Charactersing the Limits of the OpenFlow Slow-Path Richard Sanger,
[email protected] Brad Cowie,
[email protected] Matthew Luckie,
[email protected] Richard Nelson,
[email protected] University of Waikato, New Zealand 28 November 2018 The Question How slow is the slow-path? © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 2 Contents • Introduction to the Slow-Path • Motivation • Test Suite • Test Methodology • Results • Conclusions © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 3 OpenFlow Packet-in and Packet-out To move packets between the controller and network, packets are encapsulated in OpenFlow packet-in and packet-out messages and sent via the slow-path. © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 4 The Fast-Path ASIC OpenFlow Agent Ingress Egress OpenFlow Switch Network © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 5 The Slow-Path (Packet In) ASIC OpenFlow Agent Packet in OpenFlow Switch Network Control-Plane Network OpenFlow Application NIC Controller © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 6 Motivation: Control Traffic Requirements Control traffic is sensitive to bandwidth and latency Latency • Keep-alives • Flow Establishment (Reactive control) Bandwidth • Initial route exchange (BGP etc.) • Capture (Network debugging) • DoS (Misconfiguration, ICMP, etc.) © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 7 Motivation: Control Traffic Requirements Control traffic requirements must be met simultaneously. Example: consider the requirement of link detection probing. • Typical Bidirectional Forwarding Detection (BFD) requirements • < 50ms • 2,880pps (48 port switch) © THE UNIVERSITY OF WAIKATO • TE WHARE WANANGA O WAIKATO 8 Motivation: Shared Resource The slow-path is shared with all other OpenFlow messages.