Networking Notes
Difference between LAN and WAN
LAN WAN
Local Area Network Wide Area Network
network infrastructure that provides network infrastructure that provides
access to users and end devices access to other networks
But WAN’s ownership can be private or
LAN’s ownership is private.
public.
LAN covers small area i.e. within the While WAN covers large geographical area
building. like b/w cities, states etc
LAN operates on the principle While WAN works on the principle of point
of broadcasting. to point.
has a lower data transfer rate as compared
has a higher data transfer rate.
to LAN.
While the speed of WAN is slower than
The speed of LAN is high(more than WAN).
LAN.
There is more fault tolerance in LAN. While there is less fault tolerance in WAN.
LAN has a higher data transfer rate. (10 WAN has a lower data transfer rate as
mbps) compared to LAN. (150 mbps)
cheap costly
Administrative control is enforced at the
WANs are usually administered by multiple
network level and governs the security and
service providers.
access control policies.
eg - Home WiFi networks eg - Enterprise networks
# Some of the LAN examples are connected to each other through a WAN
connection.
Intranet is a term often used to refer to a private connection of LANs and WANs
that belongs to an organization. An intranet is designed to be accessible only
by the organization's members, employees, or others with authorization.
Networking Notes 1
, An extranet is a private network that allows an organization to share
information and collaborate with external parties, such as business partners,
customers, and suppliers.(to provide secure and safe access to individuals who
work for a different organization but require access to the organization’s data.)
Internet connections -
Home and small office internet connections:
1. Cable - Typically offered by cable television service providers, the internet
data signal transmits on the same cable that delivers cable television. It
provides a high bandwidth, high availability, and an always-on connection
to the internet.
2. DSL - Digital Subscriber Lines also provide high bandwidth, high availability,
and an always-on connection to the internet. DSL runs over a telephone
line. In general, small office and home office users connect using
Asymmetrical DSL (ADSL), which means that the download speed is faster
than the upload speed.
3. Cellular - Cellular internet access uses a cell phone network to connect.
Wherever you can get a cellular signal, you can get cellular internet access.
Performance is limited by the capabilities of the phone and the cell tower to
which it is connected.
4. Satellite - The availability of satellite internet access is a benefit in those
areas that would otherwise have no internet connectivity at all. Satellite
dishes require a clear line of sight to the satellite.
5. Dial-up Telephone - An inexpensive option that uses any phone line and a
modem. The low bandwidth provided by a dial-up modem connection is not
sufficient for large data transfer, although it is useful for mobile access
while traveling.
Business Internet connections: (may require higher bandwidth, dedicated
bandwidth, and managed services)
1. Dedicated Leased Line - Leased lines are reserved circuits within the
service provider’s network that connect geographically separated offices
for private voice and/or data networking. The circuits are rented at a
monthly or yearly rate.
Networking Notes 2
, 2. Metro Ethernet - This is sometimes known as Ethernet WAN. Metro
ethernets extend LAN access technology into the WAN. Ethernet is a LAN
technology you will learn about in a later module.
3. Business DSL - Business DSL is available in various formats. A popular
choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the
consumer version of DSL but provides uploads and downloads at the same
high speeds.
4. Satellite - Satellite service can provide a connection when a wired solution
is not available.
# The choice of connection varies depending on geographical location and
service provider availability.
A converged network is a platform that combines multiple networks into a
single infrastructure to transmit different types of traffic.
This allows for more efficient use of resources, simplified network
management, and improved overall reliability.
Converged networks can deliver a variety of content, including: voice, video
streams, text, and graphics.
Characteristics that are imp for network architecture -
1. Fault tolerance - the ability of a system to keep operating even when one
or more of its components fail. A fault tolerant network is one that limits the
number of affected devices during a failure. It is built to allow quick
recovery when such a failure occurs.
These networks depend on multiple paths between the source and destination
of a message. If one path fails, the messages are instantly sent over a different
link. Having multiple paths to a destination is known as redundancy.
Networking Notes 3
, Implementing a packet-switched network is one way that reliable networks
provide redundancy. Packet switching splits traffic into packets that are routed
over a shared network. A single message, such as an email or a video stream,
is broken into multiple message blocks, called packets.
Each packet has the necessary addressing information of the source and
destination of the message. The routers within the network switch the packets
based on the condition of the network at that moment. This means that all the
packets in a single message could take very different paths to the same
destination. The users are unaware of and unaffected by the router that is
dynamically changing the route when a link fails.
2. Scalability - the ability of a system, organization, or process to handle
increased demands while maintaining or improving performance. It can
also refer to how well a system can respond to changes in processing
demands, such as an increase in users or queries. A scalable network
expands quickly to support new users and applications. It does this without
degrading the performance of services that are being accessed by existing
users.
3. Quality of Service (QoS) - is a network technology that manages traffic
and prioritizes applications to ensure performance and reliable delivery of
content to all users.
When simultaneous communications are attempted across the network, the
demand for network bandwidth can exceed its availability, creating network
congestion. Congestion occurs when the demand for bandwidth exceeds the
amount available. When the volume of traffic is greater than what can be
transported across the network, devices will hold the packets in memory until
resources become available to transmit them.
The focus of QoS is to prioritize time-sensitive traffic. The type of traffic, not
the content of the traffic, is what is important. With a QoS policy in place, the
router can manage the flow of data and voice traffic, giving priority to voice
communications if the network experiences congestion.
Network Security -
Networking Notes 4
Difference between LAN and WAN
LAN WAN
Local Area Network Wide Area Network
network infrastructure that provides network infrastructure that provides
access to users and end devices access to other networks
But WAN’s ownership can be private or
LAN’s ownership is private.
public.
LAN covers small area i.e. within the While WAN covers large geographical area
building. like b/w cities, states etc
LAN operates on the principle While WAN works on the principle of point
of broadcasting. to point.
has a lower data transfer rate as compared
has a higher data transfer rate.
to LAN.
While the speed of WAN is slower than
The speed of LAN is high(more than WAN).
LAN.
There is more fault tolerance in LAN. While there is less fault tolerance in WAN.
LAN has a higher data transfer rate. (10 WAN has a lower data transfer rate as
mbps) compared to LAN. (150 mbps)
cheap costly
Administrative control is enforced at the
WANs are usually administered by multiple
network level and governs the security and
service providers.
access control policies.
eg - Home WiFi networks eg - Enterprise networks
# Some of the LAN examples are connected to each other through a WAN
connection.
Intranet is a term often used to refer to a private connection of LANs and WANs
that belongs to an organization. An intranet is designed to be accessible only
by the organization's members, employees, or others with authorization.
Networking Notes 1
, An extranet is a private network that allows an organization to share
information and collaborate with external parties, such as business partners,
customers, and suppliers.(to provide secure and safe access to individuals who
work for a different organization but require access to the organization’s data.)
Internet connections -
Home and small office internet connections:
1. Cable - Typically offered by cable television service providers, the internet
data signal transmits on the same cable that delivers cable television. It
provides a high bandwidth, high availability, and an always-on connection
to the internet.
2. DSL - Digital Subscriber Lines also provide high bandwidth, high availability,
and an always-on connection to the internet. DSL runs over a telephone
line. In general, small office and home office users connect using
Asymmetrical DSL (ADSL), which means that the download speed is faster
than the upload speed.
3. Cellular - Cellular internet access uses a cell phone network to connect.
Wherever you can get a cellular signal, you can get cellular internet access.
Performance is limited by the capabilities of the phone and the cell tower to
which it is connected.
4. Satellite - The availability of satellite internet access is a benefit in those
areas that would otherwise have no internet connectivity at all. Satellite
dishes require a clear line of sight to the satellite.
5. Dial-up Telephone - An inexpensive option that uses any phone line and a
modem. The low bandwidth provided by a dial-up modem connection is not
sufficient for large data transfer, although it is useful for mobile access
while traveling.
Business Internet connections: (may require higher bandwidth, dedicated
bandwidth, and managed services)
1. Dedicated Leased Line - Leased lines are reserved circuits within the
service provider’s network that connect geographically separated offices
for private voice and/or data networking. The circuits are rented at a
monthly or yearly rate.
Networking Notes 2
, 2. Metro Ethernet - This is sometimes known as Ethernet WAN. Metro
ethernets extend LAN access technology into the WAN. Ethernet is a LAN
technology you will learn about in a later module.
3. Business DSL - Business DSL is available in various formats. A popular
choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the
consumer version of DSL but provides uploads and downloads at the same
high speeds.
4. Satellite - Satellite service can provide a connection when a wired solution
is not available.
# The choice of connection varies depending on geographical location and
service provider availability.
A converged network is a platform that combines multiple networks into a
single infrastructure to transmit different types of traffic.
This allows for more efficient use of resources, simplified network
management, and improved overall reliability.
Converged networks can deliver a variety of content, including: voice, video
streams, text, and graphics.
Characteristics that are imp for network architecture -
1. Fault tolerance - the ability of a system to keep operating even when one
or more of its components fail. A fault tolerant network is one that limits the
number of affected devices during a failure. It is built to allow quick
recovery when such a failure occurs.
These networks depend on multiple paths between the source and destination
of a message. If one path fails, the messages are instantly sent over a different
link. Having multiple paths to a destination is known as redundancy.
Networking Notes 3
, Implementing a packet-switched network is one way that reliable networks
provide redundancy. Packet switching splits traffic into packets that are routed
over a shared network. A single message, such as an email or a video stream,
is broken into multiple message blocks, called packets.
Each packet has the necessary addressing information of the source and
destination of the message. The routers within the network switch the packets
based on the condition of the network at that moment. This means that all the
packets in a single message could take very different paths to the same
destination. The users are unaware of and unaffected by the router that is
dynamically changing the route when a link fails.
2. Scalability - the ability of a system, organization, or process to handle
increased demands while maintaining or improving performance. It can
also refer to how well a system can respond to changes in processing
demands, such as an increase in users or queries. A scalable network
expands quickly to support new users and applications. It does this without
degrading the performance of services that are being accessed by existing
users.
3. Quality of Service (QoS) - is a network technology that manages traffic
and prioritizes applications to ensure performance and reliable delivery of
content to all users.
When simultaneous communications are attempted across the network, the
demand for network bandwidth can exceed its availability, creating network
congestion. Congestion occurs when the demand for bandwidth exceeds the
amount available. When the volume of traffic is greater than what can be
transported across the network, devices will hold the packets in memory until
resources become available to transmit them.
The focus of QoS is to prioritize time-sensitive traffic. The type of traffic, not
the content of the traffic, is what is important. With a QoS policy in place, the
router can manage the flow of data and voice traffic, giving priority to voice
communications if the network experiences congestion.
Network Security -
Networking Notes 4
