An introduction to the SDN subject and OpenFlow for the Festival della Tecnologia ICT

1. 1
Customer Driven Innovation
1
Do not distribute/edit/copy without the
written consent of A10 Networks
SDN: an Introduction
Luca Profico
lprofico@a10networks.com

2. 2
Who am I
 Luca Profico
 RSE@a10networks
 A10 Networks
 Networking company based in San Jose (CA)
 10 years developing its own solutions
 3# worldwide marketshare in ADC Market; #1 in Japan
 Leader in CGN and IPv6 Migration solutions

3. 3
Software-defined Networking
• SDN concept has been around for almost 9 years now but
the concept is not yet clear
• Marketing is riding SDN with bigger and bigger promises
• What will we do with SDN?
• US ICT Event survey:
• SDN, I don’t understand it but I want it.
• All this fuss for old concepts remixed.
• Will I lose my job because of SDN?

4. 4
What is, What is Not
 SDN is not a protocol
 SDN is not a suite of protocols
 SDN is not a technology
 SDN is a concept, a methodology, an architecture that aims
at making network implementation, scalability and
management easier by separating planes

5. 5
Network Devices and Planes
Build and exchange information
ARP MAC Learning STP …
Routing protocols Neighbors …
Build and store local L2/L3 info tables
Packet processing/forwarding decisions
Forwarding table
Control
plane
Data
plane
fwd tbl
p
1
p
3
p
2

6. 6
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Network Devices and Planes

7. 7
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Network Devices and Planes

8. 8
Data
plane
fwd tbl
Data
plane
fwd tbl
Data
plane
fwd tbl
Data
plane
fwd tbl
Control
plane
Data
plane
fwd tbl
Data
plane vendor B
fwd tbl
Data
plane vendor C
fwd tbl
Network Devices and Planes

9. 9
Network
Network operating system
Middleware
vSwitchSwitch Switch Switch Switch vSwitch vSwitch
SDN Controller
Network
Application
Network
Application
Network
Application
Network
Application
Northbound API
Southbound API
SDN Implementation

10. 10
Open Networking Foundation
 Members-only organization
 Milestones
 Founded in 2011
 More than 50 members in 1st yr.
 Over 100 members in 2013 (Vendors, SPs, Telcos)

11. 11
OpenFlow
 Standard communication interface between control and
forwarding layer
 OpenFlow specs
 OF Switch specs 1.3.2 published 2013
 OF Switch specs 1.4 approved 2013
 OF-Config (conf & mgmt protocol) 1.1.1 published 2013
 Simple traffic processing
 Flow tables
 Pipeline concept
 OpenFlow Switches
 Hybrid OpenFlow Switches

12. 12
OpenFlow Tables
Flow Table
Group Table
Meter Table
Match fields Priority Counters Instructions Timeout Cookie
Group Identifier Group Type Counters Action Buckets
Meter Identifier Meter Bands Counters
MAC src MAC dst IP src IP dst TCP dport … Action Count
* 10:20:. * * * * Port 1 99
* * 217.99.* * * * Table 6 18
* .:38:aa:. * * * * drop 4
* * * 7.7.9.4 25 * drop 172
* * * * 69 * local 19
* * * * * * controller 2993

13. 13
switch
Example: Life of a Packet
Flow Table
Group
Table
Group
Table
Meter Table
Next table
Action 1
Action 2
Action 3
Next table
Action 4
Next table
Action 5
Output
Action set

14. 14
OpenFlow Challenges
 Protocol status. OF is simple. Maybe *too* simple
 Which functionalities should stay resident?
 Large networks flow programming
 Hi-rate flow table update
 Vendors proprietary protocols

15. 15
Overlays
 VLAN on traditional networks has limitations
 Number of instances
 Transport
 Overlapping
 Some solutions have been tried
 HVLAN, QinQ, PBT, PBB-TE, Mac-in-mac, …
 With SDN we talk about Overlay networks
 Used to create virtual network containers logically isolated from the
others, while sharing the underlying physical network
 Always based on encapsulation. Usually tunnels are terminated on
softswitch

16. 16
VXLAN
 Virtual Extensible LAN
 Broadest industry support
 VXLAN
 Layer 2 frames in UDP packets
 VLAN frames are preserved – multiple Layer 3 networks inside a VXLAN
segment
 Uses multicast to transport broadcasts (openflow may avoid that)
 Tenants see their own “normal” network
 Underlying network sees UDP VXLAN traffic with a segment ID
 VXLAN ID is 24 bits = 16 Million tenants sharing the same infrastructure

17. 17
50 Bytes More. Jumbo Frames!
14 bytes Outer MAC Header
20 bytes Outer IP Header
8 bytes Outer UDP Header
8 bytes VXLAN Header
Original L2 frame
(VLAN tag included)

18. 18
Multi-tenant SDN Network
Switch Switch Switch Switch Switch Switch Switch Switch
ServerServer Server Server Server Server
vServer
vServer
vServer
vServer
vSwitchvSwitch vSwitch vSwitch vSwitch vSwitch
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
vServer
SDN Controller
Network Apps/UI/…

19. 19
NVGRE, STT, NVO3
 NVGRE
 Similar to VXLAN
 Microsoft pushes it
 Overlay of choice in Hyper-V
 Does not require multicast to carry broadcast, unknown unicast, multicast
 Hyper-V embedded switch (Windows Network Virtualization Module) is pre-
populated with all host-to-tunnel mappings by powershell CMDlets
 No flooding, as there is no unknown node
 STT
 Stateless Transport Tunneling
 Encapsulation leverages some specific network card capabilities, like
TSO (TCP segmentation offload)
 Nicira developed it. Nicira has been acquired by VMware
 NVO3
 Network Virtualization Overlays 3 - Developed by a group in IETF

20. 20
SDN Actual Use Cases
 Link usage optimization
 Distributed packet filtering
 NAC for devices that do not support 802.1x
 Service insertion, service chaining
 Network traffic analysis, TAP aggregation
 Basic link/service load balancing

21. 21
SDN Challenges
 Southbound API is uncertain and will be fragmented
 Scalability issues
 Number of flows
 Performance issues
 Rate of flow-table updates
 Redundancy
 Vendors’ SDN controllers (OpenDaylight project?)
 Know-how
 Security

22. 22
Conclusions
 SDN future is uncertain, at the moment most of the
development is being done on large data
centers, backbones, virtualization spaces
 So far there is no real use for the enterprise
 The southbound API will most probably be fragmented
 It will take some time: as some analysts point out, it took
server virtualization 10 years to become mainstream, while
openflow 1° release was born in 2009
 SDN will add up to $400M within the networking market in
2014 (Doyle Research)
 In the end, the market will decide what SDN will be, where it
will be used, what applications we’ll write on it

23. 2323
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