WAN Services and VPN Technology Overview

Questions and Answers

Which of the following is NOT a type of private WAN infrastructure?

Packet switched links

Circuit-switched links

Dedicated point-to-point leased lines

Broadband Internet using DSL (correct)

What is a distinct advantage of using dedicated point-to-point leased lines?

Consistent bandwidth availability (correct)

Easier scalability

Lower costs than public solutions

Wide availability in rural areas

What technology is used predominantly in service provider networks for high bandwidth connections?

Microwave transmission

Copper cable

Satellite communication

Fiber-optic media (correct)

Which of the following public WAN technologies allows for broadband Internet access?

Cable Signup and view all the answers

What method is suggested for protecting data traveling over a public WAN?

VPNs Signup and view all the answers

Which technique is associated with long-range fiber-optic communications?

Dense wavelength division multiplexing (DWDM) Signup and view all the answers

Which of the following is a disadvantage of using public WAN infrastructure?

Inconsistent performance Signup and view all the answers

What is a characteristic of circuit-switched links?

Provides dedicated bandwidth per user Signup and view all the answers

What is the main technology used in Multiprotocol Label Switching (MPLS) to direct data between routers?

Short path labels Signup and view all the answers

Which of the following technologies is commonly being replaced by Ethernet WANs?

Frame Relay Signup and view all the answers

Which of these is NOT a listed benefit of using Ethernet WAN services?

Lower latency Signup and view all the answers

What type of media is used in the private WAN technologies discussed?

Copper or fiber-optic media Signup and view all the answers

Which of the following services is a primary technology provider for WANs?

MPLS Signup and view all the answers

Which access technology can connect to the MPLS cloud, according to its capabilities?

Any access technology Signup and view all the answers

What payload types can MPLS carry?

Any payload including IPv4, IPv6, Ethernet, ATM, and Frame Relay Signup and view all the answers

What technology is positioned as a replacement for traditional WAN technologies like Frame Relay?

Ethernet WAN Signup and view all the answers

What is a VPN primarily used for when accessing a corporate WAN?

To provide an encrypted connection over a public network Signup and view all the answers

Which of the following is NOT a benefit of using a VPN?

High latency Signup and view all the answers

What type of VPN connects entire networks, such as a branch office to a headquarters?

Site-to-site VPN Signup and view all the answers

What is a characteristic of a remote-access VPN?

It provides access for telecommuters and mobile users Signup and view all the answers

Which statement is true regarding VPN tunnels?

They are routed through the Internet. Signup and view all the answers

What must network administrators consider when choosing a WAN connection?

The purpose of the WAN Signup and view all the answers

Which term describes the connection method used by a VPN?

VPN tunnels Signup and view all the answers

How does a VPN typically achieve security?

Through encryption of data Signup and view all the answers

A VPN is an unencrypted connection between private networks over a public network.

False Signup and view all the answers

Cost savings is one of the benefits of using VPNs.

True Signup and view all the answers

Site-to-site VPNs connect individual users to a company network.

False Signup and view all the answers

Remote-access VPNs allow telecommuters to securely access a company network over the Internet.

True Signup and view all the answers

VPN tunnels use dedicated Layer 2 connections like leased lines.

False Signup and view all the answers

Scalability is a disadvantage of using VPNs.

False Signup and view all the answers

VPNs are only useful for large corporations with extensive WAN needs.

False Signup and view all the answers

VPNs provide compatibility with broadband technology as one of their benefits.

True Signup and view all the answers

ISDN Basic Rate Interface (BRI) provides two 128 kb/s bearer channels.

False Signup and view all the answers

A Primary Rate Interface (PRI) in North America delivers 23 B channels with 64 kb/s each.

True Signup and view all the answers

ISDN technology has increased in popularity due to the rise of DSL and other broadband services.

False Signup and view all the answers

Frame Relay is a Layer 3 WAN technology used to interconnect enterprise LANs.

False Signup and view all the answers

Data rates of up to 4 Mb/s are supported by Frame Relay technology.

True Signup and view all the answers

A single router can connect multiple sites using permanent virtual circuits (PVCs).

True Signup and view all the answers

ISDN can serve as a backup if a leased line fails.

True Signup and view all the answers

An edge router in Frame Relay requires multiple interfaces when using several virtual circuits.

False Signup and view all the answers

A very small aperture terminal (VSAT) can create a private WAN using satellite communications.

True Signup and view all the answers

DSL technology uses coaxial cable to transport high-bandwidth data.

False Signup and view all the answers

Cable modems provide a connection that is only available during certain hours of the day.

False Signup and view all the answers

For DSL, a modem is needed to convert an Ethernet signal into a DSL signal.

True Signup and view all the answers

Signals for VSAT travel approximately 10,000 kilometers to the satellite and back.

False Signup and view all the answers

DSL is primarily used by IT departments to support home workers.

True Signup and view all the answers

A cable television provider's network can provide less bandwidth than conventional telephone lines.

False Signup and view all the answers

A DSLAM at the provider location is used to multiplex multiple DSL subscriber lines into a single high-capacity link.

True Signup and view all the answers

A cable modem translates digital signals into broadband frequencies used for transmitting on a cable television network.

True Signup and view all the answers

WiMAX technology provides coverage over distances greater than 30 miles.

False Signup and view all the answers

Municipal Wi-Fi networks offer free internet access in many cities.

True Signup and view all the answers

A cable modem termination system (CMTS) is unnecessary for providing Internet services to subscribers.

False Signup and view all the answers

WiMAX operates similarly to Wi-Fi but at lower speeds.

False Signup and view all the answers

Wireless routers typically have a transmission range of less than 100 feet.

True Signup and view all the answers

WiMAX uses a network of wireless access points similar to Wi-Fi hotspots.

False Signup and view all the answers

Subscribers of WiMAX must be within 30 feet of a tower to access the service.

False Signup and view all the answers

Satellite Internet upload speeds are usually about one-tenth of the download speed.

True Signup and view all the answers

Cellular service is a type of wired WAN technology.

False Signup and view all the answers

The Long-Term Evolution (LTE) technology is part of the second generation of cellular technology.

False Signup and view all the answers

VSAT systems provide only one-way data communications.

False Signup and view all the answers

3G and 4G refer to the third and fourth generation of mobile phone technology.

True Signup and view all the answers

Satellite systems are much slower than analog modems.

False Signup and view all the answers

Devices using cellular technology can connect directly to the Internet.

True Signup and view all the answers

The upload speed for satellite Internet is typically higher than 500 kb/s.

False Signup and view all the answers

Multiplies the amount of bandwidth that a single strand of fiber can support and enables ______ communications over one strand of fiber.

bidirectional Signup and view all the answers

Leased lines vary in price depending on the ______ required and the distance between the two connected paths.

bandwidth Signup and view all the answers

Private WAN infrastructure may include dedicated point-to-point leased lines and ______ links.

circuit-switched Signup and view all the answers

Each channel can carry a ______ Gb/s multiplexed signal.

10 Signup and view all the answers

In North America, service providers use the T-carrier system to define the digital ______ of a serial copper media link.

transmission capacity Signup and view all the answers

Public WAN infrastructure often uses ______ access for broadband Internet.

DSL Signup and view all the answers

Data traveling over a public WAN should be protected using ______.

VPNs Signup and view all the answers

A leased line is also known as a ______ link, which is a dedicated communication path.

point-to-point Signup and view all the answers

Service provider networks typically consist of high-bandwidth fiber-optic media using ______ standards.

SONET Signup and view all the answers

For example, a T1 link supports ______ Mb/s.

1.544 Signup and view all the answers

A modern development in fiber-optic technology for long-range communications is ______.

DWDM Signup and view all the answers

Leased lines have been around since the ______, offering reliable point-to-point connections.

1950s Signup and view all the answers

Leased lines can also be referred to as ______ circuits.

leased Signup and view all the answers

One common type of packet switched link is ______ WAN.

Ethernet Signup and view all the answers

ISPs use various options to connect the local loop to the ______.

enterprise edge Signup and view all the answers

Circuit-switched links may include technologies such as ______ or ISDN.

PSTN Signup and view all the answers

Dialup WAN access may be required when no other WAN technology is available, often using modems and analog telephone ______.

lines Signup and view all the answers

Integrated Services Digital Network (ISDN) is a ______-switching technology that enables digital signal transmission.

circuit Signup and view all the answers

A modem modulates binary data into an analog signal at the ______ and demodulates it at the destination.

source Signup and view all the answers

The physical characteristics of the local loop limit the signal rate to less than ______ kb/s.

56 Signup and view all the answers

Time-division multiplexing (TDM) allows two or more signals to be transferred as ______ in one communication channel.

subchannels Signup and view all the answers

ISDN changes the PSTN connections from carrying analog signals to ______ digital signals.

time-division multiplexed Signup and view all the answers

To use traditional local loops, copper cabling transports binary computer data through the voice telephone ______.

network Signup and view all the answers

A WAN built with an on-demand connection using a ______ can provide necessary connectivity.

modem Signup and view all the answers

The WAN can connect local branches in the same city area, connect remote branches, or connect to a single ______.

branch Signup and view all the answers

The geographic scope of the WAN can be classified as local, regional, or ______.

global Signup and view all the answers

A private WAN offers the best ______ compared to public infrastructure.

security Signup and view all the answers

Public Internet infrastructure is not as secure, but offers the most flexibility and the lowest ongoing ______.

expense Signup and view all the answers

For a private WAN, it can either be dedicated or ______.

switched Signup and view all the answers

The WAN can connect internal or external employees or ______.

customers Signup and view all the answers

The traffic requirements of the WAN define what type of ______ must be supported.

traffic Signup and view all the answers

Choosing between public and private infrastructure often depends on balancing security with ______.

flexibility Signup and view all the answers

Frame Relay creates PVCs which are uniquely identified by a data-link connection identifier (DLCI) that ensures bidirectional communication between one DTE device to another, using ______.

DLCIs Signup and view all the answers

Asynchronous Transfer Mode (ATM) is built on a ______-based architecture rather than on a frame-based architecture.

cell Signup and view all the answers

ATM cells contain a 5-byte ATM header followed by ______ bytes of ATM payload.

48 Signup and view all the answers

A typical ATM line needs almost ______% greater bandwidth than Frame Relay to carry the same volume of network traffic.

20 Signup and view all the answers

Ethernet is now a reasonable WAN access option, particularly thanks to newer Ethernet standards using ______ cables.

fiber-optic Signup and view all the answers

The original maximum cable length for Ethernet was one kilometer, and with fiber-optic cable, the maximum length is ______ km using IEEE 10000Base-LX.

5 Signup and view all the answers

Cells in ATM technology are always a fixed length of ______ bytes.

53 Signup and view all the answers

When the cell is carrying segmented network layer traffic, the overhead is higher since the ATM switch must be able to ______ the packets at the destination.

reassemble Signup and view all the answers

Match the following types of VPN access with their descriptions:

Site-to-site VPN = Connects entire networks to each other Remote-access VPN = Enables individuals to access corporate networks Personal VPN = Used primarily for individual privacy and security Corporate VPN = Connects branches to headquarters Signup and view all the answers

Match the benefits of using VPNs with their descriptions:

Cost savings = Reduces the cost of dedicated lines Security = Encrypts data communications Scalability = Easily expands to accommodate growth Compatibility = Works well with existing broadband technologies Signup and view all the answers

Match the following WAN connection options with their characteristics:

Dedicated point-to-point leased lines = Private WAN infrastructure DSL = Public WAN infrastructure offering broadband Internet PSTN = Circuit-switched link Frame Relay = Packet-switched link technology Signup and view all the answers

Match the terms with their correct definitions regarding VPN tunnels:

VPN tunnel = A virtual connection through the Internet Encryption = The process of securing data Public network = The infrastructure over which VPNs operate Layer 2 connection = Traditional dedicated links like leased lines Signup and view all the answers

Match the following WAN types with their features:

Frame Relay = A Layer 3 technology for interconnecting LANs DSL = Uses telephone lines for high-speed Internet Cable broadband = Relies on cable television infrastructure VSAT = Operates using satellite technology Signup and view all the answers

Match the following WAN technologies with their descriptions:

SONET = Synchronous Optical Networking standard SDH = Synchronous Digital Hierarchy standard DWDM = Dense wavelength division multiplexing VPN = Virtual private network for secure data transit Signup and view all the answers

Match the WAN connection considerations with their focus areas:

Purpose = Defines the intended use of WAN Cost = Evaluates the budget for the connection Performance = Measures the speed and reliability Scalability = Considers how easy it is to expand the network Signup and view all the answers

Match the following terms with their definitions:

Private WAN = Dedicated infrastructure for enterprise use Public WAN = Access provided by service providers VPN = Secure connection over a public network Ethernet WAN = Packet-switched data link technology Signup and view all the answers

Match the type of VPN connection with its typical use case:

Site-to-site VPN = Connecting branch offices to headquarters Remote-access VPN = Allowing telecommuters to connect to the corporate network Client-to-server VPN = Direct connections for secure client usage Intranet VPN = Connecting internal networks securely Signup and view all the answers

Match the following WAN access technologies with their bandwidth capabilities:

Frame Relay = Data rates up to 4 Mb/s ISDN BRI = Two 128 kb/s bearer channels ISDN PRI = 23 B channels with 64 kb/s each DSL = High-bandwidth Internet access technology Signup and view all the answers

Match the VPN characteristics with their implications:

Encryption = Secures data from eavesdroppers Cost savings = Lowers total communication expenses Scalability = Facilitates network upgrades Compatibility = Ensures integration with existing systems Signup and view all the answers

Match the following WAN options with their primary use case:

VSAT = Satellite communications for private WAN Cable modem = Connection via cable television network DSLAM = Multiplexing DSL subscriber lines Fiber-optic media = High-bandwidth for service provider networks Signup and view all the answers

Match the technologies with their WAN functionality:

MPLS = A method used to direct data between routers ISDN = A traditional digital network technology DSLAM = Multiplies DSL subscriber connections Cable modem = Translates signals for cable TV networks Signup and view all the answers

Match the following connection types with their specific characteristics:

Circuit-switched = Established connection for data transmission Packet-switched = Sends data in packets over shared networks Dedicated line = Constant connection with no interruptions Broadband connection = High-speed access combining multiple channels Signup and view all the answers

Match the following WAN types with their security measures:

Public WAN = Requires VPN for data protection Private WAN = Inherently secure due to dedicated lines DSL = Uses encryption for secure connections Cable access = Vulnerable to interception without extra security Signup and view all the answers

Match the following technologies with their application areas:

ATM = Broadband transport technology DSL = Public access technology for homes Ethernet WAN = Connecting enterprise networks Satellite links = Long-range data transmission for remote areas Signup and view all the answers

Match the following WAN technologies with their characteristics:

Frame Relay = Uses PVCs identified by DLCIs ATM = Cell-based architecture with fixed-length cells Ethernet WAN = Uses fiber-optic cables to extend reach ISDN = Provides multiple bearer channels for communication Signup and view all the answers

Match the following technologies with their primary data type:

Frame Relay = Data communication ATM = Voice, video, and data Ethernet WAN = Broadband data access ISDN = Telephony and data services Signup and view all the answers

Match the following technologies with their payload structure:

ATM = 5-byte header and 48-byte payload Frame Relay = Variable-length frames Ethernet WAN = Ethernet frames ISDN = 64 kb/s channels Signup and view all the answers

Match the following WAN technologies with their overhead characteristics:

ATM = Higher overhead for Segmented traffic Frame Relay = Lower overhead for straightforward connections Ethernet WAN = Flexibility with low overhead in fiber ISDN = Fixed overhead per channel Signup and view all the answers

Match the following technologies with their bandwidth requirements:

ATM = Needs 20% more bandwidth than Frame Relay Frame Relay = Efficient for scattered data Ethernet WAN = Supports high-capacity links ISDN = Limited to 128 kb/s for BRI Signup and view all the answers

Match the following technologies with their maximum cable lengths:

Ethernet (10000Base-LX) = 5 km Ethernet (1000BASE-ZX) = 70 km Frame Relay = Subject to provider specifications ATM = Defined by physical layer constraints Signup and view all the answers

Match the following data structures with the respective WAN type:

PVC = Frame Relay Cells = ATM Ethernet frames = Ethernet WAN Bearer channels = ISDN Signup and view all the answers

Match the following characteristics with their respective technologies:

Frame Relay = Bidirectional communication through DLCIs ATM = Well-suited for voice and video traffic Ethernet WAN = Utilizes modern Ethernet standards ISDN = Integrates voice and data services easily Signup and view all the answers

Match the following ISDN interfaces with their descriptions:

Basic Rate Interface (BRI) = Provides two 64 kb/s bearer channels and one 16 kb/s delta channel Primary Rate Interface (PRI) = Delivers 23 B channels with 64 kb/s each and one D channel Bearer Channel (B) = Carries voice and data traffic Delta Channel (D) = Used for signaling and call setup Signup and view all the answers

Match the following Frame Relay characteristics with their descriptions:

Non-broadcast multi-access (NBMA) = Layer 2 technology for WAN interconnection Permanent Virtual Circuits (PVC) = Used to connect multiple sites Data rates = Can go up to 4 Mb/s or higher with some providers Edge Router = Requires a single interface for multiple circuits Signup and view all the answers

Match the following ISDN applications with their purposes:

Leased line backup = Provides additional capacity when needed Call setup = Facilitated by the delta channel Voice transmission = Can be carried by bearer channels Data transfer = Utilized through BRI and PRI connections Signup and view all the answers

Match the following terms with their definitions:

Terminal Adapter (TA) = Device connecting ISDN BRI to a router ISDN = Integrated Services Digital Network DSL = Digital Subscriber Line, a broadband technology Call signaling = Managed by the delta channel in ISDN Signup and view all the answers

Match the following aspects of BRI with their measurements:

64 kb/s = Data rate of each bearer channel 16 kb/s = Data rate of the delta channel 2 = Number of bearer channels in BRI 1 = Number of delta channels in BRI Signup and view all the answers

Match the following ISDN characteristics with their benefits:

Multiple channels = Allows for simultaneous voice and data transmission High reliability = Can serve as a backup for leased lines Standardized network = Facilitates connectivity in provider networks Dedicated connection = Ensures stable performance for ISDN users Signup and view all the answers

Match the following descriptions of WAN technologies with their types:

Frame Relay = A Layer 2 WAN technology for enterprise LANs ISDN = Provides both voice and data services DSL = Broadband technology used for high-speed Internet VSAT = Private WAN using satellite communications Signup and view all the answers

Match the following Frame Relay features with their functions:

Layer 2 = Works as a data link layer technology Voice and data = Supported on a single circuit using PVCs High capacity = Can achieve data rates above 4 Mb/s Single interface requirement = Simplifies the router configuration Signup and view all the answers

Match the following types of WAN technology with their characteristics:

Satellite Internet = Used in rural areas where other connections are unavailable 3G Wireless = Third generation cellular technology 4G LTE = Newer and faster cellular technology VSAT = Provides two-way data communication Signup and view all the answers

Match the following metrics with their descriptions:

Satellite download speed = $500 kb/s Satellite upload speed = $50 kb/s DSL speed = Higher than satellite Analog modems speed = 10 times slower than satellite Signup and view all the answers

Match the following components with their functions:

Small radio antenna = Used in devices to communicate Mobile phone tower = Connects devices to cellular networks Large antenna = Located at the top of the mobile tower Cellular device = Examples include phones and tablets Signup and view all the answers

Match the following terms with their definitions:

VSAT = Very Small Aperture Terminal 3G = Third generation cellular access 4G = Fourth generation technology LTE = Long-Term Evolution technology Signup and view all the answers

Match the following connection types with their typical uses:

DSL = High-bandwidth for home users Satellite = For rural internet access Cable = Broadband over coaxial networks Cellular = Access for mobile devices Signup and view all the answers

Match the following technologies with their advantages:

Satellite = Faster than analog modems DSL = Higher speeds than satellite Cable = Reliable broadband connection LTE = High-speed mobile internet Signup and view all the answers

Match the following descriptions with the correct technology:

3G = Communicates through a mobile tower 4G LTE = Offers significant speed improvements DSL = Utilizes telephone lines for internet Satellite = Requires a dish for communication Signup and view all the answers

Match the following types of devices with their capabilities:

Laptops = Can use cellular technology for internet Phones = Access the internet via 3G/4G Tablets = Connect to Wi-Fi and cellular networks Routers = Facilitate internet connectivity for multiple devices Signup and view all the answers

Study Notes

WAN Services Overview

WAN connections bridge local loops to enterprise edges, offering various options with distinct advantages, speeds, and costs.
Enterprises can choose between private WAN infrastructure (e.g., dedicated leased lines, circuit-switched links like PSTN or ISDN) or public WAN infrastructure (e.g., DSL, cable, satellite).
Data across public WANs should utilize VPNs for security.

Service Provider Network Infrastructure

Service provider networks are largely built on high-bandwidth fiber-optic media, primarily using SONET or SDH standards.
Dense Wavelength Division Multiplexing (DWDM) represents a new development in fiber-optic communication for long-range applications.

VPN Technology

VPNs create encrypted connections over public networks, enabling secure access to corporate WANs, essential for teleworkers and remote offices.
Unlike dedicated Layer 2 connections, VPNs utilize virtual tunnels routed through the Internet, connecting private networks to remote sites.
Key benefits of VPNs include cost savings, enhanced security, scalability, and compatibility with broadband technologies.
Two types of VPN access:
- Site-to-site VPNs: Connect entire networks, such as branch offices to headquarters.
- Remote-access VPNs: Allow telecommuters and mobile users secure access to corporate networks.

Selecting WAN Services

Numerous considerations arise when choosing a WAN connection, including its purpose and specific service offerings.
Service providers are beginning to offer Ethernet WAN services via fiber-optic cabling, leading to reduced costs, easy integration, and increased productivity.
Ethernet WANs are gaining popularity as replacements for Frame Relay and ATM connections.

Private WAN Infrastructures and MPLS

Multiprotocol Label Switching (MPLS) is a high-performance WAN technology that directs data using short path labels rather than traditional IP addresses.
MPLS is termed "multiprotocol" due to its capability to carry various data formats, such as IPv4, IPv6, Ethernet, ATM, DSL, and Frame Relay.
It utilizes labels to instruct routers on data packet handling, supporting diverse WAN technologies including T-carrier/E-carrier links, Carrier Ethernet, and more.
MPLS serves primarily as a service provider WAN technology, facilitating multiple access technologies within an MPLS cloud.

Additional Media Considerations

All discussed private WAN technologies employ either copper or fiber-optic media for communication.

VPN Technology

VPNs (Virtual Private Networks) are essential for secure remote access to corporate WANs over public networks like the Internet.
A VPN establishes an encrypted connection, using virtual tunnels instead of dedicated lines, to link private networks securely.
Benefits of using VPNs include cost savings, enhanced security, scalability, and compatibility with broadband technologies.
Two main types of VPN access:
- Site-to-Site VPNs: Connect entire networks, e.g., linking branch offices to headquarters.
- Remote-Access VPNs: Allow individual users like telecommuters to securely connect to company networks.

Choosing a WAN Link Connection

Network administrators must consider the WAN's purpose and requirements when selecting appropriate connections.
ISDN (Integrated Services Digital Network) may require a terminal adapter (TA) for connecting BRI (Basic Rate Interface) to routers.

ISDN Interfaces

Basic Rate Interface (BRI): Comprises two 64 kb/s bearer channels (B) for voice/data, and one 16 kb/s delta channel (D) for signaling.
Primary Rate Interface (PRI): In North America, it provides 23 B channels and one D channel, totaling 1.544 Mb/s.
ISDN serves as a backup option for leased lines and increases capacity as needed; however, its popularity has declined due to alternatives like DSL.

Frame Relay

Frame Relay is a Layer 2 NBMA (non-broadcast multiple access) WAN technology for connecting LANs.
Offers data rates up to 4 Mb/s, with some providers offering higher speeds.
Facilitates multiple site connections using Permanent Virtual Circuits (PVCs) with voice and data traffic.

VSAT Technology

Very Small Aperture Terminal (VSAT) utilizes satellite communications to form private WANs for remote locations lacking traditional provider services.
Operates via small satellite dishes in geosynchronous orbit, with signals traveling approximately 35,786 km.

DSL (Digital Subscriber Line)

DSL leverages existing twisted-pair telephone lines for high-bandwidth, always-on Internet connections.
Requires a DSL modem to convert Ethernet signals, and multiple subscriber lines are multiplexed via DSLAM in central offices.
Widely utilized by IT departments to support remote workers after establishing links through ISPs.

Cable Internet

Cable modems provide always-on connections using coaxial cables, offering higher bandwidth than traditional telephone lines.
Installation involves connecting a computer or LAN router to the cable modem, which translates digital signals for transmission.
CMTS (Cable Modem Termination System) is essential for sending and receiving cable modem signals within the network.

Wireless WAN Technologies

Traditional wireless access was limited by range; advancements now include:
- Municipal Wi-Fi: Cities enabling networks for public use, often at reduced rates.
- WiMAX (IEEE 802.16): A newer technology providing high-speed broadband with extensive coverage, functioning similar to cellular networks.

Satellite Internet Services

Ideal for rural areas lacking cable or DSL; VSATs enable two-way communications with upload speeds roughly one-tenth of 500 kb/s download speeds.
Outperforms analog modems significantly in speed but may lag compared to DSL and cable services.

3G/4G Cellular Technology

Cellular technology provides a wireless WAN solution for users in areas without other WAN access options.
Devices such as phones, tablets, and laptops utilize radio waves for Internet connectivity through nearby mobile towers.
Common terms include 3G/4G for third and fourth-generation cellular access and LTE (Long-Term Evolution) for advanced 4G technology.

WAN Services Overview

WAN access connection options enable ISPs to link the local loop to the enterprise edge.
Choices include private WAN infrastructures using dedicated leased lines or public WAN infrastructures utilizing broadband Internet via DSL, cable, or satellite.
Data transfer over public WAN requires protection through VPNs for security.

Service Provider Network Infrastructure

Composed of high-bandwidth fiber-optic media utilizing SONET or SDH standards.
Dense Wavelength Division Multiplexing (DWDM) enhances fiber capacity by supporting over 80 channels, each carrying up to 10 Gb/s.

Private WAN Infrastructures

Leased Lines: Long-established point-to-point connections leased from service providers, referentially called serial links, T1/E1, or T3/E3 lines.
Bandwidth and distance determine costs, with a T1 link supporting 1.544 Mb/s.

Dialup Connections

Used when no other technology is available, relying on modems and analog telephone lines.
Converts digital binary data into analog signals and vice versa, with speeds typically under 56 kb/s.

Integrated Services Digital Network (ISDN)

Circuit-switching technology allowing the PSTN to carry digital signals for higher capacity.
Utilizes Time-Division Multiplexing (TDM) to transfer multiple signals in one channel.

WAN Selection Considerations

Key questions when selecting WAN services include geographic scope (local, regional, global) and connection types (one-to-one, one-to-many, many-to-many).
Traffic requirements, including type and performance metrics, are crucial in planning.

Private vs. Public Infrastructure

Private WAN provides enhanced security; public WAN offers flexibility and lower costs.
Decisions must include whether to use dedicated or switched connections based on specific business needs.

Frame Relay

Creates Permanent Virtual Circuits (PVCs) identified by Data-Link Connection Identifiers (DLCIs) for secure communication between devices.

Asynchronous Transfer Mode (ATM)

Uses a cell-based architecture (fixed cells of 53 bytes) suited for voice and video transmission.
Requires approximately 20% more bandwidth than Frame Relay for similar traffic volumes due to additional overhead.

Ethernet WAN

Recent Ethernet standards allow the use of fiber-optic cables, increasing potential maximum cable length significantly (up to 70 km with IEEE 1000BASE-ZX).

WAN Services Overview

WAN access connection options provide distinct advantages and disadvantages based on technology, speed, and cost.
Two primary methods to obtain WAN access:
- Private WAN Infrastructure: Includes dedicated point-to-point leased lines, circuit-switched links (PSTN, ISDN), and packet-switched links (Ethernet WAN, ATM, Frame Relay).
- Public WAN Infrastructure: Offered by service providers, includes broadband Internet via DSL, cable, and satellite.

VPN Technology

VPNs (Virtual Private Networks) secure data traveling between corporate sites over public WANs by establishing encrypted connections.
VPN tunnels, virtual connections routed through the Internet, replace dedicated Layer 2 links such as leased lines.
Benefits of VPNs include:
- Cost savings
- Enhanced security
- Scalability
- Compatibility with broadband technology
Two types of VPN access:
- Site-to-Site VPNs: Connects entire networks, e.g., branch office to headquarters.
- Remote-Access VPNs: Allows telecommuters and mobile users to securely access the company network over the Internet.

Choosing a WAN Link Connection

Network administrators evaluate various factors, such as WAN purpose and required technologies, when selecting WAN connections.
ISDN connections often need a terminal adapter (TA) for Basic Rate Interface (BRI) connections to routers.

ISDN Overview

ISDN Interfaces:
- Basic Rate Interface (BRI): Offers two 64 kb/s bearer channels and one 16 kb/s delta channel for signaling.
- Primary Rate Interface (PRI): North America provides 23 B channels at 64 kb/s and one D channel, totaling up to 1.544 Mb/s.
ISDN is used for additional capacity on leased lines and as backup in case of failures but has declined with the rise of DSL and other broadband services.

Private WAN Infrastructures

Frame Relay: Layer 2 NBMA technology interconnecting LANs with data rates up to 4 Mb/s; utilizes Permanent Virtual Circuits (PVCs) identified by Data-Link Connection Identifiers (DLCI).
Asynchronous Transfer Mode (ATM): Transfers voice, video, and data in a fixed-length cell structure (53 bytes); requires more bandwidth compared to Frame Relay for similar traffic.
Ethernet WAN: Emerging as a viable WAN access option, especially with fiber-optic enhancements.
Maximum cable lengths enhanced via fiber-optics: up to 5 km (IEEE 10000Base-LX) and 70 km (IEEE 1000BASE-ZX).

Public WAN Infrastructures

Satellite Internet: Common in rural areas; provides two-way communication with specific upload and download speed characteristics (upload is slower).
3G/4G Cellular Technology: Connects remote users using radio waves to mobile towers; devices include phones, tablets, laptops, and routers.
Long-Term Evolution (LTE): Advanced 4G technology offering faster data connectivity, part of the evolving cellular service landscape.

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Description

This quiz covers the fundamental concepts of WAN services, including the comparison of private and public WAN infrastructures. It also explores service provider network infrastructure, focusing on advancements like DWDM, and the importance of VPN technology for secure data transmission. Test your understanding of how these elements come together to support enterprise networking.