Ch 02 --- sdn and openflow architecture

NDI Communications - Engineering & Training
SDN & NFV
Chapter 2 – SDN and OpenFlow

Chapter Content
Network architecture
Network components
Tables
Applications
2

Traditional Network Structure
C
C
C
C
Forwarding Plane: End to end packets forwarding
Control Plane: Track topology changes, calculating routes, QoS and
security considerations and more
M
M
M
M
Management Plane: Measurements
and configuration

Software Defined Networking (SDN)
OpenFlow
Logically centralized control Smart, Slow controller
Dumb,
Fast switches
Controller
M
Business Applications

Chapter Content
Network architecture
Network components
Tables
Applications

Traditional Switch Forwarding
L2/VLANs
Table
L3 Table
ACLs, QoS Security, LB
Packets
in
Packets
out

Open Flow Switch Forwarding
Flow table
Packets
in
Packets
out
Flow table
Flow table
Flow table
SDN Controller

Open Flow Components
Controller
OpenFlow
Channel
Flow
Table
Flow
Table
Flow
Table
Open
Flow Protocol
Group
Table
Tables pipeline
Meter
Table

The Flow Table – Principle of Operation
Flow entry
Flow entry
Flow entry
Flow entry
Controller
Open
Flow Protocol
Flow Table
Match
Condition
Instructions…. ….

OpenFlow Switch Operations
Controller
OpenFlow
Channel
Flow
Table
Flow
Table
Flow
Table
Open
Flow Protocol
Group
Table
Tables pipeline
Packet
In
Packet
Out
Meter
Table

OpenFlow Controller
Manages one or more switches via
OpenFlow channels
Uses OpenFlow protocol to
communicate with a OpenFlow
aware switch.
Provides a network wide
abstraction for the
applications on north bound.
Responsible for
programming various
tables in the
OpenFlow Switch.
OpenFlow
Switch
Controller
OpenFlow
Switch
OpenFlow
Switch
App. App.
OpenFlow Protocol
Abstraction layer

OpenFlow Controller - Redundancy
Single switch can be managed by
more than one controller for load
balancing or redundancy purpose.
In the case of more than
one controller, the
controller can take any one
of the following roles:
Master
Slave
Equal
OpenFlow
Switch
Controller
OpenFlow
Switch
OpenFlow
Switch
Controller
App. App.
OpenFlow Protocol
Abstraction layer

Controller's Architecture
Single Equal Level Master-Slave

OpenFlow Channel
Used to exchange OpenFlow message
between switch and controller.
Switch can establish single or multiple
connections to same or different
controllers (auxiliary connections).
A controller configures and manages
the switch, receives events from the
switch, and send packets out the
switch via this interface
OpenFlow
Switch
Controller Controller
OpenFlow
Protocol

OpenFlow Switch
Consists of one or more flow tables, group table and meter table.
A single switch can be managed by one or more controllers.
The flow tables and group table are used during the lookup or forwarding
phase in order to forward the packet to appropriate port.
Meter table is used to perform simple QOS operations like rate-limiting
to complex QOS operations like DiffServ
OpenFlow
Channel
Flow
Table
Flow
Table
Flow
Table
Group
Table
Packet
In
Packet
Out
Meter
Table

OpenFlow Physical & Logical Ports
Packets
In/Out
Packets
In/Out
OpenFlow
Switch
Logical
Port
Physical
Port
The OpenFlow physical ports are
switch defined ports that correspond
to a hardware interface of the
switch.
The OpenFlow
logical ports are
switch defined
ports that don’t
correspond directly
to a hardware
interface of the
switch.

OpenFlow Reserved Ports
OpenFlow reserved ports specify generic
forwarding actions such as sending to the
controller, flooding, or forwarding using non-
OpenFlow methods, such as “normal” switch
processing.
There are required and optional reserved ports:
Required: ALL, CONTROLLER, TABLE, IN
PORT, ANY
Optional: LOCAL, NORMAL, FLOOD

OpenFlow Required Reserved Ports
Packets
In/Out
Packets
In/Out
OpenFlow
Switch
Controller
IN PORT: Represents
the packet ingress
port.
ANY: Special value
used in some OpenFlow
requests when no port
is specified
ALL: Represents all ports the switch can use for
forwarding a specific packet.
CONTROLLER: Represents the control channel with the
OpenFlow controllers
TABLE: Represents the start of the OpenFlow pipeline.

OpenFlow Optional Reserved Ports
Packets
In/Out
Packets
In/Out
OpenFlow
Switch
ControllerLOCAL: Represents the switch’s local networking
stack and its management stack.
NORMAL: Represents forwarding using the
traditional non-OpenFlow pipeline of the switch.
FLOOD: Represents
flooding using the
traditional non-
OpenFlow pipeline of
the switch.

Table Types
There are 3 types of tables in the OpenFlow switch:
Flow table – the standard table that allows to forward packet to a
single port
Group table – used for special actions like multicast, broadcast,
load balancing and others
Meter table – uses Per-flow meters that enables OpenFlow to
implement various QoS operations
OpenFlow
Channel
Flow
Table
Flow
Table
Flow
Table
Group
Table
Packet
In
Packet
Out
Meter
Table

Flow Tables Structure
Match Instructions
Modify Field
Remove from queue
Forward
NORMAL
FLOOD
Virtual
Port
Physical Port
Forward
Mandatory Instructions:
• Forward packet to port(s)
• Encapsulate and forward to
controller
• Drop packet
• Send to normal processing
pipeline
• Modify Fields
Mandatory Instructions:
• Forward packet to port(s)
• Encapsulate and forward to
controller
• Drop packet
• Send to normal processing
pipeline
• Modify Fields
Optional InstructionsOptional Instructions
Timeout
Match Instructions Timeout
…
Ingress
Port
Ethernet
SA DA Type
IP
SA DA Proto
TCP/UDP
Src
VLAN
ID Priority TOS Dst
Virtual
Port
ALL
CONTROLLER
LOCAL
TABLE
IN_PORT
Drop
Priority
Priority
Priority
Priority
Counters
Counters
Counters
Counters
Cookie
Cookie
Cookie
Cookie
Flags
Flags
Flags
Flags

Instructions
Meter meter_id (optional): Direct packet to the specified meter.
Apply-Actions action(s) (Optional): Applies the specific action(s)
immediately, without any change to the Action Set.
Clear-Actions (Optional): Clears all the actions in the action set
immediately.
Write-Actions action(s) (Required): Merges the specified set of
action(s) into the current action set
Goto-Table next-table-id (Required): Indicates the next table in
the processing pipeline.

Action Set
1. copy TTL inwards: apply copy TTL inward actions to the packet
2. pop: apply all tag pop actions to the packet
3. push-MPLS: apply MPLS tag push action to the packet
4. push-PBB: apply PBB tag push action to the packet
5. push-VLAN: apply VLAN tag push action to the packet
6. copy TTL outwards: apply copy TTL outwards action to the packet
7. decrement TTL: apply decrement TTL action to the packet
8. set: apply all set-field actions to the packet
9. qos: apply all QoS actions, such as set queue to the packet
10.group: if a group action is specified, apply the actions of the relevant group
bucket(s) in the order specified by this list
11.output: if no group action is specified, forward the packet on the port specified
by the output action

Table Match
Packet in
(Start in table 0)
Match in
table N?
Update counters
Execute instructions
YES
Table-miss
entry
exist?
Drop Packet
Goto next
entry in
table N
NO
NO
YES
Execute action set
NO
YES

Data Plane – SDN Switch (Example)
Simple packet-handling rules
Pattern: match packet header bits
Actions: drop, forward, modify, send to controller
Priority: disambiguate overlapping patterns
Counters: #bytes and #packets
1. src=10.20.*.*, dest=31.22.5.*  drop
2. src = *.*.*.*, dest=3.4.*.*  forward(2)
3. src=192.1.2.3, dest=*.*.*.*  send to controller

Examples (1)
Switching
*
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN
ID
IP
Src
IP
Dst
IP
Prot
TCP
sport
TCP
dport
Action
* 00:1f:.. * * * * * * * port6
Flow Switching
port3
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN
ID
IP
Src
IP
Dst
IP
Prot
TCP
sport
TCP
dport
Action
00:20.. 00:1f..0800 vlan1 1.2.3.4 5.6.7.8 4 17264 80 port6
Firewall
*
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN
ID
IP
Src
IP
Dst
IP
Prot
TCP
sport
TCP
dport
Action
* * * * * * * * 22 drop

Examples (2)
Routing
*
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN
ID
IP
Src
IP
Dst
IP
Prot
TCP
sport
TCP
dport
Action
* * * * * 5.6.7.8 * * * port6
VLAN Switching
*
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN
ID
IP
Src
IP
Dst
IP
Prot
TCP
sport
TCP
dport
Action
* * vlan1 * * * * *
port6,
port7,
port9
00:1f..

Group Table
A group table consists of group entries. The ability for a flow
entry to point to a group enables OpenFlow to represent
additional methods of forwarding (e.g. select and all)
Group Identifier Action bucketsGroup type Counters

Meter Table
A meter table consists of meter entries, defining per-flow
meters.
Per-flow meters enable OpenFlow to implement various simple
QoS operations, such as rate-limiting, and can be combined
with per-port queues to implement complex QoS frameworks,
such as DiffServ.
Meter Identifier Meter Bands Counters
Band type Rate Burst Counters Type specific arguments

Unifies Different Kinds of Boxes
Router
Match: longest
destination IP prefix
Action: forward out a link
Switch
Match: destination MAC
address
Action: forward or flood
Firewall (Packet filtering)
Match: IP addresses and
TCP/UDP port numbers
Action: permit or deny
NAT
Match: IP address and
port
Action: rewrite address
and port
36

Example OpenFlow Applications
Dynamic access control
Seamless mobility/migration
Server load balancing
Network virtualization
Using multiple wireless access points
Energy-efficient networking
Adaptive traffic monitoring
Denial-of-Service attack detection

OpenFlow in the Wild
Open Networking Foundation
Google, Facebook, Microsoft, Yahoo, Verizon, Deutsche
Telekom, and many other companies
Commercial OpenFlow switches
HP, NEC, Quanta, Dell, IBM, Juniper, …
Network operating systems
NOX, Beacon, Floodlight, Nettle, ONIX, POX, Frenetic
Network deployments
Eight campuses, and two research backbone networks
Commercial deployments (e.g., Google backbone)

Summary
Yoram Orzach
yoram@ndi-com.com
Thank You!!!
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Ch 02 --- sdn and openflow architecture

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Ch 02 --- sdn and openflow architecture