How long do your SDN controllers take to converge?

A key latency metric for network control plane systems is
*convergence time*: the
duration between when a change occurs in a network and when
the network has converged to an updated configuration that accomodates
that change. The faster the convergence time, the better.

Convergence time depends on many variables: latencies between network devices, the number of network devices, the complexity of the replication mechanism used (if any) between controllers, storage latencies, etc. With so many variables it can be difficult to build an intuition for how the variables interact to determine overall convergence time.

The purpose of this tool is to help build that intuition. Based on analytical models of communication complexity for various replication and network update schemes, the tool quantifies convergence times for a given topology and workload. With it, you can answer questions such as "How far will my current approach scale while staying within my SLA?", and "What is the convergence time of my network under a worst-case workload?".

Accuracy - Monte Carlo simulation means we run repeated trials for a given configuration. This parameter determines how many samples we take to determine the CDF.

Operation Latency - How long does each processing
step take? Here, this includes the time to compute a write response at a single node
(W), the network latency between controllers (P_{c}) and between switches and
controllers (P_{s}), and the latency to compute a read response at a single
node (R). The distributions are currently delayed according to a Pareto distribution.
Lower alpha correspond to heavier tails.

Topology Generation - Controls the arrangement and number of controllers and switches in the network.

CDF of Time to Convergence

Time After Network Event (ms)

Operational Latency

Parameters modeled with Pareto distributions

R: Read Latency

Latency (ms)

Median: 0 ms, 99.9th %ile:
0 ms

W: Write Latency

Latency (ms)

Median: 0 ms, 99.9th %ile:
0 ms

P_{s}: Network Latency

Latency (ms)

Median: 0 ms, 99.9th %ile:
0 ms

P_{c}: Network Latency

Latency (ms)

Median: 0 ms, 99.9th %ile:
0 ms

Topology:

Number of switches:
0

Number of controllers:
0

Accuracy:
0 points

Median | 99.9th %ile | |
---|---|---|

Traditional | 0 ms | 0 ms |

Single | 0 ms | 0 ms |

1PC | 0 ms | 0 ms |

2PC | 0 ms | 0 ms |

Paxos | 0 ms | 0 ms |

If you have any questions, please contact us at andrewor14@gmail.com or cs@cs.berkeley.edu. We have a detailed writeup of this tool available upon request.