Fundamentals of IP Addressing and Routing (Overview of Network Layer…
Fundamentals of IP Addressing and Routing
Overview of Network Layer Functions
Network Layer (Routing) Logic
Routers and computers work together to perform IP routing.
Host Forwarding Logic: Send the Packet to the Default Router
R1 and R2 Logic: Routing Data Across the Network
A packet's destination is determined by a router's routing table.
R3 Logic: Delivering Data to the End Destination
End user receives packet.
How Network Layer Routing Uses LANs and WANs
Forwards Layer 3 packets (L3 PDU) based on the destination Layer 3 address in the packet.
Routing uses data link layer to encapsulate Layer 3 packets into Layer 2 frames for transmission across each successive data link.
IP Addressing and How Addressing Helps IP Routing
Defines network layer addresses that identify any host or router interface on the network.
Defines rules about which addresses will be in the same subnet
IP addressing used in the IPv4 header to list source and destination addresses.
Set of messages and processes by which routers can exchange information about routes on a network.
Rules For IP Addresses
An IP address allows a host to send and receive IP packets.
IP address is a 32-bit number.
IP address is assigned to the network interface card on a host.
Rules for Grouping IP Addresses
Grouped as Networks!
Addresses of the same group cannot be separated by a router.
IP addresses separated from each other by a router must be in different groups.
5 Classes of IP Networks
Class A: 1 - 126
Class B: 128 - 191
Class C: 192 - 223
Class D: 224 - 239
Class E: 240 - 255
Classfull IP Networks are considered the Class A, B, and C :star:
Further divides an IP network into smaller groups
IPv4 Host Routing
Router Forwarding Decisions and the IP Routing Table
IPv4 Routing Protocols
Dynamically learn routes
Select the best route
Update the routing table
Prevent routing loops
How do routers learn?
1.Each router adds routes for each subnet directly connected.to the router. :star:
2.Routers shares routes in the routing table with neighboring routers. :star:
3.After learning a new route from a neighbor, the route added to the IP table is typically the next-hop router. :star:
Other Network Layer Features
Using Names and Domain Name System
The Address Resolution Protocol
ICMP Echo and the Ping Command