PPT: Network Layer | Computer Networks - Computer Science Engineering (CSE) PDF Download

 Page 1


Network 
Layer
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Network 
Layer
Basic Networking Concepts
Network Types
PAN (Personal Area Network): Operates in very small 
area. like Bluetooth
LAN (Local Area Network): Small geographic area like 
an office
MAN (Metropolitan Area Network):  Varying by scale 
and purpose
WAN (Wide Area Network): Large area such as the 
internet
Network Layer Devices
Router: Forwards packets between networks using 
routing tables
Layer 3 Switch: Combines switching and routing 
capabilities
Network Layer protocols are IP, ICMP, ARP, DHCP, 
RIP, OSPF, BGP
Network Layer Protocols
A network is a collection of devices connected to share resources and communicate. The Network Layer enables 
internetworking - the critical function of connecting different networks together to form larger networks like the 
internet.
Page 3


Network 
Layer
Basic Networking Concepts
Network Types
PAN (Personal Area Network): Operates in very small 
area. like Bluetooth
LAN (Local Area Network): Small geographic area like 
an office
MAN (Metropolitan Area Network):  Varying by scale 
and purpose
WAN (Wide Area Network): Large area such as the 
internet
Network Layer Devices
Router: Forwards packets between networks using 
routing tables
Layer 3 Switch: Combines switching and routing 
capabilities
Network Layer protocols are IP, ICMP, ARP, DHCP, 
RIP, OSPF, BGP
Network Layer Protocols
A network is a collection of devices connected to share resources and communicate. The Network Layer enables 
internetworking - the critical function of connecting different networks together to form larger networks like the 
internet.
Internet Protocol (IP)
Logical Addressing
Assigns unique IP addresses to 
devices on networks
Routing
Determines optimal paths for 
data packets across networks
Fragmentation
Breaks packets into smaller 
pieces if they exceed MTU size
IP is the primary protocol for transmitting data 
across networks. It comes in two main types: IPv4 
with 32-bit addresses (like 192.168.1.1) providing 
approximately 4.3 billion addresses, and IPv6 with 
128-bit addresses (like 2001:0db8::1) created to 
solve address exhaustion.
An IP packet consists of a header (containing 
source/destination IP, version, TTL, protocol) and 
payload (the actual data being transmitted).
Page 4


Network 
Layer
Basic Networking Concepts
Network Types
PAN (Personal Area Network): Operates in very small 
area. like Bluetooth
LAN (Local Area Network): Small geographic area like 
an office
MAN (Metropolitan Area Network):  Varying by scale 
and purpose
WAN (Wide Area Network): Large area such as the 
internet
Network Layer Devices
Router: Forwards packets between networks using 
routing tables
Layer 3 Switch: Combines switching and routing 
capabilities
Network Layer protocols are IP, ICMP, ARP, DHCP, 
RIP, OSPF, BGP
Network Layer Protocols
A network is a collection of devices connected to share resources and communicate. The Network Layer enables 
internetworking - the critical function of connecting different networks together to form larger networks like the 
internet.
Internet Protocol (IP)
Logical Addressing
Assigns unique IP addresses to 
devices on networks
Routing
Determines optimal paths for 
data packets across networks
Fragmentation
Breaks packets into smaller 
pieces if they exceed MTU size
IP is the primary protocol for transmitting data 
across networks. It comes in two main types: IPv4 
with 32-bit addresses (like 192.168.1.1) providing 
approximately 4.3 billion addresses, and IPv6 with 
128-bit addresses (like 2001:0db8::1) created to 
solve address exhaustion.
An IP packet consists of a header (containing 
source/destination IP, version, TTL, protocol) and 
payload (the actual data being transmitted).
IP Addressing
IPv4 Address Format
32-bit address divided into 4 octets (e.g., 192.168.0.1)
Subnet Mask
Determines network and host portions (e.g., 255.255.255.0)
Types of IP Addresses
Public (globally unique), Private (local networks), Loopback 
(127.0.0.1)
IP Address Classes
Class A, B, C, D, E (based on first octet range)
IP addressing assigns unique identifiers to devices on a network. 
Each address has a network part (identifying the network) and a 
host part (identifying the specific device within that network).
Page 5


Network 
Layer
Basic Networking Concepts
Network Types
PAN (Personal Area Network): Operates in very small 
area. like Bluetooth
LAN (Local Area Network): Small geographic area like 
an office
MAN (Metropolitan Area Network):  Varying by scale 
and purpose
WAN (Wide Area Network): Large area such as the 
internet
Network Layer Devices
Router: Forwards packets between networks using 
routing tables
Layer 3 Switch: Combines switching and routing 
capabilities
Network Layer protocols are IP, ICMP, ARP, DHCP, 
RIP, OSPF, BGP
Network Layer Protocols
A network is a collection of devices connected to share resources and communicate. The Network Layer enables 
internetworking - the critical function of connecting different networks together to form larger networks like the 
internet.
Internet Protocol (IP)
Logical Addressing
Assigns unique IP addresses to 
devices on networks
Routing
Determines optimal paths for 
data packets across networks
Fragmentation
Breaks packets into smaller 
pieces if they exceed MTU size
IP is the primary protocol for transmitting data 
across networks. It comes in two main types: IPv4 
with 32-bit addresses (like 192.168.1.1) providing 
approximately 4.3 billion addresses, and IPv6 with 
128-bit addresses (like 2001:0db8::1) created to 
solve address exhaustion.
An IP packet consists of a header (containing 
source/destination IP, version, TTL, protocol) and 
payload (the actual data being transmitted).
IP Addressing
IPv4 Address Format
32-bit address divided into 4 octets (e.g., 192.168.0.1)
Subnet Mask
Determines network and host portions (e.g., 255.255.255.0)
Types of IP Addresses
Public (globally unique), Private (local networks), Loopback 
(127.0.0.1)
IP Address Classes
Class A, B, C, D, E (based on first octet range)
IP addressing assigns unique identifiers to devices on a network. 
Each address has a network part (identifying the network) and a 
host part (identifying the specific device within that network).
Class A in IP Addressing with Example
127
Maximum Networks
Total Class A networks (0 and 
127 reserved)
16.7M
Hosts Per Network
Maximum devices in each 
Class A network
8
Network Bits
Subnet mask /8 (255.0.0.0)
Class A addresses range from 0.0.0.0 to 127.255.255.255, with the first bit always set to 0. They 
use 1 octet for the network portion and 3 octets for hosts, making them ideal for extremely large 
organizations like ISPs.
For example, with IP 10.1.2.3 and subnet mask 255.0.0.0, the network ID is 10.0.0.0, and the host 
range spans from 10.0.0.1 to 10.255.255.254.