Internet Surfer: Getting Started

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Xref: bloom-picayune.mit.edu rec.radio.amateur.packet:3988 news.answers:2996 Path: bloom-picayune.mit.edu!mintaka.lcs.mit.edu!ogicse!uwm.edu!zaphod.mps.ohio-state.edu!moe.ksu.ksu.edu!matt.ksu.ksu.edu!news From: steve@matt.ksu.ksu.edu (Steve Schallehn) Newsgroups: rec.radio.amateur.packet,news.answers Subject: rec.radio.amateur.packet Frequently Asked Questions Message-ID: <196i6nINN8n9@matt.ksu.ksu.edu> Date: 15 Sep 92 19:54:31 GMT Article-I.D.: matt.196i6nINN8n9 Expires: 10/03/92 Reply-To: packet-faq@uts.amdahl.com (Amateur-Packet-Radio FAQ Coordinators) Followup-To: rec.radio.amateur.packet Distribution: world Organization: Kansas State University, Manhattan, KS Lines: 706 Approved: news-answers-request@MIT.Edu NNTP-Posting-Host: matt.ksu.ksu.edu Posted-By: auto-faq script Archive-name: packet-radio-faq Frequently Asked Questions for Amateur Packet Radio Version 1.5 4 October 1991 This document is for unlimited distribution. Please send corrections and additions to Steve Schallehn (steve@matt.ksu.ksu.edu). The Packet Radio FAQ's will be posted on a monthly basis to rec.radio.amateur.packet. The current version of this document is available via anonymous FTP at ftp.cs.buffalo.edu. 1.0 Basic Packet Radio Information 1.1 What is packet radio? 1.2 What is amateur radio? 1.3 What can I do on packet radio? 1.4 Why packet over other digital modes? 1.5 What elements make up a packet station? TNC (Terminal Node Controller) Computer or Terminal A radio 1.6 What do you mean we can all use the same channel? 1.7 What is AX.25 ? 1.8 Definitions: Commonly used terms in Amateur Packet Radio 1.9 Do's and Don'ts : Rules and Regulations 2.0 Computing Network Resources for Amateur Packet radio 2.1 What Newsgroups/mailing lists are available? 2.2 What anonymous FTP sites are available 2.3 Are there any gateways for mail or news Internet / Packet Radio BBS Gateway LAN Gateways (Packet wormholes via Internet) 3.0 Networking and special packet protocols 3.1 Are there any other protocols in use other than AX.25? 3.2 What is TCP/IP? 3.3 Networking Schemes What are some of those other networking schemes? Digipeaters KA-Nodes NET/ROM ROSE 3.4 BBS message transfer 1.0 Basic Packet Radio Information 1.1 What is packet radio? Packet radio is digital communications via amateur radio. Packet radio takes any digital data stream and sends that via radio to another amateur radio station. Packet radio is so named because it sends the data in small burst, or packets. 1.2 What is amateur radio? Amateur Radio (sometimes called Ham Radio) is individuals using specified radio frequencies for personal enjoyment, experimentation, and the continuation of the radio art. Amateur radio operators must be licensed by their government. In the United States, the Federal Communications Commission issues amateur radio licenses. Normally, a test on operating practices, radio theory, and in some cases morse code proficiency test is administered. Amateur radio is not to be used for commercial purposes. Also, amateur radio operators are restricted from using profanity and using amateur radio for illegal purposes. For more information on Amateur Radio in general, see the monthly frequently asked questions posting in rec.radio.amateur.misc. 1.3 What can I do on packet radio? Keyboard-to-Keyboard contacts: Like other digital communications modes, packet radio can be used to talk to other amateurs. For those who cannot use HF frequencies, 2 amateurs can talk to each other from long distances using the packet radio network. Packet BBS operations: Many cities have a packet Bulletin Board System (BBS) attached to their local packet network. Amateurs can check into the BBS's and read messages from other packet users on almost any topic. BBS's are networked together over the packet network to allow messages to reach a broader audience than your local BBS users. Private messages may also be sent to other packet operators, either locally or who use other BBSs. BBS's have the latest ARRL, AMSAT, and propagation bulletins. Many BBS's have a file section containing various text files full of information on amateur radio in general. DX Packet Cluster: A recent development is use of packet radio for DX spotting. HF operators connect to the local DX Packet Cluster for the latest reports on DX. Often a user will 'spot' some hot DX and distribute the DX report real time. File Transfer: With special software, amateurs can pass any binary files to other amateurs. Currently, this is done with TCP/IP communications, YAPP, and other specialized protocols. Satellite Communications: Many of the amateur radio satellites contain microcomputer systems that can provide special information to amateurs. Some satellites contain CCD cameras on board and you can download images of the earth and the stars. Others provide store and forward packet mailboxes to allow rapid message transfers over long distances. Some satellites use AX.25, some use special packet protocols developed for satellite communications. A few transmit AX.25 packets over FM transmitters, but most use SSB transmissions. 1.4 Why packet over other digital modes? Packet has three great advantages over other digital modes: transparency, error correction, and automatic control. The operation of a packet station is transparent to the end user; connect to the other station, type in your message, and it is sent automatically. The Terminal Node Controller (TNC) automatically divides the message into packets, keys the transmitter and sends the packets. While receiving packets, the TNC automatically decodes, checks for errors, and displays the received messages. In addition, any packet TNC can be used a packet relay station, sometimes called a digipeater. This allows for greater range by stringing several packet stations together. Packet radio provides error free communications because of built in error detection schemes. If a packet is received, it is checked for errors and will be displayed only if it is correct. With VHF/UHF packet, many countries allow packet operators to operate in automatic control mode. This means that you can leave your packet station on constantly. Other users can connect to you at any time they wish to see if you are home. Some TNC's even have Personal BBS's (sometimes called mailboxes) so other amateurs can leave you messages if you are not at home. Another advantage of packet over other modes is the ability for many users to be able to simultaneously use the same frequency channel simultaneously. 1.5 What elements make up a packet station? TNC (Terminal Node Controller) A TNC contains a modem to decode the audio signals into digital signals. It also contains a modem and a micro- computer to convert the digital signals into text that can be sent over a RS-232 port to the computer. The CPU also handles the protocol overhead of the packet station. When you send data, it takes the text, puts error checking on it (CRC) and also puts it in an envelope for sending. When receiving a signal, it takes it out of the envelope, and sends the message to the computer. Most TNC's use 1200 baud for local UHF/VHF packet and 300 baud for long distance HF packet communications. For VHF/UHF packet, higher speeds modems are available, but often are harder to interface. Computer or Terminal This is the user interface. A computer running a terminal program or just a dumb terminal can be used. For computers, any phone modem communications program can be adapted for packet use or customized packet radio programs are available. A radio For 1200 baud UHF/VHF packet, commonly available narrow band FM voice radios are used. For HF packet, 300 baud data is used over single side band modulation. For high speed packet (anything greater than 1200 baud), special radios or modified FM radios must be used. 1.6 What do you mean we can all use the same channel? Packet radio uses a protocol called AX.25. AX.25 specifies channel access (ability to transmit on the channel) to be handled by CSMA (Carrier Sense Multiple Access) If you need to transmit, your TNC monitors the channel to see if someone else is transmitting. If no one else is transmitting, then the radio keys up and the TNC sends it's packet. All the other stations hear the packet and do not transmit until you are done. Unfortunately, 2 stations could accidentally transmit at the same time. This is called a collision. If a collision occurs, neither TNC will receive a reply back from the last packet it sent. Each TNC will wait a random amount of time and then retransmit the packet. In actuality, a more complex scheme is used to determine when the TNC transmits. See the "AX.25 Protocol Specification" for more information. 1.7 What is AX.25 ? AX.25 (Amateur X.25) is the communications protocol used for packet radio. A protocol is a standard for how two computer systems are to communicate with each other, somewhat analogous to using business format when writing a business letter. AX.25 was developed in the 1970's and based of the wired network protocol X.25. Because of the difference in the transport medium (radios vs wires) and because of different addressing schemes, X.25 was modified to suit amateur radio's needs. AX.25 includes a digipeater field to allow other stations to automatically repeat packets to extend the range of transmitters. One advantage of AX.25 is that every packet sent contains the senders and recipients amateur radio callsign, thus providing station identification with every transmission. 1.8 Definitions: Commonly used terms in Amateur Packet Radio HDLC : (High-Level Data Link Control Procedures) A standard for high level link control. (ISO 3309) AX.25 : Amateur X.25 protocol. The basis of most packet systems. See section 1.7. TAPR : Tucson Amateur packet Radio. Was the first group to create a packet radio TNC using AX.25. Soon a TAPR TNC became cloned by many others. TAPR continues development of packet radio equipment. digipeater : A packet radio station used for repeating packets. See section 3.3.1 for more information. digi : Short name for a digipeater NET/ROM : A scheme for packet radio networking. See section 3.3.3 for more information. TCP/IP : Transmission Control Protocol/Internet Protocol. A set of utility programs used over AX.25. See sections 3.2 for more information. KA9Q NOS : (KA9Q Network Operating System) A TCP/IP program originally developed by Phil Karn, KA9Q. Currently there are many different versions available. See section 3.2 for more information. NODE : A network node. Often a network node running NET/ROM. KA-Node : A simple networking scheme developed by TNC maker Kantronics. See section 3.3.2 for more info. CSMA : Carrier Sense Multiple Access. A system allowing many stations to use the same radio frequency simultaneously for packet communications. TNC : Terminal Node Controller. See section 1.5 for more information. AMPR : Amateur Packet Radio. 44 net : The class A network designator for TCP/IP amateur packet radio. All numerical TCP/IP addresses are in the format of 44.xxx.xxx.xxx . ampr.org : The high level domain recognized on Internet for amateur packet radio TCP/IP. RS-232 : (RS-323C) A standard for interconnection of serial peripherals to small computer systems. In packet radio, RS-232 is the most common interface between TNC's and the Computer/Terminal. protocol : A standard used for intercommunications between different computer systems. CRC : Cyclical Redundancy Code. The error detection scheme included in each packet. Verify that the packet was received error free. KISS : Keep It Simple Stupid. A simple interface developed for communications between TNCs and computers. This allows for most of the packet processing to be handled by the computer. Commonly used with packet TCP/IP software. modem : Modulator/Demodulator. Converts the analog signals into binary data stream (a series of ones and zeros) for the TNC or a micro-computer . First step in decoding packets. FCC : Federal Communications Commission. Regulates and issues licenses for amateur radio in the United States. FM : Frequency Modulation. The radio modulation scheme used for VHF and UHF packet communications. SSB : Single Side Band Modulation. The radio modulation scheme use for HF packet and satellite packet communications. AFSK : Audio Frequency Shift Keying. A method of representing digital information by using different audio frequencies modulated on a carrier. FSK : Frequency Shift Keying. A method of representing digital information by shifting the radio carrier different amounts to represent ones and zeros. LAN : Local Area Network. A packet network developed for communications throughout a city or region. Often, the LAN uses separate frequencies from inter-city packet links. 1.9 Do's and Don'ts : Rules and Regulations NOTE: These regulations apply only to amateurs regulated by the FCC (United States), but often are similar to regulations in other countries. [Since I have no experience with amateur radio in other countries, I cannot make any comments. Please bring any notable exceptions to my attention. -Steve] Although there are no specific rules that apply to amateur packet radio, the general amateur radio rules force some restrictions on packet usage. Can I set up a TNC at home and one at work so I can check my Electronic mail via packet? This cannot be done without special restrictions. Amateur radio rules prohibit any business. Since you could have mail from your boss (or maybe even someone selling you something over Internet), that would constitute business activity and is specifically prohibited. Profanity can also be a complication. Since you have no control over the language used in E-mail, proper filtering is required. Since no filter scheme can catch every offense, it is best to say every message must be hand filtered. I would like to set up a packet radio gateway between a land line computer network and the packet network. Is this possible? Yes, and there are several such gateways in use, but they must be managed with caution. Electronic mail may be pass FROM the packet network INTO the land line network without intervention. However, mail passed TO packet radio is considered third party traffic (the sender is not an amateur) and these messages must be hand filtered to assure that rules of message content are followed. It's my license if I send use packet radio illegally anyway, so what does anyone else care! Packet radio is one of the few NETWORKED systems in amateur radio. Many people have helped develop the network and there are many amateurs who own parts of the packet radio network. Sending packet BBS mail, digipeating, and sharing the channel involves the licenses of MANY people. Because of FCC rules stating that anything to come out of a transmitter (either in automatic mode or via your direct control) is the licensees responsibility, one illegal message sent over the packet radio network could literally jeopardize the license of thousands of other amateurs. When in doubt, it is best to check with other amateurs about sending the message before it is sent. I have some ideas on how to use packet radio in a new way, but I don't know if it is legal. Who could tell me if I can do it legally? The worst thing you can do is talk to the FCC about such an issue. The FCC rules are written to be general enough to encompass but not restrict new radio activities. In the past, any non-thought-out requests sent to the FCC have meant a reduction of privilege for all amateur radio operators. The best source for legal assistance is your national amateur radio association. In the United States, that is the American Radio Relay League (ARRL). Another good place for such conversations is over Usenet/packet mailing lists, or the amateur radio BBS network. 2.0 Computing Network Resources for Amateur Packet radio This section summarizes the resources available on Internet for amateur packet radio operators. 2.1 What Newsgroups/mailing lists are available? This is a list of all groups that regularly discuss amateur packet radio. For newsgroups, join the group through use of your news reader. For mailing lists, add a '-request' to the end of the list name to request subscriptions. For listserv groups, send mail to 'listserv' at the node which contains the list. The first line of the mail should be 'SUBSCRIBE groupname yourname'. Send the command 'help' for more information. rec.radio.amateur.packet (Newsgroup): General discussions involving Packet Radio. rec.radio.amateur.misc (Newsgroup): General amateur radio discussion. Usually does not contain any particular information about Amateur Packet Radio. rec.radio.amateur.policy (Newsgroup): Discussion of regulation policies regarding every aspect of amateur radio. Occasionally deals with polices of packet coordination and legal issues of packet radio. rec.radio.swap (Newsgroup): General For-Sale for any radio equipment. Occasionally will have packet equipment for sale. Recommended location for any amateur packet radio for-sale items. info-hams@ucsd.edu (Listserv group): A digest redistribution of the rec.radio.amateur.misc Usenet discussion. packet-radio@ucsd.edu (Listserv group): A digest redistribution of the rec.radio.amateur.packet Usenet discussion. ham-policy@ucsd.edu (Listserv group): A digest redistribution of the rec.radio.amateur.policy Usenet discussion hs-modem@wb3ffv.ampr.org (Mailing list): Discussion of high speed modems and radios available and future plans. Also includes discussion of networking using high speed modems. tcp-group@ucsd.edu (Mailing list): Group discussion technical developments of TCP/IP over packet radio and use of the NOS TCP/IP programs. gateways@uhm.ampr.org (mailing list): Discussion of current gateways and future plans for gateways. May deal with sensitive internetworking issues. For all lists at ucsd.edu, archives may be found via anonymous FTP at ucsd.edu. Some listserv groups also have archives. Send the command 'help' to the group's listserv for more information. Digest mailings for the ucsd.edu discussions are also available. Send mail to listserv@ucsd.edu with the first line being 'longindex' for more information. 2.2 What anonymous FTP sites are available for getting packet radio information and programs? This is a sampling of FTP sites that carry amateur packet radio related files. Consult the Archie archive server for info on locating particular files. For more information on using archie, send mail to archie@cs.mcgill.edu with the line 'help'. ucsd.edu Primary distribution site of KA9Q's derived TCP/IP packages. Also, general packet radio information. wsmr-simtel20.army.mil Very large collection of amateur radio software. wuarchive.wustl.edu Mirror site of Simtel20 archives. Unix directory structure - Easier to use then the simtel20 archive. ftp.cs.buffalo.edu Supplimental archive site for amateur radio information. Contains current copies of all rec.radio.amatuer.* FAQ's. tomcat.gsfc.nasa.gov Packet software including Baycomm, Rose, G8BPQ, NOS, etc. 2.3 Are there any gateways for mail or news between Internet and Amateur Packet radio? Internet / Packet Radio BBS Gateway Jim Durham, W2XO, maintains a gateway between Internet and the Packet radio BBS system. To mail from Internet to Packet: 1. Mail to: "bbs@w2xo.pgh.pa.us" 2. Make the first line of the text a Packet BBS "send" command, ie: SP TOCALL @ BBSCALL.ROUTING-HINTS < FROMCALL 3. The "subject" line of the Internet mail becomes the "title" line of the Packet BBS mail. NOTE: Because of FCC regulations, Jim must hand filter each message sent FROM Internet TO the Amateur Packet Radio BBS system. Messages should be of minimal length and appropriate content. Read Section 1.9 (Do's and Don'ts: Rules and Regulations) regarding appropriate usage of packet radio for more information. Always include the routing hints with the BBS callsign. To mail from Packet to Internet: 1. The amateur radio operator must have his callsign registered in the gateway alias list. If you want to mail from packet to a specific amateur on Internet, send mail to 'durham@w2xo.pgh.ps.us' (Internet) or 'W2XO @ W2XO.#WPA.PA.USA.NAOM' (Packet BBS mail) with his/her amateur callsign and their Internet address. 2. Once the above is accomplished, packet BBS mail should be sent to 'CALL @ W2XO.#WPA.PA.USA.NAOM'. The mail will automatically be forwarded to the Internet address of the amateur with the 'CALL' callsign. Jim Durham's Internet address is 'durham@w2xo.pgh.ps.us'. LAN Gateways (Packet wormholes via Internet) Currently a group of amateurs are experimenting with connecting packet LANs together via Internet IP inside IP Encapsulation. Some of the gateways only accept TCP/IP packets, others AX.25 packets. These gateways uses the Internet as a transport medium, thus it is impossible to access the packet radio network from Internet. For more information, join the Gateways mailing list by sending mail to "gateways-request@uhm.ampr.org". 3.0 Networking and special packet protocols This is a sample of some of the more popular networking schemes available today. By far, there are more customized networking schemes used than listed. Consult your local packet network guru for specific network information. 3.1 Are there any other protocols in use other than AX.25? AX.25 is considered the defacto standard protocol for amateur radio use and is even recognized by many countries as a legal operation mode. However, there are other standards. TCP/IP is used in some areas for amateur radio. Also, some networking protocols use other packet formats than AX.25. Often, special packet radio protocols are encapsulated within AX.25 packet frames. This is done to insure compliance with regulations requiring packet radio transmissions to be in the form of AX.25. However, details of AX.25 encapsulation rules vary from country to country. 3.2 What is TCP/IP? TCP/IP stands for Transmission Control Protocol/Internet Protocol. This is commonly used over the Internet wired computer network. The TCP/IP suite contains different transmission facilities such as FTP (File Transfer Protocol), SMTP (Simple Mail Transport Protocol), Telnet (Remote terminal protocol), and NNTP (Net News Transfer Protocol) The KA9Q NOS program (also called NET) is the most commonly used version of TCP/IP in packet radio. NOS originally was written for the PC compatible. However, NOS has been ported to many different computers such as the Amiga, Macintosh, Unix, and others. Smaller computers like the Commodore 64 and the Timex- Sinclar do not currently have version of NOS available. 3.3 Networking Schemes What are some of those other networking schemes? During the early days of amateur packet radio, it became apparent that a packet network was needed. To this end, the following packet network schemes where created. Digipeaters The first networking scheme with packet radio was Digipeaters. Digipeaters would simply look at a packet, and if it's call was in the digipeater field, it would resend the packet. Digipeaters allow the extension of range of a transmitter by retransmitting any packets addressed to the digipeater. This scheme worked well with only a few people on the radio channel. However, as packet became more popular, digipeaters soon were clogging up the airwaves with traffic being repeated over long distances. Also, if a packet got lost by one of the digipeaters, the originator station would have to retransmit the packet again, forcing every digipeater to transmit again and causing more congestion. KA-Nodes Kantronics improved on the digipeater slightly and created KA- Nodes. As with digipeaters, KA-Nodes simply repeat AX.25 frames. However, a KA-Node acknowledges every transmission each link instead of over the entire route. Therefore, instead of an end- to-end acknowledgement, KA-Nodes allow for more reliable connections because acknowledgments only carried on one link. KA-Nodes therefore are more reliable than digipeaters, but are not a true network. It is similar like having to wire your own telephone network to make a phone call. NET/ROM NET/ROM was one of the first networking schemes to try to address the problems with digipeaters. A user connects to a NET/ROM as if connecting to any other packet station. From there, he can issue the NET/ROM commands to instruct it to connect to another user locally or connect to another NET/ROM. This connect then connect again means that to a user's TNC, you are connected to a local station only and it's transmissions does not have to be digipeated over the entire network and risk loosing packets. This local connection proved to be more reliable. NET/ROM don't use all of the AX.25 protocol. Instead, they use special AX.25 packet called Unnumbered Information (UI) packets and then put their own special protocol on top of AX.25. This is again used to increase efficiency of it's transmissions. NET/ROM is a commercial firmware (software put on a chip) program that is used as a replacement ROM in TAPR type TNC's. Other programs are available to emulate NET/ROM. Among them are TheNet, G8BPQ node switch, MSYS, and some versions of NET. NET/ROM nodes, at regular intervals, transmit to other nodes their current list of known nodes. This is good because as new nodes come on-line, they are automatically integrated in the network, but if band conditions such as ducting occur, often unreachable nodes are entered into node lists. This causes the NET/ROM routing software to choose routes to distant nodes that are impossible. This problem requires users to develop a route to a distant node manually defining each hop instead of using the automatic routing feature. ROSE Rose is another networking protocol derived from X.25. Rose nodes have a static list of the nodes it can reach. For a user to use a ROSE switch, he issues a connect with the destination station and in the digipeater field places the call of the local rose switch and the distant rose switch the destination station can hear. Other then that, the network is completely transparent to the user. The static routing tables ROSE uses ensures that packet routing does not use unreliable links such as NET/ROM suffers from. However, ROSE suffers from it's inability to change it's routing table as new nodes come on line. The operator must manually change every routing table, thus ROSE networks require greater maintenance times. 3.4 BBS message transfer Many of the BBS programs used in packet radio allow for mail and bulletins to be transferred over the packet radio network. The BBS's use a special forwarding protocol developed originally by Hank Oredsen, W0RLI. Besides full service BBS's, many TNC makers have developed Personal BBS software to allow full service BBS to forward mail directly to the amateurs TNC. This allows operators to receive packet mail at night and avoid tying up the network during busy hours. - End of Amateur Packet Radio Frequently Asked Questions -