Each network, be it the ARPAnet, NSFnet or a regional network, has its own operations center. The ARPAnet is run by BBN, Inc. under contract from DARPA. Their facility is called the Network Operations Center or NOC. Cornell University temporarily operates NSFnet (called the Network Information Service Center, NISC). It goes on to the

regionals having similar facilities to monitor and keep watch over the goings on of their portion of the Internet. In addition, they all should have some knowledge of what is happening to the Internet in total. If a problem comes up, it is suggested that a campus network liaison should contact the network operator to which he is directly connected. That is, if you are connected to a regional network (which is gatewayed to the NSFnet, which is connected to the ARPAnet...) and have a problem, you should contact your regional network operations center.

RFCs

The internal workings of the Internet are defined by a set of documents called RFCs (Request for Comments). The general process for creating an RFC is for someone wanting something formalized to write a document describing the issue and mailing it to Jon Postel (postel@isi.edu). He acts as a referee for the proposal. It is then commented upon by all those wishing to take part in the discussion (electronically of course). It may go through multiple revisions. Should it be generally accepted as a good idea, it will be assigned a number and filed with the RFCs.

The RFCs can be divided into five groups: required, suggested, directional, informational and obsolete. Required RFC's (e.g. RFC-791, The Internet Protocol) must be implemented on any host connected to the Internet. Suggested RFCs are generally implemented by network hosts. Lack of them does not preclude access to the Internet, but may impact its usability. RFC-793 (Transmission Control Protocol) is a suggested RFC. Directional RFCs were discussed and agreed to, but their application has never come into wide use. This may be due to the lack of wide need for the specific application (RFC-937 The Post Office Protocol) or that, although technically superior, ran against other pervasive approaches (RFC-891 Hello). It is suggested that should the facility be required by a particular site, animplementation be done in accordance with the RFC. This insures that, should the idea be one whose time has come, the implementation will be in accordance with some standard and will be generally usable. Informational RFCs contain factual information about the Internet and its operation (RFC-990, Assigned Numbers). Finally, as the Internet and technology have grown, some RFCs have become unnecessary. These obsolete RFCs cannot be ignored, however. Frequently when a change is made to some RFC that causes a new one to be issued obsoleting others, the new RFC only

contains explanations and motivations for the change. Understanding the model on which the whole facility is based may involve reading the original and subsequent RFCs on the topic.

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(Appendix B contains a list of what are considered to be the major RFCs necessary for understanding the Internet).