You can now use Windows Messenger. The next step is to actually participate in an online conversation, using Windows Messenger. Keep in mind that as long as you have the email addresses of the people with whom you want to talk and they have allowed you to see when they are online, you can start a conversation with any of them, either on your local home network or somewhere out on the Internet at large. The following example features you and one of your children using IM. You are on the bedroom computer, and your child is supposed to be doing homework on the family room computer. Being a kid, your little angel tends to stray, and his attention drifts to online games and other frivolous activities, so you need to periodically check in to see how things are progressing. You could carry out this scenario by calling out to the child, but bedrooms tend to be a fair distance from family rooms, which means you'd have to raise your voice or go downstairs. Instead, you can take advantage of the technology offered by a tool such as IM to find out in real-time, without having to raise your voice, what is going on. Here's how you do it:
While signed in to Windows Messenger, double-click the contact (in this case, your son) with whom you want to start a conversation.
Type into the text box next to the Send button and then click Send. For the sake of this example, type hello and then click Send.
You and your recipient both receive a message window showing the conversation so far, like the one in Figure 5.11.
Figure 5.11. A Windows Messenger conversation.
Learning More About SIP
Windows Messenger, like many other IM solutions, uses Session Initiation Protocol (SIP) to accomplish the communication capabilities you can achieve on your network. The details of SIP are beyond the scope of this book and may not be for the faint of heart. However, if you end up dealing with corporate scenarios as a user, you may encounter situations in which IM will not work because some administrators do not allow SIP to pass through their firewalls.
SIP is really intended to merge all communications so that in the near future you will make your telephone, video, IM, and any other communications sessions using SIP on an integrated platform. If you are dead set on learning more about SIP, you should start with where it was first defined as a proposed standard. As in many other cases, the Internet Engineering Task Force (IETF) proposed SIP. You can read all about it at www.ietf.org/rfc/rfc3261.txt.