ENSA_Module_7.pptx_wide_area_network_concepts

Module 7: WAN Concepts
Enterprise Networking, Security,
and Automation v7.0 (ENSA)

2
© 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Module Objectives
Module Title: WAN Concepts
Module Objective: Explain how WAN access technologies can be used to satisfy business
requirements.
Topic Title Topic Objective
Purpose of WANs Explain the purpose of a WAN.
WAN Operations Explain how WANs operate.
Traditional WAN Connectivity Compare traditional WAN connectivity options.
Modern WAN Connectivity Compare modern WAN connectivity options.
Internet-Based Connectivity Compare internet-based connectivity options.

3
7.1 Purpose of WANs

4
Purpose of WANs
LANs and WANs
A WAN is a telecommunications network that spans over a relatively large geographical
area and is required to connect beyond the boundary of the LAN.
Local Area Networks (LANs) Wide Area Networks (WANs)
LANs provide networking services
within a small geographic area.
WANs provide networking services
over large geographical areas.
LANs are used to interconnect local
computers, peripherals, and other
devices.
WANs are used to interconnect
remote users, networks, and sites.
A LAN is owned and managed by
an organization or home user.
WANs are owned and managed by
internet service, telephone, cable,
and satellite providers.
Other than the network
infrastructure costs, there is no fee
to use a LAN.
WAN services are provided for a
fee.
LANs provide high bandwidth
speeds using wired Ethernet and
Wi-Fi services.
WANs providers offer low to high
bandwidth speeds, over long
distances.

5
Purpose of WANs
Private and Public WANs
A private WAN is a connection that is dedicated to a single customer.
Private WANs provide the following:
• Guaranteed service level
• Consistent bandwidth
• Security
A public WAN connection is typically provided by an ISP or telecommunications service
provider using the internet. In this case, the service levels and bandwidth may vary, and
the shared connections do not guarantee security.

6
Purpose of WANs
WAN Topologies
WANs are implemented using the following logical topology designs:
• Point-to-Point Topology
• Hub-and-Spoke Topology
• Dual-homed Topology
• Fully Meshed Topology
• Partially Meshed Topology
Note: Large networks usually deploy a combination of these topologies.

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Purpose of WANs
WAN Topologies (Cont.)
Point-to-Point Topology
• Employs a point-to-point circuit between two endpoints.
• Involves a Layer 2 transport service through the service provider network.
• The point-to-point connection is transparent to the customer network.
Note: It can become expensive if many point-to-point connections are required.

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Purpose of WANs
Hub-and-Spoke Topology
• Enables a single interface on the hub router to be shared by all spoke circuits.
• Spoke routers can be interconnected through the hub router using virtual circuits and
routed subinterfaces.
• Spoke routers can only communicate with each other through the hub router.
Note: The hub router represents a
single point of failure. If it fails, inter-
spoke communication also fails.

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Purpose of WANs
Dual-homed Topology
• Offers enhanced network redundancy, load balancing, distributed computing and
processing, and the ability to implement backup service provider connections.
• More expensive to implement than single-homed topologies. This is because they
require additional networking hardware, such as additional routers and switches.
• More difficult to implement because they require additional, and more complex,
configurations.

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Purpose of WANs
Fully Meshed Topology
• Uses multiple virtual circuits to connect all
sites
• The most fault-tolerant topology
Partially Meshed Topology
• Connects many but not all sites

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Purpose of WANs
Carrier Connections
Another aspect of WAN design is how an organization connects to the internet. An
organization usually signs a service level agreement (SLA) with a service provider. The
SLA outlines the expected services relating to the reliability and availability of the
connection.
The service provider may or may not be the actual carrier. A carrier owns and maintains
the physical connection and equipment between the provider and the customer. Typically,
an organization will choose either a single-carrier or dual-carrier WAN connection.

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Purpose of WANs
Carrier Connections (Cont.)
A single-carrier connection is when an
organization connects to only one
service provider. An SLA is negotiated
between the organization and the
service provider.
A dual-carrier connection provides
redundancy and increases network
availability. The organization negotiates
separate SLAs with two different service
providers.

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Purpose of WANs
Evolving Networks
Network requirements of a company can change dramatically as the company grows
over time.
• A network must meet the day-to-day operational needs of business, and it must be
able to adapt and grow as a company changes.
• Network designers and administrators meet these challenges by carefully
choosing network technologies, protocols, and service providers.
• Networks can be optimized by using a variety of network design techniques and
architectures.
To illustrate differences between network size, we will use a fictitious company called
SPAN Engineering as it grows from a small, local, business into a global enterprise.

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Purpose of WANs
Evolving Networks (Cont.)
Small Network
SPAN, a small fictitious company,
started with a few employees in a
small office.
• Uses a single LAN connected to
a wireless router for sharing data
and peripherals.
• Connection to the internet is
through a common broadband
service called Digital Subscriber
Line (DSL)
• IT support is contracted from the
DSL provider.

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Purpose of WANs
Campus Network
Within a few years SPAN grew and
required several floors of a building.
The company now required a
Campus Area Network (CAN).
• A firewall secures internet
access to corporate users.
• In-house IT staff to support and
maintain the network.

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Purpose of WANs
Branch Network
• A few years later, the company
expanded and added a branch site
in the city, and remote and regional
sites in other cities.
• The company now required a
metropolitan area network (MAN)
to interconnect sites within the city.
• To connect to the central office,
branch offices in nearby cities used
private dedicated lines through
their local service provider.

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Purpose of WANs
Distributed Network
• SPAN Engineering has now
been in business for 20 years
and has grown to thousands of
employees distributed in offices
worldwide.
• Site-to-site and remote access
Virtual Private Networks (VPNs)
enable the company to use the
internet to connect easily and
securely with employees and
facilities around the world.

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7.2 WAN Operation

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WAN Operations
WAN Standards
Modern WAN standards are defined and managed by a number of
recognized authorities including the following:
• TIA/EIA - Telecommunications Industry Association and Electronic Industries
Alliance
• ISO - International Organization for Standardization
• IEEE - Institute of Electrical and Electronics Engineers

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WAN Operations
WANs in the OSI Model
Most WAN standards focus on the physical layer
and the data link layer.
Layer 1 Protocols
• Synchronous Digital Hierarchy (SDH)
• Synchronous Optical Networking (SONET)
• Dense Wavelength Division Multiplexing (DWDM)
Layer 2 Protocols
• Broadband (i.e., DSL and Cable)
• Wireless
• Ethernet WAN (Metro Ethernet)
• Multiprotocol Label Switching (MPLS)
• Point-to-Point Protocol (PPP) (less used)
• High-Level Data Link Control (HDLC) (less used)
• Frame Relay (legacy)
• Asynchronous Transfer Mode (ATM) (legacy)

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WAN Operations
Common WAN Terminology
There are specific terms used to describe WAN
connections between the subscriber (i.e., the
company / client) and the WAN service provider.
WAN Term Description
Data Terminal
Equipment (DTE)
Connects the subscriber LANs to the WAN
communication device
Data Communications
Equipment (DCE)
Device used to communicate with the
provider
Customer Premises
Equipment (CPE)
This is the DTE and DCE devices located on
the enterprise edge
Point-of-Presence
(POP)
The point where the subscriber connects to
the service provider network
Demarcation Point The physical location in a building or
complex that officially separates the CPE
from service provider equipment.

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WAN Operations
Common WAN Terminology (Cont.)
WAN Term Description
Local Loop (last mile) The copper or fiber cable that connects the
CPE to the CO of the service provider
Central office (CO) The local service provider facility or building
that connects the CPE to the provider
network
Toll network Includes backhaul, long-haul, all-digital,
fiber-optic communications lines, switches,
routers, and other equipment inside the
WAN provider network
Backhaul network Connects multiple access nodes of the
service provider network
Backbone network Large, high-capacity networks used to
interconnect service provider networks and
to create a redundant network.

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WAN Operations
WAN Devices
There are many types of devices that are specific to WAN environments.
WAN Device Description
Voiceband
Modem
Dial-up modem – uses telephone lines
Legacy device
DSL Modem /
Cable Modem
Collectively known as broadband modems, these
high-speed digital modems connect to the DTE
router using Ethernet.
CSU/DSU Digital-leased lines require a CSU and a DSU. It
connects a digital device to a digital line.
Optical Converter Connect fiber-optic media to copper media and
convert optical signals to electronic pulses.
Wireless Router /
Access Point
Devices are used to wirelessly connect to a WAN
provider.
WAN Core
devices
WAN backbone consists of multiple high-speed
routers and Layer 3 switches.

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WAN Operations
Serial Communication
• Almost all network communications
occur using a serial communication
delivery. Serial communication transmits
bits sequentially over a single channel.
• In contrast, parallel communications
simultaneously transmit several bits
using multiple wires.
• As the cable length increases, the
synchronization timing between multiple
channels becomes more sensitive to
distance. For this reason, parallel
communication is limited to very short
distances

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WAN Operations
Circuit-Switched Communication
A circuit-switched network establishes a
dedicated circuit (or channel) between
endpoints before the users can communicate.
• Establishes a dedicated virtual connection
through the service provider network
before communication can start.
• All communication uses the same path.
• The two most common types of circuit-
switched WAN technologies are the public
switched telephone network (PSTN) and
the legacy Integrated Services Digital
Network (ISDN).

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WAN Operations
Packet-Switched Communication
Network communication is most commonly
implemented using packet-switched
communication.
• Segments traffic data into packets that are
routed over a shared network.
• Much less expensive and more flexible
than circuit switching.
• Common types of packet-switched WAN
technologies are:
• Ethernet WAN (Metro Ethernet),
• Multiprotocol Label Switching (MPLS)
• Frame Relay
• Asynchronous Transfer Mode (ATM).

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WAN Operations
SDH, SONET, and DWDM
Service provider networks use fiber-optic infrastructures to transport user data between
destinations. Fiber-optic cable is far superior to copper cable for long distance transmissions due
to its much lower attenuation and interference.
There are two optical fiber OSI layer 1 standards available to service providers:
• SDH - Synchronous Digital Hierarchy (SDH) is a global standard for transporting data over
fiber-optic cable.
• SONET - Synchronous Optical Networking (SONET) is the North American standard that
provides the same services as SDH.
SDH/SONET define how to transfer multiple data, voice, and video communications over optical
fiber using lasers or light-emitting diodes (LEDs) over great distances.
Dense Wavelength Division Multiplexing (DWDM) is a newer technology that increases the
data-carrying capacity of SDH and SONET by simultaneously sending multiple streams of data
(multiplexing) using different wavelengths of light.

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7.3 Traditional WAN
Connectivity

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Traditional WAN Connectivity
Traditional WAN Connectivity Options
To understand the WANs of today, it helps
to know where they started.
• When LANs appeared in the 1980s,
organizations began to see the need to
interconnect with other locations.
• To do so, they needed their networks to
connect to the local loop of a service
provider.
• This was accomplished by using
dedicated lines, or by using switched
services from a service provider.

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Common WAN Terminology
Point-to-point lines could be leased from a service provider and were called “leased
lines”. The term refers to the fact that the organization pays a monthly lease fee to a
service provider to use the line.
• Leased lines are available in different fixed capacities and are generally priced
based on the bandwidth required and the distance between the two connected
points.
• There are two systems used to define the digital capacity of a copper media serial
link:
• T-carrier - Used in North America, T-carrier provides T1 links supporting bandwidth up to
1.544 Mbps and T3 links supporting bandwidth up to 43.7 Mbps.
• E-carrier – Used in Europe, E-carrier provides E1 links supporting bandwidth up to 2.048
Mbps and E3 links supporting bandwidth up to 34.368 Mbps.

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Common WAN Terminology (Cont.)
The table summarizes the advantages and disadvantages of leased lines.
Advantages
Simplicity Point-to-point communication links require minimal expertise to install and maintain.
Quality Point-to-point communication links usually offer high quality service, if they have adequate
bandwidth.
Availability Constant availability is essential for some applications, such as e-commerce. Point-to-point
communication links provide permanent, dedicated capacity which is required for VoIP or Video
over IP.
Disadvantages
Cost Point-to-point links are generally the most expensive type of WAN access. The cost of leased line
solutions can become significant when they are used to connect many sites over increasing
distances.
Limited
flexibility
WAN traffic is often variable, and leased lines have a fixed capacity, so that the bandwidth of the
line seldom matches the need exactly.

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Circuit-Switch Options
Circuit-switched connections are provided by Public Service Telephone Network
(PSTN) carriers. The local loop connecting the CPE to the CO is copper media.
There are two traditional circuit-switched options:
Public Service Telephone Network (PSTN)
• Dialup WAN access uses the PSTN as its WAN connection. Traditional local loops can
transport binary computer data through the voice telephone network using a voiceband
modem.
• The physical characteristics of the local loop and its connection to the PSTN limit the rate of the
signal to less than 56 kbps.
Integrated Services Digital Network (ISDN)
• ISDN is a circuit-switching technology that enables the PSTN local loop to carry digital signals.
This provided higher capacity switched connections than dialup access. ISDN provides for data
rates from 45 Kbps to 2.048 Mbps.

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Packet-Switch Options
Packet switching segments data into packets that are routed over a shared network. It allows
many pairs of nodes to communicate over the same channel.
There are two traditional (legacy) circuit-switched options:
Frame Relay
• Frame Relay is a simple Layer 2 non-broadcast multi-access (NBMA) WAN technology that
is used to interconnect enterprise LANs.
• Frame Relay creates PVCs which are uniquely identified by a data-link connection identifier
(DLCI).
Asynchronous Transfer Mode (ATM)
• Asynchronous Transfer Mode (ATM) technology is capable of transferring voice, video, and
data through private and public networks.
• ATM is built on a cell-based architecture rather than on a frame-based architecture. ATM
cells are always a fixed length of 53 bytes.
Note: Frame relay and ATM networks have been largely replaced by faster Metro Ethernet and internet-based solutions.

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7.4 Modern WAN
Connectivity

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Modern WAN Connectivity
Modern WANs
Modern WANS have more connectivity
options than traditional WANs.
• Enterprises now require faster and more
flexible WAN connectivity options.
• Traditional WAN connectivity options
have rapidly declined in use because
they are either no longer available, too
expensive, or have limited bandwidth.
The figure displays the local loop connections most
likely encountered today.

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Modern WAN Connectivity Options
New technologies are continually emerging. The
figure summarizes the modern WAN connectivity
options.
Dedicated broadband
• Fiber can be installed independently by an
organization to connect remote locations directly
together.
• Dark fiber can be leased or purchased from a
supplier.
Packet-switched
• Metro Ethernet – Replacing many traditional WAN
options.
• MPLS – Enables sites to connect to the provider
regardless of its access technologies.
Internet-based broadband
• Organizations are now commonly using the global
internet infrastructure for WAN connectivity.

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Ethernet WAN
Service providers now offer Ethernet WAN service
using fiber-optic cabling.
The Ethernet WAN service can go by many
names, including the following:
• Metropolitan Ethernet (Metro E)
• Ethernet over MPLS (EoMPLS)
• Virtual Private LAN Service (VPLS)
There are several benefits to an Ethernet WAN:
• Reduced expenses and administration
• Easy integration with existing networks
• Enhanced business productivity
Note: Ethernet WANs have gained in popularity and are now commonly being used to replace the
traditional serial point-to-point, Frame Relay and ATM WAN links.

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MPLS
Multiprotocol Label Switching (MPLS) is a high-performance service provider WAN routing
technology to interconnect clients without regard to access method or payload.
• MPLS supports a variety of client access methods (e.g., Ethernet, DSL, Cable, Frame Relay).
• MPLS can encapsulate all types of protocols including IPv4 and IPv6 traffic.
• An MPLS router can be a customer edge (CE) router, a provider edge (PE) router, or an
internal provider (P) router.
• MPLS routers are label switched routers (LSRs). They attach labels to packets that are then
used by other MPLS routers to forward traffic.
• MPLS also provides services for QoS support, traffic engineering, redundancy, and VPNs.

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7.5 Internet-Based
Connectivity

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Internet-Based Connectivity
Internet-Based Connectivity Options
Internet-based broadband connectivity is an alternative to using
dedicated WAN options.
Internet-based connectivity can be divided into wired and
wireless options.
Wired Options
• Wired options use permanent cabling (e.g., copper or fiber)
to provide consistent bandwidth, and reduce error rates and
latency. Examples: DSL, cable connections, and optical
fiber networks.
Wireless Options
• Wireless options are less expensive to implement
compared to other WAN connectivity options because they
use radio waves instead of wired media to transmit data.
Examples: cellular 3G/4G/5G or satellite internet services.
• Wireless signals can be negatively affected by factors such
as distance from radio towers, interference from other
sources and weather.

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DSL Technology
Digital Subscriber Line (DSL) is a high-speed,
always-on, connection technology that uses
existing twisted-pair telephone lines to provide
IP services to users.
DSL are categorized as either Asymmetric
DSL (ADSL) or Symmetric DSL (SDSL).
• ADSL and ADSL2+ provide higher downstream
bandwidth to the user than upload bandwidth.
• SDSL provides the same capacity in both
directions.
DSL transfer rates are dependent on the
actual length of the local loop, and the type
and condition of the cabling.

42
DSL Connections
Service providers deploy DSL connections in the local loop. The connection is set up
between the DSL modem and the DSL access multiplexer (DSLAM).
• The DSL modem converts the Ethernet signals from the teleworker device to a
DSL signal, which is transmitted to a DSL access multiplexer (DSLAM) at the
provider location.
• A DSLAM is located at the Central Office (CO) of the provider and concentrates
connections from multiple DSL subscribers.
• DSL is not a shared medium. Each user has a separate direct connection to the
DSLAM. Adding users does not impede performance.

43
DSL and PPP
ISPs use PPP as the Layer 2 protocol for broadband DSL connections.
• PPP can be used to authenticate the subscriber.
• PPP can assign a public IPv4 address to the subscriber.
• PPP provides link-quality management features.
There are two ways PPP over Ethernet (PPPoE) can be deployed:
• Host with PPoE Client - The PPPoE client software communicates with the DSL modem
using PPPoE and the modem communicates with the ISP using PPP.
• Router PPPoE Client - The router is the PPPoE client and obtains its configuration from
the provider.

44
Cable Technology
Cable technology is a high-speed always-on connection technology that uses a coaxial cable
from the cable company to provide IP services to users.
The Data over Cable Service Interface Specification (DOCSIS) is the international standard for
adding high-bandwidth data to an existing cable system.
• The optical node converts RF signals to light pulses over fiber-optic cable.
• The fiber media enables the signals to travel over long distances to the provider headend where a Cable
Modem Termination System (CMTS) is located.
• The headend contains the databases needed to provide internet access while the CMTS is responsible
for communicating with the cable modems.
Note: All the local subscribers share the same cable bandwidth. As more users join the service, available bandwidth may drop
below the expected rate.

45
Optical Fiber
Many municipalities, cities, and providers install fiber-optic cable to the user
location. This is commonly referred to as Fiber to the x (FTTx) and includes
the following:
• Fiber to the Home (FTTH) - Fiber reaches the boundary of the residence.
• Fiber to the Building (FTTB) - Fiber reaches the boundary of the building with the
final connection to the individual living space being made via alternative means.
• Fiber to the Node/Neighborhood (FTTN) – Optical cabling reaches an optical
node that converts optical signals to a format acceptable for twisted pair or coaxial
cable to the premise.
Note: FTTx can deliver the highest bandwidth of all broadband options.

46
Wireless Internet-Based Broadband
Wireless technology uses the unlicensed radio spectrum to send and receive data.
• Municipal Wi-Fi - Municipal wireless networks are available in many cities providing
high-speed internet access for free, or for substantially less than the price of other
broadband services.
• Cellular – Increasingly used to connect devices to the internet using radio waves to
communicate through a nearby mobile phone tower. 3G/4G/5G and Long-Term
Evolution (LTE) are cellular technologies.
• Satellite Internet - Typically used by rural users or in remote locations where cable and
DSL are not available. A router connects to a satellite dish which is pointed to a service
provider satellite in Geosynchronous orbit. Trees and heavy rains can impact the
satellite signal.
• WiMAX - Worldwide Interoperability for Microwave Access (WiMAX) is described in the
IEEE standard 802.16 Provides high-speed broadband service with wireless access
and provides broad coverage like a cell phone network rather than through small Wi-Fi
hotspots.

47
VPN Technology
VPNs can be used to address security concerns incurred when a remote office worker uses broadband
services to access the corporate WAN over the internet.
A VPN is an encrypted connection between private networks over a public network. VPN tunnels are routed
through the internet from the private network of the company to the remote site or employee host.
There are several benefits to using VPN:
• Cost savings - Eliminates expensive, dedicated WAN links and modem banks.
• Security - Advanced encryption and authentication protocols protect data from unauthorized access.
• Scalability - Corporations can add large amounts of capacity without adding significant infrastructure.
• Compatibility with broadband technology - Supported by broadband service providers such as DSL and
cable.
VPNs are commonly implemented as the following:
• Site-to-site VPN - VPN settings are configured on routers. Clients are unaware that their data is being
encrypted.
• Remote Access - The user is aware and initiates remote access connection. For example, using HTTPS in
a browser to connect to your bank. Alternatively, the user can run VPN client software on their host to
connect to and authenticate with the destination device.

48
ISP Connectivity Options
There are different ways an organization can connect to an ISP. The
choice depends on the needs and budget of the organization.
• Single-homed –Single connection to the ISP using one link.
Provides no redundancy and is the least expensive solution.
• Dual-homed - Connects to the same ISP using two links.
Provides both redundancy and load balancing. However, the
organization loses internet connectivity if the ISP experiences an
outage.
• Multihomed -The client connects to two different ISPs. This
design provides increased redundancy and enables load-
balancing, but it can be expensive.
• Dual-multihomed - Dual-multihomed is the most resilient
topology of the four shown. The client connects with redundant
links to multiple ISPs. This topology provides the most
redundancy possible. It is the most expensive option of the four.

49
Broadband Solution Comparison
Each broadband solution has advantages and disadvantages. If there are multiple broadband
solutions available, a cost-versus-benefit analysis should be performed to determine the best
solution.
Some factors to consider include the following:
• Cable - Bandwidth is shared by many users. Therefore, upstream data rates are often slow
during high-usage hours in areas with over-subscription.
• DSL - Limited bandwidth that is distance sensitive (in relation to the ISP central office).
Upload rate is proportionally lower compared to download rate.
• Fiber-to-the-Home - This option requires fiber installation directly to the home.
• Cellular/Mobile - With this option, coverage is often an issue, even within a small office or
home office where bandwidth is relatively limited.
• Municipal Wi-Fi - Most municipalities do not have a mesh Wi-Fi network deployed. If is
available and in range, then it is a viable option.
• Satellite - This option is expensive and provides limited capacity per subscriber. Typically
used when no other option is available.

50
Lab – Research Broadband Internet Access Options
In this lab, you will complete the following objectives:
• Investigate Broadband Distribution
• Research Broadband Access Options for Specific Scenarios

51
7.6 Module Practice and Quiz

52
Module Practice and Quiz
Packet Tracer – WAN Concepts
In this lab, you will do the following:
• Describe different WAN connectivity options

53
What did I learn in this module?
• A Wide Area Network (WAN) is required to connect beyond the boundary of the LAN.
• A private WAN is a connection that is dedicated to a single customer.
• A public WAN connection is typically provided by an ISP or telecommunications service
provider using the internet.
• WANs are implemented using the following logical topologies: Point-to-Point, Hub-and-
Spoke, Dual-homed, Fully Meshed, and Partially Meshed.
• A dual-carrier connection provides redundancy and increases network availability. The
organization negotiates separate SLAs with two different service providers.
• Site-to-site and remote access Virtual Private Networks (VPNs) enable the company to use
the internet to securely connect with employees and facilities around the world.
• Modern WAN standards are defined and managed by a number of recognized authorities:
TIA/EIA, ISO, and IEEE.
• Layer 1 optical fiber protocol standards include SDH, SONET, and DWDM. Layer 2 protocols
define how data will be encapsulated into a frame.
• Layer 2 protocols include broadband, wireless, Ethernet WAN, MPLS, PPP, HDLC.

54
• Serial communication transmits bits sequentially over a single channel. In contrast, parallel
communications simultaneously transmit several bits using multiple wires.
• The two most common types of circuit-switched WAN technologies are PSTN and ISDN.
• Common types of packet-switched WAN technologies are Ethernet WAN and MPLS. There
are two optical fiber OSI layer 1 standards.
• SDH/SONET define how to transfer multiple data, voice, and video communications over
optical fiber using lasers or LEDs over great distances.
• Circuit-switched connections were provided by PSTN carriers.
• ISDN is a circuit-switching technology that enables the PSTN local loop to carry digital
signals.
• Packet switching segments data into packets that are routed over a shared network.
• Frame Relay is a simple Layer 2 NBMA WAN technology used to interconnect enterprise
LANs.
• ATM technology is capable of transferring voice, video, and data through private and public
networks. It is built on a cell-based architecture rather than on a frame-based architecture.

55
• Modern WAN connectivity options include dedicated broadband, Ethernet WAN and MPLS
(packet-switched), along with various wired and wireless version of internet-based
broadband.
• MPLS is a high-performance service provider WAN routing technology to interconnect clients.
MPLS supports a variety of client access methods (e.g., Ethernet, DSL, Cable, Frame Relay).
MPLS can encapsulate all types of protocols including IPv4 or IPv6 traffic.
• Internet-based broadband connectivity is an alternative to using dedicated WAN options.
• Examples of wired broadband connectivity are Digital Subscriber Line (DSL), cable
connections, and optical fiber networks.
• Examples of wireless broadband include cellular 3G/4G/5G or satellite internet services.
• DSL is a high-speed, always-on, connection technology that uses existing twisted-pair
telephone lines to provide IP services to users.
• Cable technology is a high-speed always-on connection technology that uses a cable
company coaxial cable to provide IP services to users.

56
• Newer developments in wireless technology include Municipal Wi-Fi, Cellular, Satellite
internet, and WiMAX.
• VPN tunnels are routed through the internet from the private network of the company to the
remote site or employee host.
• ISP connectivity options include single-homed, dual-homed, multihomed, and dual-
multihomed.

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