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Existing campus network infrastructure is not designed to effectively handle the transmission of big data sets. Performance degradation in these networks is often caused by middleboxes -- appliances that enforce campus-wide policies by deeply inspecting all traffic going through the network (including big data transmissions). We are developing a Software-Defined Networking (SDN) solution for our campus network that grants privilege to science flows by dynamically calculating routes that bypass certain middleboxes to avoid the bottlenecks they create. Using the global network information provided by an SDN controller, we are developing graph databases approaches to compute custom paths that not only bypass middleboxes to achieve certain requirements (e.g., latency, bandwidth, hop-count) but also insert rules that modify packets hop-by-hop to create the illusion of standard routing/forward despite the fact that packets are being rerouted. In some cases, additional functionality needs to be added to the path using network function virtualization (NFV) techniques (e.g., NAT). To ensure that path computations are run on an up-to-date snapshot of the topology, we introduce a versioning mechanism that allows for lazy topology updates that occur only when "important" network changes take place and are requested by big data flows.
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Contra: A Programmable System for Performance-aware Routing
We present Contra, a system for performance-aware routing that can adapt to traffic changes at hardware speeds. While point solutions exist for a fixed topology (e.g., a Fattree) with a fixed routing policy (e.g., use least utilized paths), Contra can operate seamlessly over any network topology and a wide variety of sophisticated routing policies. Users of Contra write network-wide policies that rank network paths given their current performance. A compiler then analyzes such policies in conjunction with the network topology and decomposes them into switch-local P4 programs, which collectively implement a new, specialized distance-vector protocol. This protocol generates compact probes that traverse the network, gathering path metrics to optimize for the user policy dynamically. Switches respond to changing network conditions by routing flowlets along the best policy-compliant paths. Our experiments show that Contra scales to large networks, and that in terms of flow completion times, it is competitive with hand-crafted systems that have been customized for specific topologies and policies.
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- Award ID(s):
- 1837030
- PAR ID:
- 10195188
- Date Published:
- Journal Name:
- 17th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2020
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
