Networking Jargon
The_Duke247
the_duke247@mail.box.sk
networking, cisco, jargon
ADSL: (Asymmetrical Digital Subscriber Line)
Standard in high bandwidth transmission media.
DTR of 604kpbs upstream and 2,048Mpbs downstream.
Trials are now being launched in the UK with ADSL by
BT among other companies.
BASE 2/5/10-1000
Ethernet networking that can transmit over many cable
mediums such twisted pair, co-axial cable, fibre etc.
depending on the actual standard.
Bridge:
A piece of hardware that is used to connect two internal
networks, LAN's, to each other which work on the same
standard e.g. Ethernet>Ethernet etc.
BT: (British Telecom)
Inventors of the ISDN line and the closest thing to a
commercial monopoly the UK has ever seen. Regulated by
an independent watchdog called OFTEL who monitor and
ensure they conform to various standards and anti-monopoly
laws.
Bus:
A network backbone is present with all nodes on the network
sharing a common pathway to the server to which it interacts.
CCITT (Consultative Committee for International Telegraph and
Telephony)
Committee that administers and introduced standards we know
today such as V.21, V.22 and X.25 digital data transmissions.
Client/Server:
The server lives to "serve" other nodes on the network e.g.
the workstations that rely on the server to perform tasks,
deliver software, process user accounts etc.
A typical client/server model. Many people think that
servers are hardware, they are not. A server is a piece
of software that configures the hardware to server clients
over a distributed or contained network.
The types of protocols used are usually request/reply
protocols which simplify the processes in a "connectionless"
manner.In a network where nodes are connected and configured
identically, this client/server model serves a network in a
more efficient manner as only three layers of OSI need to be
applied to implement and administer the network.
The physical and data link layers are used in order to send the
data to the server and thus back to the requesting client.
This is still "connectionless" as this process is handled by
the hardware e.g. the Ethernet card.Layer 5, the request/reply
protocol, is used to define which requests and replies are
legal and no layers above this are used.
DCE (Data Communications Equipment)
Hardware devices that establish connections such as modem etc.
form the group called DCE.
DTE (Data Terminal Equipment)
Devices that act as a data source.
Ethernet Address:
48-bit number, as oppose to the 32-bit IP address, which is
used to identify each Ethernet network adaptor.
Ethernet:
LAN developed by Xerox® and Intel®. LAN type that connects
upto 1024 devices at a minimum of 10Mbps over fibre, twisted
pair and co-axial cable.
Firewall:
Any piece of hardware, hardware firewalls are the original
and best, or software that can act as the first line (not
always the first) and block certain traffic from entering
or leaving the network.
They usually work on a rule base which is configured to the
client's needs. Cisco has become the market leaders with their
PIX, among others, series firewalls. They also have the
ability to block ports etc.
FRAD: (Frame Relay Assember/Disassembler)
Packet switching network that assembles/disassembles packets
leaving the network into the format required for frame relay.
Frame Relay:
Long distance, high bandwidth transmission which is similar to
X.25 but differentiates as it has error checking on both ends
of the line.
FTP:
FTP is the File Transfer Protocol working on port 21 usually.
A client would make a request to the server to obtain or send
files to the server using the GET or SEND commands. The server
would usually require some kind of authentication based around
a pre-setup user account or a guest account with the login
simply being "guest" and the password being the users email
address.
A full list of commands can be gained by logging into a FTP server:
FTP ftp.server.com:21 and typing help after login.
Full Duplex:
The process of being able to send data two ways at the same
time e.g. simultaneous 2-way data transfer e.g. the
phone line.
GGP:
Gateway to Gateway Protocol. Similar to routing information
protocol in that it is a vector-distance based protocol.
Used in Core Gateways for interaction.
Half-Duplex:
Two way data communications technique that cannot handle
simultaneous data transfer e.g. standard CB radio etc.
HTTP: (Hypertext Transfer Protocol)
The process involved with a workstation receiving data from a
web server using a browser on port 80. Apache, Zeus and IIS
are all examples of web server software that conform to this
protocol.
Hub:
Network hardware that allows different nodes to be connected
at one common point in order for information to be relayed
through different clients.
IPX®: (Internet Packet Exchange)
Novell® Netware®'s own networking standard that is used for LAN's
and is almost very reliable. Although not based on TCP/IP, it
is still very good and used a lot today.
ISDN: (Integrated Digital Service Network)
Developed by BT (British Telecom) in the UK, this was one of
the first standards available which would prove commercial
enough to the home user and good enough for businesses for
video conferencing. It boasted, and still does... heh,
128Kpbs DTR upstream (via 2 64K lines using and paying for
2 phone calls in the UK... :o( ) and 64K DTR upstream.ISDN
terminal adaptor cards must be used in conjunction with the
digital phone lines.
LAN:
Local Area Network. A network that is comprised within the
physical boundaries of a building or one area. Usually based
around 10/100 Base-T architecture, LAN's conform to high
bandwidth transmission rules and are now common place within
all major organisations.
Mesh:
Each network node is interconnected. This is a very messy
topology which proves hard to maintain and administer for
network management staff.
Microsoft:
What happens when mummy let's you spend too much time in the
garage with a friend who does a lot more than you, makes nicer
things but somehow you get all the credit and become the rich
kid who everyone loves to hate. Imagine if he built planes?...
Wow, doesn't even bear thinking about.
MODEM: (MOdulator DEModulator)
Analogue device that connects to the standard analogue phone line
to convert anaglogue>digitial and vice versa between the two
connecting nodes in a PPP (Point to Point) protocol session.
NetBIOS:
Internal networking standard. This is not a protocol in itself
but runs over the existing NetBEUI protocol on port 139.
This has been the subject of OOB (Out of Band) data attacks
by new users to the internet.WinNuke '95 was a popular program
that exploited this hole.The main hole was present in Windows
'95 OSR 1, was closed down I believe in OSR 2 and was totally
patched in Windows '98.
I am unsure of the exact facts but I
believe those to be correct.NetBIOS is an internal networking
standard meaning it does not have any routing capabilities,
cannot work in conjunction with the RIP (Routing Information
Protocol), so therefore cannot be used to connect to any other
external entity.
Node:
Any piece of hardware on a network that has it's own
address is called a node. It is a functional piece of
equipment that requires configuration on the mask/network
it resides.
NT 4.0:
Network Operating System, allegedly, inspired (well actually
probably someone's idea) and developed by Microsoft. They
spent years trying to get one of their operating systems to
go over on to a server and actually operate with something
else other than itself, and sometimes has problems doing that.
Even when they did, they had to have it accompany in two
separate packages which would interact. NT was a good idea
in theory, then again so was Corel Linux.
Null Modem:
Any piece of hardware on a network that has it's own address
is called a node. It is a functional piece of equipment
that requires configuration on the mask/network it resides.
Cable used to serially connect two computers.
PING: (Packet InterNet Groper)
PING data is sent out to see if a host is deemed reachable,
"alive", or not. PING data is set an initial TTL (Time to
Live) when it is sent out. If the host is not reached in
a specified TTL, the host is deemed unreachable and offline.
The number of places the PING data travels through to get to
the destination is called the number of "hops".
Port:
A software controlled logical interface that expects certain
types of data to arrive for processing e.g. FTP works on 21,
Finger on 79, NetBIOS on 139 etc.For a more in-depth explanation
of this subject, please visit http://blacksun.box.sk and download
the excellent tutorial on Sendmail written by "R a v e N",
very nice glossary in there which explains "ports" a little bit
more in depth than me.
Ring:
Not physically a ring shape but a network topology where each
computer is connected to each other and the last computer,
broadcast node, is the server. Polling is used on this
network topology.
RIP:
Routing Information Protocol. The protocol that is used by the
router.
RIP assumes a low cost route value in order for a message to
reach it's destination from the router table held in router
memory or computer memory. The lowest cost value is assigned
for the message as this is equal to the fastest transmission
route for the message to take.
routed and gated:
Two routing daemons used by UNIX systems administrators to
maintain the Routing Information Protocol. They can be used
to select a desirable or undesirable path across a network.
Both are daemons that perform practically the same job. They
are in essence, routing daemons that work as part of the
gateway protocols standard.
Routing:
This is the process concerned with the transport of information,
or messages, from one machine to another. A packet header is
present within each message and each machine that the message
enters scans and reads the packet data.
If the destination IP address of the message matches the particular
machine that is scanning it, the message is retained and processed.
If the IP address does not match the machine currently scanning, the
message will be 'forwarded' throughout the remainder of the network
until the correct machine is found. Also, it could be forwarded to
a gateway or bridge if the message is to leave that particular
segment or whole network.
Simplex:
One way data transfer and I use the term "client/server", although
this is not to be mixed up with the original client/server approach
it helps me explain my own point in my own words. The server
delivers goods to the client and the client cannot respond.
Typically used for broadcast networks and I believe SNMP uses this
type of transfer as well. TV companies use simplex transmission
for analogue (wave form) broadcasts.
SMTP:
Working on port 25, this is the protocol that interfaces with the
respective program in order to send mail from one sender to
another recipient.
SNMP: (Simple Network Management Protocol)
Used in order to manage the network. Monitoring logs etc. are
sent back to the workstation on the network that controls them
via this protocol.
Socket API:
Socket Application Programming Interface. Used for creating
applications that will interact and use TCP/IP standards.
Star:
Fast network topology. Each node on the network has a direct
connection with the server. No common pathway, or backbone,
is used and this results in high traffic bandwidth levels.
TCP/IP:
Transmission Control Protocol/Internet Protocol. Developed
by ARPA, Advanced Research Projects Agency, as a means of
allowing nodes on a network to interact and share resources.
Comprises of Telnet, FTP etc.
The OSI 7 Layer Model
APPLICATION
|
| < Protocol Interfaces
|
PRESENTATION
|
|
|
SESSION
|
|
|
TRANSPORT
|
|
|
NETWORK
|
|
|
DATA LINK
|
|
|
PHYSICAL
The Physical Layer:
The maximum bit rate, the actual data that is to be sent in
binary form are handled here. Also, the transmission methods
that can be used e.g. simplex, half-duplex and duplex
transmission are defined here. Simplex transmission can
handle data in one way at one time, half-duplex can handle
bi-directional data at one time and duplex can handle
bi-directional simultaneous data transmission.
The Data Link:
In an ideal network in an ideal world, every packet would
reach it's destination in uncorrupted form and printers
would never receive SKEW etc. Of course, this isn't the
case and there has to be some kind of error detection in
order to detect/correct these problems.
At it's most basic level, the data link level sorts the
data into "frames" and sees they are all received correctly.
The Network Layer:
On a small to medium sized LAN, the sender would put the
message on the network to be taken down by the recipient.
On a WAN or large scale LAN bridged to many networks... this
wouldn't be possible. The message would have to overcome many
"hops" in order to reach the recipient. The distance to each
recipient each time would vary depending on physical distance,
network traffic, maximum bandwidth etc.The process of deciding
which route to take is called "routing" and is the job of the
network layer at it's most basic function.
The Transport Layer:
As mentioned, the distance between sender and receiver can be
somewhat of a jerky one and packets can and frequently do get
lost in transit. The transport layer provides a reliable
connection and a solution to secure packet transit.
A typical example would be that the transport layer receives
a message from the session layer and then breaks them down
into adequate sizes and then send the data off. The session
layer at this point would assume the data would not be lost
and the most basic of functions of this layer are complete.
The Session Layer:
Although not recognised in the DoD (Department of Defence)
protocol suite, this layer is an enhanced version of the
transport layer. It allows "checkpoints" to be inserted into
particularly long transfers so in the event of a crash, the
whole route does not have to be re-established and hence a
more efficient process.
The Presentation Layer:
Previous layers have been concerned with making sure the data
gets from sender to receiver in the best possible time and
condition.
The presentation layer is not concerned with this. It is concerned
with structured data packets and can make easier interaction
between machines which have a different data representation
technique.
The Application Layer:
These are nothing more than a group of applications that work at
the user interaction level to perform miscellaneous tasks based
over protocols such as email, FTP etc.
Trace Route:
The process of identifying, and maybe resolving, the host name and
IP address or un-resolved host name came from. Used for IP tracing.
CLI> windows= tracert
LINUX = traceroute
UDP: (User Datagram Protocol)
Connectionless protocol which can be unreliable as it
doesn't support error correction and detection. It is used for
a simple send/reply transmission.
(
geocities.com/eljehad1)