How SDN will shape networking

https://www.youtube.com/watch?v=c9-K5O_qYgA

1980s
- Specialized applications, specialized OS, specialized hardware
- Vertically integrated, closed, proprietary
Then
- Open interface, rapid innovation, huge industry
Availability of merchant switching chips
- On top of there: multiple control planes
SDN
Example
- Interesting comparisons across OSPF (245 pages), Distributed System (101 pages), Dijkstra's Algorithm (4 pages)
- Start by building a distributed system!
  - Replication comes at a cost (complexity, not elegant)
  - Instead
    Being refactored through different abstractions and different interfaces; make it easier to introduce new functionalities over time
Openflow Forwarding Abstraction
- Standardization have the benefits to give abstractions (but in a pragmatic way; perfection is not the goal here)
- Match Action Table
  - Actually all layers of the network is doing this
  - As general as possible to match any header that you define
  - How to use minimal sets of actions (meaningful set of primitives); leaving rooms for chip vendors to be able to implement it in hardware, and box vendors to differentiate by adding additional features / capabilities
- Protocol independent
- Backward compatible
- Technology independent
  - Switches, routers, WiFi APs
SDN in development

Customize networks to local needs
- e.g. Add distributed load balancing
  - What if we can jointly optimize path and server?
  - Easy for testing
Eliminate unneeded features
- Features not needed in the network, can increase reliability
Creation of virtual, isolated networks
- Isolate sets of users, multi-tenancy

Innovation at software speed
- Define the operations in software
- Can start doing much of the testing in software
- E.g. Mininet: Rapid for prototyping
  - Light weight emulation; take any of these pieces, move them over machines and cores
  - Fast
    Emulate network with 10s of switches on one laptop
    Emulate network with 1000s of switches in server rack
  - Rapid transfer
    Deploy unmodified code directly into live network
Standards (if any) will follow software development
Technology exchange with partners
- Across boundaries, combine the boundaries use BGP etc.
Technology transfer from universities

Standardized forwarding abstraction
Provable network properties at every step
- E.g. header space analysis: static checking
- Network transfer function: set of Bollean expressions
- Only relies on <match, action>
- Can prove reachability

Last updated 1 year ago