Load-Sensitive Routing of Long-Lived IP Flows

ACM SIGCOMM Computer Communication Review, 2006

Extensive measurement studies have shown that end-to-end Internet path performance degradation is correlated with routing dynamics. However, the root cause of the correlation between routing dynamics and such performance degradation is poorly understood. In particular, how do routing changes result in degraded end-to-end path performance in the first place? How do factors such as topological properties, routing policies, and iBGP configurations affect the extent to which such routing events can cause performance degradation? Answers to these questions are critical for improving network performance.In this paper, we conduct extensive measurement that involves both controlled routing updates through two tier-1 ISPs and active probes of a diverse set of end-to-end paths on the Internet. We find that routing changes contribute to end-to-end packet loss significantly. Specifically, we study failover events in which a link failure leads to a routing change and recovery events in which a l...

… Annual Joint Conference of the IEEE …, 1998

We study a new approach to routing multi-class traffic flows with guaranteed bandwidth requirements. The approach is based on our concept of load profiling (Bestavros and Matta, 1997). We thoroughly characterize routing performance using load profiling and contrast it to routing using load balancing and load packing. We do so both analytically and via extensive simulations on virtual path (VP) based networks. Our findings confirm that load balancing is not desirable as it results in VP bandwidth fragmentation, which adversely ...

Lecture Notes in Computer Science, 2003

Finding a path in the network for a new incoming connection able to guarantee some quality parameters such as bandwidth and delay is the task of QoS routing techniques developed for new IP networks based on label forwarding.

Proceedings of the 2003 conference on Applications, technologies, architectures, and protocols for computer communications - SIGCOMM '03, 2003

Intra-domain traffic engineering can significantly enhance the performance of large IP backbone networks. Two important components of traffic engineering are understanding the traffic demands and configuring the routing protocols. These two components are inter-linked, as it is widely believed that an accurate view of traffic is important for optimizing the configuration of routing protocols and through that, the utilization of the network.

Telecommunications Networks - Current Status and Future Trends, 2012

ACM SIGCOMM Computer Communication Review, 2007

Dynamic load balancing is a popular recent technique that protects ISP networks from sudden congestion caused by load spikes or link failures. Dynamic load balancing protocols, however, require schemes for splitting traffic across multiple paths at a fine granularity. Current splitting schemes present a tussle between slicing granularity and packet reordering. Splitting traffic at the granularity of packets quickly and accurately assigns the desired traffic share to each path, but can reorder packets within a TCP flow, confusing TCP congestion control. Splitting traffic at the granularity of a flow avoids packet reordering but may overshoot the desired shares by up to 60% in dynamic environments, resulting in low end-to-end network goodput.

Physical Review E, 2004

We analyze different strategies aimed at optimizing routing policies in the Internet. We first show that for a simple deterministic algorithm the local properties of the network deeply influence the time needed for packet delivery between two arbitrarily chosen nodes. We next rely on a real Internet map at the autonomous system level and introduce a score function that allows us to examine different routing protocols and their efficiency in traffic handling and packet delivery. Our results suggest that actual mechanisms are not the most efficient and that they can be integrated in a more general, though not too complex, scheme.

Intra-domain Traffic Engineering (TE) aims to route around failures and congestion, and balance load in an ISP's network. Current TE relies on offline methods which use long term average traffic demands. It cannot react to traffic changes caused by BGP reroutes, diurnal traffic variations, attacks, or flash crowds. Further, current TE deals with network failures by pre-computing alternate routings for a limited set of failures. It may fail to prevent congestion when unanticipated or combination failures occur even though the network may have enough capacity to handle those failures. Since ISPs must ensure that each path in the network can cope with the peak load both during normal operation and under failures, current TE requires extensive over-provisioning. This paper presents TeXCP, an online distributed TE protocol that balances load in real-time, responding to actual traffic demands and failures. TeXCP uses multiple paths to deliver demands from an ingress to an egress router, adaptively moving traffic from overutilized to under-utilized paths. These adaptations are carefully designed such that, though done independently by each edge router based on local information, they balance load in the whole network without oscillations. We prove TeXCP is stable and show it is easy to implement. Our extensive simulations show that, for the same traffic demands, a network that uses TeXCP can support the same utilization and failure resilience as a network that uses traditional offline TE, but with a half or a third of the capacity.

IEEE Network, 1999

In today's Internet, individuals, campuses, and organizations obtain IP connectivity from transit providers. Internet interprovider routing is governed by bilateral traffic exchange agreements between providers. Such independently established policies can adversely impact the stability and analyzability of Internet routing. We describe an architecture for coordinating Internet routing policies. This architecture allows providers to publish high-level specifications of their policies, and to analyze the effects of their policies on Internet routing. Several pieces of the architecture have been implemented and are in production use; we also discuss the experiences gleaned from these deployments

2008

ABSTRACT The global Internet routing infrastructure is a large scale distributed system where routing changes occur all the time. While prior work on Internet routing dynamics examined routing stability to individual destinations, in this paper we study the routing stability of the Internet as a whole. We use the observed changes in the number of routes over each ASAS link as a metric and measure such changes from multiple vantage points over a period of one year.