Lecture 6: Software Defined Networks"

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1 Lecture 6: Software Defined Networks" CSE 222A: Computer Communication Networks Alex C. Snoeren Thanks: Nick McKeown, Jeremy Stribling, Kai & Lin

2 Lecture 6 Overview" Project discussion Software Defined Networking overview Onix discussion CSE 222A Lecture 6: Software Defined Networks" 2

3 Evolution of Computing" App App App App App App App App App App App Specialized Applications Open Interface Specialized Operating System Windows (OS) or Linux or Mac OS Open Interface Specialized Hardware Microprocessor CSE 222A Lecture 6: Software Defined Networks" 3

4 Evolution of Networking?" App App App App App App App App App App App Specialized Features Specialized Control Plane Specialized Hardware Open Interface Control Plane or Control Plane or Control Plane Open Interface Merchant Switching Chips CSE 222A Lecture 6: Software Defined Networks" 4

5 Software Defined Networking" f ( View) Control Programs f ( View) f ( View) Control Programs Control Programs Abstract Network View Network Virtualization! Global Network View Network OS! Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding CSE 222A Lecture 6: Software Defined Networks" 5

6 OpenFlow" If header = x, send to port 4 If header = y, overwrite header with z, send to ports 5,6 If header =?, send to me Flow Table CSE 222A Lecture 6: Software Defined Networks" 6

Basic OF Operations" Match arbitrary bits in headers:" Header! Data! Match: 1000x01xx0101001x!

7 Basic OF Operations" Match arbitrary bits in headers:" Header! Data! Match: 1000x01xx x! Match on any header, or new header" Allows any flow granularity" Action" Forward to port(s), drop, send to controller" Overwrite header with mask, push or pop" Forward at specific bit-rate" " " CSE 222A Lecture 6: Software Defined Networks" 7

8 What is a Network OS?" ONIX provides abstractions for network management Basic functionalities: State distribution primitives between controllers and network elements. Virtualized network elements A global view & control of the network Very different from Active Networking vision (node local) CSE 222A Lecture 6: Software Defined Networks" 8

9 Onix Architecture" CSE 222A Lecture 6: Software Defined Networks" 9

10 Design Requirements" Generality: Support a wide range of network management applications Scalability: No inherent limitations due to the platform Reliability: Graceful failure handling Performance: Sufficient performance CSE 222A Lecture 6: Software Defined Networks" 10

11 Onix API" Developers program against a network graph Nodes represent physical network entities CSE 222A Lecture 6: Software Defined Networks" 11

12 Network Information Base" The NIB is the focal point of the system State for applications to access External state changes imported into it Local state changes exported from it CSE 222A Lecture 6: Software Defined Networks" 12

13 Scalability" Physical controller becomes a bottleneck: Memory: to keep NIB CPU and bandwidth: to process events This is a classic distributed systems problem Partitioning Aggregation CSE 222A Lecture 6: Software Defined Networks" 13

14 Partitioning For Scale" Multiple dimensions available to applications: Onix instances with different computations tasks Onix instances have only subsets of the NIB Switches connect to a subset of Onix instances CSE 222A Lecture 6: Software Defined Networks" 14

15 Aggregating for Scale" Reduce fidelity of information before disseminating within the cluster CSE 222A Lecture 6: Software Defined Networks" 15

16 Aggregating for Scale" Reduce fidelity of information before disseminating within the cluster CSE 222A Lecture 6: Software Defined Networks" 16

Consistency" Onix provides two storage options Replicated transactions (SQL) storage One-hop memory-based DHT Do we need strong consistency for forwarding state between the

17 Consistency" Onix provides two storage options Replicated transactions (SQL) storage One-hop memory-based DHT Do we need strong consistency for forwarding state between the controller and routers? Do we need strong consistency for NIB stored in controllers? Is it reasonable to ask applications for consistency preference and resolving conflicts?

18 Reliability" Network Element & Link Failures: Applications' responsibility Connectivity Infrastructure Failures: Assumed reliable Onix Failures: Onix provides distributed coordination facilities provided for app failover CSE 222A Lecture 6: Software Defined Networks" 18

19 Discussion" What are the security implications of Onix? Is Onix flexible and general enough for networking management? Are there applications you can run on a centralized network but not on a distributed one? CSE 222A Lecture 6: Software Defined Networks" 19

20 For Next Class " Read and review Vahdat s Fat Tree paper Submit project groups by Friday morning to Siva group members & idea(s) CSE 222A Lecture 6: Software Defined Networks" 20

OpenFlow and Onix. OpenFlow: Enabling Innovation in Campus Networks. The Problem. We also want. How to run experiments in campus networks?

OpenFlow and Onix. OpenFlow: Enabling Innovation in Campus Networks. The Problem. We also want. How to run experiments in campus networks? OpenFlow and Onix Bowei Xu boweixu@umich.edu [1] McKeown et al., "OpenFlow: Enabling Innovation in Campus Networks," ACM SIGCOMM CCR, 38(2):69-74, Apr. 2008. [2] Koponen et al., "Onix: a Distributed Control