A Seminar paper presentation for the course: distributed systems

1. CIDC: AN EAST-WEST
INTERFACE FOR
DISTRIBUTED SDN
CONTROL PLANE
Sina Ebrahimi
Advisor: Saeed Jalili, PhD
Distributed Systems

2. OUTLINE
• Introduction
• Related Work
• Network model and description of CIDC
• Some implemented services in CIDC interface
• Experiments description
• Evaluation analysis
• Conclusion
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3. INTRODUCTION
• What is SDN?
• Main idea: To remove the control plane (decisional part) from network
devices and shift it to a single controlling point.
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Application
Plane
Control
Plane
Data Plane

4. INTRODUCTION
• Centralization of control provides an abstract topology view of the
underlying infrastructure to our network applications.
• Results: Simplification of network management and the development
of new services.
• Some challenges appear when the size of network grows:
• Scalability
• Performance
• Capacity of the controller to handle lots of requests
• Ability to scale geographically
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5. INTRODUCTION
• Two main propositions of control plane design to tackle those latter
issues:
• Logically centralized design:
• Distributes the load between controllers and uses a shared database to unify
decisions
• Requires extensive synchronization between controllers
• Suitable for intra-domain network architecture
• Logically distributed design:
• Proposed to extend SDN for large distributed networks
• Each controller can manage its domain and distribute necessary data to other
controllers
• Usable in large data centers and WAN networks that suffer from high cost and
latency
• Suitable for inter-domain network architecture
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6. INTRODUCTION
• Primary importance in logically distributed control planes:
• Communication between controllers
• This paper’s contribution:
• Providing an east-west interface called Communication Interface for Distributed
Control Plane (CIDC)
• CIDC provides:
• Communication modes (Notification, Service, and Full)
• New mechanism based on policy sharing to support distributed services such as
DFS or DLBS
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7. RELATED WORK
• Many controllers use the logically centralized control approach
• Like ONIX, HyperFlow, and OpenDayLight
• ODL forms a cluster to support multiple controllers
• Not feasible for logically distributed architecture where each controller has its
own database
• Cluster consumes more resources to build information trees
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8. RELATED WORK
• Some controllers use the logically distributed architecture
• Like SDNi, and East-West (EW) Bridge
• EW Bridge is designed to support different controllers with various local network
view storage systems (no shared db between controllers)
• EW Bridge uses Publish/Subscribe model to synchronize data
• Some challenges should be solved:
• Scalability under high load
• Sharing various services between controllers
• Security
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9. NETWORK MODEL OF CIDC
• CIDC interface uses an event-driven paradigm
• When a modification is observed in data plane, new events are sent to the
controller and the interface starts sharing these events to other controllers.
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10. NETWORK MODEL OF CIDC
• CIDC interface is used by each controller to synchronize its stats and
services with neighboring controllers
• Each controller plays the role of a Consumer for external events and a
Producer for internal events.
• 4 essential modules of CIDC :
• Producer
• Consumer
• DataUpdater
• DataCollector
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11. NETWORK MODEL OF CIDC
• Algorithm of CIDC:
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12. NETWORK MODEL OF CIDC
• 3 Communication modes that will customize the role of each controller
in the network, and add (if necessary) fine-grained control of sensitive
domain.
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13. IMPLEMENTED SERVICES IN CIDC INTERFACE
• Distributed Firewall Service
• Only Controller is able to inspect packets
• Forwarding device can be programmed to behave as a firewall
• Admin could apply his rules one time and the controller does the rest by
automatically exchanging these rules with other controllers (if necessary).
• Distributed Load Balancer Service
• DLBS shares LB rules to other domains using CIDC interface, allowing clients to
request for remotely available services.
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Two
Approaches

14. IMPLEMENTED SERVICES IN CIDC INTERFACE
• Service Algorithm for both DLBS and DFS:
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15. EXPERIMENTS DESCRIPTION
• The experiment is a comparison of:
• OpenDayLight (Hydrogen Release)
• Uses cluster mode to build a logically centralized control plane
• FloodLight (with CIDC interface)
• Supports logically distributed control plane using CIDC
• Establishes full mesh connections between controllers
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16. EXPERIMENTS DESCRIPTION
• Emulated topologies:
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(a) Gridnet
(b) HiberniaUK (c) Claranet
(d)
Marwan

17. EXPERIMENTS DESCRIPTION
• A large ring WAN topology
• Each local network is interconnected with neighboring networks using GRE
tunnel
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18. EVALUATION ANALYSIS
• Event synchronization delay between controllers
17/21Girdnet_3 topology

19. EVALUATION ANALYSIS
• Memory consumption
• Number of exchanging events in CIDC is optimized, and each controller
sends just its local events.
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Memory Consumption in Claranet_4
topology

20. EVALUATION ANALYSIS
• Inter-controller communication overload
• ICO: Total rate of bidirectional traffic exchanged between controllers
• ODL replicates all data trees to all members to keep network consistent
• CIDC shares data based on configured mode, which reduces the amount of
data that the controller must distribute
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21. CONCLUSION
• CIDC could synchronize notification and services without performance
penalty, and provide fine-grained control of events between controllers
• The vast majority of state changes and services could be synchronized lightly
and quickly
• The simulations showed good results of CIDC in terms of delay, overhead and
system consumption
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22. REFERENCE PAPER
• An East-West interface for distributed SDN control plane
• Published in:
• Elsevier Journal:
• Computers and Electrical Engineering, Volume 57 Issue C
• January 2017
• Authors:
• (From University of Rabat, Morocco)
• Fouad Benamrane
• Moad Ben Memoun
• Redouane Benaini
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Thanks for your attention…
Any Questions?