Note: The idea for a glossary was suggested by Tony Sanders
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.
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
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
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
Well, that was the intent, anyway. According to Ehud Gavron
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.
Next section: Resources
18.1 Glossary of Internet Service Terms
18.2 Glossary of Internetworking (Wholesaler) Terms