CCNA BASICS (networks & types of networks)

 CCNA - CISCO CERTIFIED NETWORK ASSOCIATED 

1. Basic -- CCNA, CCNA Security, CCNA Wireless , CCNA Voice, CCNA Design.
2. Professional -- CCNP , CCWD, CCWP, CCVD, CCDP, CCIP.
3. Experts -- CCIE, CCIE Security, CCIE Wirless, CCIE Voice, CCDF, CCIE Service Provider.

• Network :- Network is a interconnection of the media, connectivity, equipment & Devices to share the data and resources .

                       Why do we need to secure or protect the Network?

We need to protect the network, as constant threats to the network against the resources in the share. These could be valuable information or data on our employees and customers, or even more about our produscts or companies. Most of these threats in the form of :

1. Viruses, worms & TrojansHorses.
2. Spyware & Adware.
3. Zero - day attacks, Also known as Zero - hour Attacks
4. Hacker Attacks
5. Denial of service
6. The data interception & theft.
7. Identity Theft

• Network Topology  - We are using Start topology  now a days note it.

1. Ring Topologies :- In a ring network, every device has exactly two neighbors for communication purpose. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise") . A failure in any cable or devices breaks the loop and can take down the entire network. 

   To Implement a ring network, one  typically uses FDDI, SONET, or Token Ring technology. Ring  topology  are found in some office buildings or school campuses.

 2 .  Bus Topology  -- Bus networks (not to be confused with the system bus of a computer ) use a common backbone to connect all devices . A single cable, the backbone function as a shared communication medium that devices attach or tap into with an interface connector . A device wanting to communication with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually  accepts and processes the message.

       Speed - 10mbps , Co -axial cable, terminate connector

 3. Start Topology  -- In this type of network topology, each node of the network is connected to a central node of the network is connected to a central node, which is known as a hub. The data that is transmitted between the network nodes passes across the central hub. A distributed star is formed by the network nodes across the central hub. A distributed star is formed by the interconnection of two or more individual star networks. The centralized nature of a star network provides a certain amount of simplicity while also achieving isolation of each devices in the network.

  Technologies - Ethernet & Mac Address , UTP Cable , Media Access Method (CSMA/CD) , Speed -                10mbps to 10gbps.  

       If you want to read Network Toplogies in detail CLICK HERE

•  Network  Device :Now a days switches are used mostly . Network switch is a computer networking device that connects network segments or networks devices. they have minimum 4 ports & maximum 48 ports . It has media access method CSMA/CA .

         # Duplex - full , Speed - 10mbps to 10gbps , Media - UTP & Optical fiber , Topology - Star , Technology - Ethernet it works on the base of MAC ( Media Access Control)  Address. MAC Address is a address of an ethernet interface is unic in whole world ==> In Hexa Decimal Form.

        # Switch has two types memories are :-

1> Lookup Table / Mac Address Table/ filter Table.

2> Buffer memory 

 NOTE :-- Each Hexa has 4bit address

Posted in: CCNA