SIP User Agents Configuration and Fault Finding


Published on

1 Like
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

SIP User Agents Configuration and Fault Finding

  1. 1. Outline of the Hands-on Tutorial <ul><li>SIP User-Agent </li></ul><ul><ul><li>Register </li></ul></ul><ul><ul><li>Make calls </li></ul></ul><ul><li>Fault-Finding Tools </li></ul><ul><ul><li>Observe the Packets of SIP Messages </li></ul></ul><ul><li>SIP Registrar/Proxy Server </li></ul><ul><ul><li>Configuring SER (SIP Express Router) </li></ul></ul><ul><li>How do you know other SIP islands </li></ul><ul><ul><li>DNS SRV/ENUM/ISN </li></ul></ul><ul><li>How to authenticate users </li></ul><ul><ul><li>LDAP, RADIUS </li></ul></ul><ul><li> </li></ul>
  2. 2. SIP UAs and SIP Message Analysis Quincy Wu National Chi Nan University Email:
  3. 3. Exercise 1: SIP UA operations <ul><li>Download & Install SIP UA </li></ul><ul><li>Download & Install Ethereal </li></ul><ul><li>Packet Analysis Using Ethereal </li></ul><ul><ul><li>SIP signaling flow </li></ul></ul><ul><ul><li>RTP traffic </li></ul></ul><ul><ul><li>SIP headers </li></ul></ul><ul><ul><li>SDP Contents </li></ul></ul><ul><ul><li>Call Hold/Retrieve </li></ul></ul>
  4. 4. Windows-based SIP UA <ul><li>Microsoft Windows Messenger </li></ul><ul><li>NBEN UA </li></ul><ul><li>X-Lite </li></ul>
  5. 5. SIP UA – Windows Messenger <ul><li>By default, Windows XP installs Windows Messenger Version 4.7 </li></ul><ul><li>There are two messengers from Microsoft </li></ul><ul><ul><li>MSN Messenger 6.2, 7.0 </li></ul></ul><ul><ul><li>Windows Messenger 4.7, 5.1 </li></ul></ul><ul><li>Inside Windows Messenger - How it Communicates </li></ul><ul><ul><li> </li></ul></ul>
  6. 6. Step 1: Configure
  7. 7. Step 2: REGISTER
  8. 8. Step 3: Make A Call
  9. 9. Step 4: Ringing
  10. 10. Step 5: Conversation
  11. 11. Step 6: Answer A Call
  12. 12. SIP UA – NBEN UA <ul><li>NBEN UA is a SIP User Agent which provides easy interface for IP telephony. </li></ul><ul><li>This software was developed as a tool for VoIP tutorials in Taiwan. </li></ul><ul><li>You can type the digits and make phone calls directly, without typing the complete SIP URI ( ) </li></ul><ul><li>It supports features like Hold/Retrieve, Redial, Speed Dial, Transfer. </li></ul>
  13. 13. Features <ul><li>NBEN UA runs on Windows 2000/XP/2003. </li></ul><ul><li>Both signaling and media data are transported on UDP. </li></ul><ul><ul><li>SIP: port 5060 </li></ul></ul><ul><ul><li>RTP: port 9000 </li></ul></ul><ul><li>Supported audio codec: </li></ul><ul><ul><li>G.711 (64Kbps) </li></ul></ul><ul><ul><li>G.729 (8Kbps) </li></ul></ul><ul><ul><li>G.723.1 (6.3Kbps) </li></ul></ul>
  14. 14. Download NBEN SIP UA <ul><li>Download link & Installation guide can be found at http:/ /voip .tw /Download/ </li></ul><ul><li>Phone numbers are assigned in a separate configuration file. </li></ul><ul><li>Try to call each other and see the signaling of SIP. </li></ul><ul><li>Each SIP UA is required to possess a public IP address. </li></ul><ul><ul><li>A patch is available to traverse NAT by utilizing STUN. </li></ul></ul>
  15. 15. SIP UA - X-Lite <ul><li>X-Lite - The Best Free Softphone </li></ul><ul><li>A FREE premium SIP softphone with many PBX-like features. </li></ul><ul><li>Open standards-based design (SIP) allows for maximum network interoperation and integration. </li></ul><ul><li>Download from </li></ul>
  16. 16. Features <ul><li>Touch-tones [DTMF] </li></ul><ul><li>3 Lines, Multiple Proxies </li></ul><ul><li>Line Hold </li></ul><ul><li>Inbound Call 'Ignore' </li></ul><ul><li>Inbound Call 'Go to Voicemail' </li></ul><ul><li>Dial/ Redial/Hangup </li></ul><ul><li>Caller ID [SIP ID] </li></ul><ul><li>Call Timer </li></ul><ul><li>Mute </li></ul><ul><li>Microphone & Speakers Levels </li></ul><ul><li>Microphone & Speakers Meters </li></ul><ul><li>Recent Calls Dialed </li></ul><ul><li>Recent Calls Received </li></ul><ul><li>Speed Dial </li></ul><ul><li>G.711u+a/iLBC/GSM codecs </li></ul><ul><li>NAT/Firewall support </li></ul><ul><li>Specify NAT IP to be written in SIP messages </li></ul><ul><li>Supports Windows 98SE/NT4/ME/2000/XP </li></ul>
  17. 17. Step 1: Configuration
  18. 18. Step 2: Make/Receive Calls <ul><li>Automatically send a REGISTER request to registrar when the program starts up. </li></ul><ul><li>Dial digits, and domain realm will be appended automatically. </li></ul>
  19. 19. Packets Capturing & Analyzing
  20. 20. Fault-Finding Tools <ul><li>Ethereal </li></ul><ul><ul><li>GUI on Windows XP/Linux/FreeBSD </li></ul></ul><ul><li>Tcpdump/tEthereal/ngrep </li></ul><ul><ul><li>Plaintext on Linux/FreeBSD </li></ul></ul><ul><li>SIPSAK </li></ul><ul><ul><li>“ Traceroute” of SIP </li></ul></ul>
  21. 21. Ethereal – What Is It? <ul><li>Every network manager at some time or other needs a tool that can capture packets off the network and analyze them. </li></ul><ul><li>In the past, such tools were either very expensive, proprietary, or both. </li></ul><ul><li>With the advent of Ethereal, all that has changed. </li></ul><ul><li>&quot;A rose by any other name would smell as sweet.&quot; - William Shakespeare </li></ul>
  22. 22. Features of Ethereal <ul><li>Available for UNIX and Windows. </li></ul><ul><li>Capture and display packets from any interface on a UNIX system. </li></ul><ul><li>Display packets captured under a number of other capture programs: </li></ul><ul><ul><li>tcpdump </li></ul></ul><ul><ul><li>Network Associates Sniffer and Sniffer Pro </li></ul></ul><ul><ul><li>NetXray </li></ul></ul><ul><ul><li>Microsoft Network Monitor </li></ul></ul><ul><li>Filter packets on many criteria. </li></ul><ul><li>Colorize packet display based on filters </li></ul><ul><li>Allow people to add new protocols to Ethereal. </li></ul>
  23. 23. Where to Get Ethereal <ul><li>Official site: </li></ul><ul><li>Local mirror: http:/ /voip .tw /Download/ </li></ul>
  24. 24. Install Ethereal under Windows <ul><li>Install WinPcap 3.1. </li></ul><ul><ul><li>WinPcap is an architecture for packet capture and network analysis for the Win32 platforms. </li></ul></ul><ul><ul><li>It includes </li></ul></ul><ul><ul><ul><li>a kernel-level packet filter, </li></ul></ul></ul><ul><ul><ul><li>a low-level dynamic link library (packet.dll), and </li></ul></ul></ul><ul><ul><ul><li>a high-level and system-independent library (wpcap.dll, based on libpcap version 0.6.2) </li></ul></ul></ul><ul><li>Install Ethereal 0.10.13. </li></ul>
  25. 25. Starting Ethereal
  26. 26. Capturing packets with Ethereal
  27. 27. The Capture Preferences dialog box
  28. 28. Stop after you have collected enough packets
  29. 29. File – Save As
  30. 30. Show Packet in New Window
  31. 31. Capture Filters
  32. 32. Filtering While Capturing
  33. 33. Syntax of the tcpdump capture filter language <ul><li>[not] primitive [and|or [not] primitive ...] </li></ul><ul><ul><li>tcp port 23 and host </li></ul></ul><ul><ul><li>tcp port 23 and not host </li></ul></ul><ul><li>tcpdump filter language is explained in the man page. </li></ul>
  34. 34. Capturing SIP signaling (filter: udp port 5060)
  35. 35. SIP Call Establishment <ul><li>It is simple, which contains a number of interim responses. </li></ul>
  36. 36. Basic Call Flow
  37. 40. REGISTER
  38. 41. 200 OK
  39. 42. INVITE
  40. 43. SDP in INVITE
  41. 44. 200 OK
  42. 45. SDP in 200 OK
  43. 46. ACK
  44. 47. Capturing the packets of Media Data
  45. 48. RTP Traffic (udp port 9000) <ul><li>What’s wrong? </li></ul>
  46. 49. Tools – Decode As RTP
  47. 50. Display Filter
  48. 51. Display – Colorize Display
  49. 52. Emphasize the packets you are interested in
  50. 53. Hold/Unhold of NBEN UA
  51. 54. Hold
  52. 55. Retrieve
  53. 56. Summary <ul><li>We demonstrate the functions of Windows Messenger and NBEN UA, which are two SIP User Agents with friendly user interface. </li></ul><ul><li>We demonstrate the functions of Ethereal, which is a powerful tool for packets capturing & analyzing: </li></ul><ul><ul><li>Capture Filters </li></ul></ul><ul><ul><li>Colorized Packets </li></ul></ul><ul><li>Practice using this tool to capture SIP signaling in the following call flows </li></ul><ul><ul><li>REGISTER – 200 OK </li></ul></ul><ul><ul><li>INVITE – 200 OK - ACK </li></ul></ul><ul><ul><li>BYE – 200 OK </li></ul></ul><ul><ul><li>Hold/Retrieve </li></ul></ul>