I-Net+ Exam Notes

I-Net+ Certification awarded by CompTIA organization is a widely recognized certification in the area of Internetwoking technologies.  To attain I-Net+ certification, one need to score at least 73%, and there will be around 72 questions. The duration of the exam is 90 minutes. These exams basically test the Knowledge of Networking Technology and Knowledge of Networking Practices. The exam consists of 65 questions and a maximum allowable time of 90 minutes. For further details, you can visit the official website here. Once you pass I-Net+, a reasonable familiarity is expected in the areas of Internet Basics, Internet Clients, Web development, Networking, Security, and business concepts. Some areas, such as TCP/IP model, Address resolution, and networking protocols, and other important basic concepts are covered in both network+ and I-Net+.

Acronyms:

-          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.

-          CA stands for Certificate Authority.

-          DLL stands for Dynamic Link Labrary

-          ODBC stands for Open Data Base Connectivity.

-          VRML stands for Virtual Reality Modeling Language

-          PEG stands for Joint Photographic Expers Group.

-          PNG stands for portable Network Graphics

-          TIFF stands for Tag image File Format

-          MPEG stands for Moving Pictures Experts Group

-          PDF stands for Portable Document Format.

-          AVI stands for Audio Video Interleaved.

-          PKI stands for Public Key infrastructure.

1. 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 segment".

- 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 (Node)".

-          Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.

-          The range of numbers from 224.0.0.0 to 239.255.255.255 is used for multicast packets. This is known as Class D address range.

-          The default subnet mask for

o        Class A network: 255.0.0.0

o        Class B network: 255.255.0.0

o        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 Windows later.

3. ATM:

-          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:

o        T1: 1.544 MBPS consisting of 24 channels of 64 kBPS

o        T2: 6.312 MBPS consisting of 96 channels of 64 kBPS

o        T3: 43 MBPS consisting of 672 channels of 64 KBPS

5. DSL:

-          DSL 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.

-          There are several categories of DSL:

o        Asymmetric DSL (ADSL): Here data flow is asymmetric. Data flow in one direction is different from that in the other direction.

o        Symmetric DSL (SDSL): Here the data flow is symmetric, that the data flows equally in both directions.

o        Other not so much used or known types of DSL are BDSL, HDSL, and VDSL.

6. The range of numbers from 224.0.0.0 to 239.255.255.255 is used for multicast packets. This is known as Class D address range.

7. 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 connectionless protocol.

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 202.122.154.11.

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 network.

12. Important port numbers:

The 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.

It is also important to know that FTP, Telnet, SMTP use TCP; whereas TFTP, SNMP use UDP.

13. Repeaters, Bridges, and Routers:

-          Repeaters work at Physical layer (Layer 1),

-          Bridges and simple switches work at Data Link Layer (Layer 2),

-          Routers work at Network Layer (Layer 3) of ISO Reference Model.

14. Gateway is used to translate protocols, as it works at application layer.

15. Telnet requires an username and password to access.

16. ISDN:

-          ISDN specifies two standard access methods:

-          BRI (Basic Rate Interface):

o        Consists of two B channels (64Kbps) and one D channel (16Kbps).

o        The B channels can be used for digitized speech transmission or for relatively high-speed data transport.

o        The D channel carries signaling information (call setup) to control calls on B channels.

-          PRI (Primary Rate Interface):

o        Consists of 23 B channels and one D channel  with a bandwidth of 1.544Mbps.

o        PRI uses a DSU/CSU for a T1 connection. B stands for Bearer Channel.

17. 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.

-          Numbers above 1023 are used by upper layers to set up sessions with other hosts and by TCP to use as source and destination addresses.

18. Some of the important commands useful in trouble shooting TCP/IP networks:

I.                   Ipconfig: Displays TCP/IP configuration values, including IP address, subnet mask, and default gateway.

II.                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.

III.              Route:  Displays and manipulates route information.

IV.              Tracert: Determines the route packets take to reach the specified destination.

19. 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 NetWare.

20. 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.

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