K. Salah1 An Analytical Tool to Assess Readiness of Existing Networks for Deploying IP Telephony K. Salah & M. Almashari Department of Information and Computer Science King Fahd University of Petroleum and Minerals, Saudi Arabia

IEEE ISCC’06K. Salah2 Outline Introduction and challenging questions Introduction and challenging questions Existing tools Existing tools Drawbacks of existing tools Drawbacks of existing tools Advantages of analytical tool Advantages of analytical tool Bandwidth bottleneck analysis Bandwidth bottleneck analysis Network delay analysis Network delay analysis Analytical tool Analytical tool Concluding Remarks Concluding Remarks

IEEE ISCC’06K. Salah3 Introduction Importance of VoIP Importance of VoIP  Unification of data and voice networks  It is easier to run, manage, and maintain. Existing IP networks are best effort and VoIP requires QoS Existing IP networks are best effort and VoIP requires QoS Challenging questions Challenging questions  What are the QoS requirements for VoIP?  How will the new VoIP load impact the QoS of currently running network services and applications?  Will my existing network support VoIP and satisfy the standardized QoS requirements?  If so, how many VoIP calls can the network support before upgrading prematurely any part of the existing network hardware?

IEEE ISCC’06K. Salah4 Existing Tools Ample of commercial tools Ample of commercial tools NetIQ Brix Networks Agilent Cisco Avaya Siemens Uses two common approaches for assessing the deployment of VoIP Uses two common approaches for assessing the deployment of VoIP  Take network measurements and then predict the readiness based on the health of network  Inject real VoIP traffic and measure QoS

IEEE ISCC’06K. Salah5 Drawbacks of Existing Tools Commercial Commercial Injection approach can be intrusive to operation of existing network Injection approach can be intrusive to operation of existing network None offers a comprehensive approach or methodology for successful VoIP deployment. None offers a comprehensive approach or methodology for successful VoIP deployment.  No answers to all challenging questions, e.g. Number of calls Call distribution Call flow Future growth Impact on existing network apps

IEEE ISCC’06K. Salah6 Advantages of an Analytical Tool No cost No cost  Typical institutions  For well-to-do institutions: Can be used to measure the degree of accuracy of commercially- available tools, and thus help in selecting the proper tool to use. Based on an analytical approach to easily and quickly predict the number of voice calls that can be supported. Based on an analytical approach to easily and quickly predict the number of voice calls that can be supported.  The learning curve of using complicated commercial curve is minimized No injection method, and thus non disruptive to network services and operations No injection method, and thus non disruptive to network services and operations Address all concerns and challenging questions Address all concerns and challenging questions

IEEE ISCC’06K. Salah7 A typical network topology

IEEE ISCC’06K. Salah8 Practical steps Determine VoIP characteristics and requirements Determine VoIP characteristics and requirements Determine VoIP traffic flow and call distribution Determine VoIP traffic flow and call distribution Define performance thresholds and growth capacity Define performance thresholds and growth capacity Perform network measurements Perform network measurements Early modifications to existing network Early modifications to existing network Theoretical Analysis Theoretical Analysis OPNET Simulation OPNET Simulation Final modifications to existing network Final modifications to existing network

IEEE ISCC’06K. Salah9 VoIP Traffic Characteristics and Requirements Gatekeeper Gatekeeper Gateway Gateway IP phones IP phones M2E delay for a single call M2E delay for a single call  150ms according to G.714  Sender: 50 ms  Receiver: 45 ms  Network: 80 ms

IEEE ISCC’06K. Salah10 VoIP Traffic Characteristics and Requirements Bandwidth for a single call Bandwidth for a single call  64kbps in one direction  G.711 codec samples 20ms of voice per packet  Thus a rate of 50 pps  Each packet contains 160 voice samples (to give 8000 samples per second)  With RTP+UDP+IP+Ethernet headers  50 pps = 90.4 kbps  Bidirectional 100 pps kbps

IEEE ISCC’06K. Salah11 VoIP Traffic Flow and Call Distribution

IEEE ISCC’06K. Salah12 Define Performance Thresholds and Growth Capacity Network delay Network delay  VoIP applications  Or other sensitive Packet Loss Packet Loss Router and Switch Processing Router and Switch Processing Link Utilization Link Utilization

IEEE ISCC’06K. Salah13 Perform Network Measurements

IEEE ISCC’06K. Salah14 Upfront Network Assessment and Modifications

IEEE ISCC’06K. Salah15 The analytical approach Bandwidth bottleneck analysis Bandwidth bottleneck analysis Delay analysis Delay analysis

IEEE ISCC’06K. Salah16 BW bottleneck analysis

IEEE ISCC’06K. Salah17 Network Delay Analysis Poisson VoIP Traffic Poisson VoIP Traffic Using Jackson Theorem Using Jackson Theorem Links: M/D/1 Links: M/D/1 Router and Switches: M/M/1 Router and Switches: M/M/1

IEEE ISCC’06K. Salah18

IEEE ISCC’06K. Salah19 Network Capacity Algorithm i.Add background traffic ii.Add one call based on distribution and flow iii.For each node calculate the new arrival rate – not all nodes are affected. iv.Compute packet network delay for all flows by summing up individual delays per node v.If network delay < 80 ms, go to ii, otherwise STOP.

IEEE ISCC’06K. Salah20 Analytical Tool Generic Generic GUI GUI Analytical engine Analytical engine  BW bottleneck analysis  Compute iteratively the network delay

IEEE ISCC’06K. Salah21 GUI

IEEE ISCC’06K. Salah22 Network Tree

IEEE ISCC’06K. Salah23 Reports

IEEE ISCC’06K. Salah24 Validation Matlab code verifies results Matlab code verifies results OPNET simulation gives very close results. OPNET simulation gives very close results.

IEEE ISCC’06K. Salah25 Concluding Remarks VoIP will play a vital role in future. VoIP will play a vital role in future. There is a need for a way to assess the readiness of existing networks promptly. There is a need for a way to assess the readiness of existing networks promptly. The proposed analytical approach and tool eases the deployment of IP telephony Easy Fast Generic New version of the tool will include drag-and-drop network drawings New version of the tool will include drag-and-drop network drawings

K. Salah26 Q & A