The document discusses several topics related to computer networking including network topologies, physical and logical topologies, OSI and TCP/IP models, IP addressing, subnetting, routers, routing protocols, VLANs, and data flow diagrams. It provides information on LAN/MAN/WAN standards, the seven layers of the OSI model, classes of IP addresses, configuring router interfaces, routing protocols like OSPF and EIGRP, using VLANs to segment networks, and creating basic data flow diagrams.
3. Network Topologies
3
Network topology defines the structure of the network.
One part of the topology definition is the physical topology,
which is the actual layout of the wire or media.
The other part is the logical topology,which defines how the
media is accessed by the hosts for sending data.
5. 5
One early solution was the creation of local-area network
(LAN) standards which provided an open set of guidelines for
creating network hardware and software, making equipment
from different companies compatible.
What was needed was a way for information to move
efficiently and quickly, not only within a company, but also
from one business to another.
The solution was the creation of metropolitan-area networks
(MANs) and wide-area networks (WANs).
6. OSI Model
6
To address the problem of networks increasing in size
and in number, the International Organization for
Standardization (ISO) researched many network
schemes and recognized that there was a need to
create a network model that would help network
builders implement networks that could communicate
and work together and therefore, released the OSI
reference model in 1984.
7. The OSI Reference Model
7
7 Application
6 Presentation
5 Session
4 Transport
3 Network
2 Data Link
1 Physical
9. Network and Host Addressing
9
Using the IP address of the
destination network, a router can
deliver a packet to the correct
network.
When the packet arrives at a
router connected to the
destination network, the router
uses the IP address to locate the
particular computer connected to
that network.
Accordingly, every IP address has
two parts.
10. IP Address Classes
10
IP addresses are divided into classes to define the large,
medium, and small networks.
Class A addresses are assigned to larger networks.
Class B addresses are used for medium-sized networks,
Class C for small networks.
Class D for multicasting
Class E for research& development centre
11. Introduction to Subnetting
11
Subnetting a network means to use the subnet mask to divide the
network and break a large network up into smaller, more efficient and
manageable segments, or subnets.
With subnetting, the network is not limited to the default Class A, B, or
C network masks and there is more flexibility in the network design.
Subnet addresses include the network portion, plus a subnet field and
a host field.The ability to decide how to divide the original host portion
into the new subnet and host fields provides addressing flexibility for
the network administrator.
12. 12
SIEMENS
NIXDORF
SIEMENS
NIXDORF
Host A
Host B
IP Address: 128.0.10.4
HW Address: 080020021545
ARP Reply
ARP Request - Broadcast to all hosts
What is the hardware address for IP address 128.0.10.4?
SIEMENS
NIXDORF
Fig. 32 How does ARP work? (TI1332EU02TI_0004 The Network Layer, 47)
13. RARP
13
Reverse Address Resolution Protocol (RARP) associates a known MAC addresses
with an IP addresses.
A network device, such as a diskless workstation, might know its MAC address but not
its IP address. RARP allows the device to make a request to learn its IP address.
Devices using RARP require that a RARP server be present on the network to answer
RARP requests.
14. Introduction to Routers
14
A router is a special type of computer. It has the same basic components as a
standard desktop PC. However, routers are designed to perform some very specific
functions. Just as computers need operating systems to run software applications,
routers need the Internetwork Operating System software (IOS) to run configuration
files. These configuration files contain the instructions and parameters that control the
flow of traffic in and out of the routers. The many parts of a router are shown below:
17. Configuring Interfaces
17
An interface needs an IP Address and a Subnet Mask to be configured.
All interfaces are shutdown by default.
The DCE end of a serial interface needs a clock rate.
Router#config t
Router(config)#interface serial 0/1
Router(config-if)#ip address 200.100.50.75 255.255.255.240
Router(config-if)#clock rate 56000 (required for serial DCE only)
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#int f0/0
Router(config-if)#ip address 150.100.50.25 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#exit
Router#
On older routers, Serial 0/1 would be just Serial 1 and f0/0 would be e0.
s = serial e = Ethernet f = fast Ethernet
18. Introducing Routing
18
Routing is the process that a router uses to forward packets
toward the destination network. A router makes decisions
based upon the destination IP address of a packet. All devices
along the way use the destination IP address to point the
packet in the correct direction so that the packet eventually
arrives at its destination. In order to make the correct
decisions, routers must learn the direction to remote networks.
21. OSPF
(OSPF) Open Shortest Path First.
It is open standard pure link state routing protocol.
It support different vendors. Its maximum hope
count is unlimited. Its default AD value is 110.
It support auto summarization. It is a class less
routing protocol.
It support Discontiguous, VLSM/CIDR & class less
IP addressing . It also support AS no.
It create three separate table for sharing
information.
1. Neighbor ship table
2. Topology table
24. EIGRP
24
Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco-
proprietary routing protocol based on Interior Gateway Routing Protocol
(IGRP).
Unlike IGRP, which is a classful routing protocol, EIGRP supports CIDR
and VLSM.
Compared to IGRP, EIGRP boasts faster convergence times, improved
scalability, and superior handling of routing loops.
Furthermore, EIGRP can replace Novell Routing Information Protocol
(RIP) and AppleTalk Routing Table Maintenance Protocol (RTMP),
serving both IPX and AppleTalk networks with powerful efficiency.
EIGRP is often described as a hybrid routing protocol, offering the best
of distance vector and link-state algorithms.
25. VLANs
25
VLAN implementation combines Layer 2 switching and Layer 3 routing
technologies to limit both collision domains and broadcast domains.
VLANs can also be used to provide security by creating the VLAN
groups according to function and by using routers to communicate
between VLANs.
A physical port association is used to implement VLAN assignment.
Communication between VLANs can occur only through the router.
This limits the size of the broadcast domains and uses the router to
determine whether one VLAN can talk to another VLAN.
This is the only way a switch can break up a broadcast domain!