Advanced Computer Networks - Systems Group1... · 2016-04-18 · Software Defined Networking: Challenges . ACN: Network virtualization | | Consistency Ensuring multiple decision elements

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Patrick Stüdi, Ankit Singla, Desislava Dimitrova

12.04.2016 1

Advanced Computer Networks Control and Data plane

D. Dimitrova

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Distributed control plane

http://aryaka.com/

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Centralized control plane

http://aryaka.com/

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Fast reaction time (Efficiency)

Quick behaviour updates (Scale)

Flexible flow management (Innovation)

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SDN is better

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SDN vs Virtual Networks

Source: VMWare

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SDN layer cake

Control applications

Controller

Infrastructure

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SDN layer cake

SDN Controller

Open Flow protocol

Local CPU/NPU

Switching fabric

Control applications

Controller

Infrastructure

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Control plane: Management functionality that provides instructions on

how traffic should be handled.

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SDN

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Data plane: Forwarding functionality that moves traffic and forms a topology.

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SDN

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It needs as input … It provides as output …

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SDN: Control plane

Source: bavaria.travel.com

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It needs as input Discovery messages Topology changes Flow stats

It provides as output Flow handling instructions

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SDN: Control plane

SDN Controller

Open Flow protocol

Local CPU/NPU

Switching fabric

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aka Network Operating System (NOS)

Implements control functionality Topology discovery & abstraction Rule conflict avoidance

Communicates with the data plane Open Flow protocol P4 Platform-secific protocols

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SDN: Control plane

SDN Controller

Open Flow protocol

Local CPU/NPU

Switching fabric

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Implementation: Single- vs multi-threaded

Deployment Centralized Physically distributed [KoT10, ToA10] Logically distributed [ShR10] Hierarchical controllers [YaS12]

Flow management mode Proactive mode [ReJ10] Reactive mode [CaM07]

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SDN: Control plane

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Implements the OpenFlow protocol [OF14] Messages, incl. flow rules and corresponding actions Switch & controller behaviour

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SDN: Control channel

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Parser: header state machine

Control program: table graph

Actions

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P4: Programming Protocol-independent Packet Processors

Source: J. Rexford, Princeton

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Protocol independent

Target independent

Reconfigurable

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P4: Programming Protocol-independent Packet Processors

Source: J. Rexford, Princeton

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Streaming algorithms on packets Matching on some headers (40 fields) Perform some actions

Wide range of functionality Mapping header fields Buffering and marking Forwarding Traffic monitoring Access control …

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SDN: Data plane

Local CPU/NPU

Switching fabric

match action

OF rules = (match,action)

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Packet handling Based on (match,action) pairs Multi-stage matching tables

Installed flow

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SDN: Data plane

Local CPU/NPU

Switching fabric

OF rule = (match XYZ, fwd)

action = fwd

Table X SRAM

Table Y TCAM

Table Z TCAM

Action fwd = 2

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New flow

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SDN: Data plane

Local CPU/NPU

Switching fabric

OF rule = (match XYZ, fwd)

action = fwd

Table X SRAM

Table Y TCAM

Table Z TCAM

Action fwd = 2

SDN Controller

Buffer

Pkt to controller

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ASIC fast packet processing slow & expensive updates

FPGA and NPU fast, reconfigurable hard to program

CPU slow packet processing easy to program

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SDN: Data plane

Source: Altera

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References for the interested [CaM07] M. Casado, M.J. Freedman, J. Pettit, J. Luo, N. McKeown, and S. Shenker. Ethane: Taking

control of the enterprise. In SIGCOMM Computer Commun. Review. 2007. [KoT10] T. Koponen, M. Casado, N. Gude, J. Stribling, L. Poutievski, M. Zhu, R. Ramanathan, Y.

Iwata, H. Inoue, T. Hama, et al. Onix: A distributed control platform for large-scale production networks. OSDI. 2010.

[OF14] OpenFLow Specification v1.4. Open Networking Foundation [ReJ10] Rexford, M.J. Freedman, and J. Wang. Scalable flow-based networking with DIFANE. In

SIGCOMM 2010 [ShR10] R. Sherwood, M. Chan, A. Covington, G. Gibb, M. Flajslik, N. Handigol, T.Y. Huang, P.

Kazemian, M. Kobayashi, J. Naous, et al. Carving research slices out of your production networks with openflow. In SIGCOMM Computer Commun. Review. 2010.

[ToA10] A. Tootoonchian and Y. Ganjali. Hyperflow: A distributed control plane for openflow. In INM. 2010.

[YaS12] S.H. Yeganeh and Y. Ganjali. Kandoo: a framework for efficient and scalable offloading of control applications. In HotSDN. 2012.

N. Kang, Z. Liu, J. Rexford, D. Walker. Optimizing the "one big switch" abstraction in software-defined networks. In CoNEXT 2013

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SDN: Control plane

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References for the interested G. Lu, R. Miao, Y. Xiong, and Ch. Guo. Using CPU as a traffic co-processing unit in commodity

switches. In HotSDN. 2012. J. Naous, D. Erickson, G.A. Covington, G. Appenzeller, and N. McKeown. Implementing an OpenFlow

switch on the NetFPGA platform. In ANCS. 2008. Charalampos Rotsos, Nadi Sarrar, Steve Uhlig, Rob Sherwood, and Andrew W. Moore. OFLOPS: an

open framework for openflow switch evaluation. In PAM. 2012. M. Kuzniar, P. Peresini and D. Kostic. What You Need to Know About SDN Flow Tables. In PAM.

2015 D.Y. Huang, K. Yocum, and A.C. Snoeren. High-fidelity switch models for software-defined

network emulation. In HotSDN. 2013. P. Bosshart, G. Gibb, H.-S. Kim, G. Varghese, N. McKeown, M. Izzard, F. Mujica, and M.

Horowitz. Forwarding metamorphosis: fast programmable match-action processing in hardware for SDN. In SIGCOMM. 2013.

E. Kohler, R. Morris, B. Chen, J. Jannotti, and M.F. Kaashoek. The click modular router. In ACM Trans. Comput. Syst. 2000.

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SDN: Data plane

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SDN in practice

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Scalability Decision elements responsible for many routers

Response time Delays between decision elements and routers

Reliability Surviving failures of decision elements and routers

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Software Defined Networking: Challenges

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Consistency Ensuring multiple decision elements behave consistently

Security Network vulnerable to attacks on decision elements

Interoperability Legacy routers and neighboring domains

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Software Defined Networking: Challenges

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Above the control plane

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Implement diverse control functionality Routing Bandwidth provisioning Load balancing Packet inspection Monitoring …..

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Software Defined Networking: Control applications

SDN Controller

Open Flow protocol

Local CPU/NPU

Switching fabric

Control applications