Switching

 Switching:

• switching is a process in which data will be switched from the source to destination.

Types of Switching

•  Layer 2 switching
• Layer 3 switching
• Multi-Layer switching

Layer 2 Switching

 process in which data can be forward on the basis of layer 2 addresses.

Types of layer 2 switching

• Ethernet switch
• Frame-Relay switch
• ATM switch

Ethernet Switching

 process in which we forward traffic on basis of the mac address.

Function / Process of layer2 ethernet switch

• Address Learning
• Filtering and Forwarding Decision
• Loop Avoidance

Layer3 Devices can perform three types of switching

Process Switching: devices perform routing lookup for each received packet

Fast Switching: RP will look up the routing table for the first packet after that SE will generate a short-cut entry in cache memory and for the next packet, SE will check the short-cut entry. and RP will get free.

CEF switching (cisco express forwarding)

CEF: creates two tables FIB and Adjacency table

FIB: it is a replica of the routing table.

Packet Rewriter: when a packet crosses a layer3 device, it will always respond to rewrite header checksum, layer2 information, and TTL.