University Of Maryland1 A Study Of Cyclone Technology

University Of Maryland2 Table of Content Overview Contributions The need for time-based resource management Cyclone technology - basic idea Description of a Cyclone network Clock synchronization Data movements Connection management Scheduling Adaptation layer Fault handling Performance Advantages and limitations Open issues

University Of Maryland3 Current networking –event-based, on-demand resource allocation –best effort performance New classes of traffic placing stringent requirements on the communications Time-based resource management in a synchronous manner End-to-end coordination among network components –no congestion, loss, jitter –better utilization of bandwidth one byte header reduced control messages reduced routing information –well-suited network environment for traffic with stringent timing requirements Overview

University Of Maryland4 Contributions Time-based networking technology –components –protocols –operations –host interface Time-based resource management Alternate way of managing resources in networking –without requiring very accurate and highly synchronized clocks –without consuming significant amount of bandwidth for handling timing variability

University Of Maryland5 Time-based Resource Management In Networking t1t2 t3t4 t5t6 t7t8 t9t10 A B Data Loss t1t2 t3t4 t5t6 t7t8 t9t10 A B Data Loss Prevention Delay and Jitter A B t1t2 t3t4 t9t10 t5t6 t7t8 t11t12 Delay and Jitter Control A B t1t2 t3t4 t9t10 t5t6 t7t8 t11t12

University Of Maryland6 Cyclone Technology - Basic Idea tAtA t A +s A t A +2s A t A +3s A tA+isAtA+isA t A +(i-1)s A t A +(i+1)s A tBtB t B +s B t B +2s B t B +(j-1)s B t B +(j+1)s B tB+jsBtB+jsB... tAtA t A +s A t A +d t A +s A +d

University Of Maryland7 Data Movements - Basic Incoming linkOutgoing link Slot bufferPointer buffer Free slot list

University Of Maryland8 Data Movements controller switch host

University Of Maryland9 Types Of Traffic Supported Connection-oriented Scheduled traffic –data available at known time instant (temporal profile) –resources reserved when establishing a connection On-demand traffic –source routing –dynamic resource allocation –possible loss of a chunk

University Of Maryland10 Description Of Cyclone Network Chunk Slot and slot time Time tag Period Fixed design parameters –the size of a chunk –the duration of a period

University Of Maryland11 Chunk Types Three types - Control/Scheduled/On-demand Control chunk –multiple sub-chunks in a chunk –connection request chunk –confirm/reject/abort/terminate chunk –pathfinder chunk Scheduled chunk –scheduled traffic data chunk –scheduled traffic data acknowledgement/retransmission request chunk On-demand chunk –on-demand traffic data chunk –on-demand traffic data acknowledgement/retransmission request chunk markerchecksum

University Of Maryland12 Multiple Sub-chunks In A Chunk

University Of Maryland13 Connection Request Chunk

University Of Maryland14 Confirm/Reject/Abort/Terminate Chunk

University Of Maryland15 Pathfinder Chunk

University Of Maryland16 Scheduled Traffic Data and Acknowledgement/Retransmission Request Chunk

University Of Maryland17 On-Demand Traffic Data And Acknowledgement/Retransmission Request Chunk

University Of Maryland18 Cyclone Network Model controller switch Incoming link 1 Incoming link m outgoing link 1 outgoing link m Backup Incoming link 1’ Backup Incoming link m’ Backup outgoing link 1’ Backup outgoing link m’ 1’ m’ host

University Of Maryland19 Clock Synchronization Markers are sent to indicate the beginning and ending of a period A node obtains the clock information of upstream nodes A local clock rate is set to the average of incoming clock rates and its own rate A local clock phase is set considering clock phase information Clock Adjustment At A Node With Four Incoming Links

University Of Maryland20 Connection Establishment/Termination ABCDE

University Of Maryland21 Time Relationship Of Scheduling Timeline of incoming link Timeline of outgoing link (same speed)  Timeline of outgoing link (slower) Timeline of outgoing link (faster) t1t2 t3t4 t3 t4

University Of Maryland22 Single-Pass Scheduling Approach Available slot list (2, 3, 5, 6, 7) (3, 6, 7) (3) (1, 3, 4, 5) First available slot column assignment Assignment before reusing the buffer space

University Of Maryland23 Double-Pass Scheduling Approach Available slot list (1, 2, 3, 4, 6) (2, 3, 4) Available slot list (1, 2, 3, 4, 6) (2, 3, 4)

University Of Maryland24 Double-Pass Scheduling Approach Available slot list (1, 2, 3, 4, 6) (2, 3, 4)

University Of Maryland25 Adaptation Layer Receive information from an application and provide the appropriate information to a temporal regulator in the form acceptable to a Cyclone network –Specify temporal profile for a scheduled traffic –Provide scheduled data chunks according to the temporal profile specified –Detect bit-errors –Initiate appropriate recovery mechanisms –Initiate command control chunks –Detect data loss for on-demand traffic Supports existing applications and communications with non-Cyclone networks

University Of Maryland26 Fault Handling Backup link approach –line condition monitor –backup link pointer –automatic switching to backup Application-dependent recovery mechanism –primary and secondary connections –altering partial or entirety of a path Reader-writer flag for handling timing variability

University Of Maryland27 Summary Of Scheduling Techniques

University Of Maryland28 Performance Studies Data transfer Connection admission –long term connections –single node and multiple nodes

University Of Maryland29 Type Of Traffic Studied Regularly spaced traffic Random pattern traffic

University Of Maryland30 Regularly Spaced Traffic (S5-S7)

University Of Maryland31 (S7) 98.1% Loading

University Of Maryland32 Random Pattern (S8)

University Of Maryland33 Random Pattern (S9)

University Of Maryland34 Random Pattern (S10)

University Of Maryland35 Random Pattern (S11)

University Of Maryland36 Multiple Nodes Multiplied probability End-to-end delay is added

University Of Maryland37 Summary Of Performance Issues A couple of millisecond per node connection establishment overhead Close to 100% loading for identical, regularly spaced traffic Above 90% loading for regularly spaced traffic Above 80% loading for arbitrary pattern traffic, requesting 10% of bandwidth More than 50% of acceptance when links are 80% loaded, requesting 10% of bandwidth

University Of Maryland38 Summary Time-based resource management approach in networking All aspects of a computer network required to support time-based resource management –both scheduled and on-demand traffic –end-to-end resource usage scheduling in time –calendar-based data movements –existing applications and communications with non-Cyclone network –fault condition handling The feasibility of Cyclone technology –end-to-end delay –connection establishment overhead –the probability of connection acceptance

University Of Maryland39 Advantages Temporal determinacy Loss free and jitter free end-to-end data delivery with minimal latency, without sustaining significant delays in connection establishment Nearly all of the bandwidth available for the actual transmission of data High loading without having any adverse impact on performance Well-suited for hardware implementation Highly scalable

University Of Maryland40 Limitations Temporal determinacy –temporal profile of a connection be known ahead –not current practice in networking Handling applications with significant variability Synchronous system

University Of Maryland41 Open Issues Alternative designs and policies Optimization of many system parameters Design tradeoff and optimization for specific applications Dynamic monitoring of performance Support existing internetworking protocols other than TCP/IP Extensions to point-to-point links and point-to-point connections Hardware design

University Of Maryland42 Value Added Time-based resource management Alternate way of managing resources in networking –without requiring very accurate and highly synchronized clocks –without consuming significant amount of bandwidth for handling timing variability Current applications with stringent timing requirement will perform better Lead to development of new classes of applications that are possible only when tight timing guarantee can be given

University Of Maryland43 Pathfinder D1S3 checksumpaddingmarkerSD

University Of Maryland44 Connection Establishment/Termination ABCDE