18.0 Glossary of Common Terms and Acronyms

Note: The idea for a glossary was suggested by Tony Sanders . At present, it's woefully incomplete and additions will be warmly appreciated.

18.1 Glossary of Internet Service Terms

These are words, phrases and acronyms dealing with Internet Services issues. There is a second glossary below for words dealing with Internetworking wholesale issues such as CIDR blocks and what-not.

Bandwidth. (1) The maximum amount of information that can be transmitted at any given time. A 56k leased line connection, for example, has 56k of bandwidth. (2) An abstract unit of measure of the load something puts on an Internet connection. "Multimedia through the Internet uses too much bandwidth for a 56k connection." Often used in Usenet to refer to stupid questions or wasteful flames, i.e. "this is all a waste of bandwidth".

Client. A program that is run by users on their machine. It issues requests to a server, which is generally located on another system. For example, here's how a Gopher conversation might work: Connection Client Program Server Program Active Send me your menu Here it is (sends menu) | Receives menu from server |

Displays the menu on the screen Lets client choose an option Client chooses option Client finds out what machine | to connect to and asks server | on that machine for the data | Client receives data Server sends data | Client displays data to user

As you can see from this rough sketch, this off-loads a great deal of stuff from the server program, so that it can process client requests more efficiently. This also makes the system appear very fast, since requests to page through the document can be handled by the client and run as fast as the client can. This is dramatically different from connecting to the remote system and retrieving the file from the remote system screen by screen; depending on the remote system's response time, this could appear many times slower than the client/server approach.

For example, the FTP client takes the user commands to transfer files and passes them to th FTP server. The server then sends the file to the client, which then passes it on to the user as appropriate.

Note that in the case of Gopher and WWW, the actual connections are very brief. In the example above, the connection is only active when there is a "|" in the "Connection Active" column. This makes use of the server much more efficient then under protocols such as Telnet, where a connection is established for the length of the session.

CSLIP (Compressed SLIP). SLIP with compression for a more efficient connection. See SLIP.

ECPA (Electronic Communications Privacy Act). A law passed a few years back that says that all electronic mail cannot be read by the people running the system. Its main concrete achievement seems to have been the placing of a notice on all BBSs saying that there is no private mail function on their systems, despite the continued existance of same on the menu.

Flame. An insulting message, normally with little real content. A Flame War is a seemingly endless exchange of such messages.

FTP. File Transfer Protocol. This refers to a protocol describing the way files can be transferred over a TCP/IP network, such as the Internet. The program used to implement this protocol is also called FTP. Normally, a FTP program is included with your basic networking software, and little needs to be done to make it work on your system. However, if you want to offer anonymous FTP, which lets users on the Internet obtain files from your system, you are urged to consult a book on such as the O'Reilly TCP book.

GOPHER. A relatively simple-minded menu interface to the net, Gopher presents a list of menu options. Each option can refer to a resource in a different location on the Internet. Gopher is especially useful for new user information, since it's so simple to use; the World Wide Web is superior in every other way. Unfortunately, there is a rather expensive royalty that you must pay in order to use Gopher for anything commercial; because of this and the ability of WWW to do more interesting things, Gopher is fading in popularity. Veronica is a service that lets you search Gopher servers around the world for various keywords; it's one of th better ways to find something specific through the Internet.

HTML. (HyperText Markup Language). This is the scheme used to design World Wide Web pages. Raw HTML is strikingly similar to the text formatters of old, while lamentably incompatible with any text formatter language I know of. Fortunately, there are numerous tools that can help you write HTML with reasonable efficiency; check out WWW page [[ www page where this stuff is ]] To do well as an Internet provider, you'll probably need to learn how to deal with HTML, since you'll almost certainly want to design your own WWW page to promote your system.

HTTP. (HyperText Transfer Protocol). This is the protocol used for information transmitted over the World Wide Web (WWW).

InterNIC. The government-funded service, run by a company called Network Solutions, that parcels out IP addresses and domain names. Complaints about slow service have been heard quite loudly in recent months.

IRC (Internet Relay Chat). This is a direct interactive way for people to hold conversations using the computer. The level of conversation tends to be pretty low, and rather on the dull side, but many users love it. See the IRC section, earlier in this FAQ.

LYNX. A non-graphical WWW client suitable for shell or BBS account users. See WWW (World Wide Web).

MOSAIC. A World Wide Web graphical client program, usable only under SLIP connections. See WWW.

News, aka NetNews, USENET News, Internet News, etc. This is a messaging system that is one of the most famous and popular parts of the net. See the detailed FAQ section on news for details.

PPP. Point-to-Point Protocol. A newer and supposedly better way to connect your site to the Internet via a single serial line. See SLIP.

RFC. Request for Comment. This is an informal system for proposing Internet standards. The technical people who work on the Internet upload RFCs to the NIC, where they are given a number and published. Many of them are later adopted as Internet standards.

Server. A program running on a remote system that provides information to a client. See Client for a detailed explanation.

SLIP. Serial In-Line Protocol. This is one of several ways to attach a computer to the Internet via a simple (and cheap) modem connection. See the earlier discussion on connecting your system to the Internet for additional information.

TELNET. Telnet is a program that lets you remotely log in to any other system on the Internet (assuming you have access). In the olden days, university systems used to give guest accounts on their mainfame computers so members of the public who could afford a modem and computr could take a peek. Unfortunately, due to the higher level of obnoxiousness of current Internet denizens, this has become far less common. People can, however, use Telnet to connect to various bulletin boards and special interest systems hooked up to the Internet.

TCP/IP. Transmission Control Protocol/Internet Protocol. The protocol used to send information through the Internet

WWW (World Wide Web). This is probably the best Internet browsing system - certainly the most fun one to use. It's not as simple to use as Gopher, but it provides many more interesting options, including integrated graphics if you use the Mosaic browser. See the detailed section on the Web earlier in this document.

18.2 Glossary of Internetworking (Wholesaler) Terms

You will see these terms a lot, but for the most part you won't need to deal with the actual concepts behind them.

IMPORTANT NOTE ABOUT THIS SECTION: This is one of the most horribly confusing things about being an Internet provider. Unless you're wildly successful, you'll never have to deal with any of this stuff. This section is not necessarily accurate; I recieved some contradictory answers to my questions and had to rely on gut instinct to figure out what was what. Corrections and amplifications are warmly encouraged.

ASN. Autonomous system number, used in BGP4 routing. If you're just starting out with a single connection through a single provider, your provider will take care of all your routing for you. Once you decide to get multiple redundant connections (i.e. a T1 through Net-99 and another T1 through ISI Network Associates), your system will have to decide which provider you want to route through. This is done via the BGP4 protocol. What this means in practice is that you need to get a lot of memory on your router, and you'll really have to understand how routing works.

The ASN itself is a unique identifier for your network, which can be used to direct requests thereto. Once the requests are in your network, your own network software takes over and delivers the request to the proper machine.

ATM (Asynchronous Transfer Mode) is one of the most confusing concepts presently on the net. I've sifted through about a dozen conflicting explanations in an effort to get the truth to you, our loyal readers.

So first, relax: If you don't understand it, you're not alone. Many actual experts don't understand it.

ATM is a datalink-level protocol. This means that it's a way that multiple switches can communicate with each other, regardless of the actual data being transmitted. Think of a regular IP packet as a letter within an envelope. ATM is a process where that letter gets put in a bigger envelope, more stuff gets scribbled on the side of it, and it goes its merry way to the end. Once it's at the end, the original IP packet is removed from the envelope and sent to the IP host on the other end. So the hosts think everything's being done in IP, even though it isn't.

Why would one do such a silly-sounding thing? Because IP itself is not well suited to applications like full-motion video, which need a steady stream of small packets and reserved bandwidth in which to run them steadily. ATM will work very well with full motion video, and it encapsulates IP (a fancy term for putting it in the bigger envelope), so it can push around IP packets without knowing what they really are. According to Ehud Gavron , "It's greatest strength is supposed to be its use of fixed-size cells (48 bytes). Fixed sized cells are easier to fast-switch than variable length packets due to inherent efficiencies in DMA buffer transfers. However, the less than ideal size was achieved by mixing the European recommendation for voice usage (32 bytes) with the US recommendation for digital data (64 bytes). As it is, 48 bytes carries a non-compressed IP header, TCP header and up to 8 bytes of data. Extra processing work is done to squeeze more data in."

As you might guess, ATM is really suited only to extremely high speed links - 45MBPS or greater. In fact, many ATM systems are planned for connections more than three times this speed!

CIDR () Block. In the old days, where men were men, women were women, and the Internet was just a little baby, you would go to an organization called the InterNIC to get your IP addresses. The InterNIC would look in its collection, dig up an address, and send it back to you.

There were two problems with this approach as the Internet got bigger. First, each address did not carry any indication of its location with it, which meant that each Internet provider and major gateway had to have an entry in its routers for it. Second, as the Internet got bigger and bigger, issuance of addresses from the InterNIC got slower and slower.

Thus, the CIDR Block, a group of consecutive IP Numbers handed over to a single provider. Let's say you used Net-99 as your provider. Net-99 has a CIDR block obtained from the InterNIC. They issue you an IP number from the block immediately, so there's no delay to get your number from the InterNIC. When someone wants to get your address, it looks up it in its master list, containing CIDR blocks, and finds that you're a part of Net-99's. It then knows to speed the packets to Net-99 without any further processing. Net-99 then handles delivery of the packets to you.

If we didn't have CIDR blocks, the first site would have to look up your full IP number in the list, which would require a large list containing every IP number on the planet. Because Net-99 does the final resolution of the address, that would be needless lookups and thus slower network operation.

What would happen if I changed my provider from Net-99 to ISI Network Associates? ISI has another CIDR block, so the easiest step from their point of view is to give you a different IP number within their CIDR block. This might create considerable confusion as you were switching providers, because some people would know you as a Net-99 client and route you to the wrong place. Eventually, the information would filter through all the net's name servers, and all would be well.

What if you wanted to keep your original IP number? There are ways to bypass the CIDR block system in that particular case, although the providers on both sides would rather you not use them.

In all these cases, your site itself doesn't need to know anything about routing, other than how to get from your system to your provider. Let's say you grew to a large size and could afford multiple T1 connections to the Internet. Say you got an ISI connection and a Net-99 connection, thus giving you two redundant paths to the Internet. This is called a "Multi-Homed" connection, and requires that you get an IP number from the InterNIC, since you are not in the CIDR block of any single provider. [I'm not positive of that last statement; elaborations would be helpful]. A multi-homed connection requires that you run BGP4 (see its separate entry), which lets you manage all routing yourself. Running BGP4 on a multi-homed connection requires a router on the level of a CISCO 4000-series or better, so it's not for the faint of heart or light of wallet. But then again, neither is getting multiple T1 connections.

IETF (Internet Engineering Task Force). They are responsible for Internet standard creating and engineering/design issues. For example, they are working on IPng (Internet Protocol/Next Generation). Not part of the Internet Society.

ISOC (The Internet Society). According to Ehud Gavron , "The Internet Society is a private for-profit organization which has nothing to do with the running of the Internet. You might consider it as one big Internet glee club or fan club. Its actions are purely advisory and it is merely coincidental that any of its members are also members of the IETF and other organizations that really do promulgate Internet standards." Their WWW server lists a lot of papers and symposia they're responsible for. See http://www.isoc.orgfor more information.

MAE-East. An interchange point for network providers where they can peer together, run by Metropolitan Fiber Systems (MFS) in Washington, DC. Highly successful; pretty much everyone seems to be on it. It's located on the East Coast, creating the odd West Coast phenomenon of packets that start in Los Angeles, head off across the country to MAE-East and the cross the country again to land in the Bay Area. Some people consider this revenge on the CIX router in the West coast, where traffic from the East coast would whiz over to the CIX router, go through it, and then go back East to its destination. Absurdities like these are amazingly common in routing.

MAE-East+ is coming; hopefully it will ease congestion problems currently affecting the present MAE-East. MAE-West+ is also on its way. If the NAPs ever amount to anything, their ultra-high speed connections may eventually eclipse MAE-East.

Multi-Homed Connection. This means you use more than one wholesaler for your Internet connections. The good news is that you get greater reliability this way, since you can route through your second provider if the first fails. The bad news is that you open up a big can of worms in dealing with things like CIDR blocks and BGP4 routing. For more information on this, see the CIDR Block section, above.

Multiple Interconnection Points. National providers such as Sprint, MCI and Net-99 are encouraged by the NSF to have multiple interconnection points across the country and around the world. This lets them provide more reliable service; if one of the points goes down, packets are re-routed through the other available paths. This way, the Internet can continue to operate, even if there was (say) a nuclear attack on Washington, DC.

NAP. Interchange points for network providers set up by the government to replace the NSF backbone. According to Steven N Goldstein , "NSF set them up to ensure that the network service providers (NSPs) that provide national transit for the NSF regionals would be multiply interconnected. That much was required or NSF [decreasing] subsidy to the Regionals ... In addition, the NAPs were intended to be open to other service providers, *at their option*, or interconnection. There are plenty of other interconnect alternatives for those who are adverse to NAPs."

Well, that was the intent, anyway. According to Ehud Gavron , "The NAPs are better than MAE-East because they interconnect using the vBNS (very high speed backbone network service) at OC-3 rates (156GBPS over SONET). The NAPs are worse than MAE-East because they aren't up, the interconnections aren't up, there is no vBNS and it's not running yet."

NACR. Network Address Change Request. A Network Add or Change request form, used by ISPs to request MERIT to update its Policy Routing Database (PRDB). NCARs have to be acknowledged by the ASs listd as routing from the backbone to the home AS hosting the network.

SWAB. Another interconnect, this one between AlterNet and PSI.

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