• Rethinking End-to-End Congestion Control in Software-Defined Networks

    Monia Ghobadi, Soheil Hassas Yeganeh and Yashar Ganjali

    The central suggestion is that centrally controlled SDN networks are in a position to choose which version of TCP will work best. OpenTCP tunes TCP for traffic and network conditions. Different TCP flavours perform better at different times or in different conditions e.g. datacentre TCP (DCTCP).

  • The RTT distribution of TCP flows on the Internet and its impact on TCP based flow control

    Srinivas Shakkottai, R. Srikant, Nevil Brownlee, Andre Broido and kc claffy
    CAIDA technical report

    This paper looks at RTT and how they affect TCP flows. Because of limited data they look at how to derive RTTs from analysis of tcpdump data (unidirectional).

    Methods of getting estimates of RTT are:

    • SYNSYN-ACKACK – the time stamp between SYN and ACK in triple handshake.

    • Flight method – look at packets with near identical inter-packet times. Calculate time between start of flights (attempt to ignore rate-limited flows).

  • How many tiers? Pricing in the Internet transit market

    Vytautas Valancius, Christian Lumezanu, Nick Feamster, Ramesh Johari and Vijay Vazirani

    This paper deals with the problem of ISPs selling contracts to other (customer) ISPs. Transit ISPs implement policies which price traffic by volume or by destination with volume discount and cheaper prices to destinations which cost them less. The paper studies destination based tiered pricing with the idea that ISPs should unbundle traffic and sell pricing in tiers according to destination to maximise profits.

    The background section offers a useful taxonomy of current bundles sold by transit ISPs. This arises from discussions with ISPs.

  • Serval: An End-Host Stack for Service-Centric Networking

    Eric Nordstrom, David Shue, Prem Gopalan, Robert Kiefer, Matvey Arye, Steven Y. Ko, Jennifer Rexford and Michael J. Freedman
    USENIX Symposium on Networked Systems Design and Implementation

    This paper looks at the problem of accessing services on a network which are potentially geographically distributed (for example, the closest server for a particular service). Serval allows the discovery of end-points for services and allows them to seamlessly migrate so ‘‘end-points can seamlessly change network addresses, migrate flows across interfaces… [with] uninterrupted service access." Serval runs on an unmodified network layer. Application communicate with service names (identifying the changing group of hosts providing a service) not addresses and ports.

  • Software-defined internet architecture: decoupling architecture from infrastructure

    Barath Raghavan, Martin Casado, Teemu Koponen, Sylvia Ratnasamy, Ali Ghodsi and Scott Shenker

    Paper advocates decoupling of network architecture from network infrastructure – Software Defined Internet Architecture (SDIA). Problem is to allow new architectures without falling back to a “clean slate” deployment.


    • Architecture: “the current IP protocol or any… convention on how packets are handled”.

    • Infrastructure: “physical equipment… (routers, switches, fibre, cables etc)”

  • Time-Dependent Internet Pricing

    Carlee Joe-Wong, Sangtai Ha and Mung Chiang
    Internet Technologies and Applications Conference

    This paper looks at time-dependent pricing schemes. A day is split into 48 half hour periods indexed by an integer. The system is known as TUBE (Time-dependent Usage-based Broadband-price Engineering). They use a control loop to adapt the prices ISPs charge users in response to changing behaviour.

  • OpenRadio: a programmable wireless dataplane

    Manu Bansal, Jeffrey Mehlman, Sachin Katti and Philip Levis
    Hot SDN

    Open Radio is a design for a programmable wireless dataplane. Wireless protocols evolve quickly and infrastructure for wireless must support this. Protocol changes are continuous but many basestations deployed. OpenRadio exposes an interface to program PHY and MAC layers. Key contributions

    1. Decouple protocol definition from hardware

    2. Abstraction layer for protocols decoupling processing and decision

    Design goals

    • 20MHz processing for OFDM complexity protocols

  • On the 95 percentile billing method

    Xenofontas Dimitropoulos, Paul Hurley, Andreas Kind and Marc Ph. Stoecklin
    Passive and Active Measurement Conference

    This paper describes the commonly used 95-percentile billing method which is often used by ISPs to bill other ISPs. The 95-percentile billing method is as follows:

    • Set a billing rate $y per Mbps (Megabit per second).

    • Take a month of traffic counts for the entity you wish to bill.

    • Split the traffic into equal sized time periods of length T (often 5 minutes).

    • Calculate the mean rate in Mbps for each time period.

  • Logically centralized?: state distribution trade-offs in software defined networks

    Dan Levin, Andreas Wundsam, Brandon Heller, Nikhil Handigol and Anja Feldmann
    Hot SDN


    Assumption behind paper is that control plane is decentralised but logically centralised. Physically centralised dismissed as impossible due to:

    1. responsiveness

    2. reliability

    3. scalability

    Controller component choices:

    • Strongly consistent – controller components always operate on the same world view. Imposes delay and overhead.

  • Good things come to those who (can) wait: or how to handle Delay Tolerant traffic and make peace on the Internet

    Nikolaos Laoutaris and Pablo Rodriguez
    Proc. of ACM HotNets-VII

    This paper talks about time shifting Delay Tolerant (DT) traffic in order to reduce bills for ISPs. Two schemes are posited

    • User incentives – users are encouraged to delay downloading with a reward scheme

    • Internet Post Offices (IPOs) – storage for store-and-forward relays for DT traffic.