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Hello Hema,

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Thariaans Network Solutions

Bangalore

Learning CCNA would help understand the basics of networking & security. You can find jobs as network administrator in large enterprises or start you own to support smaller companies to setup infrastructure. if you need any further information contact me, i have 15+ years of consulting & training experience

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GOOD LUCK

Sunitha

• Divides a Single Broadcast domain into Multiple Broadcast domains.
• By default, all ports of the switch are in VLAN1.
• VLAN1 is known as Administrative VLAN or Management VLAN or Native VLAN
• Controls broadcast like ARP
• Provides hierarchical subnet usage
• VLAN provides Layer 2 Security
• VLAN configuration issues:
• A switch creates a broadcast domain.
• VLANs help manage broadcast domains.
• VLANs can be defined on port groups, users or protocols.
• LAN switches and network management software provide a mechanism to create VLANs
• VLANs help control the size of broadcast domains and localize traffic.
• VLANs are associated with individual networks.
• Devices in different VLANs cannot directly communicate without the intervention of a Layer 3 routing device.

 VLAN RANGE

VLAN range is 1-4094

• 1-1001 are usable normal-range VLANs
• 1002-1005 are reserved for token ring
• 1006-4094 are extended-range VLANs 

CONFIGURATION

VLAN Creation 

Switch(config)# vlan
Switch(config-Vlan)# name
Switch(config-Vlan)# Exit

Access Port Configuration

ACCESS PORT = Switchport configured for only a single broadcast domain (VLAN).

Switch(config)# interface
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan

Verify using
Switch # show VLAN

CSMA or CD: The management of collision in the network can also be done with the implementation of Protocol – Carrier Sense Multiple Access or Collision Detection. This is a type of contention protocol which would define as to how to respond when the detection of collision is done.

Even when the two devices attempt to simultaneously transfer the packages simultaneously. Th Ethernet permits each of the devices to send messages at any point in time without waiting for the network permission. So once the collision is detected, each of the devices that transmit packet delays the random amount of time before the packet is retransmitted. In case if another collision occurs, the device would wait twice as long before the retransmission is tried upon.

To know about switching, you first need to know why you needed Switches. What purpose they serve in networking. You will know everything as read through the post.

Switches are successor of Hubs. Hubs were literally dumb devices they didn’t provide any security nor do they store any MAC addresses. So, the switch were introduced to overcome these issue

Switch is a device used on a computer network to physically connect devices together. Multiple cables can be connected to a switch to enable networked devices to communicate with each other. Switches manage the flow of data across a network by only transmitting a received message to the device for which the message was intended. Each networked device connected to a switch can be identified using a MAC address, allowing the switch to regulate the flow of traffic. This maximizes security and efficiency of the network.

Because of these features, a switch is often considered more "intelligent" than a network hub. Hubs neither provide security, or identification of connected devices. This means that messages have to be transmitted out of every port of the hub, greatly degrading the efficiency of the network.

Basic Functions of a switch involves :

Learning :  Learning MAC addresses

Forwarding : Forwarding Packets to destination

Preventing Loops : Using STP(Spanning Tree Protocol)

Ethernet Switch

Based on CSMA/CD if collision occurs the sender wait for a random period of time Switched Ethernet removes the possibility of Collision and can be operated in full-duplex. For interoperatibilty between different links Auto negotiation should be enabled

A standard switch

Also called as intelligent hub as it stores the MAC and IP address both of the packet in the arp table. We can operate a network on Full Duplex because of switch. i.e. We can receive and send the packet at the same time. Which was not possible earlier.

Switch eliminates the collision domain. i.e. packets doesn’t collide.

Separates collision domain (How many receivers can receive traffic without collision).

 Its separates the broadcast domain. Its does by using the VLANs. Each vlan is a separate broadcast domain.

If you have any queries in understanding feel free to write to me.