Equal Cost Multipath Routing in FOKUS OpenSDNCore

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  • UWB

    Equal Cost Multipath Routing in FOKUS OpenSDNCore

    Hai Dinh Tuan

    Next Generation Networks & Future Internet Technologies Projects

  • Introduction ECMP & SDN Problems Solutions Demo Remark

    Agenda

  • The separation of

    control plane (routing

    functionalities) and

    data plane (forwarding

    functionalities)

    Introduction - SDN

    Source: SDNCentral

  • Shortest path first (SPF) algorithm calculates the single shortest path

    from a source node to a destination is used in Link-state protocols

    such as OSPF and IS-IS.

    Equal Cost Multipath is a Traffic Engineering technique that enables

    using several equal cost paths in IP routing

    Introduction - ECMP

  • Introduction ECMP (2)

    Which path(s) is used for packet forwarding from A to G?

  • Shortest Path First

    Only 1 path {A,D,G} is stored in forwarding table

  • Equal Cost Multipath Routing

    Multiple paths {A,D,G}, {A,E,D,G}, {A,E,F,G} are used for forwarding

  • Routing

    Problems in this project

    IMPLEMENT ECMP IN OPENSDNCORE

    Controller-switch communication

    Forwarding

    How to calculate all possible paths

    How to implement all paths in switches

    How to choose path for packet forwarding

    Controller Switch

  • Routing Problems

  • Set each links cost along the shortest path to infinite, and run the

    shortest path calculation again each time

    Arc cutting method

  • How it works (1)

    A single shortest part is discovered by Dijkstra's algorithm as normal

  • How it works (2)

    Delete one link of shortest path by setting its weight to infinitive

  • How it works (3)

    Execute Dijkstra's algorithm one more time and compare path cost

  • How it works (4)

    Delete another link of shortest path

  • How it works (5)

    Continue using Dijkstra's algorithm

  • How it works (6)

    Finally, multiple equal cost paths are discovered

  • Communication Problems

  • What type of messsages to be transfered between controller

    and swiches?

    FlowMod message

    GroupMod message

    How to implement all posible paths?

    FlowMod Add Flow Entry message

    GroupMod Add Bucketmessage

    Message types

  • Forwading Problems

  • Which path selection scheme should be used? Random? Round Robin? Hash-based?

    Packet forwarding

  • Which path selection scheme should be used? Random Round Robin? Hash-based

    Packet forwarding

  • Random ECMP

  • CONTROLLER SIDE

  • SWITCH SIDE

  • ENTRY LOOKUP OPERATION

  • Hash based ECMP

  • CONTROLLER SIDE

  • SWITCH SIDE

  • ENTRY LOOKUP OPERATION

  • Comparison

    Random ECMP Hashed based ECMP

    Advantages

    Simple, implement only on the Controller

    Deterministic behavior

    Work well with any switchProvides control over

    path selection

    Disadvantages

    Possible congestionRequire more

    computing resources

    Possible congestion

  • Demo Topology

  • Remark

    Expected outcomes Results

    Successful implementation of ECMP in OpenSDNCore

    Detailed documentation

    Efficient communication between supervisor and student

    Gather experiences

  • Remark

    Expected outcomes Results

    Successful implementation of ECMP in OpenSDNCore

    Detailed documentation (to be submitted)

    Efficient communication between supervisor and student

    Gather experiences

  • UWBTHANK YOUHai Dinh Tuan

    Next Generation Networks & Future Internet Technologies Projects