SDN in TETRA Group Communication - Voice Switching

Transcription

1 SDN in TETRA Group Communication - Voice Switching Author: Saumya Paulose Supervisor: Prof. Jukka Manner Instructor: M.Sc. Antti Tuominen Place of Work: Airbus Defence and Space, Helsinki

2 Contents Need for the study SDN OpenFlow TETRA Current Voice switching System Using SDN switch in Voice switching Measurements Conclusion

3 Need for the study and objectives Drive towards the feasibility study Virtualization trend in telecom field o Easy to develop, test and deploy new services o Custom hardware can be replaced with virtualized functions End-of-Life (EOL) of hardware components may need system design changes and increase maintenance cost SDN allows programmatic control over generic switch device Objectives Study the feasibility of COTS SDN switches replacing current voice switching unit Focus on Group Call and Ethernet/IP transport only

4 SDN Traditional Network SDN Network

5 SDN Seperating control plane from data plane. Defenitions OpenSDN SDN via Existing APIs SDN via Hypervisor based overlay networks Features of SDN plane separation, a simplified device, centralized control, network automation and virtualization, and openness.

6 OpenFlow Communication Interface standard between controller and SDN device, i.e. South Bound Interface OpenFlow Switch OpenFlow based/compatible switch OpenFlow only and Hybrid mode Hardware-based and Software-based switches OpenFlow Controller OpenFlow Channel OpenFlow Protocol

7 OpenFlow

8 OpenFlow Switch Tables Flow Table Fields Match Fields Priority Instructions Counters TimeOut Cookie Flags Idle_timeout Hard_timeout Forward Packet to port Forward Packet to Controller Forward Packet to another Flow Table Drop Packet Ingress Port VLAN ID Eth MAC Type Src Dst IP Src Dst Prot TCP/UDP sport dport

9 OpenFlow Switch Tables Group Table Fields Group ID Group Type Counters Action Buckets All Indirect Select Fast Failover

10 TETRA Open Standard developed by European Telecommunications Standards Institute (ETSI) Defines several interfcase and services related to Professional Mobile Radio (PMR) Interfaces -Air Interface, Peripheral Equipment Interface, Inter-System Interface Modes of Operations Voice plus Data (V+D) Direct Mode Operation (DMO) Packet Data Optimized (PDO) Encryption Techniques Air Interlace Encryption (AIE) End-to-end Encryption

11 TETRA System RT RT TBS TBS DXT DXT DWS RT TETRA Radio Terminal TBS TETRA Base Station DXT Digital Exchange for TETRA DWS Dispatch Work Station RT TBS DXT TBS

12 Airbus TETRA System Voice Communication One-to-One Communication o 2 participants o Duplex or Semi-duplex Group Communication o More than 2 participants o Semi-duplex Combined Group Calls Emergency Calls Announcements Short Data Servcies

13 Existing System - Voice Switching Signalling traffic goes to Signalling Unit Control and Management Unit add necessary table entries in Switching Unit Voice traffic reaches Switching unit Multiplied and forwarded to the recipients

14 Using SDN switch in Voice switching Difference between Existing System and Proposed System

15 Using SDN switch in Voice switching

16 Using SDN switch in Voice switching Switching Commands from Switch Control Unit reaches SDN Controller Application SDN Controller Application processes the commands and extracts the details of calling party and recipients. Flow modification messages are sent to the SDN switch to add, modify or delete flow entries and group entries. Voice packets reach the OpenFlow Switch and find appropriate matching flow entry. As instructed by flow entry, packets are forwarded to corresponding group enrty. Group Entry does multiplication and modification of voicepackets and forwards modified voice packets to recipients.

17 Voice Switching at SDN switch

18 Experimental Set Up

19 Measurements Switch parameters -Number of Flow entries, Group entries and Action buckets RTT of UDP QoS packets =0,35 ms Flow entry time -1 flow entry took 20ms and 3000 flow entries took 700ms 300 Average Switch Entry Time Time taken in ms Time Number of flows added

20 Conclusion Study found the proposed system is feasible Multiplication of packets is possible Used switch supports 32 group entries with 8 action buckets Security Redundancy Current capacity offering of COTS SDN switches are small, when considering requirements. Future study - replace hardware switch with software switch

21 Questions?????

22 Thank You...