This is a presentation on a research work we had done on software defined networking. It involves improving data plane processing in SDN networks by embedding application-level intelligence

1. ET2541: Advanced Topics in Telecommunication
systems
Application-aware Data-Plane Processing in SDN
Nitin Reddy Ayyagari
Pruthviraj Reddy Kanmantha
{niay14, prkb14@student.bth.se}

2. Software-Defined Networking
 Key Aspects:
 Changing traffic patterns and rise of Cloud Services-bandwidth hungry
 Current infrastructure limitations-complexity, vendor lock-in and
scalability
 SDN-New paradigm in network automation, aims to meet the dynamic
needs of future networks
 Decoupling control plane from the forwarding plane in a network
 Enabling software programs to monitor, operate and manage networks
 Reduction in CAPEX and OPEX, flexible traffic managment and
enhanced control over the network
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
1

3. OpenFlow
 Key Aspects
 Programmability of data plane through an open API like OpenFlow
 Operates through <match, action> rules
 Forwarding rules installed in network
Elements by centralized controller
 Parsing of packet headers-checked against
entries, corresponding actions taken!
 Implemented in TCAM
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ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
2
SDN Framework

4. Need for application
awareness in data-plane
processing
 Key Aspects
 Current works more focused in programmability of control plane and little
with respect to data plane
 Parsing of headers limited to L2-L4
 More functionality can be extended by adding upto L7 processing
 Different services have different requirements, think about multi-tenant
data centres
Ex: Bandwidth requirement for Web browsing and Video Streaming
 Network functions such as Load balancing and Firewall require deep
packet inspection above transport layer.
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
3

5. Application-aware architecture
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
4
 Flow specific actions- inspection and
matching of various packet fields
 Packets Kernel Flow table Flow table
pipeline Connection manager
Controller
 Round trip delay from Switch to the
controller
 Application logic locally at data plane
instead of controller
 Intercept the packets before being sent to
the controller
 Adds stateful app processing capability to
Fig: Extended SDN architecture
Source: Bell labs, Alcatel Lucent

6. App table
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
Kurt Tutschku
 Introduction of App table, similar to Flow table in principle
 Experimented a case where request from client, directed
to servers based on L7 processing(content-aware
processing)
 Reduced response times with less overhead
 Service chaining of apps possible
 Terminate all further action based on specific event
occurrence
 Downside is no dynamic addition of app logic without
disruption

7. Tagging approach : TagFlow
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ET2541: Adv. Topics in Telecom.-
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 OpenFlow, an open API for SDN
based on <match,action> rules
 Main problem: predefined protocol headers,
need for support for more protocols,
convergence of fields
 OpenFlow v1.1 has 15 fields, v1.3 has 40 fields
 Approach: Tagging vs Hashing
 Offloading classification load and label
assignment at network edge
 Theme: Application layer classification at the
edge and one field matching at the core
 Tag attached at the end of the packet for
Source: Akihiro Nakao,
University of Tokyo
Fig 1: TagFlow system architecture

8. TagFlow
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
Kurt Tutschku
 TagFlow supports a more flexible field-matching using
tagging approaches as an alternative to OpenFlow
 Tag classification- on basis of security, priority based
forwarding
 Advantage: Much less overhead on core network
 Experimented on FLARE switch-open deeply
programmable switch
 Tagging < Hashing < Deep packet inspection in terms of
processing times

9. User-defined actions
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
Kurt Tutschku
 Actions in OpenFlow are not flexible to modify
 No feasibility of adding user-defined actions to the
current architecture
 User, here refers to the network operator and not end-
user
 Freedom to implement new functions rather than doing it
through middle boxes
 Running applications in south bound data plane
promising than running in north bound control plane
 Lack of accessibilty of packet payload to control plane,
consequence is difficulty in matching more than one bit
stream
 Implementing two security solutions in control and data

10. Other approaches
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
Kurt Tutschku
 Middle boxes extensively deployed! May not vanish in
foreseeable future
 ETTM: End to the Middle, centralized software being
implemented on certain end points
 Middle boxes extensively manipulate the packet headers
 Flow Tag approach to track the flows of the packets
between middle boxes
 Not revolutionary solutions, only for improving current
state of the infrastructure

11. Conclusion
• Rethinking networking
– Open interfaces to the data plane
– Separation of control and data
– Application awareness in routing and data processing
• Significant momentum
– In both research and industry
LP2 2014/15
ET2541: Adv. Topics in Telecom.-
systems - Technical Lecture 1
Kurt Tutschku