A Computer Networks

1. A Project on
Computer
networks

2. Explanation
Router is Internetworking device that forwards
data packets toward their destinations through a
process known as routing.
A router is a device that forwards data packets
between computer network creating an overlay
internetwork.
A router is connected to two or more data lines
from different networks. When a data packet
comes in one of the lines, the router reads the
address information in the packet to determine
its ultimate destination.

3. Explanation
Then, using information in its routing table or routing policy, it directs the
packet to the next network on its journey.
Routers perform the "traffic directing" functions on the internet. A data packet
is typically forwarded from one router to another through the networks that
constitute the internetwork until it reaches its destination node

4. Routers
 Complex networks usually require routers instead of bridges because routers
provide filtering and network traffic control.
 Routers have the ability to connect multiple segments and multiple networks.
 Networks connected by multiple routers are called internetworks.
 Routers operate at the Network layer of the OSI model.
 Routers use the logical address of the OSI Network layer.
 Routers do not forward broadcast traffic and therefore define broadcast domains.

5. Group of Routers…
 There are two major groups of router interfaces:
 LAN Interfaces
 WAN Interfaces

6. How a Router Works…
 When data packets are transmitted over a network (say the
Internet), they move through many routers (because they pass
through many networks) in their journey from the source
machine to the destinationmachine.
 Routers work with IP packets, meaning that it works at the level of
the IP protocol.

7. How does
Routers works…
 Based on thedestination and
source IP addresses of the
packet, the router decides which
neighbour it will forward it to.
 It chooses the route with the
least cost, and forwards the
packet to the first router on that
route.
 When a packet of data
arrives at a router, its
header information is scrutinized
by the router.

8. TYPES OF ROUTERS:
 There are several types of
routers in the market.
 Broadband Routers
 Wireless Routers
 Core Routers
 Edge Router

9. Broadband Routers





10. Wireless Routers
 Wireless routers create a wireless signal in your home or office.
So, any computer within range of Wireless routers can connect it
and use Internet.
 It works much like a wired router but replaces wires with wireless
radio signals to communicate within and to external network
environments.
 It enables you to run a computer or gaming system from
anywhere in the house without having to run cables through the
walls
 In order to secure your Wireless routers, you simply need to
come secure it with password or get your IP address. Then, you'll
log on into your router with the user ID and passwords will that
come with your router
 Example:-Netgear (Nighthawk X4S)

11. Core Router
 A core router is a router designed to operate in the Internet
backbone, or core.
 To full fill this role, a router must be able to support multiple
telecommunications interfaces of the highest speed in use in the
core Internet and must be able to forward IP packets at full
speed on all of them. It must also support the routing protocols
being used in the core.
 Example:- Cisco Systems (CRS, NCS series)

12. Edge Router
 Edge devices are that which provide entry points into
enterprise or service provider core networks. Examples
include routers, routing switches, integrated access
devices (IAD), multiplexers, and a variety of
metropolitan area network (MAN) and wide area
network (WAN) access devices. Edge devices also
provide connections into carrier and service provider
networks.
 Example:- Ubiquiti EdgeRouter X (ER-X), EdgeRoute

13. Routing
Protocols
 A routing protocol specifies
 how routers communicate with each other, disseminating
information that enables them to select routes between any
two nodes on a computer network.
 Routing algorithms determine the specific choice of route.
Each router has a priori knowledge only of networks attached
to it directly.
 A routing protocol shares this information first among
immediate neighbors, and then throughout the network. This
way, routers gain knowledge of the topology of the network.

14. Types of routing protocols
Enhanced Interior Gateway
Routing Protocol (EIGRP)
Interior Gateway Routing
Protocol (IGRP)

15. Advantages
While switches are the device of choice for improving performance on a
network, routers are used to segment large networks into internetworks made
up of smaller networks.
Routers and switches are often used in combination.
•Routers can connect different network architectures, such as Ethernet and
Token Ring.
Routers can choose the best path across the network using dynamic routing
techniques.
Routers can reduce network traffic because they do not retransmit network
broadcast traffic.

16. Disadvantages
Routers work only with routable network protocols; not all protocols are routable.
•Routers are more expensive than bridges or repeaters.
Dynamic router communications (inter-router communication) causes additional
network traffic.
Routers are slower than bridges or repeaters because they must analyze a data
transmission from the Physical to the Network layer.