SDN的形成与工作原理.ppt

* * * * * * * * * Motivations Tables might correctly reflect the policy, but… …hardware might not follow tables Hardware errors (e.g. memory or ASIC errors) Link failure Malicious hardware Who cares? Healthcare networks (e.g. HIPAA compliance) Credit card financial networks (e.g. PCI compliance) Military and intelligence networks Anyone who needs correct operation Software Defined Network (SDN) Global Network View Network Virtualization Packet Forwarding Packet Forwarding Packet Forwarding Abstract Network View Control Programs Control Programs Control Programs Packet Forwarding Network OS Packet Forwarding Match, Action Match, Action Match, Action Match, Action Match, Action … … Match, Action Match, Action Match, Action Match, Action Match, Action … … Match, Action Match, Action Match, Action Match, Action Match, Action … … Match, Action Match, Action Match, Action Match, Action Match, Action … … Match, Action Match, Action Match, Action Match, Action Match, Action … … Test every rule in every table? Isolate any fault? What is the minimum number of test packets to Test Packets Fault Localization How it worksAutomatic Test Packet Generation Automatic Test Packet Generation Test Packets Stanford Backbone Demo How many packets needed? 4,000 packets (despite 750,000 rules) Sent by end-hosts, or by switches Testing 10x per second, requires 1% of link-rate Lets us find run time errors fast What’s next Automatic performance testing Loss rate, flow rate, latency Example Application mapped to a congested router queue ATPG will Identify the queue Determine which headers (applications) incur poor performance 3. Interactive DebuggingFinding bugs, and their root cause, in an operational network Nikhil Handigol Brandon Heller Vimal Jeyakumar David Mazières Backtrace: Software Programming Function A(): u = B(v) Function B(): w = C(x) Function C(): y = error Breakpoint