal Article |
Year of Publication | 2023 |
Journal | IEEE Communications Letters |
Volume | 27 |
Issue | 6 |
Pagination | 1649-1653 |
Date Published | 06/2023 |
Publisher | IEEE |
ISSN | 1558-2558 |
Keywords | erasure reconstruction, mmWave, Multipath scheduling |
URL | https://ieeexplore.ieee.org/document/10107383 |
DOI | 10.1109/LCOMM.2023.3269526 |
Journal Article
Investigating Predictive Model-Based Control to Achieve Reliable Consistent Multipath mmWave Communication
Computer Communications 194 (2022): 29-43.Status: Published
Investigating Predictive Model-Based Control to Achieve Reliable Consistent Multipath mmWave Communication
Millimeter-wave (mmWave) radio is a key building block in 5G and beyond cellular networks. However, mmWave channels are very sensitive to environmental conditions and depend on Line-of-Sight connections to provide very high data rates. Achieving reliable, consistent communication — i.e., a steady link rate together with low delay — over mmWave links is therefore a challenging problem. The goal of this work is to explore the use of predictive control to manage and simultaneously use multiple available mmWave paths to achieve reliable consistent communication by means of a multipath proxy. We investigate transient solutions of Markov Modulated Fluid Queues (MMFQ) to model the short-term evolution of the proxy’s packet queue, consistent with the use of Markovian models to capture the behavior of mmWave channel blocking. We propose a combination of models that can be solved using newly proposed matrix-analytic techniques in a timely enough manner for use in real-time control. This gives us a prediction, over a short time horizon, of either proxy queue distributions or probabilities of reaching particular proxy buffer levels. Thus, it enables the proxy to make preemptive path decisions in order to maintain a desired Quality of Service. A proof-of-concept simulation study demonstrates the efficacy of our proposed MMFQ-based predictive approach over both static and purely reactive control approaches. Further, we explore the potential benefits of a hybrid approach to path management, combining both predictive and reactive control. This can allow the controller to cater for unforeseen events that cannot be forecast by the predictive controller, mitigating the resulting extra queuing and corresponding delay spikes.
Afilliation | Communication Systems |
Project(s) | The Center for Resilient Networks and Applications, Department of Mobile Systems and Analytics |
Publication Type | Journal Article |
Year of Publication | 2022 |
Journal | Computer Communications |
Volume | 194 |
Pagination | 29-43 |
Date Published | 10/2022 |
Publisher | Elsevier |
Keywords | 5G/6G/+, mmWave, Mobile networks, Multipath, Proxy |
URL | https://www.sciencedirect.com/science/article/pii/S0140366422002596 |
DOI | 10.1016/j.comcom.2022.07.011 |
Proceedings, refereed
Reliable Consistent Multipath mmWave Communication
In International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM'21). New York, NY, USA: ACM, 2021.Status: Published
Reliable Consistent Multipath mmWave Communication
Reliable consistent communication over millimeter-wave (mmWave) channels is a challenging problem due to their sensitivity to blocking of Line of Sight connections. Even though mmWave is a key building block in 5G and future generation cellular networks, making solutions to this problem space important. Our aim is to use predictive control to manage and simultaneously use multiple available mmWave paths to achieve reliable consistent communication (i.e. steady transmission rate with low delay) with a multipath proxy. To this end we investigate transient solutions of Markov Modulated Fluid Queue models (MMFQ), apt because the mmWave blocking has been modeled with Markovian models. We propose a combination of models that can be solved using newly proposed matrix analytic techniques in a timely enough manner for use in real-time control. This gives us a prediction of either proxy queue distributions or probabilities of reaching proxy buffer levels over a short time horizon, enabling the proxy to make preemptive path decisions to maintain a desired Quality of Service. A proof of concept simulation study demonstrates the efficacy of our proposed MMFQ-based predictive approach over either static or purely reactive control approaches.
Afilliation | Communication Systems |
Project(s) | Department of Mobile Systems and Analytics, The Center for Resilient Networks and Applications |
Publication Type | Proceedings, refereed |
Year of Publication | 2021 |
Conference Name | International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM'21) |
Pagination | 149–158 |
Date Published | 11/2021 |
Publisher | ACM |
Place Published | New York, NY, USA |
ISBN Number | 9781450390774 |
Notes | Authors' version of the work available. Please refer to DOI for the definitive version. |
URL | https://doi.org/10.1145/3479239.3485684 |
DOI | 10.1145/3479239.3485684 |
Journal Article
Online Identification of Groups of Flows Sharing a Network Bottleneck
IEEE/ACM Transactions on Networking 28 (2020): 2229-2242.Status: Published
Online Identification of Groups of Flows Sharing a Network Bottleneck
Abstract—Most Internet hosts today support multiple access technologies and network interfaces. Multipath transport protocols, like MPTCP, are being deployed (e.g., in smartphones), allowing transparent simultaneous use of multiple links. Besides providing increased resilience to link failures, multipath trans- ports may better exploit available (aggregate) capacity across all interfaces. The safest way to ensure fairness is to assume that any subflows of a multipath end-to-end connection may share bottleneck links, but knowledge of non-shared bottlenecks could allow multipath senders to exploit more capacity without being unfair to other flows. The problem of reliably detecting the existence of (non)-shared bottlenecks is not trivial and is compounded by the fact that bottlenecks may change due to traffic dynamics. In this paper we focus on practical methods to reliably group flows that share, possibly dynamic, bottlenecks online and in a passive manner (i.e., without injecting measurement traffic). We introduce a novel dynamic clustering algorithm that we apply to update our previous shared bottleneck flow grouping (SBFG) method standardized by the IETF, based on delay statistics. We also adapt an offline SBFG method based on wavelet filters to enable it for online operation. These SBFG methods are evaluated by a simple testbed, rigorous simulation and real-world Internet experiments in a testbed comprised of multihomed hosts. Our results suggest that there is no clear winner, and selection of the “best” SBFG method will have to consider tradeoffs regarding accuracy, lag, and application requirements.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, Department of Mobile Systems and Analytics, The Center for Resilient Networks and Applications |
Publication Type | Journal Article |
Year of Publication | 2020 |
Journal | IEEE/ACM Transactions on Networking |
Volume | 28 |
Number | 5 |
Pagination | 2229--2242 |
Publisher | IEEE/ACM |
ISSN | Print ISSN: 1063-6692, Electronic ISSN: 1558-2566 |
Keywords | dynamic clustering, Internet congestion control, multipath congestion control., shared bottleneck detection |
Notes | Published in the Early Access area on IEEE Xplore. The content is final as presented with the exception of pagination and |
DOI | 10.1109/TNET.2020.3007346 |
Proceedings, refereed
On the importance of TCP splitting proxies for future 5G mmWave communications
In IEEE Local Computer Networks (LCN) Symposium on Emerging Topics in Networking. IEEE, 2019.Status: Published
On the importance of TCP splitting proxies for future 5G mmWave communications
Abstract—5G mmWave technology promises capacities 10 to 100 times that of 4G. However, mmWave links are very sensitive to having direct line of sight between sender and receiver, with dramatically fluctuating capacities due to transient blocking and shadow fading, which can substantially degrade TCP performance. TCP-splitting proxies (SPEPs) are often used to improve TCP performance over wireless links. We investigate current operator SPEPs (used in 4G LTE networks) under mmWave-like dynamics using the MONROE testbed. We introduce a mmWave emulation model for an urban canyon scenario, and use it to evaluate how current operational SPEPs impact the performance. Our results from experiments including four operators and three countries, indicate that SPEPs will be even more important for 5G mmWave than they are in LTE. Current 4G SPEPs provide significant, though not optimal, benefits under mmWave-like conditions, allowing them to be utilized as the network transitions to 5G technology.
Afilliation | Communication Systems |
Project(s) | MAMI: Measurement and Architecture for a Middleboxed Internet, MONROE: Measuring Mobile Broadband Networks in Europe , Department of Mobile Systems and Analytics, The Center for Resilient Networks and Applications |
Publication Type | Proceedings, refereed |
Year of Publication | 2019 |
Conference Name | IEEE Local Computer Networks (LCN) Symposium on Emerging Topics in Networking |
Pagination | 108--116 |
Date Published | 10/2019 |
Publisher | IEEE |
ISBN Number | 978-1-7281-2561-9 |
URL | http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9000661&isnumber... |
DOI | 10.1109/LCNSymposium47956.2019.9000661 |
Proceedings, refereed
A Framework for Less than Best Effort Congestion Control with Soft Deadlines
In 2017 IFIP Networking Conference (IFIP Networking) and Workshops. IEEE, 2017.Status: Published
A Framework for Less than Best Effort Congestion Control with Soft Deadlines
Applications like inter data-centre synchronisation or client-to-cloud backups require a reliable end-to-end data transfer, however, they typically do not have strong capacity or latency constraints, just a loose delivery deadline. Besides, their potential to disrupt more quality-constrained flows should be kept to a minimum. These applications could be well served by a transport protocol providing a less-than-best-effort (LBE) or scavenger service rather than TCP but, neither TCP nor standard LBE methods like LEDBAT consider any notion of deadline or completion time. TCP simply tries to maximise the use of available capacity, while LEDBAT tries to enforce an LBE behaviour regardless of any timeliness requirements.
This paper introduces a framework for adding both LBE behaviour and awareness of “soft” delivery deadlines to any congestion control (CC) algorithm, whether loss-based, delay-based or explicit signaling-based. This effectively allows it to turn an arbitrary CC protocol into a scavenger protocol that dynamically adapts its sending rate to network conditions and remaining time before the deadline, to balance timeliness and transmission aggressiveness. Network utility maximization (NUM) theory provides a solid foundation for the proposal. The effectiveness of the approach is validated by numerical and simulation experiments, with TCP Cubic and Vegas used as examples.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | 2017 IFIP Networking Conference (IFIP Networking) and Workshops |
Publisher | IEEE |
ISBN Number | 978-3-901882-94-4 |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570334752.pdf |
DOI | 10.23919/IFIPNetworking.2017.8264853 |
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
In IFIP Networking. IFIP, 2017.Status: Published
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
A number of recently proposed Active Queue Management (AQM) mechanisms instantiate shallow buffers with burst tolerance to minimise the time that packets spend enqueued at a bottleneck. However, shallow buffering causes noticeable TCP performance degradation as a path’s underlying round trip time (RTT) heads above typical intra-country levels. Using less-aggressive multiplicative backoffs in TCP can compensate for shallow bottleneck buffering. AQM mechanisms may either drop packets or mark them using Explicit Congestion Notification (ECN), depending on whether the sender marked packets as ECN-capable. While a drop may therefore stem from any type of queue, an ECN-mark indicates that an AQM mechanism has done its job, and therefore the queue is likely to be shallow. We propose ABE: “Alternative Backoff with ECN”, which consists of enabling ECN and letting individual TCP senders back off less aggressively in reaction to ECN-marks from AQM-enabled bottlenecks. Using controlled testbed experiments with standard NewReno and CUBIC flows, we show significant performance gains in lightly-multiplexed scenarios, without losing the delay-reduction benefits of deploying AQM. ABE is a sender-side-only modification that can be deployed across networks incrementally (requiring no flag-day) and offers a compelling reason to deploy and enable ECN across the Internet.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | IFIP Networking |
Publisher | IFIP |
Keywords | AQM, congestion control, ECN, low latency, tcp |
Notes | Best Paper Award |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570335770.pdf |
Evaluating CAIA Delay Gradient as a Candidate for Deadline-Aware Less-than-Best-Effort Transport
In Workshop on Future of Internet Transport (FIT 2017). IFIP, 2017.Status: Published
Evaluating CAIA Delay Gradient as a Candidate for Deadline-Aware Less-than-Best-Effort Transport
Less-than-best-effort (LBE) congestion control offers a low-priority service for applications tolerant to high latency and low throughput, like peer-to-peer file transfers or automatic software updates. There are, however, situations where it would be beneficial for the application to specify a soft deadline for task completion. Examples of such situations could be completion of backup tasks or synchronisation between CDN data centres. Since network conditions change over time, a deadline-aware LBE (DA-LBE) congestion control would need the ability to dynamically adapt how aggressively it competes for capacity to meet the soft deadline, trading low-priority behaviour for timeliness. One candidate that shows promise as a LBE congestion control is CAIA Delay Gradient (CDG). CDG uses changes in measured end-to-end delay to control the congestion window. CDG has several parameters that might help tune its “aggressiveness” in a way that might help achieve the goal of DA-LBE congestion control. We have evaluated CDG in order to establish how it can be tuned to exhibit different degrees of LBE behaviour under varying network conditions. Our results show that it is possible to control CDG to vary its aggressiveness in a consistent way, making it a prime candidate to implement a DA-LBE congestion control system.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | Workshop on Future of Internet Transport (FIT 2017) |
Publisher | IFIP |
ISBN Number | 978-3-901882-94-4 |
Keywords | congestion control, deadline-aware congestion control, Less-than-Best-Effort Service, scavenger service |
URL | http://dl.ifip.org/db/conf/networking/networking2017/1570350870.pdf |
DOI | 10.23919/IFIPNetworking.2017.8264882 |
Path Transparency Measurements from the Mobile Edge with PATHspider
In IEEE/IFIP Mobile Network Measurements Workshop. IEEE, 2017.Status: Published
Path Transparency Measurements from the Mobile Edge with PATHspider
Afilliation | Communication Systems |
Project(s) | MONROE: Measuring Mobile Broadband Networks in Europe |
Publication Type | Proceedings, refereed |
Year of Publication | 2017 |
Conference Name | IEEE/IFIP Mobile Network Measurements Workshop |
Publisher | IEEE |
DOI | 10.23919/TMA.2017.8002922 |
Journal Article
NEAT: A Platform- and Protocol-Independent Internet Transport API
IEEE Communications Magazine 55, no. 6 (2017): 46-54.Status: Published
NEAT: A Platform- and Protocol-Independent Internet Transport API
The sockets Applications Programming Interface (API) has become the standard way that applications access the transport services offered by the Internet Protocol stack. This paper presents NEAT, a user-space library that can provide an alternate transport API. NEAT allows applications to request the service they need using a new design that is agnostic to the specific choice of transport protocol underneath. This not only allows applications to take advantage of common protocol machinery, but also eases introduction of new network mechanisms and transport protocols. The paper describes the components of the NEAT library and illustrates the important benefits that can be gained from this new approach. NEAT is a software platform for developing advanced network applications that was designed in accordance with the standardization efforts on Transport Services (TAPS) in the Internet Engineering Task Force (IETF), but its features exceed the envisioned functionality of a TAPS system.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Journal Article |
Year of Publication | 2017 |
Journal | IEEE Communications Magazine |
Volume | 55 |
Issue | 6 |
Pagination | 46-54 |
Date Published | 06/2017 |
Publisher | IEEE |
ISSN | 0163-6804 |
DOI | 10.1109/MCOM.2017.1601052 |
Research Notes | https://www.neat-project.org/publications/#papers |
Operating ranges, tunability and performance of CoDel and PIE
Computer Communications 103 (2017): 74-82.Status: Published
Operating ranges, tunability and performance of CoDel and PIE
Bufferbloat is excessive delay due to the accumulation of packets in a router’s oversized queues. CoDel and PIE are two recent Active Queue Management (AQM) algorithms that have been proposed to address bufferbloat by reducing the queuing delay while trying to maintain a high bottleneck utilization. This paper fills a gap by outlining what are the operating ranges, that is the network characteristics (in terms of round-trip times and bottleneck capacity), for which these algorithms achieve their design goals. This new approach to the problem lets us identify deployment scenarios where both AQM schemes result in poor performance when used with default parameters. Because PIE and CoDel have been proposed with RED’s deployment issues in mind, it was essential to evaluate to what extent we can tune them to achieve various trade-offs and let them control the queuing delay outside their default operating range. We find that, by appropriate tuning (1) the amount of buffering can easily be controlled with PIE, (2) the Round Trip Time (RTT) sensitivity of CoDel can be reduced. Also, we observe there is more correlation between the congestion level, the achieved queuing delay and the targeted delay with CoDel than with PIE. This paper therefore concludes there is no single overall best AQM scheme, as each scheme proposes a specific trade-off.
Afilliation | Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Journal Article |
Year of Publication | 2017 |
Journal | Computer Communications |
Volume | 103 |
Pagination | 74-82 |
Date Published | 05/2017 |
Publisher | Elsevier |
Keywords | AQM, Bufferbloat, CoDel, congestion control, PIE |
DOI | 10.1016/j.comcom.2016.07.013 |
Technical reports
AQM Characterization Guidelines
IETF, 2016.Status: Published
AQM Characterization Guidelines
Unmanaged large buffers in today's networks have given rise to a slew of performance issues. These performance issues can be addressed by some form of Active Queue Management (AQM) mechanism, optionally in combination with a packet scheduling scheme such as fair queuing. The IETF Active Queue Management and Packet Scheduling working group was formed to standardize AQM schemes that are robust, easily implementable, and successfully deployable in today's networks. This document describes various criteria for performing precautionary characterizations of AQM proposals. This document also helps in ascertaining whether any given AQM proposal should be taken up for standardization by the AQM WG.
Afilliation | Communication Systems, Communication Systems, Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency, The Center for Resilient Networks and Applications |
Publication Type | Technical reports |
Year of Publication | 2016 |
Date Published | 07/2016 |
Publisher | IETF |
ISSN Number | 2070-1721 |
Keywords | Active Queue Management |
URL | https://tools.ietf.org/html/rfc7928 |
Public outreach
AQM for ISPs - decision maker video
RITE website: Reducing Internet Transport Latency, 2016.Status: Published
AQM for ISPs - decision maker video
This video is directed at decision makers in Network operators and equipment manufacturers. It contains a to-the-point explanation of some key technologies that needs to go into the Internet to reach the next evolutionary step.
Afilliation | Communication Systems |
Publication Type | Public outreach |
Year of Publication | 2016 |
Publisher | Reducing Internet Transport Latency |
Place Published | RITE website |
Keywords | AQM, Internet latency, ISP |
URL | https://videopress.com/v/WskDNI5r |
Journal Article
De-ossifying the Internet transport layer: A survey and future perspectives
IEEE Communications Surveys and Tutorials (2016).Status: Published
De-ossifying the Internet transport layer: A survey and future perspectives
It is widely recognized that the Internet transport layer has become ossified, where further evolution has become hard or even impossible. This is a direct consequence of the ubiquitous deployment of middleboxes that hamper the deployment of new transports, aggravated further by the limited flexibility of the Application Programming Interface (API) typically presented to applications. To tackle this problem, a wide range of solutions have been proposed in the literature, each aiming to address a particular aspect. Yet, no single proposal has emerged that is able to enable evolution of the transport layer. In this work, after an overview of the main issues and reasons for transport-layer ossification, we survey proposed solutions and discuss their potential and limitations. The survey is divided into five parts, each covering a set of point solutions for a different facet of the problem space: 1) designing middleboxproof transports, 2) signaling for facilitating middlebox traversal, 3) enhancing the API between the applications and the transport layer, 4) discovering and exploiting end-to-end capabilities, and 5) enabling user-space protocol stacks. Based on this analysis, we then identify further development needs towards an overall solution. We argue that the development of a comprehensive transport layer framework, able to facilitate the integration and cooperation of specialized solutions in an application-independent and flexible way, is a necessary step toward making the Internet transport architecture truly evolvable. To this end, we identify the requirements for such a framework and provide insights for its development.
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Journal Article |
Year of Publication | 2016 |
Journal | IEEE Communications Surveys and Tutorials |
Date Published | 11/2016 |
Publisher | IEEE |
ISSN | 1553-877X |
Keywords | API, middleboxes, protocol-stack ossification, transport protocols, user-space networking stacks |
DOI | 10.1109/COMST.2016.2626780 |
Poster
NEAT – A New, Evolutive API and Transport-Layer Architecture for the Internet
12th Swedish National Computer Networking Workshop (SNCNW 2016), Sundsvall, Sweden, June 1-2, 2016, 2016.Status: Published
NEAT – A New, Evolutive API and Transport-Layer Architecture for the Internet
Afilliation | Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Poster |
Year of Publication | 2016 |
Date Published | 06/2016 |
Place Published | 12th Swedish National Computer Networking Workshop (SNCNW 2016), Sundsvall, Sweden, June 1-2, 2016 |
Keywords | application-aware networking, Internet architecture, ossification, transport API, transport layer |
DOI | 10.5281/zenodo.55588 |
Proceedings, refereed
On the Cost of Using Happy Eyeballs for Transport Protocol Selection
In Applied Networking Research Workshop (ANRW). ACM, 2016.Status: Published
On the Cost of Using Happy Eyeballs for Transport Protocol Selection
Concerns have been raised in the past several years that introducing new transport protocols on the Internet has become increasingly difficult, not least because there is no agreed-upon way for a source end host to find out if a transport protocol is supported all the way to a destination peer. A solution to a similar problem—finding out support for IPv6—has been proposed and is currently being deployed: the Happy Eyeballs (HE) mechanism. HE has also been proposed as an efficient way for an application to select an appropriate transport protocol. Still, there are few, if any, performance evaluations of transport HE. This paper demonstrates that transport HE could indeed be a feasible solution to the transport support problem. The paper evaluates HE between TCP and SCTP using TLS encrypted and unencrypted traffic, and shows that although there is indeed a cost in terms of CPU load to introduce HE, the cost is relatively small, especially in comparison with the cost of using TLS encryption. Moreover, our results suggest that HE has a marginal impact on memory usage. Finally, by introducing caching of previous connection attempts, the additional cost of transport HE could be significantly reduced.
Afilliation | Communication Systems, Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2016 |
Conference Name | Applied Networking Research Workshop (ANRW) |
Pagination | 45-51 |
Date Published | 07/2016 |
Publisher | ACM |
ISBN Number | 978-1-4503-4443-2 |
Keywords | CPU load, Happy Eyeballs, memory usage, SCTP, tcp, TLS, Transport-protocol selection |
URL | https://irtf.org/anrw/2016/anrw16-final27.pdf |
DOI | 10.1145/2959424.2959437 |
Towards a Flexible Internet Transport Layer Architecture
In IEEE LANMAN. IEEE, 2016.Status: Published
Towards a Flexible Internet Transport Layer Architecture
There is a growing concern that the Internet transport layer has become less adaptive to the requirements of new applications, and that further evolution has become very difficult. This is because a fundamental assumption no longer holds: it can no longer be assumed that the transport layer is only in the scope of end-hosts. The success of TCP and UDP and the ubiquity of middleboxes have led to ossification of both the network infrastructure and the API presented to applications. This has led to the development of workarounds and point solutions that fail to cover many facets of the problem. To address this issue, this paper identifies requirements for a new transport layer and then proposes a conceptual architecture that we argue is both flexible and evolvable. This new architecture requires that applications interface to the transport at a higher abstraction level, where an application can express communication preferences via a new richer API. Protocol machinery can use this information to decide which of the available transport protocols is used. By placing the protocol machinery in the transport layer, the new architecture can allow for new protocols to be deployed and enable evolution of the transport layer.
Afilliation | Communication Systems, Communication Systems |
Project(s) | NEAT: A New, Evolutive API and Transport-Layer Architecture for the Internet |
Publication Type | Proceedings, refereed |
Year of Publication | 2016 |
Conference Name | IEEE LANMAN |
Publisher | IEEE |
ISBN Number | 978-1-4673-9882-4 |
ISSN Number | 1944-0375 |
Keywords | application-aware networking, Internet architecture, ossification, transport API, transport layer |
DOI | 10.1109/LANMAN.2016.7548846 |
Technical reports
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
Melbourne, Australia: Centre for Advanced Internet Architectures (CAIA), Swinburne University of Technology, 2015.Status: Published
Alternative Backoff: Achieving Low Latency and High Throughput with ECN and AQM
CoDel and PIE are recently proposed Active Queue Management (AQM) mechanisms that minimize the time packets spend enqueued at a bottleneck, instantiating shallow, 5 ms to 20 ms buffers with short-term packet burst tolerance. However, shallow buffering causes noticeable TCP performance degradation when a path’s underlying round trip time (RTT) heads above 60ms to 80ms (not uncommon with cross-continental and inter-continental traffic). Using less-aggressive multiplicative backoffs is known to compensate for shallow bottleneck buffering. We propose ABE: “Alternative Backoff with ECN”, which consists of enabling Explicit Congestion Notification (ECN) and letting individual TCP senders use a larger multiplica- tive decrease factor in reaction to ECN-marks from AQM- enabled bottlenecks. Using a mix of experiments, theory and simulations with standard NewReno and CUBIC flows, we show significant performance gains in lightly- multiplexed scenarios, without losing the delay-reduction benefits of deploying CoDel or PIE. ABE is a sender- side-only modification that can be deployed incrementally (requiring no flag-day) and offers a compelling reason to deploy and enable ECN across the Internet.
Afilliation | Communication Systems, Communication Systems, Communication Systems |
Project(s) | The Center for Resilient Networks and Applications |
Publication Type | Technical reports |
Year of Publication | 2015 |
Date Published | 07/2015 |
Publisher | Centre for Advanced Internet Architectures (CAIA), Swinburne University of Technology |
Place Published | Melbourne, Australia |
URL | http://caia.swin.edu.au/reports/150710A/CAIA-TR-150710A.pdf |
Report on Prototype Development and Evaluation of Network and Interaction Techniques
RITE Eu FP7 Project 317700, 2015.Status: Published
Report on Prototype Development and Evaluation of Network and Interaction Techniques
Afilliation | Communication Systems, Communication Systems |
Publication Type | Technical reports |
Year of Publication | 2015 |
Date Published | 09/2015 |
Publisher | RITE Eu FP7 Project 317700 |
Keywords | Algorithms, characterisation, co-ordination, congestion, Data Communication, Delay, Internet, metrics, networks, overhead, Performance, QoS, standardisation |
URL | https://riteproject.files.wordpress.com/2015/12/rite-deliverable-2-3.pdf |
Proceedings, refereed
Internet Latency: Causes, Solutions and Trade-offs
In EuCNC Special session on latency, 2015.Status: Published
Internet Latency: Causes, Solutions and Trade-offs
This paper is a digest of [1], an extensive survey discussing the merits of over 300 techniques for reducing Internet latency. It gives a broad overview of the causes, solutions, and trade-offs involved in reducing latency in the Internet. The overview covers key sources of delays and proposed solutions: due to the structural arrangement of the network, how network end-points interact, along the end-to-end path, related to link capacities, within end-hosts, and those that address multiple sources. Trade-offs are discussed in terms of the latency reduction different techniques provide versus their deployability
Afilliation | Communication Systems |
Publication Type | Proceedings, refereed |
Year of Publication | 2015 |
Conference Name | EuCNC Special session on latency |
Date Published | 05/2015 |
URL | https://riteproject.files.wordpress.com/2015/12/p548-hayes.pdf |
Tackling Bufferbloat in Capacity-limited Networks
In Proceedings of EuCNC 2015. Paris, 2015.Status: Published
Tackling Bufferbloat in Capacity-limited Networks
Over-provisioned network buffers, often at the Internet edge, induce large queuing delay and high latency; this issue is known as Bufferbloat. In response to this, a set of recently proposed Active Queue Management (AQM) algorithms attempt to reduce standing queues, while maintaining the bottleneck utilisation at an acceptable level. This paper assesses the performance of two AQM schemes (CoDel and FQ-CoDel) over capacity-limited networks with large Round-Trip Time (RTT). In such settings, these AQM schemes have difficulty controlling the buffering level, resulting in both momentarily high queuing delay and low bottleneck utilisation, even if the methods are claimed to be insensitive to link rates and round-trip delays. We explore this issue and show that it is possible to adapt the parameterisation of CoDel and FQ-CoDel to offer a higher bottleneck utilisation while maintaining a low queuing delay. We present experiments over an emulated test bed and a satellite network to confirm that our new parameterisation improves the download time of moderate-size files and reduces the latency for capacity-limited and large-RTT networks.
Afilliation | Communication Systems, Communication Systems |
Project(s) | The Center for Resilient Networks and Applications |
Publication Type | Proceedings, refereed |
Year of Publication | 2015 |
Conference Name | Proceedings of EuCNC 2015 |
Place Published | Paris |
Keywords | AQM, Bufferbloat, CoDel, Rural Broadband |
Talks, contributed
MONROE: Measuring Mobile Broadband Networks in Europe
In IRTF/ISOC Workshop on Research and Applications of Internet Measurements, 2015.Status: Published
MONROE: Measuring Mobile Broadband Networks in Europe
Afilliation | , Communication Systems |
Publication Type | Talks, contributed |
Year of Publication | 2015 |
Location of Talk | IRTF/ISOC Workshop on Research and Applications of Internet Measurements |
Type of Talk | Measurement platforms & tools |
URL | https://irtf.org/raim-2015 |
Journal Article
Reducing Internet Latency: A Survey of Techniques and their Merits
IEEE Communications Surveys and Tutorials 18, no. 3 (2014): 2149-2196.Status: Published
Reducing Internet Latency: A Survey of Techniques and their Merits
Latency is increasingly becoming a performance bottleneck for Internet Protocol (IP) networks, but historically networks have been designed with aims of maximizing throughput and utilization. This article offers a broad survey of techniques aimed at tackling latency in the literature up to August 2014, and their merits. A goal of this work is to be able to quantify and compare the merits of the different Internet latency reducing techniques, contrasting their gains in delay reduction versus the pain required to implement and deploy them. We found that classifying techniques according to the sources of delay they alleviate provided the best insight into the following issues: 1) the structural arrangement of a network, such as placement of servers and suboptimal routes, can contribute significantly to latency; 2) each interaction between communicating endpoints adds a Round Trip Time (RTT) to latency, especially significant for short flows; 3) in addition to base propagation delay, several sources of delay accumulate along transmission paths, today intermittently dominated by queuing delays; 4) it takes time to sense and use available capacity, with overuse inflicting latency on other flows sharing the capacity; and 5) within end systems delay sources include operating system buffering, head-of-line blocking, and hardware interaction. No single source of delay dominates in all cases, and many of these sources are spasmodic and highly variable. Solutions addressing these sources often both reduce the overall latency and make it more predictable.
Afilliation | Communication Systems, Communication Systems |
Project(s) | RITE: Reducing Internet Transport Latency |
Publication Type | Journal Article |
Year of Publication | 2014 |
Journal | IEEE Communications Surveys and Tutorials |
Volume | 18 |
Issue | 3 |
Pagination | 2149–2196 |
Date Published | 10/2016 |
Publisher | IEEE Communications Society |
ISSN | 1553-877X |
Other Numbers | ISSN: 1553-877X |
Keywords | Internet, latency, network |
URL | http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=6... |
DOI | 10.1109/COMST.2014.2375213 |
Proceedings, refereed
The New AQM Kids on the Block: An Experimental Evaluation of CoDel and PIE
In 17th IEEE Global Internet Symposium. Toronto: IEEE, 2014.Status: Published
The New AQM Kids on the Block: An Experimental Evaluation of CoDel and PIE
Active Queue Management (AQM) design has again come into the spotlight of network operators, vendors and OS developers. This reflects the growing concern and sensitivity about the end-to-end latency perceived by today's Internet users. CoDel and PIE are two AQM mechanisms that have recently been presented and discussed in the IRTF and the IETF as solutions for keeping latency low. To the best of our knowledge, they have so far only been evaluated or compared against each other using default parameter settings, which naturally presents a rather limited view of their operational range. We set thus to perform a broader experimental evaluation using real-world implementations in a wired testbed. We have in addition compared them with a decade-old variant of RED called Adaptive RED, which shares with CoDel and PIE the goal of ``knob-free'' operation. Surprisingly, in several instances results were favorable towards Adaptive RED.
Afilliation | Communication Systems |
Publication Type | Proceedings, refereed |
Year of Publication | 2014 |
Conference Name | 17th IEEE Global Internet Symposium |
Date Published | 04/2014 |
Publisher | IEEE |
Place Published | Toronto |
DOI | 10.1109/INFCOMW.2014.6849173 |
Proceedings, refereed
A Survey of Latency Reducing Techniques and their Merits
In Proc. ISOC Workshop on Reducing Internet Latency, 2013.Status: Published
A Survey of Latency Reducing Techniques and their Merits
Afilliation | Communication Systems, Communication Systems |
Publication Type | Proceedings, refereed |
Year of Publication | 2013 |
Conference Name | Proc. ISOC Workshop on Reducing Internet Latency |
Date Published | 09/2013 |
Keywords | Algorithms, characterisation, co-ordination, congestion, Data Communication, Delay, Internet, metrics, networks, overhead, Performance, QoS, standardisation |
Notes | (Position Paper) |
URL | http://www.internetsociety.org/sites/default/files/pdf/accepted/16_rite-... |