chapter 02 03
TRANSCRIPT
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 1/53
WANs and Router Basics
Chapter 1: WANs & Routers
Chapter 2: Router CLI
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 2/53
Table of Contents
WAN Devices
WAN StandardsWAN Technologies
Router Basics
Router User
Interface
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 3/53
WAN Devices
Table of Contents
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 4/53
WAN Services
WANs provide for the exchange of data packets/frames between
routers/bridges and the LANs theysupport.
A WAN interconnects LANs that
are usually separated by largegeographic areas.
WANs connect devices. Such
devices include...
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 5/53
RoutersRouters offer many servicesincluding:InternetworkingWAN serial interfaces
Routers can operate as...Internal RoutersBackbone Routers
Area Border Routers
Autonomous System Boundary
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 6/53
WAN Bandwidth Switches
Service provider equipment thatconnects to WAN bandwidth for
voice, data and videocommunications.
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 7/53
Modems
Also called CSU/DSUs (channelservice units/digital service units)
Interface with voice-gradeconnection in order to convertanalog signal to digital.
Represents the DCE side of theDTE/DCE connection.
More on DTE/DCE later
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 8/53
Communication Servers
Concentrates dial-in and dial-outservices.
Equipment is usually at the serviceprovider’s site.
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 9/53
WAN Standards
Table of Contents
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 10/53
WAN Standards
What layers of the OSI model doWAN standards describe?
Physical and Data Link Layers
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 11/53
WAN Physical Layer
Protocols that describe how to provideelectrical, mechanical, operational, and
functional connections for WAN services. These services are most often obtained
from WAN service providers such asRBOCs, alternate carriers, post-
telephone, and telegraph (PTT) agencies.Describes the interface between the
data terminal equipment (DTE) and the
data circuit-terminating equipmentDCE .
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 12/53
WAN Physical Layer
Typically, the DCE is the serviceprovider and the DTE is the
attached device.In this model, the services offeredto the DTE are made availablethrough a modem or a CSU/DSU.
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 13/53
WAN Physical Layer
Several physical layer standardsspecifying this interface between
the DTE & DCE are...EIA/TIA-232EIA/TIA-449V.24V.35X.21G.703
EIA-530
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 14/53
WAN Data-Link Layer
WAN data link protocols describehow frames are carried between
systems on a single data link. They include protocols designed tooperate over dedicated point-to-
point, multipoint, and multi-accessswitched services.
WAN standards are defined and
managed by a number of
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 15/53
WAN Data-Link Encapsulations
High-Level Data Link Control (HDLC)Cisco default encapsulation; typically
used between routers running CiscoIOS; replacing SDLC
Streamlined: no windowing or flowcontrol
may not be compatible with differentvendors because of the way eachvendor has chosen to implement it.
HDLC supports both point-to-point and
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 16/53
WAN Data-Link Encapsulations
Frame Relayuses high-quality digital facilities;
uses simplified framing with no errorcorrection mechanisms(connectionless!!);
it can send Layer 2 information muchmore rapidly than other WANprotocols
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 17/53
WAN Data-Link Encapsulations
PPP (Point-to-Point Protocol)Developed by IETF; replacing SLIP
Contains a field to identify thenetwork layer protocol
PPP can check for link quality during
connection establishmentSupports PAP (PasswordAuthentication Protocol) & CHAP(Challenge Handshake Authentication
Protocol)
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 18/53
WAN Technologies
Table of Contents
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 19/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitched
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitched
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 20/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitched
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitched
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 21/53
Dedicated Digital Services
T series in U.S. and E series inEuropeUses time division multiplexing to“slice up” data and assign time slotsfor transmissions T1 = 1.544 Mbps
T3 = 44.736 Mbps
E1 = 2.048 Mbps
•Uses twisted pair& fiber
•Extremelypopular
•Moderate cost
Dedicated Digital Servicesprovide full-time connectivity
through a point-to-point link
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 22/53
Dedicated Digital Services
Digital Subscriber Lines(xDSL); the x stands for a family of
technologiesNew WAN Technology for home use;decreasing bandwidth with increasing
distance from the phone companiesCO.
Data rates as high as 51.84 Mbps butmore common to be in the 100s of
Kbps
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 23/53
Dedicated Digital Services
Synchronous Optical Network (SONET)
Specialized high bandwidthtechnology for use at various OpticalCarrier speeds (OC) ranging from51.84 Mbps (OC-1) to 9,952 Mbps (OC-192)
Uses lasers to divide the wavelengthof the light into sections that can carry
large amounts of data (Wave Division
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 24/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitch
ed
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitched
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 25/53
Analog Services
Dial-up Modems (switchedanalog)
Limited to 56 kbpsWorks with existing phone network
Low cost and widespread usage
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 26/53
Analog Services
Cable Modems (Shared Analog)Puts data signals on the same cable
as television signalsIncreasing in popularity
Maximum bandwidth can be 10 Mbps,
though this degrades as more usersattach to a given network segment(behaving like an unswitched LAN)
Cost is relatively low; usage is small
but increasing; the medium is coaxial
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 27/53
Analog Services
Terrestrial
Bandwidthstypically in the 11Mbps range
Cost is relativelylow
Line-of-sight isusually required
Usage is moderate
Satellite
Can serve mobileusers and remoteusers
Usage iswidespread
Cost is very high
Wireless
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 28/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitch
ed
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitch
ed
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 29/53
Circuit Switched Services
Plain Old Telephone System (POTS)
Not a computer data service but...POTS is an important component of ourcommunication infrastructure and
It is still the standard for designing
reliable networks
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 30/53
Circuit Switched Services
Integrated Services DigitalNetwork (ISDN)
Historically important--first dial-updigital service
Cost is moderate; max. bandwidth =
128 kbps for BRI (Basic Rate Interface)2 B channels @ 64kps and 1 D channel @16kps
B channels are voice/data channels; D for
signaling
B
B
D
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 31/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitch
ed
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitch
ed
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 32/53
Packet Switched Services
X.25 (Connection-oriented)Older WAN technology developed in
1970sReliable--X.25 has been extensivelydebugged and is now very stable--literally no errors in modern X.25
networksStore & Forward--Since X.25 storesthe whole frame to error check itbefore forwarding it on to the
destination, it has an inherent delay
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 33/53
Packet Switched Services
Frame Relay (Connectionless)More efficient and much faster than
X.25Packet switched version of ISDN(which is circuit switched); data ratesup to 44.736Mbps with 56kbps and384kbps being the most popular
Used mostly to forward LAN IP and IPXpackets but can be used to forward
other types of traffic
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 34/53
WAN Technologies Overview
Dedicated
• T1, E1, T3,E3
•xDSL
•SONET
Analog
•Dial-upmodems
•Cablemodems
•Wireless
Switched
CircuitSwitch
ed
• POTS
• ISDN
PacketSwitch
ed
• X.25
• Frame
Relay
CellSwitch
ed
• ATM
• SMDS
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 35/53
Cell Switched Services
Asynchronous Transfer Mode (ATM)Relatively new WAN Technology
related to broadband ISDN; max.bandwidth = 622 MbpsDeveloped in order to provide onetechnology for both WANs and LANs to
transport data, video, and voice. (HighCost)Key Benefits:
One network for all traffic--voice, data,video
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 36/53
Cell Switched Services
Switched Multimegabit DataService (SMDS)
Closely related to ATM; SMDS is theMAN (Metropolitan Area Network)implementation of ATM
High Cost with max. bandwidth44.736 Mbps
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 37/53
Acronym Name Max. Bandwidth Comments
T1, T3 T1, T3 1.544 & 44.736 Mbps Widely used telecommunications
xDSL Digital Subscriber Line 384 kbps New technology over phone linesSONET
Synchronous Optical
Network9,992 Mbps Very fast optical fiber transmission
Dial-up Modem Modem 56 kbps Mature technology over phone lines
Cable Modem Cable Modem 10 Mbps New technology using cable TV
Terrestrial Wireless Wireless 11 Mbps Microwave and laser links
Satellite Wireless Wireless 2 Mbps Microwave and laser links
POTSPlain Old Telephone
Service4 kHz Analog The Standard for Reliability
ISDNIntegrated Services
Digital Network128 kbps Data and Voice Together
X.25 X.25 An Old Reliable, Workhorse
Frame Relay Frame Relay up to 44.736 Mbps A flexible new workhorse; son of ISDN
ATMAsynchronous
Transfer Mode622 Mbps High powered Networks
SMDS Switched MultimegabitData Service 1.544 & 44.736 Mbps MAN variant of ATM
Cell Switched Services
Dedicated Digital Services
Analog Services
Circuit Switched Services
Packet Switched Services
WAN T ech nolog ies Re view
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 38/53
Router Basics
Table of Contents
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 39/53
Internal Components
RAM NVRAM Flash ROM
InterfacesConsole
Auxiliary
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 40/53
RAM
Temporary storage for routerconfiguration files
RAM content is lost on power downor restart
Stores...
Routing tablesARP cache
Fast switching cache
Packet buffering
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 41/53
NVRAM
Non-volatile RAM
Stores backup/startup
configuration filesContent is not lost when router ispowered down or restarted.
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 42/53
Flash
EEPROM (Electronically ErasableProgrammable Read-Only Memory)
Holds the Cisco IOS (InternetOperating System)
Allows updating of software
without replacing the Flash chipMultiple versions of IOS can bestored
Retained on power down
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 43/53
ROM
Contains POST (Power On Self Test)
A bootstrap program (loads the
Cisco IOS)And operating system softwareBackup, trimmed down version of the
IOSUpgrades require installing new chipset
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 44/53
Interfaces
Network connections throughwhich packets enter and exit the
routerAttached to the motherboard or asseparate modules.
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 45/53
Labs
Before moving on to Ch. 3, makesure you have done both of the
required labs for Ch. 2Lab 2.2.2
Lab 2.2.3.2
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 46/53
Router User Interface
Table of Contents
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 47/53
User EXEC Modes
User modeLimited mode used for checking the
routers status, looking at routingtables, etc. You cannot configure the routerOnce you’ve typed the password to
enter user mode, you will see the >prompt. The word “Router” will be thename of the router.
Password:
Means you’re in
user mode
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 49/53
Command Lists
To get a list of commands availablein either user mode or privileged
mode, enter a ? at the prompt.Router> ?
Router# ?
Since the available commands willbe more than the screen can hold,you will get the --More-- messageat the bottom.
Hitting the space bar will advance
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 50/53
ipflash:interfacesipx version parser
Router# show ?
Getting Help on a Command
The ? can be used with a partialcommand to learn all the availablecommands that match what you
entered. To use this help feature, enter the
partial command, then tap the spacebar, then type ?For example... The Router returned all
the available commands
for “show”
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 51/53
Error Indicator
When you’ve entered an error inthe command string, a carat (^)
symbol will indicate where the erroroccurred.
For example...Router# show runing-config
^
% Invalid input detected at the ‘^’ marker
8/14/2019 Chapter 02 03
http://slidepdf.com/reader/full/chapter-02-03 52/53
Labs
Before taking the Ch. 2/3 test,make sure you have done both of
the required labs for Ch. 3Lab 3.2.1
Lab 3.2.2