2. 1 Research Methodology

3. 2 Doctor of Technology Thesis A Multi-Channel Network Architecture Based on Fast Circuit Switching by Per Lindgren

4. 3 At the end you should have heard … Optical Multi-Channel Networks; Packet switched or circuit switched networks Understand about DTM; New Interface design to cater for High bandwidth networks;

5. 4 About Per Lindgren Per Lindgren VP Business Development (founder) Net Insight. Born 1967. Ph.D. in Teleinformatics (KTH 1996). Per was previously Assistant Professor at KTH, where he was involved in the DTM project, among other things. He has also been involved in the DIM project.

6. 5 Rationale for this study Evolution of Fiber and Optical networks; Increase of link Capacities Broadband networks vs Integration of Video, VoIP, and other distributed multimedia applications Integration of communication, computing and media

7. 6 Issues addressed by this thesis Bottlenecks in processing and buffering in switch points; Bottlenecks in network links (fiber), protocols and host interfaces Consequences of a communication bottleneck change ( I.e., circuit-switched versus packet-switched networks)

8. 7 New Proposal New network architecture based on DTM New Host Interface

9. 8 The thesis examines Optical multi-channel networks, eg. Based on WDM Believe that parallel channel structure in such networks is more cost effective solution than increasing the bit rate of a single bit stream. The interface between the network and the host interface and the host interface design

10. 9 What technology at the time this thesis was written ATM FDDI Fast Ethernet was springing

11. 10 End to end communication A Switching Device B Network A Network B

12. 11 End to End Communication Protocol Interface design Communication media Communication media Interface design Protocol Design Switch point Routing protocol

13. 12 Domain = Scope of the Thesis Two different aspects of end-to-end communication: Service requirements and Performance aspects, within two different areas: –Network Architecture –Host Interface Design

14. 13 Contents of the thesis (179 pages) Introduction …………………………………………………………………8 pages Architecture for high Capacity Communications: Background ………………………………………………………..3 Existing Network Architectures ……………………………. 10 Multichannel Network Systems …………………………….. 6 Host Interface Design …………………………………………. 10 DTM –Circuit Switching Enhanced for Future Integrated Services: Basic Principles of DTM ………………………………………… 7 DTM Protocol Suite ………………………………………………. 30 DTM Enhancements ………………………………………….. 6 DTM Prototype Network …………………………………….. 8

15. 14 Contents of the thesis DTM Using Parallel Bitstreams: ………………………………………… 35 pages Parallel DTM Protocol Aspects………………………………. Parallel DTM Hardware aspects ……………………………. Parallel DTM Synchronization Aspects…………………….. Prototype Implementation……………………………………… Distributed Switching……………………………………………. Simulation of Parallel DTM……………………………………. Simulation Results……………………………………………….. DTM Host Interface………………………………………………………….. 20 pages The DTM Shared Memory Host Interface……………….. A Low-Cost Interface to the DTM Network………………. Hardware Aspects of the Prototype Interface…………… Performance Measurements ………………………………….. Conclusion and Future Work ……………………………………………..3+3 Pages References …………………………………………………………………….. 16 pages with 205 ref

16. 15 Packet Switching Internet Network

17. 16 Circuit Switching Telephone Network

18. 17 Competing Technologies ATM – Asynchronous Transfer Mode Gigabit Ethernet FDDI – Fiber Distributed Data Interface DPT – Dynamic Packet Transport DTM – Dynamic Synchronous Transfer Mode

19. 18 Competing Technologies

20. 19 ATM – What is it? Pros? And Cons? Asynchronous Transfer Mode (ATM) is a packet switching and multiplexing technology designed as a general-purpose connection oriented (virtually circuit switched) transport mechanism for a wide range of services. Asynchronous Transfer Mode (ATM) Benefits –Supports different types of data –High transmission rates –Good support for real-time traffic –Scales easily –Well suitable for long distances Drawbacks –Complex technology –Expensive –Does not interoperate well with Ethernet –No support for broadcast or multicast –Only QoS for some ATM traffic classes – Large amount of overhead

21. 20 FDDI – What is it? Pros? and Cons? FDDI uses a dual ring topology. During normal operation, the primary ring is used for data transmission, and the secondary ring remains idle. The primary purpose of the dual rings is to provide superior reliability and robustness. Benefits Reliable Built in redundancy Large MTU size Well tested Drawbacks Limited traffic capacity (100 Mbps) More expensive Lacks multicast support No future potential

22. 21 Gigabit Ethernet- What is? Pros and Cons Ethernet standard 802.3 started in the 1973 Improved to fast ethernet – 100Mbps 1995 Began the Gigabit Ethernet standard 802.3z 10Gbps Standard 802.3ae on the way 10Gbps Standard 802.3ae Benefits Cheap Well known Commonly used Simple to manage Support for multicast and broadcast Low overhead Drawbacks No Bandwidth guarantees Best effort – Problems for applications such as VoIP, VC or any Real time application Small MTU size Limited management capability

23. 22 DTM – What is it? Pros? And Cons? Developed at KTH Built in circuit switching technology Built in circuit switching technology But utilizes the best features of Circuit and packet switching technologies It enables the user to set up and tear down the circuits instantly (like in a packet switched system) while getting reservation of bandwidth (which all circuit switched systems offer) Benefits –Offers true QoS –Dynamic increase/decrease of bandwidth (DTM channels) –Fixed overhead size (depending on number of nodes), i.e. not proportional to link data speed. Small total overhead –Fast set-up and tear-down of channels compared to other circuit switched technologies –Simple and good support for multicast –Compatible with other technologies, support for IP-routing, Ethernet bridging, VLAN and E1/T1 tunneling. Can be run on dark fiber, DWDM and SDH/SONET (not all DTM versions) –Deterministic delay –High capacity

24. 23 DTM – What is it? Pros? And Cons? … Drawbacks Circuit switched. Setting up a connection takes time (even though it is faster than other circuit switched alternatives), which is negative for short transfers New technology with an uncertain future Dynarc and Net Insight develop different protocols that are incompatible Minimum channel speed is 512 kbps, which might be unnecessary high for small transfers Complex, with unnecessarily many parameters Expensive,

25. 24 DPT – What is it? Pros? and Cons? Developed by CISCO Official name is Resilient Packet Ring - IEEE 802.17Official name is Resilient Packet Ring - IEEE 802.17 DPT is designed to be an IP packet optimized transport solution. Combine the bandwidth efficiency and services-rich capabilities of IP routing with the self-healing capabilities of fiber rings. The key applications for DPT include cable data backbone access rings and regional transport rings. Benefits –Fair allocation of bandwidth –Low overhead –Effective use of bandwidth (Spatial Reuse) –Very Reliable and Robust –Redundancy and large MTU size – native multicast support and can distinguish between high priority and low priority packets Drawbacks –Double ring needed –Delays caused by buffering in nodes

26. 25 Host Interface Design RAM CPU Host Interface System Bus Transmission Medium Bottlenecks

27. 26 DTM –Circuit Switching Enhanced for Future Integrated Services: DTM Enhancements Fast Channel Creation Fast Channel Establishment over several hops Dynamic Signaling Base Frames consisting of multiple cycles Virtual Networks Slot Reuse in DTM Parallel DTM Switch Replication DTM Prototype Network Fig 1. DTM Prototype Node

28. 27 DTM Using Parallel Bit streams Two ways to increase transmission capacity: Increase bit rate on the fiber; Use parallel bit streams In both we can use Wavelength division multiplexing (WDM) Space Division Multiplexing (SDM) The proposed solution uses parallel bit streams with WDM

29. 28 DTM Using Parallel Bitstreams … Prototype Implementation –The prototype uses replicated hardware to receive data on both wavelengths simultaneously. –That is possible due to use of two demux, two slot counters and two channel tables on the board.That is possible due to use of two demux, two slot counters and two channel tables on the board. Distributed Switching –Distributed Switching scheme between two fibers in parallel DTM is done electrically. –Is based on the shared medium to avoid switch bottleneck Simulation of Parallel Analyses were performed with regard to Slot Utilization, blocking and access delay for a dual bus with a varying number of parallel bit streams The effects of different user requirements, resource management schemes and traffic scenarios were also analysed.

30. 29 DTM Using Parallel Bitstreams … DTM Simulation Results It has been shown that Centralized Slot management schemes perform very well specially with partially-equipped nodes; Fragmentation of the pool of free slots is normally very modest; This scheme simplifies network management; Disadvantages setup delay increases; nodes are dependent on the slot server, which makes the system sensitive to failures

31. 30 DTM Using Parallel Bitstreams … DTM Simulation Results Distributed scheme has several benefits compared to the centralized. No risk of bottlenecks caused by a a single node; Access delay is shorter, redundancy is higher; Scales well to longer buses A Hybrid scheme is however likely to give the best overall performance. For instances distribute slots along nodes. Keep part in several slot servers that share the global state information.

32. 31 DTM Host Interface DTM shared memory host interface: Segmentation and reassembly (SAR) protocol is implemented in hardware in the board Incoming and outgoing channels operate simultaneously; Congestion control is not needed as DTM uses circuit switching; The Interface is based on shared memory in order to reduce the number of transfers over the host systems bus; The interface uses interrupts for comm state changes with the processor; The interface is designed to support fast connection establishment. Buffers are allocated to channels without involving CPU Fig 4. DTM Host Interface

33. 32 DTM Host Interface … A Low-Cost Interface to the DTM Network: Proposed for equipment that doesn’t need processing capability such as a video terminal. Hardware Aspects of the Prototype Interface The hardware implementation of the host interface was done between a DTM Network and SUN SPARCstation.

34. 33 DTM Host Interface Performance Measurements Performance measurements were done using Sparcstation 2 and 10 and with memory buffers from 4KB to 1MB, in systems using different cache mechanisms Measurements show that the less System Bus access the better. The faster the system bus the better. Performance will also increase if no no update to the main memory is required when the buffer is flashed.

35. 34 Conclusion With evolution of fiber optics, the bottleneck in the communication infrastructure is moving from capacity in the links to place in the network where processing and storage is needed, for example in switch points. The main argument is circuit-switched networks have a simple communication architectures with low requirements on processing of data elements that make them well- suited to handle high capacity in fibers. Convergence of communication, computing and media imposes new requirements on the services the network must provide.

36. 35 Research Methodology Used Introduction Domain Problem = purpose Expected Results General Background Framework in time and Technology Development and Experimentation Conclusions

37. 36 What I have learnt through this reading Nothing that we say today is guaranteed to remain true for tomorrow. Anything we say could be valid within a certain timestamp even if the time stamp is too large for our life This study was done under some assumptions: WDM precision diff & not economically viable Cost of laser beamers and sensors were very high to make it viable.

38. 37 Contribution to the Knowledge Knowledge so conceived is not a process that converges toward an ideal view; it is an ever increasing ocean of alternatives, each of them forcing the others into greater articulation, all of them contributing, via this process of competition, to the development of our mental faculties Prof Naess

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