VOIP Troubleshooting using ClearSight Analyzer™


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  • AppDancer is a young, vital company. Since our inception, we have maintained the release schedule of one minor release each quarter, with a major upgrade each year. In return for our aggressive engineering schedule, we have been rewarded and recognized by leading industry groups, such as Networld
  • <ポイント> 1.なぜ、 VoIP が導入されるようになってきたのだろうか。 2. IP 電話とは。 3.どのような仕組みになっているのだろうかか。 4.音声を、どのようにして IP パケットにするのだろうか。 5.どのようにして接続されるのだろうか。 6.音声品質はどこで影響されるのだろうか。 7.アクセス方法は。 8. IP 電話サービスの歴史は。 9.国内及び国際の動向は。
  • 通信の流れと以下のメソッドの役割を説明します。 INVITE(Request) : 発信側ユーザから通信を起動 TRYING(Response) : 通信条件 ( コーデック、ポート条件等 ) と送信条件を提示 RINGING(Response) : 着信側ユーザが呼び出し状態になったことを通知受信条件 ( コーデック、ポート番号等 ) と送信条件を提示してもよい OK(Response) : 着信側ユーザが通話可能状態になったことを通知受信条件 ( コーデック、ポート番号等 ) と送信条件を提示 ( 必須 ) ACK(Request) : 送信確 ( レスポンスを期待しないリクエスト ) BYE(Request) : 通信終了要求 OK(Response) : 完了 SIP の通信の開始時は以下のようなシーケンスの流れになっています。 INVITE  -> 200 OK  ← ACK   -> このようにスリーウェイハンドシェークになっていることが分かります。 SIP では UDP 上で使用されることが多いため、上のような3つやり取りがあります。 ※ Trying は現在処理が継続中であることを相手に通知する応答メッセージです。 ※ Ringing は呼び出し中であることを通知する応答メッセージです。
  • ・ RTP は、音声や画像のストリームごとに一つのセッションを確立します。 ・送信と受信は別々のセッションです。(但し、アプリケーションによっては送受信を一つ   のセッションで行うものもあります。) ・ RTP と RTCP での一つのセッションを、〝論理チャネル〟と呼びます。 ・ RTCP の UDP ポート番号= RTP+ 1の番号を使用します。
  • 主観的評価(人間による評価) 人間が音響や音声の品質の良さを心理的判断に基づいて行い評価します。 ・ MOS ( ITU-T P.800 勧告) 客観的評価(機械による評価) 主観的評価の要因となる物理的な特徴量を選び、これらの客観的な測定をすることにより、人間が評価したものと同等の評価値を測定する客観的な品質評価法です。 できるだけ MOS に近い評価が得られるように、様々な工夫がなされています。 ・ PESQ ( ITU-T P.862 勧告) ・ PSQM ( ITU-T P.861 勧告) ・ PSQM+ ・ PSQM99 ・ PAMS ・ R 値  など
  • VOIP Troubleshooting using ClearSight Analyzer™

    1. 1. VOIP Troubleshooting using ClearSight Analyzer™
    2. 2. Agenda <ul><li>ClearSight – Company Overview </li></ul><ul><li>ClearSight Analyzer Overview </li></ul><ul><li>VoIP Analysis with ClearSight Analyzer </li></ul><ul><ul><li>Signaling Protocols </li></ul></ul><ul><ul><li>Media Protocols </li></ul></ul><ul><li>Hands on Examples </li></ul><ul><li>Q & A </li></ul>
    3. 3. ClearSight – Company Overview <ul><li>Founded March, 2001 as AppDancer </li></ul><ul><ul><li>Founders created “Sniffer Pro” </li></ul></ul><ul><li>Name/Product Launch – October, 2003 </li></ul><ul><li>HQ: San Mateo, California </li></ul><ul><li>Fiscal 2004: </li></ul><ul><ul><ul><li>6 Figure Operating Income, on </li></ul></ul></ul><ul><ul><ul><li>Mid-7 Figure Revenues </li></ul></ul></ul><ul><li>Worldwide Partnership - Spirent Communications </li></ul><ul><li>Received Key Editorial Accolades </li></ul>
    4. 4. ClearSight Analyzer™ Overview
    5. 5. Traditional Network Analyzers: <ul><li>Use The “Bottom-Up Approach” </li></ul><ul><li>Troubleshooting Based Upon Raw Packets – Not Necessarily Real-Time </li></ul><ul><li>Focus on lower-layer elements – </li></ul><ul><ul><li>Physical Errors </li></ul></ul><ul><ul><li>Host Tables </li></ul></ul><ul><ul><li>Top Talkers </li></ul></ul><ul><ul><li>Utilization </li></ul></ul><ul><li>Neither Intuitive Nor Easy! </li></ul>
    6. 6. Traditional Analyzer GUI
    7. 7. The “ClearSight” View
    8. 8. Bridging The Gap <ul><li>ClearSight’s Analyzer Enhances the IT Professional’s Ability To: </li></ul><ul><ul><li>Quickly Identify Trends, Issues and Problems </li></ul></ul><ul><ul><li>Determine if They’re </li></ul></ul><ul><ul><ul><li>Physical </li></ul></ul></ul><ul><ul><ul><li>Environmental </li></ul></ul></ul><ul><ul><ul><li>User - Related </li></ul></ul></ul><ul><li>Facilitates Deployment of Optimum Resource Levels </li></ul>
    9. 9. Product Portfolio Special Edition ClearSight Analyzer 1 Gigabit 10 Gigabit NEM Operator Enterprise Software-Only Full Duplex Segment Appeal Hardware Performance Distributed SMB
    10. 10. VoIP Technology
    11. 11.   VoIP Technology VoIP  ( Voice over IP) PBX  ( Private Branch Exchange) GW ( Gate Way) PSTN ( Public Switched Telephone Network) PBX IP packet Fixed-line telephone IP phone PBX PBX /GW PSTN IP network IP phone PBX /GW ( VoIP ) ( The conventional telephone ) Fixed-line telephone Fixed-line telephone Fixed-line telephone Difficult to Troubleshoot
    12. 12. VoIP Signaling Protocols <ul><li>The p rotocol s which manage setup, transfer, maintenance, and disconnect of a call in an IP telephone </li></ul><ul><li>Protocols which exchange information on terminal capabilities and/or CODEC’s </li></ul><ul><li>Typical VoIP signaling protocols </li></ul><ul><ul><li>SIP </li></ul></ul><ul><ul><li>H.323 </li></ul></ul><ul><ul><li>Cisco Skinny </li></ul></ul><ul><ul><li>MGCP </li></ul></ul><ul><ul><li>MEGACO </li></ul></ul>
    13. 13. Physical Layer Data Link Layer Network Layer ( IP )   UDP RTP RTCP Movie H.26x Voice G.7xx   UDP ( TCP ) SIP   (Session Initiation Protocol) SDP (Session Description Protocol) Signaling protocols Media protocols VoIP Protocol Stack (SIP example)
    14. 14. ClearSight Creates a Call List <ul><li>ClearSight creates a group of associated protocol sessions for each call – </li></ul><ul><li>Also automatically creates a call list </li></ul>
    15. 15.   SIP Request Method & Response <Method> INVITE : Used to initiate the session ACK :   Used as a confirmation that the final response has been received BYE :   Used to terminate a session REGISTER : Used by a user-agent client to log in and register its address with a SIP server       OPTIONS : Queries a server as to its capabilities Cancel : Used to terminate a pending <Response> 1xx   Provisional 2xx   Success 3xx   Redirection 4xx   Request Failure 5xx   Server Failure 6xx   Global Failure
    16. 16.   SIP Ladder Display < Direct communication between two terminals >
    17. 17. SIP Server Example SIP server IP phone 100 IP phone 100 SIP SIP RTP < Communication through a SIP server >
    18. 18. SIP Ladder Display < Communication through a SIP server>
    19. 19.   Media Protocols : RTP & RTCP Voice ( A <- B ) RTP RTCP Voice ( B -> A ) RTP RTCP Video( A <- B ) RTP RTCP Video ( B -> A ) RTP RTCP A B <ul><li>● RTP ( real time transport protocol ) RFC1889 </li></ul><ul><ul><li>RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over multicast or unicast network services. </li></ul></ul><ul><li>● RTCP ( RTP control protocol ) RFC1889 </li></ul><ul><ul><li>RTCP is companion protocol of RTP. This is used for quality feedback of the voice packets. </li></ul></ul>
    20. 20. RTP Flow Statistics
    21. 21. Major Elements of Voice Quality <ul><li>Packet loss </li></ul><ul><ul><ul><li>< 1% :  Negligible impact </li></ul></ul></ul><ul><ul><ul><li>3-5% : Momentary pauses in conversations </li></ul></ul></ul><ul><ul><ul><li>10% :  Considerable deterioration of quality </li></ul></ul></ul><ul><ul><ul><li>> 20% :  Difficult to carry on any conversation </li></ul></ul></ul><ul><li>Latency </li></ul><ul><ul><ul><li>> 25ms : Requires echo cancellation </li></ul></ul></ul><ul><ul><ul><li>< 150ms : Typically no discernable problem </li></ul></ul></ul><ul><ul><ul><li>150-400ms : Although the voice quality of user application is affected, use is possible if you understand it. </li></ul></ul></ul><ul><ul><ul><li>> 400 ms : Unsuitable for most applications. </li></ul></ul></ul><ul><li>Jitter </li></ul><ul><li>Echo </li></ul>
    22. 22. <ul><li>The subjective evaluation method </li></ul><ul><ul><li>MOS (Mean Opinion Score) ITU-T recommendation P.800 </li></ul></ul><ul><li>The objective evaluation method using Perception model </li></ul><ul><ul><li>PSQM   (Perceptual Speech Quality Measurement) ITU-T recommendation </li></ul></ul><ul><ul><li>PAMS   (Perceptual Analysis Measurement System) British telecom </li></ul></ul><ul><ul><li>PESQ   (Perceptual Evaluation of Speech Quality) ITU-T recommendation P.862 </li></ul></ul><ul><li>The objective evaluation method using Calculation model </li></ul><ul><ul><li>R-Value (E-Model)   ITU-T recommendation G.107 </li></ul></ul>Voice Quality Evaluation Method Phone Intermediate device Phone IP Network It Talks It Talks IP Network Test Equipment Voice File Deteriorated Voice Signal Original Voice Signal Intermediate device Intermediate device Intermediate device
    23. 23. Scoring R-Value and MOS
    24. 24. VoIP Analysis with ClearSight Analyzer™
    25. 25. ClearSight VoIP Advantages <ul><li>Multiple Physical Segment Correlation (Real-time and post analysis) </li></ul><ul><li>The next generation trouble-shooting tool for data and voice convergence </li></ul><ul><li>Real-time VoIP playback – including distributed remote </li></ul><ul><li>The only trouble-shooting tool supporting video playback </li></ul><ul><li>Extensive playback CODEC support </li></ul><ul><li>Real time QOS, VoIP alarms and triggers </li></ul><ul><li>Integrated VoIP SLA </li></ul><ul><li>Reporting: VoIP Summary, SLA Trending, and Per-conversation QOS Report </li></ul><ul><li>VoIP Application level filter – Eg.; phone number </li></ul><ul><li>VoIP/WiFi QOS analysis over AP and WiFi LAN switch </li></ul>
    26. 26. VoIP QoS Report
    27. 27. VoIP Playback <ul><li>ClearSight Supported CODECs for playback </li></ul><ul><ul><li>Audio CODECs G711(U-law / A-law), G.729, G.723, G.722, etc. </li></ul></ul><ul><ul><li>Video CODECs JPEG(411, 422, 111), H.263 Mode A/B </li></ul></ul>
    28. 28. VoIP Reporter <ul><li>ClearSight Supported CODECs for playback </li></ul><ul><ul><li>Audio CODECs G711(U-law / A-law), G.729, G.723, G.722, etc. </li></ul></ul><ul><ul><li>Video CODECs JPEG(411, 422, 111), H.263 Mode A/B </li></ul></ul>
    29. 29. ClearSight Analyzer™ Hands on Examples
    30. 30. Solving a Typical VoIP Problem SIP Phones can ring each other, however, Phone A->B: No problem Phone B->A : I can’t hear you ! Q. WHY ?                    OK ! OK! Ring!! Ring!! Phone A Phone B Phone B Phone A I can’t hear anything ! I can hear you. NG ! OK !
    31. 31. VoIP System ClearSight Phone A 〔 〕 SIP Server Phone B 〔 〕 L3 Switch L3 Switch Router Router Cloud C Hub
    32. 32. Signaling Flow
    33. 33. WLAN Switch - AirSpace - Aruba Etc. HUB SIP Server ClearSight AP1 AP2 move WLAN SIP phone 1 Initial RTP flow RTP flow after roaming ClearSight solution for VoIP over WLAN Switch WLAN SIP phone 2 WLAN SIP phone 2 <ul><li>Voice quality analysys </li></ul><ul><li>VoIP signaling analysis </li></ul><ul><li>Roaming analysis </li></ul>WLAN packets over Ethernet encapsulated with special header
    34. 34. AireSpace Decode Sample – packets between AP and WLAN Switch LWAPP Encapsulation header
    35. 35. VoIP ladder display of WLAN VoIP phone traffic – traffic between AP and WLAN Switch
    36. 36. The Next Generation VoIP Trouble-shooting Tool