tain RFC number or read through the RFC index, which contains all the RFCs published by the IETF. Any reader who is used to looking for information in other standardiza- tion bodies' Web pages will soon notice that the IETF does not require any Appendix kind of password or membership information in order to download any specification-they are available for free to any individual. Finding docu- ments on the IETF Web page is much simpler than in other organizations, where it is difficult to keep track of the different versions of a certain document. Readers might also find it useful to surf through the "IETF Working Groups" link. From there it is possible to access the Web pages of the dif- ferent working groups. The reader will especially find the charters of SIP, SIMPLE, and MMUSIC very interesting. Another working group that might be of interest is IPTEL. The Web page of a working group also contains instructions about how to join the mailing list of that specific working group. Reading the archives of any mailing list will provide the reader with several examples of the tech- nical discussions that are carried out within the IETF community. Note however that the mailing list of a working group is intended to be used by the engineers that are developing the protocol. The mailing list is not the proper place for people who are not very familiar with SIP to post basic questions about the protocol. There exists another mailing list for gen- eral information and discussions of existing implementations called "SIP implementors." Information about how to get subscribed to this mailing list can be also found in the SIP working group Web page (http://www.ietf. org/html.charters/sip-charter.html). In the next section, we will see where to find a useful set of Frequently Asked Questions (FAQ). Henning Schulzrinne's SIP Web page We have seen that the IETF Web site is the best place to download protocol specifications and to get subscribed to mailing lists. However, if you are after general SIP information, Henning Schulzri