LAB #1 SETTINGUP SIP SERVER FOR VOIP



LAB #1 SETUP PC to PC VoIP CALL WITH SIP SERVER

OBJECTIVE

The purpose of this lab is to give students a better understanding on one of VoIP protocols, SIP (Session Initiation Protocol).

REQUIRED SOURCES

• A Windows PC

• A Xlite SIP Softphone

• High-speed Internet connection

• A set of microphone and speaker

INTRODUCTION TO SIP

Session Initiation Protocol (SIP), a standard for multimedia conferencing over IP, has been developed by the Internet Engineering Task Force (IETF). SIP is an application-layer control protocol used to establish, modify and terminate sessions between two or more end systems.

Like other VoIP protocols, SIP is designed to address the functions of signaling and session management within a packet telephony network. Signaling allows call information to be carried across network boundaries. Session management provides the ability to control the attributes of an end-to-end call.

SIP supports five facets of establishing and terminating multimedia communications:

a) User location: determination of the technical parameters, such as IP address required to reach an end system to be used for communication, and association of end users with end systems;

b) User availability: determination of the available of the end system, and the willingness of the called party to engage in communication;

c) Endpoint capabilities: determination of the media capabilities of the end system, such as media types, media parameters, etc.;

d) Session setup: establishment of a session between the originating and destination end system;

e) Session management: handling the transfer and termination of sessions, modifying session parameters, and invoking services.

SIP COMPONENTS AND MESSAGES

There are two key components in a SIP-based network, User Agents and Servers. Figure 1 is showed SIP Agent and Server communication.

SIP is a peer-to-peer protocol. The peers in a session are called User Agents (UAs). A user agent can function in one of the following roles:

• User Agent Client (UAC) – initiates the SIP requests.

• User Agent Server (UAS) – contacts the user when a request is received and returns a response on behalf of that user. The response may be an acceptance, a rejection, or a redirection of the request.

[pic]

Figure 1: SIP Agent and Server Communication

SIP servers include:

• Proxy server – makes requests on behalf of other clients and possibly translates a message, as necessary, before forwarding.

• Redirect server – accepts a SIP request, maps the address into another address, and then returns the new address to the Client.

• Registrar server – accepts the REGISTER requests and may be co-located with the Proxy or Redirect servers.

• Location server – provides a service to the Proxy or Redirect servers by obtaining information regarding the callee’s possible location.

SIP components are identified with a SIP Uniform Resource Locator, or URL, which takes a form similar to that used with e-mail systems, such as userID@. The user part could consist of a user name or telephone number; the host part could consist of a domain name or numeric network address.

PROCEDURE

Step One: Setting up Windows PC with OnDo SIP server

1. download OnDo SIP Server from the link below:



Choose “OnDo SIP Server.EXE” file under Installer Program (Windows OS Only) window to download. [Refer Figure 2 OnDo SIP Server Installation Setup]

Note: before downloading the software, you need to register first. Fill the bottom part with the following contents:

[pic]

Figure 2: OnDo SIP Server Installation Setup

2. Click “Continue” to “Accept” SIP Server License Agreement. Then “Save” target file on the computer hard drive.

3. Install OnDo SIP Server software by running “oss1_5_3_0.exe” file.

4. Under Welcome to the OnDO SIP server 1.5 Setup Wizard window:

a) Click “Next” → “I Agree” → “Next” → “Next” (keep all default settings) → “Install” → “Finish” → Press any key to continue under terminal window.

Step Two: Configure OnDo SIP Server

1. Start OnDo SIP Server by double clicking [pic] “OnDo SIP Server Admintool” icon on the desktop.

2. Check “Accept” under License Agreement; check “Educational Use”, then click “Next” → “Yes”.

3. Enter User ID with “sa”; Password with “sa”, and then click “Login”. You should have same display on the screen as Figure 3 Start/Shutdown (status: Active).

[pic]

Figure 3: Start/Shutdown (status: Active)

[pic]

Figure 4: Registered List (empty)

4. Status:

Click “Status” tab, and write down your interface IP address (i.e. SIP Server IP address). (Figure 5 Server Status)

[pic]

Figure 5: Server Status

5. Config:

a) Do the system configuration following Figure 6 Configuration

[pic]

Figure 6: Configuration

b) Click “Save” to save all entries.

6. Start/Shutdown:

In order to take all the settings in effect, you need to restart the server by clicking “Start/Shutdown” tab → “Shutdown” → “OK” → “Start”. Make sure your status is in Active.

7. Now go back to Server Status section, you can view the information entered in the configuration procedure.

Step Three: Setting up Xlite SIP Softphone

1. Download Xlite SIP Softphone from the link below:



OR



2. Install the Xlite on the PC.

3. Open Xlite SIP Softphone from you PC by clicking “Start” → “Programs” → “Xlite” → “Xlite”.

4. From the Xlite window:

a) Click “[pic]” → “SIP Accounts Settings”.

[pic]

b) Click → “Add”.

[pic]

c) Enter User (i.e. desired extension no.), eg. “555”.

d) Enter Authorization user name “555” (same as above).

e) Enter SIP Server IP (Interface IP) address in “Domain field”.

[pic]

f) Click “OK” → “Close”.

5. Verification:

a) From the Xlite Display window, you should see a message saying “Discovering Network”.

b) If registration is successful, you should see the following.

[pic]

c) Go back to OnDo SIP Server, click “Registered” tab, You should see that the Xlite SIP Softphone is registered as a user/phone number of 555, with a contact URL of sip:@142.214.186.52, among other registration information. [Refer Figure 7 Registered List].

[pic]

Figure 7: Registered List

Step Four: Making VoIP Calls

To make a call from one Windows PC to another Windows PC by using X-Lite SIP Softphone, follow these steps:

1. Setup calling environment on a second Windows PC.

a) Pick up a new user ID, i.e. “556”.

b) Repeat Step Three: Setting up Xlite SIP Softphone to configure the new extension.

2. Verification:

c) From the X-Lite Display window, you should see a message saying “Discovering Network”.

d) If registration is successful, you should see the following.

[pic]

e) Go back to OnDo SIP Server, click “Registered” tab, you should see your new updated Registered List, you should see the new user with user ID “556”. [Refer Figure 8 Registered List_updated].

[pic]

Figure 8: Registered List_updated

2. Connect your speaker and microphone on both Windows PCs.

3. From X-Lite on one of the Windows PC (i.e. the PC with user ID 555), enter 556 and click [pic] icon to initiate a call.

4. User “556” should receive an incoming call.

[pic]

5. Click [pic] icon, to answer call.

[pic]

6. Monitor OnDo SIP Server:

a) Go back to OnDo SIP Server, click “Sessions” tab.

b) Observe the changes of the “Status” before and after the Client terminal accepts the invitation by clicking “Refresh”. (Hint: “Inviting” to “Talking”).

c) Write down any other information which you observe.

Step Five: More Conversations

Congratulation! You just have made your first VoIP call on your own SIP Server. Now, you can have more fun with more than one client. Try to set up more clients with different user IDs on different PC’s by repeating Step Three, and monitor the changes on the OnDO SIP Server.

QUESTIONS

1. What is the major fallback in this method of configuring the OnDo SIP Server?

2. How can this problem be rectified? (Hint: Go to Config tab in SIP server and explore other configuration settings).

Step Six: Capture Packets by Ethereal

1. Update Ethereal software by visiting the website below and installing the newest version of Ethereal.



2. Load Ethereal Network Analyzer:

“Start” → “Programs” → “Ethereal” → “Ethereal”.

3. Capture packets:

a) Click “[pic]” (List available capture interface) icon. [Refer Figure 9 Ethereal: Capture Interfaces].

b) Make a call and start a conversation from your X-Lite to another other X-Lite user on a different PC.

[pic]

Figure 9: Ethereal: Capture Interfaces

c) Click “Capture” button on the available interface. [Refer Figure 10 Capture Window].

[pic]

Figure 10: Capture Window

d) Finish the call, and click “Stop” button to stop the capture process on the Ethereal: Capture window. Now you will see a summary for each packet captured (e.g. packet number, time, source destination addresses and protocol type, etc.) [Refer Figure 11 Ethereal User Interface].

[pic]

Figure 11: Ethereal User Interface

Step Seven: Analyze the Packets captured

1. Select the particular packet from the “listing of captured packets” window.

2. In Figure 11 Ethereal User Interface, SIP (session initialization protocol) was selected. Note the request line & message header tags.

3. For getting information about the VoIP call by clicking “Statistics” → “VoIP Calls”, refer Figure 12 Ethereal: VoIP Calls.

[pic]

Figure 12: Ethereal: VoIP Calls

4. To observe the VoIP Call conversation process, do the following steps:

a) Click “Statistics” → “Flow Graph…”.

b) Make different combination for available options, then click ‘OK”. [Refer Figure 13 Ethereal: Flow Graph].

[pic]

Figure 13: Ethereal: Flow Graph

c) Figure 14 Graph Analysis shows the complete connection process.

[pic]

Figure 14: Ethereal: Graph Analysis

QUESTIONS

1. List the different protocols that appear in the protocol column in the packet-listing window.

2. What protocol is used for a call made using X-Lite phone?

3. How long did it take from when the “Request: Invite” was sent until the “OK” was received?

4. Briefly conclude what you have learnt from the Ethereal packet capturing section.

The end!

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UAC

UAS

UAS

UAC

Redirect

Proxy

Location

Registrar

SIP User Agent (UA)

SIP User Agent (UA)

SIP Server

Signalling messages between User Agent and Server

Note: “Active” is showed in the Status field. This means the OnDo SIP Server is Active. Click “Registered” tab [refer to Figure 4 Registered List (empty)], Registered List should be empty. This is because we haven’t connected any SIP UA to this LAN.

á3p plpóplrnrrr²r´r¶rDsŒs1tòNote: in your Administrator SIP URL section, put your own interface IP address obtained from previous step.

i.e. 555@your_interface_ip.

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