1.0 Wired and Wireless Network
Topologies
N10-008
Objectives for 1.0
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Topology
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Network’s physical and logical layout
Other Topologies
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Bus
Ring
Star
Mesh
Wireless
Bus Topology
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Trunk/Backbone to connect all computers on network
Bus Topology (Pros and Cons)
Pros
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Cons
Cheap & easy
Less cable
Doesn’t need special network equipment
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Network disruption may occur when
adding/removing a computer
Difficult to troubleshoot
Break in cable prevents all systems from
accessing the network
Ring Topology
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Logical ring
Data travels in circular fashion from one computer to another on the network
Ring Topology (Pros and Cons)
Pros
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Cons
Cable faults are easily located, makes
troubleshooting easier
Moderately easy to install
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Expansion to network causes network
disruption
Single break in cable can disrupt entire
network
Star Topology (Hub-and-Spoke)
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All computers and other network devices connect to central device
Each connection requires a single cable to be connected to hub/switch
Star Topology (Pros and Cons)
Pros
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Cons
Easily expand without disruption to the
network
Cable failure affects only a single user
Easy to troubleshoot
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Requires more cable than other topologies
Central connecting device allows for a
single point of failure
Requires add. Networking equipment to
create network layout
Mesh Topology
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Wired Mesh Topology incorporates unique network design which each
computer on network connects to every other
Creates a point-to-point connection between every device on network
High level of redundancy
Mesh Topology (Pros and Cons)
Pros
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Cons
Provides redundant paths between LAN
topologies
Network can be expanded without
disruption to current users
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Requires more cable than other topologies
Implementation is complicated
Hybrid Topology
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Creates redundant point-to-point network connection between only specific
network devices (like servers)
Most often seen in WAN implementations but can be used in any network
Infrastructure Wireless Topology
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Commonly used to extend a wired LAN
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includes wireless devices
Communicates with Wired LAN through an AP/WAP
Ad Hoc Wireless Topology
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Devices communicate directly among themselves without using an AP
Provides a quick method to share files & resources among a small number of
systems
Wired Mesh Topology
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Costly due to cabling required to interconnect all computer systems
Don’t need cables running between systems
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Makes wireless mesh networks fairly common
Each network node is interconnected to other nodes on the network
Self-Healing (Wireless Mesh Networks)
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In wireless mesh networks
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Refers to the network’s ability to adapt to network failure and even function should a node be
moved from one location to another
Scalable (Wireless Mesh Networks)
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In wireless mesh networks
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Using wireless, you’re able to add new systems to the network without the need of expensive
cables
Local Area Network (LAN)
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Data network restricted to single geographic location
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Typically a relatively small area
■ i.e. Office building or school
Wireless LAN (WLAN)
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Provide a flexible & secure data communications system that augments
Ethernet LAN or replaces it
Transmissions send & receive data using RF signals
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Are dependent on a hotspot
Wide Area Network (WAN)
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Network spans more than one geographic location
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Often connecting separated LANs
WANs are slower than LANs
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Often require add. & costly hardware like routers
Metropolitan-Area Network (MAN)
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Confined to a certain geographic area
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i.e. University Campus or City
They utilize an ISP/Telecommunications Provider
Campus-Area Network (CAN)
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Defined area that links buildings & consists or multiple LANs within that
limited geographical area
Encompass a whole college campus/portion of it
Storage-Area Network (SAN)
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Clustered storage
Lets you use multiple devices to increase performance
Provide file-level access
Software-Defined Wide Area Network (SDWAN)
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Extension of SDNs
Commonly used in telco and data centers
Support apps from anywhere:
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Public/Private Clouds
On-Premise Data Centers
Multiprotocol Label Switching (MPLS)
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WAN technology used in high-performance based telco networks
Uses short path labels instead of longer network addresses to direct data
from one node to another
Multipoint Generic Routing Encapsulation (mGRE)
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Extension of GRE
Configured as point-to-point tunnel between two sites
Extends capability from a limited number of sites by establishing tunnels
Digital Subscriber Line (DSL)
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Internet access method, uses a standard phone line to provide high-speed
Internet access
Associated w/high-speed Internet access
Asymmetric Digital Subscriber Line (ADSL)
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Most common DSL
Provides high data rate in only ONE direction
Enables fast download speeds but slower upload speeds
Symmetric DSL (SDSL)
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Offers same speeds for uploads and downloads
Most suitable for business applications
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Web hosting, Intranets & E-Commerce
Rate-Adaptive DSL (RADSL)
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Variation of ADSL
Modify transmission speeds based on signal quality
Very High-Bit-Rate (HDSL)
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Symmetric technology that offers identical transmission rates in both
directions
Doesn’t allow line sharing w/analog phones
High-Rate Digital Subscriber Line (HDSL)
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Provides a bidirectional high-data-rate service that can accommodate
services
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Videoconferencing
Symmetric technology
Cable Broadband
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Internet access method available in areas that have digital cable television
Inexpensive & reliable
For small businesses and home offices
Public Switched Telephone Network (PSTN)
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Includes equipment that goes into connecting two points
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Like a cable, networking equipment & telephone exchanges
Considered a POTS
Collection of interconnected telephone wires throughout the world
T-Carrier Lines
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High-speed dedicated digital lines that can be leased from telephone
companies
Support both voice and data transmissions
Often used to create point-to-point private networks
They are 4 T-Carrier Lines (Transmission Speeds):
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T1: 1.544 Mbps
T2: 6.312 Mbps
T3: 44.736 Mbps
T4: 274.176 Mbps
Metro-Optical Networks (MONs)
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Optical networks that can span up to several 100 kilometers
Used to serve Metropolitan areas
Passive Optical Network (PON)
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Unpowered optical splitters that split fiber so it can service a number of
locations
Optical Line Termination (OLT)
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Split the number of Optical Network Units (ONUs) at the end of each run
Optical Network Units (ONUs)
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At the end of each run (typically near the end user) get combined
w/wavelength division multiplexing (WDM-PON)
Dense Wavelength-Division Multiplexing (DWDM)
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Replaces (SONET/SDH) regenerators w/(EDFAs)
Main components:
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Terminal multiplexer
Line repeaters
Terminal Demultiplexer
Erbium-Doped Fiber Amplifiers (EDFAs)
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Amplify the signal and enable it to travel a greater distance
Coarse Wavelength-Division Multiplexing (CWDM)
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Commonly used w/television cable networks
Demarcation Point
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Connection point between the operator’s part of the network and customer’s
portion of the network
Smart Jack
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Form of hardware at the demarcation point
Known as a Network Interface Device (NID)
Performs the following functions:
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Loopback feature
Signal amplification
Surge protection
Remote alarms
Channel Service Unit/Data Service Unit (CSU/DSU)
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Translator between the LAN data format & WAN data format
A digital modem
Hypervisor
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Software/Hardware combination that makes it possible to manage multiple
virtual machines existing on 1 host
Two Types:
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Type 1: Bare Metal - independent OS and boots before OS
Type 2: Hosted - dependent on OS and can’t boot until OS is up, needs OS to stay up to operate
Network Function Virtualization (NFV)
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Method of virtualizing network services instead of running them on
proprietary hardware
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Think: Routers, firewalls & load balancers
Virtual Network Interface Cards (vNICs)
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Common virtual network components include:
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Virtual routers & switches
Shared memory
Virtual CPUs
Storage (shared/clustered)
Virtual Router
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Works like a physical router, but is software only
Virtual Switch (vSwitch)
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Software program that allows one virtual machine (VM) to communicate with
another
Allows VM to use hardware of the host OS (the NIC) to connect to the Internet