CCNA About Layerd Models:-

            -: Layered Models:-

The Layered Approach:-

  -       A reference model is a conceptual blue print of how communication should take place.

  -       It Address all the processes required for effective communication and devices these processes into logical groupings called layers.

  -       When a communication system is designed in this manner, It’s known as layered architecture.

                     -: The OSI Model:-

  -      The OSI isn’t a physical model. Rather it’s a set of guide line that application developers can use to create and implement applications that run on a network.

  -       It also provides a framework for creating and implementing networking standards, devices and internetworking schemes.

                                         

                                -: The Upper Layer :-

7. Application     -     Provides user interface.

6. Presentation   -    (i) Present Data.

                            -    (ii) Handles Processing such as encryption.

5. Session           -     Keeps different Application’s data.

                                 -: The Lawyer Layer :-

4. Transport       -     (i) Provides reliable or unreliable delivery.

                           -     (ii) Performs error correction before retransmit. 

3. Network         -     Provides logical addressing which routers use for path Determination.

2. Data Link       -     (i) Combines packets into bytes, and bytes into frames,

                           -     (ii) Provides access to media using MAC address    

                           -     (iii) Performs error detection not correction.

1. Physical          -     (i) Moves bits between devices

                           -     (ii) Specifies voltage, Write speed and pin out of cable.

                                -: The Layer Functions:-

7. Application     -    File Print, Message, Data Base and Application services.

6. Presentation   -    Data encryption, Compression and Translation service.

5. Session           -    Dialog Control.

4. Transport       -    End to End Connection

3. Network         -    Routing

2. Data Link       -    Framing

1. Physical          -    Physical Topology

CCNA - About Internetworking Basics

-: Internetworking Basics:-

Here’s A list of some of the things that commonly cause LAN traffic congestion:-

-           Too many hosts in a broadcast Domain.

-           Broadband Storms.

-           Multicasting.

-           Low Bandwidth.

-           Adding hubs for connectivity to the network.

-           A Bunch of ARP or IPX traffic (IPX is a Novell protocol that is such as IP, But really chatty. Typically not used today’s networks.)

There are two advantage of using routers in your network:-

-           They don’t forward broadcast by default.

-           They can filter the network based on layer3 (Network Layer) information (e.g. IP address).

Four Router Functions in your Network can be listed as follows:-

-           Packet Switching

-           Packet Filtering

-           Internetwork Communication

-           Path Selection

CCNA ( -: Router Mode:- )

-: Router Mode:-

   -1. Interface mode/user mode                                To routing information

   -2. Privilege mode/Addministrator                        To trouble shooting

   -3. Configuration mode/Globlization mode            To add the commands 

- : MODE:-

1. Router>  It is a user mode.

2. Router> enable

3. Router# It is privilege mode.

4. Router#configure terminal

5. Router(config) # It is a Global mode

6. Router(config) #exit

            To come out from mode one by one.

CCNA ( -: Router:- )

                            -: Router:-

Hardware Component in Router:-

1. CPU
2.   -RAM                                        Running data/online process
3.   -NVRAM                                  As a Hard Disk
4.   -ROM                                        BIOS chip
5. LOGIC BOARD                     
6. INTERFACE PORTS
7.   -SMPS                                       To AC power supply

Types of Interface ports:-

1.   -Serial Port                                To connnect Router to Router         
2.   -Ethernet/FastEthernet            To send rate 1-100MBPS/100-1000 MBPS
3.   -Auxilary Port                           To WAN
4.   -BRI/PRI Port                           To ISDN Line
5.   -Console Port                            PC to Router & Router to PC
6.   -Power Port                               To AC Power Supply

Types of Router:-

1.   -Fix                                              Under 2500 Series
2.   -Modular                                     External 2600 Series
3.   -MPLS                                         To Multicasting & Security Purpose.

CCNA ( -: Protocol:- )

-: Protocol:-

1. RIP (Routing Information Protocol):- RIP is an entire gateway protocol that manages the exchange of routing table information among routes. RIP unable router to exchange their routing table at a free defines internal.

This way is efficient & way to replaced by the Open Shortest Path First protocol. Which updates the routing table only then network change occurred. The RIP is a distance vector protocol that is defined in two versions. That is Version­­₁ & Version₂.

2. IGRP (Interior Gateway Routing Protocol):- IGRP is distance vector routes protocol. This implies, that is router sends all or a part of routing table in a routing message update.

3. EIGRP (Enhance Interior Gateway Routing Protocol):- Host Introduce as an improvement to IGRP. EIGRP host created using IGRP as the base & adding additional function to IGRP.

4. OSPF (Open Shortest Path First):- The OSPF is a link state routing protocol use to handle routing for internet protocol transmission. A link state routing protocol update in routing table on. Then network changes occur router at a free define interval.

5. CHSAP (Challenge Hand Shake Authentication Protocol):- CHSAP is used to establish secure communication between router server & node. Servers send a challenge to the node.