The document discusses the redesign of the LTE packet core using Network Function Virtualization (NFV) and Software-Defined Networking (SDN), highlighting their benefits in flexibility and scalability. It compares performance through various EPC prototypes and finds that NFV excels in control plane throughput, while SDN handles higher data plane traffic. Ongoing research focuses on optimizing designs and enhancing performance metrics for future implementations.

1. Redesigning the LTE Packet Core
with NFV and SDN
Mythili Vutukuru
Assistant Professor, CSE
IIT Bombay

2. Network Func<on Virtualiza<on (NFV)
Source: http://www.globalservices.bt.com/uk/en/point-of-view/nfv

3. SoAware Defined Networking (SDN)
Source: http://cacm.acm.org/magazines/2014/10/178789-abstractions-for-software-deOined-networks/

4. Why SDN and NFV?
• Why NFV?
– Easier to develop software appliances
– Elastic scaling with distributed software
• Why SDN?
– Flexibility in changing control plane logic
– Easier scaling of commodity data plane
• Applications
– Middleboxes (Oirewalls, DPI, load balancers)
– Appliances in telecom networks (LTE packet core, customer
premise equipment)

5. LTE Evolved Packet Core (EPC)
Attach/register
Data
• Complex functionality in hardware appliances
• DifOicult to scale, inOlexible, expensive

6. Proposal: NFV EPC
• Flexible, scalable software appliances
• Use commodity high-end servers, data centers

7. Proposal: SDN EPC
• Flexible software-based control plane
• Commodity SDN switches in data plane

8. So, what is the future of EPC?
• Several proposals that use NFV and SDN to redesign LTE
packet core in 5G and beyond.
• Probably no clear winner: which design is better depends
on several factors.
• A few commercial startups in trial mode.
• No open-source software implementation to compare
performance of various designs
– A few frameworks focus on standards compliance only
– No published performance comparison of prototypes
– DifOicult for researchers to compare across designs

9. Our work: Enable Performance
Comparison of EPC Design Choices
• Goals:
– Develop various candidate EPC prototypes
– Common framework to compare design choices
– Implement features that impact performance
– Modular, extensible, open-source code
• Non goals: full standards compliance, real
life deployments

10. Our NFV-based EPC
• RAN simulator to simulate user+base station
• Multi-threaded program to simulate multiple users
• Simulated users can attach, detach, send data trafOic to sink

11. Our SDN-based EPC
• Floodlight SDN controller and Open vSwitch SDN switches
• SDN switch (“Default Switch”) connects RAN to EPC

12. Experimental Setup
• NFV EPC
– OpenStack private cloud
– Components run on KVM-based VMs
• SDN EPC
– Software SDN switches: OpenvSwitch on Linux
– Floodlight controller on high end server
– Some experiments with all components on same
physical machine – to overcome network bottleneck
• Similar CPU and memory for both setups for fair
comparison

13. Experimental Method
• Experiments
– Users in simulated RAN continuously register and
detach (control plane)
– Attached simulated users continuously pump TCP
trafOic (data plane)
• Metrics
– Control plane throughput (number of registrations/sec)
– Data plane throughput (bps forwarded by gateways)
– Latency, processing overheads

14. Results: Control Plane
NFV SDN
• NFV EPC gives much higher control throughput
• SDN EPC limited by controller -switch communication
• Latency and processing overhead comparable
~9,000 req/s
~3,000 req/s

15. Results: Data Plane
NFV SDN
• SDN EPC handles much higher data plane trafOic
• NFV EPC limited by OS network stack in the VM and host
~120 Mbps
~45 Gbps

16. Summary of results
• NFV or SDN for EPC? Well, it depends on…
– Mix of trafOic (control vs. data)
– SpeciOic implementation used
• Performance of both prototypes can be improved
– Distributed / hierarchical SDN controllers
– Optimized NFV data plane (e.g., using DPDK)
– Elastic, scalable network functions
• Many other points to explore in the design space
• Our comparison is not the Oinal word; only the
beginning of an exploration of design choices

17. Ongoing research using our code
• Design of a multicore VNF when using kernel bypass like
DPDK: how to steer packets to app cores?
– Hardware multiqueue or software distribution
– Partition using application sematics or TCP header?

18. Our code on GitHub
• https://github.com/networkedsystemsIITB
• v1.0 of both EPCs released in June 2016
• v1.1 of NFV EPC (distributed EPC) released Nov 2016
• v2.0 of both EPCs expected in next few months
– Hierarchical SDN controllers
– Improved data plane using Intel DPDK, netmap
– Userspace network stack based on multicore-TCP