LAN Switching
Lan Switching
Lan Switching (Layer 2 switching) use media access control address that is MAC address from network interface cards (NICs) for forward frames.It maintain MAC address table.Its has fixed bandwidth and has a broadcast domain.
Switches are a fundamental part of most networks. It let multiple users communicate directly with each other.It offer the feature like collision-free, high-speed networking.
Switches has three main task
Learn : Its store device location in MAC table,and maintain MAC table.
Forward : It forward frame to device according to MAC table.
Removing : It remove loop in layer 2.
Benefits that can be realized by using LAN switches:
Increased network scalability
Improved bandwidth performance for each network user
Multiple simultaneous connections
Reduced congestion and information transmission delay
No single point of failure
Switches are of two types :
Layer 2 switches—Also called desktop or workgroup switches.
Layer 3 switches—Also called routing switches or multilayer switches.
Types of switching mode
1) Store and Forward
2) FreMent free
3) Cut through
1) Store and Forward : It is default switching method for distribution layer switches.
When frame completed then switch copied the frame into its memory and check Cyclic Redundancy Check (CRC) for errors.A frame with an error will be dropped and valid frame will be forwarded to the destination device.
Latency – > High
Error checking – > yes
2) Cut Through
By default cut-through switching mode is enabled
It start forwarding the frame when its read the destination details in the packet header.It is faster than store-and-forward mode as it forward data before it completely receiving entire frame.
Latency -> law
Error checking -> no
3) Fragment Free
It is also referred to as modified Cut Through.
This is a hybrid version of Store and Forward method and Cut and Through method.For error it check first 64 bytes of frame ,it will process only valid frame that is if first 64 bytes is correct. Runt (frame less than 64 bytes) is an invalid frame type.
Latency -> medium
Error checking -> on 64 bit of frames.
Type of Switching
Dedicate Line
It is a point to point connection. It is most expensive mode of communication. In this communication method you use it or not you have to pay it for.
Circuit Switching
In circuit switching a dedicated circuit or channel is establish for transmission. Example in telephone line where end to end connection is established.
Packet Switching
Packet switching is a method of data transmission in a network in a form of packet,packet is a smallest unit of data.Once the packet received at destination point it reassembled.
VPN
VPN is used to create safe and encrypted connection. As we know that internet is a less secure network so we can use VPN which make it safe for use.
VPN allow remote users to safely connect to its office via internet. Major implementations of VPN include OpenVPN and IPsec.
Frame Relay
Frame Relay is the most cost effective method of communication. Frame relay cut data into smaller unit called frames.it does not check any error,and leaves any necessary error correction at endpoint hence overall speed is fast.
