1. Customer Driven Innovation
SDN: an Introduction
Luca Profico
lprofico@a10networks.com
Do not distribute/edit/copy without the
written consent of A10 Networks
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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
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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?
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4. What is, What is Not
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SDN is not a protocol
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SDN is not a suite of protocols
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SDN is not a technology
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SDN is a concept, a methodology, an architecture that aims
at making network implementation, scalability and
management easier by separating planes
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5. Network Devices and Planes
Build
and
exchange
informa2on
ARP
Control
plane
STP
…
Neighbors
…
MAC
Learning
Rou2ng
protocols
Build
and
store
local
L2/L3
info
tables
Data
plane
Packet
processing/forwarding
decisions
fwd
tbl
Forwarding
table
p
1
p
2
p
3
5
6. Network Devices and Planes
Control
plane
Control
plane
Control
plane
Control
plane
Data
plane
Data
plane
Data
plane
Data
plane
fwd
tbl
fwd
tbl
fwd
tbl
fwd
tbl
6
7. Network Devices and Planes
Control
plane
Control
plane
Control
plane
Control
plane
Data
plane
Data
plane
Data
plane
Data
plane
fwd
tbl
fwd
tbl
fwd
tbl
fwd
tbl
7
8. Network Devices and Planes
Control
plane
Data
plane
Data
fwd
tbl
plane
fwd
tbl
Data
plane
Data
fwd
plane
vendor
B
tbl
fwd
tbl
Data
plane
Data
fwd
plane
vendor
C
tbl
Data
plane
fwd
tbl
fwd
tbl
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9. SDN Implementation
Network
Network
Network
Network
Applica2on
Network operating system Applica2on
Applica2on
Applica2on
Northbound
API
Middleware
SDN
Controller
Southbound
API
Switch
vSwitch
Switch
Network Switch
Switch
vSwitch
vSwitch
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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)
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11. OpenFlow
†
Standard communication interface between control and
forwarding layer
†
OpenFlow specs
¿
¿
OF Switch specs 1.4 approved 2013
¿
†
OF Switch specs 1.3.2 published 2013
OF-Config (conf & mgmt protocol) 1.1.1 published 2013
Simple traffic processing
¿
Flow tables
¿
Pipeline concept
¿
OpenFlow Switches
¿
Hybrid OpenFlow Switches
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12. OpenFlow Tables
Flow Table
Match fields Priority
Counters
Instructions
Timeout
Cookie
Group Table
Group Identifier
Group Type
Counters
Action Buckets
Meter Table
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
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13. Example: Life of a Packet
Flow Table
Next table
Group Table
Action 1
Action 2
Action 3
Next table
Group Table
Action 4
Next table
switch
Action set
Action 5
Output
Meter Table
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14. OpenFlow Challenges
†
Protocol status. OF is simple. Maybe *too* simple
†
Which functionalities should stay resident?
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Large networks flow programming
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Hi-rate flow table update
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Vendors proprietary protocols
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15. Overlays
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VLAN on traditional networks has limitations
¿
¿
Transport
¿
†
Number of instances
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
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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
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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)
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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
°
°
†
STT
¿
¿
¿
†
Hyper-V embedded switch (Windows Network Virtualization Module) is prepopulated with all host-to-tunnel mappings by powershell CMDlets
No flooding, as there is no unknown node
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
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20. SDN Actual Use Cases
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Link usage optimization
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Distributed packet filtering
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NAC for devices that do not support 802.1x
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Service insertion, service chaining
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Network traffic analysis, TAP aggregation
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Basic link/service load balancing
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21. SDN Challenges
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Southbound API is uncertain and will be fragmented
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Scalability issues
¿
†
Number of flows
Performance issues
¿
Rate of flow-table updates
†
Redundancy
†
Vendors’ SDN controllers (OpenDaylight project?)
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Know-how
†
Security
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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
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