I-Net+ Exam Notes
- DSL stands for Digital Subscriber Line
DHCP stands for Dynamic Host Configuration Protocol
PPP stands for Point to point protocol
HTTP stands for
Hyper Text Transfer Protocol
WWW stands for
World Wide Web
HTML stands for
Hyper Text Markup Language
PPTP stands for
Point to Point Tunneling Protocol
L2F stands for
Layer 2 Forwarding
L2TP stands for
Layer 2 Tunneling Protocol
MIME stands for
Multipurpose Internet Mail Extensions.
stands for Certificate Authority.
stands for Dynamic Link Labrary
stands for Open Data Base Connectivity.
stands for Virtual Reality Modeling Language
stands for Joint Photographic Expers Group.
stands for portable Network Graphics
stands for Tag image File Format
stands for Moving Pictures Experts Group
stands for Audio Video Interleaved.
stands for Public Key infrastructure.
Internetwork IP addressing:
IP addresses are written using decimal numbers separated by
decimal points. This is called dotted decimal notation of
expressing IP addresses.
The different classes of IP addresses is as below:
N: Network address part
H: Host address part
- Network address of all zeros means "This network or
- Network address of all 1s means " all
networks", same as hexadecimal of all Fs.
- Network number 127 is reserved for loop-back tests.
- Host (Node) address of all zeros mean "This Host
Host (Node) address of all 1s mean "all Hosts (Nodes)
" on the specified network.
The range of numbers from 126.96.36.199 to 188.8.131.52 is
used for multicast packets. This is known as Class D
The default subnet mask for
Class A network: 255.0.0.0
Class B network: 255.255.0.0
Class C network: 255.255.255.0
2. TCP/IP protocol suite was initially developed based on
Unix operating system and it is native to Unix. TCP/IP
protocol suite was added to other operating systems like
ATM, Asynchronous Transfer Mode, uses 53 byte cells for all
transmissions All cells are 53 byte long and consist of a
5 byte header and 48 bytes of data.
4. T1,T2, and T3 connections:
The speeds of the Tx connections are as given below:
T1: 1.544 MBPS consisting of 24 channels of 64 kBPS
T2: 6.312 MBPS consisting of 96 channels of 64 kBPS
T3: 43 MBPS consisting of 672 channels of 64 KBPS
uses existing copper phone lines. The access speeds can be
up to 9 MBPS. but has distance limitations and available
in only certain exchange areas.
are several categories of DSL:
DSL (ADSL): Here data flow is asymmetric. Data flow in one
direction is different from that in the other direction.
DSL (SDSL): Here the data flow is symmetric, that the data
flows equally in both directions.
not so much used or known types of DSL are BDSL, HDSL, and
The range of numbers from 184.108.40.206 to 220.127.116.11 is used for
multicast packets. This is known as Class D address range.
Telnet, FTP, and TFTP:
TCP/IP is the protocol used when you are Telnetting to a
remote host. Telnet is used for terminal emulation that
runs programs remotely.
FTP is used to transfer files. FTP is a connection-oriented
protocol. It uses TCP/IP for file transfer.
TFTP (Trivial File Transfer Protocol) uses UDP. TFTP is a
8. A valid IP address on a host / node can't start with
127; 127.X.X.X is reserved for local loop back. A valid IP
address can't be larger than 255 (in any octet), The
maximum allowed value is 255 in any or combination of
octets. For example, 150.206.256.31 is an invalid IP,
since one octet exceeded the value 255. An example of
valid IP is 18.104.22.168.
9. Tracert, Ping use ICMP as their base protocol. ICMP
messages are carried in IP data grams.
10. SMTP is used to upload mail to the mail server. POP3 is
used for downloading mail from a mail server to a client
machine running POP3 client.
11. A firewall is a security mechanism, which prevents
unauthorized access to a network or a resource on a
Important port numbers:
port numbers used by different programs are as below:
FTP: Port #21
Telnet: Port #23
SMTP: Port #25
SNMP: Port #161
WWW: port 80,
NNTP: port 119,
POP: port 110.
is also important to know that FTP, Telnet, SMTP use TCP;
whereas TFTP, SNMP use UDP.
Repeaters, Bridges, and Routers:
Repeaters work at
Physical layer (Layer 1),
simple switches work at Data Link Layer (Layer 2),
Routers work at
Network Layer (Layer 3) of ISO Reference Model.
Gateway is used to translate protocols, as it works at
Telnet requires an username and password to access.
two standard access methods:
BRI (Basic Rate
of two B channels (64Kbps) and one D channel (16Kbps).
channels can be used for digitized speech transmission or
for relatively high-speed data transport.
channel carries signaling information (call setup) to
control calls on B channels.
PRI (Primary Rate
of 23 B channels and one D channel with
a bandwidth of 1.544Mbps.
PRI uses a
DSU/CSU for a T1 connection. B stands for Bearer Channel.
TCP/IP port assignments used in the Internet: Originating
source port numbers are dynamically assigned by source
host, and usually greater than 1023. The following are the
recommended port numbers:
Numbers 0 - 255
are used for public applications
Numbers 255 -
1023 are assigned to companies so that they can use these
port numbers in their applications.
1023 are used by upper layers to set up sessions with
other hosts and by TCP to use as source and destination
Some of the important commands useful in trouble shooting
Ipconfig: Displays TCP/IP configuration values,
including IP address, subnet mask, and default gateway.
Ping: This command can be used to verify whether
the target ip address or host name is present. You need to
specify the target IP address or host name.
and manipulates route information.
Tracert: Determines the route packets take to reach
the specified destination.
HTTP is the protocol used for accessing the World Wide Web
services. HTTP operates over TCP/IP. TCP/IP is the
protocol, which is used by all internet applications such
as WWW, FTP, Telnet etc.
IPX/SPX is proprietary protocol stack of Novell
TCP is a full-duplex, connection-oriented protocol. It
incorporates error checking as well. UDP (User Data gram
Protocol): UDP is a thin protocol. UDP is a connectionless
protocol. It doesn't contact the destination before
sending the packet and doesn't care whether the packet is
reached at the destination. UDP uses port number 6.
The above notes is
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