Exploiting Path Diversity in Datacenters using MPTCP-aware SDN
Date Issued
November 30, 2015
DOI
10.1109/ISCC.2016.7543794
Abstract
Recently, Multipath TCP (MPTCP) has been proposed as an alternative transport
approach for datacenter networks. MPTCP provides the ability to split a flow
into multiple paths thus providing better performance and resilience to
failures. Usually, MPTCP is combined with flow-based Equal-Cost Multi-Path
Routing (ECMP), which uses random hashing to split the MPTCP subflows over
different paths. However, random hashing can be suboptimal as distinct subflows
may end up using the same paths, while other available paths remain unutilized.
In this paper, we explore an MPTCP-aware SDN controller that facilitates an
alternative routing mechanism for the MPTCP subflows. The controller uses
packet inspection to provide deterministic subflow assignment to paths. Using
the controller, we show that MPTCP can deliver significantly improved
performance when connections are not limited by the access links of hosts. To
lessen the effect of throughput limitation due to access links, we also
investigate the usage of multiple interfaces at the hosts. We demonstrate,
using our modification of the MPTCP Linux Kernel, that using multiple subflows
per pair of IP addresses can yield improved performance in multi-interface
settings.
approach for datacenter networks. MPTCP provides the ability to split a flow
into multiple paths thus providing better performance and resilience to
failures. Usually, MPTCP is combined with flow-based Equal-Cost Multi-Path
Routing (ECMP), which uses random hashing to split the MPTCP subflows over
different paths. However, random hashing can be suboptimal as distinct subflows
may end up using the same paths, while other available paths remain unutilized.
In this paper, we explore an MPTCP-aware SDN controller that facilitates an
alternative routing mechanism for the MPTCP subflows. The controller uses
packet inspection to provide deterministic subflow assignment to paths. Using
the controller, we show that MPTCP can deliver significantly improved
performance when connections are not limited by the access links of hosts. To
lessen the effect of throughput limitation due to access links, we also
investigate the usage of multiple interfaces at the hosts. We demonstrate,
using our modification of the MPTCP Linux Kernel, that using multiple subflows
per pair of IP addresses can yield improved performance in multi-interface
settings.