NETWORK ROUTING AND ITS CONCEPTS
Network routing is the process of determining and selecting the best path for data packets
to travel across one or more networks from their source to their destination, and it's a
fundamental concept in data communication. Key concepts include routing protocols,
routing tables, and different routing methods like static and dynamic routing .
Here's a more detailed explanation:
1. What is Routing?
Definition:
Routing is the process of finding the best path for data packets to travel across a network.
Importance:
It's essential for the efficient and reliable transfer of data between different networks and
devices.
Function:
Routers, which are network devices, use routing protocols and routing tables to make
decisions about which path to take for data packets.
2. Key Concepts:
Routing Protocols:
These are sets of rules that routers use to exchange routing information and determine the
best paths.
Examples:
RIP (Routing Information Protocol): A distance-vector protocol that uses hop count to
determine the shortest path.
OSPF (Open Shortest Path First): A link-state protocol used in large networks, prioritizing
cost over hop count.
BGP (Border Gateway Protocol): Used for routing between different autonomous systems
(networks).
Routing Tables:
These tables store information about the network topology, including the IP addresses of
other networks and the best paths to reach them.
ROUTING METHODS:
Static Routing: Routers are manually configured with the best path to reach specific
destinations.
NETWORK ROUTING AND ITS CONCEPTS
Dynamic Routing: Routers automatically update their routing tables based on network
changes, using routing protocols.
Autonomous Systems (AS):
A collection of networks under the same administrative control, often used in the context of
BGP routing.
3. How Routing Works:
Packet Transmission : A device sends a data packet to the nearest router.
Router Receives Packet: The router receives the packet and consults its routing table to
determine the next hop.
Packet Forwarding: The router forwards the packet towards its destination, based on the
routing table's information.
Repeat: This process continues until the packet reaches its final destination.
Introduction to Network Routing
Routing is the process of selecting a path across one or more networks for data packets to
travel from their source to their destination. It is crucial for ensuring efficient
communication in packet-switching networks like the Internet. Routing decisions are made
by specialized network devices called routers.
2. How Routing Works
Routers use internal routing tables to make decisions about how to route packets. When a
router receives a packet, it reads the packet’s headers to determine its destination and then
consults its routing table to find the best path. This process happens millions of times per
second, enabling seamless data transmission across networks.
Routing Example
Consider a data packet that needs to travel from Computer A to Computer B. The packet can
pass through multiple networks, and the router determines the most efficient path based on
factors like speed and network congestion.
NETWORK ROUTING AND ITS CONCEPTS
3. Routers and Their Functions
Routers are network devices that connect two or more IP networks or subnetworks. They
are responsible for forwarding data packets to their destination based on information in
their routing tables. Routers are used in both small-scale (home and office) and large-scale
(Internet) networks to ensure data packets reach their intended destinations.
Functions of Routers:
Forwarding Packets: Directing data packets to their destination.
Routing Tables: Maintaining tables to decide the best path for packet transmission.
Connecting Networks: Linking different IP networks and subnetworks.
4. Routing Protocols
Routing protocols are standardized methods for routers to communicate and determine the
best paths for data packets. These protocols can be classified into different types based on
their functions and where they are used.
Common Routing Protocols
IP (Internet Protocol): Specifies the origin and destination of each data packet.
BGP (Border Gateway Protocol): Used to announce which networks control which IP
addresses and the connections between networks. It is a dynamic routing protocol used
between different autonomous systems.
OSPF (Open Shortest Path First): Dynamically identifies the fastest and shortest routes
within an autonomous system.
RIP (Routing Information Protocol): Uses hop count to determine the shortest path between
networks.
Routing Protocols and Their Characteristics
Protocol Type Description
IP= Network LayerSpecifies = the origin and destination of data packets.
BGP= Exterior Gateway Protocol= Announces
network control and connections between different autonomous stems.
OSPF = Interior Gateway Protocol =Identifies the fastest and shortest routes within an
autonomous system.
NETWORK ROUTING AND ITS CONCEPTS
RIP= Interior Gateway Protocol=Uses hop count to determine the shortest path between
networks.
STRUCTURE OF A ROUTER:
The router is a physical or virtual internetworking device that is designed to receive,
analyze, and forward data packets between computer networks.
NETWORK ROUTING AND ITS CONCEPTS
Routers are used to connect networks together.
Route packets of data from one network to another.
Cisco became the de facto standard of routers because of their high-quality router
products.
Routers, by default, break up a broadcast domain.
Important Point About Router
Router work on Network Layer of OSI Model.
Router is a routing device use to create route for transmitting data packets.
Router is use to connect two or more different network.
Router sends data in the form packets.
It works in full duplex.
Multiple devices can send data at the same time.
Router stores IP address.
Types of Router:
Broadband Routers: Broadband routers can do different types of things.
Broadband routers can be used to connect computers or to connect to the
Internet.
Wireless (Wi-Fi) Routers: Wireless routers create a wireless signal in your home or
office. So, any PC within range of Wireless routers can connect it and use your
Internet.
Core router: A core router is a router in a computer network that routes data
within a network, but not between networks.
Edge Router: This type of router is placed at the edge of the ISP network, that is
normally configured to external protocol like BGP (Border gateway protocol) to
another BGP of other ISP or large organization. A router that resides within the
middle or backbone of the LAN network rather than at its periphery. In some
instances, a core router provides a stepdown backbone, interconnecting the
distribution routers from multiple building of a campus (LAN), or Large Enterprise
Location (WAN). They tend to be optimized for a high bandwidth.
Virtual router: A virtual router is a backup router used in a VRRP setup.
How does a router work?
A router receives and sends data packets.
It determines the best path for data to travel from one device to another.
It analyses network metrics like speed, capacity, and delay to find the best path.
It forwards requests to a domain name system (DNS) server to get the correct IP
address for a server.
NETWORK ROUTING AND ITS CONCEPTS
It sends the request to the server, which then sends a data packet back to the
router.
The router forwards the data packet to the device.
uses of a router :
Routers can connect multiple devices to the internet.
They can create local networks of devices.
They can connect multiple computer networks together.
They can allow multiple devices to use a single internet connection.
Types of routers :
Wired routers, Wireless routers, Core routers, Edge routers, Physical routers, Virtual
routers, and VPN routers.
Routers come in various types to suit different networking needs, including wired,
wireless, core, edge, physical, virtual, VPN, and normal routers, each serving specific
purposes in network infrastructure.
Here's a breakdown of some common router types:
Based on Connectivity:
Wired Routers:
These routers connect devices to the internet using Ethernet cables, offering higher
speeds and reliability compared to wireless connections.
Wireless Routers:
These routers offer Wi-Fi connectivity, allowing devices to connect wirelessly to the
internet.
VPN Routers:
These routers have built-in VPN capabilities, enabling secure and private network
connections.
Bridge Router (router):
This type of router acts as both a bridge and a router, forwarding data between
networks and routing it to specific systems within a network.
Based on Network Role:
Core Routers:
These powerful routers are used in large networks to manage the flow of data packets
within the core of the network.
NETWORK ROUTING AND ITS CONCEPTS
Edge Routers:
These routers connect local networks to wider networks, acting as a critical touchpoint
between networks.
Distribution Routers:
These routers are located in the distribution layer of a telecommunications service
provider's IP network, sitting between the acsscess and core layers.
Other Types:
Virtual Routers: These are software-based routers that run on virtual machines,
offering flexibility and cost-effectiveness.
Physical Routers: These are traditional hardware routers that perform the routing
function.
Normal Routers: These are general-purpose routers that connect devices to the
internet.
BASIC ROUTER CONFIGUARTION:
To configure a Cisco router, you'll need to access the command-line interface (CLI), enter
global configuration mode, and then use specific commands to set up basic settings like
hostname, IP addresses, and interfaces.
NETWORK ROUTING AND ITS CONCEPTS
Here's a step-by-step guide:
1. Access the Router's CLI:
Establish a Connection: Use a console cable (RJ-45 to USB) to connect your
computer to the router's console port.
Open a Terminal Program: Use a terminal program like PuTTY (Windows) or
Terminal (macOS/Linux).
Configure Terminal Settings: Set the baud rate to 9600, data bits to 8, parity to
none, and stop bits to 1.
2. Enter Privileged EXEC Mode:
Access the Router: Once connected, you'll see the router's prompt (e.g.,
Router>).
Enter Enable Mode: Type enable and press Enter.
Enter Password (if configured): If a password is set for privileged EXEC mode,
enter it.
3. Enter Global Configuration Mode:
From Privileged EXEC Mode: Type configure terminal and press Enter.
You'll see the prompt change to: Router(config).
4. Configure Basic Settings:
Set the Hostname: Type hostname <your_hostname> (e.g., hostname R1).
Set the Domain Name (Optional): Type ip domain-name <your_domain_name>
(e.g., ip domain-name example.com).
Configure Interface:
Enter Interface Configuration Mode: Type interface <interface_name> (e.g.,
interface GigabitEthernet0/0).
Assign IP Address: Type ip address <ip_address> <subnet_mask> (e.g., ip
address 192.168.1.1 255.255.255.0).
Set Interface Status: Type no shutdown to enable the interface.
Configure Default Gateway (Optional): Type ip default-gateway
<gateway_ip_address> (e.g., ip default-gateway 192.168.1.254).
Set the Password (Optional):
Privileged EXEC Password: Type enable secret <your_password>.
Console Password: Type line console 0 then password <your_password> then
login.
Set the Console Password:
NETWORK ROUTING AND ITS CONCEPTS
Enter Line Configuration Mode: Type line console 0.
Set Password: Type password <your_password>.
Enable Login: Type login.
Set Vty Password:
Enter Line Configuration Mode: Type line vty 0 4.
Set Password: Type password <your_password>.
Enable Login: Type login.
5. Save the Configuration:
Exit Configuration Mode: Type exit.
Save the Running Configuration to Startup Configuration: Type copy running-
config startup-config.
