A hybrid network traffic engineering system

Abstract

This paper describes traffic analysis undertaken to answer certain questions needed to design a hybrid network traffic engineering system (HNTES). The hybrid network in question consists of an IP-routed network and a dynamic virtual-circuit network, and the role of HNTES is to identify and redirect α-flows, which are defined as flows in which the number of bytes exceeds a threshold H (1 GB) over at least one α-interval (1 minute). NetFlow data from ESnet was analyzed. Our findings show that raw IP α-flows (identified by the 5-tuple) are mostly short-lived (80% are shorter than 2 minutes), which implies that HNTES should use an offline mechanism for identifying α-flows and preconfiguring policy-based routes to redirect packets for these flows to virtual circuits since setup delay is about 1 minute. An offline mechanism using prefix flow identifiers (/32 source and destination IP addresses or /24 source and destination subnets) appears to be highly effective because α-flow generating sources and sinks typically have static public IP addresses. For example, an analysis of two months of NetFlow data from an ESnet router shows that more than 94% of the total number of bytes from α-flows would have been redirected had a /24 based offline HNTES solution been deployed.