Open SDN Switch OS
Rob Sherwood
Big Switch Networks
Ethernet Technology Summit 2014
Santa Clara, CA USA
April-May 2014
1
Rob Sherwood
• CTO, Software architect at
Big Switch Networks
• ONF: former chair of ArchWG
and vice-chair of TestingWG
• Working in OpenFlow/SDN
since 2008
• Wrote the FlowVisor:
• http://flowvisor.org
Santa Clara, CA USA
April-May 2014
2
Outline
• Motivation: Open Networking
• SDN Basics
• Switch Software
• Open Network Linux
• OF-DPA
• Conclusions and Community
SDN Architectural Evolution
BEFORE
NOW
Automation Tool
Automation Tool
APIs
North-bound
APIs
SDN App
North-bound
APIs
SDN App
SDN Controller
SDN Controller
CP/DP
Separation
OpenFlow
&
Extensions
OpenFlow
(Thick) NetOS
OF
(Thin) SDN OS
Network HW
• Too many moving parts (multiple SDN SW vendors)
• OF agent SW from HW vendor!
• Limited access to switch ASIC access
OpenFlow
is just API
Network HW
•
•
•
•
SDN SW solution from single vendor
Exactly like the hypervisor/server model
Full access to switch ASIC
Accelerate HW/SW disaggregation
SDN Architectural Evolution
Cloud
Fabric
Automation Tool
Big Tap
Big Switch
Network’s
Commercial
Products
This talk:
Open Source
Switch OS
©2014 BIG SWITCH NETWORKS, INC.
WWW.BIGSWITCH.COM PROPRIETARY AND CONFIDENTIAL
SDN App
SDN Controller
(Thin) SDN OS
Network HW
5
Isn’t Networking already open?
All Hardware
Specs Public
X86 Servers
 Open
Binary SDK
for Packet
Forwarding
NPU, FPGA, SoC
Closed OS,
Open Control
Plane APIs
DC – 1U
ToRs, Spines
Closed OS,
Open APIs for
Policy, Stats
Multi-chassis
Routers
10 Gb/s
100 Gb/s
1 Tb/s
Aggregate Throughput 
10 Tb/s
Isn’t Networking already open?
All Hardware
Specs Public
X86 Servers
 Open
Binary SDK
for Packet
Forwarding
NPU, FPGA, SoC
Closed OS,
Open Control
Plane APIs
This talk
DC – 1U
ToRs, Spines
DC – 1U
ToRs, Spines
Closed OS,
Open APIs for
Policy, Stats
Multi-chassis
Routers
10 Gb/s
100 Gb/s
1 Tb/s
Aggregate Throughput 
10 Tb/s
Goal: One Big Switch
Controller 1
Spine
Leaf
Controller 2
Line Card
Line Card
4
5
1
2
3
4
5
6
Leaf
Line Card
Chassis-based
Fabric
6
Leaf
3
Leaf
Line Card
2
Spine
Line Card
1
Spine
Supervisor 2
Fabric Backplane
Supervisor 1
These designs
are
fundamentally
the same!
Leaf-Spine
Fabric
Forwarding Abstraction: Flow Table
Flow
Table
Flow
FlowTable
Table
Priority
Match
Action List
500
IP.proto=6
TCP.dst=22
TTL--,
Fwd:port 3
200
IP.dst=
128.8/16
*
Queue: 4
100
DROP
• “Assembly Language of Networking”
• Too low-level for most operators
• Active work in the Open Networking Foundation to bring
OpenFlow to feature parity with “closed flow”
Switch Scaling: Understanding Tables


Classical OpenFlow versus Modern
Proactive and Multi-table OpenFlow
Processing
Pipeline
VLAN
Table
L2 Table:
L3 Table:
100K+
Entries
100K+
Entries
Early OpenFlow
implementations only
used the most flexible
table.
• Didn’t scale well
• Scale forced reactive
population
• Reactive caused
controller load and
addition scale
problems
Our Modern OpenFlow
implementation leverages
all tables
• Scales like traditional
• Allows proactive
population
• Proactive reduces
controller load and
allows for headless
control
ACL Table:
~2k Entries
OpenFlow does NOT imply
Flow-based Networking
Egress Table
10
OUtline
• Motivation: Open Networking
• SDN Basics
• Switch Software
• Open Network Linux
• OF-DPA
• Conclusions and Community
Switch Light Architecture
Big Network
Controllers
Legend
Open
Network
Linux
OpenFlow
Agent
CLI
Switch Light OS
Indigo
Loxi
BSN Open
ZTN
Loader
BSN
Closed
3rd Party
Closed
Source
SSH
Fan
Control
NTP
Syslog
SNMP
LibC on Debian Wheezy Base Distribution
ONL Linux Kernel
I2C
GPIO
Device
Trees
Indigo/ASIC Driver
ASIC SDK
ASIC
Switch Light is our Indigo OpenFlow Agent running on Open
Network Linux on x86 or ASIC-based hardware.
Open Network Linux
A Linux distribution for bare metal switches
• Open-sourced commercial code, build scripts, drivers from Switch Light
• Part of Open Compute Project (OCP)
• Project goals:
• Improve perception/de-risk bare metal
• “Crowd source” larger Switch Light HCL
• Released mid-January: Initial results
• Strong community response from ODMs, OCP
• Accton self-supporting three new boxes, more ODMs interested
• Other vendors investigating ONL for their own purposes
• Info: http://opennetlinux.org – under construction
ONL – Supported Hardware
• ONL Support is
Pre-cursor to
Switch Light
Support
• Working on OCP
box from Interface
Masters with x86
support
OpenFlow Datapath Abtraction: OF-DPA
Indigo
open
driver
OF-DPA
SDK
Chip
OF-DPA API
closed
Conclusion and Community
• Many Open Source projects
• Take the pieces or the whole: ONL
• Didn’t have time: Indigo and Loxi
• All of these projects are used by BSN
• Quality, tested code
• “Productized” modern OpenFlow
• Join at: opennetlinux.org/community
• Comments and feedback welcome