This article was forwarded to you by gtoal@an-teallach.com (Graham Toal): --------------------------------- cut here ----------------------------- Newsgroups: mail.cypher Received: from post.demon.co.uk by mailhost.an-teallach.com with SMTP id AA11163 ; Thu, 23 Sep 93 12:41:47 GMT Received: from relay2.uu.net by post.demon.co.uk id aa07673; 23 Sep 93 9:14 BST Received: from toad.com by relay2.UU.NET with SMTP (5.61/UUNET-internet-primary) id AA19504; Thu, 23 Sep 93 04:09:31 -0400 Received: by toad.com id AA29715; Thu, 23 Sep 93 01:03:46 PDT Received: by toad.com id AA29712; Thu, 23 Sep 93 01:03:11 PDT Return-Path: <karn@qualcomm.com> Received: from qualcomm.com ([129.46.62.22]) by toad.com id AA29707; Thu, 23 Sep 93 01:03:08 PDT Received: from servo.qualcomm.com by qualcomm.com; id AA27850 sendmail 5.65/QC-main-2.1 via SMTP Thu, 23 Sep 93 01:00:40 -0700 for cypherpunks@toad.com Received: by servo; id AA10225 sendmail 5.67/QC-subsidiary-2.1 Thu, 23 Sep 93 01:00:39 -0700 for cypherpunks@toad.com Date: Thu, 23 Sep 93 01:00:39 -0700 From: Phil Karn <karn@qualcomm.com> Message-Id: <9309230800.AA10225@servo> To: cme@ellisun.sw.stratus.com Cc: cypherpunks@toad.com In-Reply-To: Carl Ellison's message of Tue, 14 Sep 93 23:53:23 EDT <9309150353.AA06198@ellisun.sw.stratus.com> Subject: more than spread spectrum This idea of setting up your own independent network isn't as far fetched as it sounds, at least in a relatively local area with critical mass. The router nodes already exist, in the form of my own TCP/IP code for the PC, or any of several other packages including the various freeware UNIX clones. Radio transmission equipment operating under Part 15 of the FCC rules is already available. Under Part 15, you don't need a license; the radio transmitter does have to be "type accepted" by the FCC but since you buy that as a prepackaged box you don't have to worry about it. The section of Part 15 that is particularly interesting is either 15.247 or 15.249 (can't remember which). It allows you to run up to 1 watt of power, quite a bit for an unlicensed service, on any of several "ISM" (aka "garbage") bands as long as you use spread spectrum with a minimum processing gain of 10dB. The most popular is 902-928 Mhz, with another band in the vicinity of 2450 Ghz coming up fast. Ahthough most Part 15 equipment is designed primarily for use within office environments, it can be and is used over point-to-point paths of 5-10 km with the proper directional antennas. Although Part 15 users are not allowed to cause harmful interference and must accept interference from other users (microwave ovens generally operate on 2450 Mhz), in practice these nets seem to work pretty well if they're properly engineered. Besides, the inherent distributed redundancy available in a packet network should be able to compensate for momentary outages due to interference. Unlike the amateur service, which has some particularly draconian "acceptable use" policies (despite a recent liberalization, encryption is still illegal), there are *no* restrictions on the use of Part 15 equipment. Encryption is not only legal, some boards have hardware encryption support (e.g., the NCR Wavelan has a DES chip). This particular board operates at 2 megabits/sec on the 902-928 Mhz band with 250 mW of power. There is an even more interesting development in the works: "data PCS". In essence, this is "Part 15" style operation on dedicated spectrum, i.e., new spectrum in the 1.8-2.2 Ghz band that will not have to be shared. The specific intent of data PCS is to allow users to build their own ad-hoc networks without having to rely on the facilities of (and pay money to) carriers such as telephone companies. Phil --------------------------------- cut here -----------------------------