Wans And Router Basics

WANs and Router Basics Chapter 1: WANs & Routers Chapter 2: Router CLI

Table of Contents WAN

Devices

WAN

Standards

WAN

Technologies Router Router

Basics

User Interface

WAN Devices

Table of Contents

WAN Services WANs

provide for the exchange of data packets/frames between routers/bridges and the LANs they support. A WAN interconnects LANs that are usually separated by large geographic areas. WANs connect devices. Such devices include...

Routers Routers

offer many services including: Internetworking WAN

serial interfaces

Routers

can operate as...

Internal

Routers Backbone Routers Area Border Routers Autonomous System Boundary

WAN Bandwidth Switches Service

provider equipment that connects to WAN bandwidth for voice, data and video communications.

Modems Also

called CSU/DSUs (channel service units/digital service units) Interface with voice-grade connection in order to convert analog signal to digital. Represents the DCE side of the DTE/DCE connection. More on DTE/DCE later

Communication Servers Concentrates

dial-in and dial-out

services. Equipment is usually at the service provider’s site.

WAN Standards

Table of Contents

WAN Standards What

layers of the OSI model do WAN standards describe? Physical

and Data Link Layers

WAN Physical Layer Protocols

that describe how to provide electrical, mechanical, operational, and functional connections for WAN services. These services are most often obtained from WAN service providers such as RBOCs, alternate carriers, posttelephone, and telegraph (PTT) agencies. Describes the interface between the data terminal equipment (DTE) and the data circuit-terminating equipment (DCE).

WAN Physical Layer Typically,

the DCE is the service provider and the DTE is the attached device. In this model, the services offered to the DTE are made available through a modem or a CSU/DSU.

WAN Physical Layer Several

physical layer standards specifying this interface between the DTE & DCE are... EIA/TIA-232 EIA/TIA-449 V.24 V.35 X.21 G.703 EIA-530

WAN Data-Link Layer WAN

data link protocols describe how frames are carried between systems on a single data link. They include protocols designed to operate over dedicated point-topoint, multipoint, and multi-access switched services. WAN standards are defined and managed by a number of

WAN Data-Link Encapsulations High-Level Cisco

Data Link Control (HDLC)

default encapsulation; typically used between routers running Cisco IOS; replacing SDLC Streamlined: no windowing or flow control may not be compatible with different vendors because of the way each vendor has chosen to implement it. HDLC supports both point-to-point and

WAN Data-Link Encapsulations Frame uses

Relay

high-quality digital facilities; uses simplified framing with no error correction mechanisms (connectionless!!); it can send Layer 2 information much more rapidly than other WAN protocols

WAN Data-Link Encapsulations PPP

(Point-to-Point Protocol)

Developed

by IETF; replacing SLIP Contains a field to identify the network layer protocol PPP can check for link quality during connection establishment Supports PAP (Password Authentication Protocol) & CHAP (Challenge Handshake Authentication Protocol)

WAN Technologies

Table of Contents

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

Dedicated Digital Services Dedicated Digital Services provide full-time connectivity point-to-point Tthrough series inaU.S. and E serieslink in Europe Uses

time division multiplexing to “slice up” data and•assign time slots Uses twisted pair for transmissions & fiber T1

= 1.544 Mbps •Extremely T3 = 44.736 Mbps popular E1 = 2.048 Mbps •Moderate cost

Dedicated Digital Services Digital

Subscriber Lines (xDSL); the x stands for a family of technologies New

WAN Technology for home use; decreasing bandwidth with increasing distance from the phone companies CO. Data rates as high as 51.84 Mbps but more common to be in the 100s of Kbps

Dedicated Digital Services Synchronous

Optical Network

(SONET) Specialized

high bandwidth technology for use at various Optical Carrier speeds (OC) ranging from 51.84 Mbps (OC-1) to 9,952 Mbps (OC192) Uses lasers to divide the wavelength of the light into sections that can carry large amounts of data (Wave Division

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

Analog Services Dial-up

Modems (switched

analog) Limited

to 56 kbps Works with existing phone network Low cost and widespread usage

Analog Services Cable Puts

Modems (Shared Analog)

data signals on the same cable as television signals Increasing in popularity Maximum bandwidth can be 10 Mbps, though this degrades as more users attach to a given network segment (behaving like an unswitched LAN) Cost is relatively low; usage is small but increasing; the medium is coaxial

Analog Services Wireless Terrestrial Bandwidths

typically in the 11 Mbps range Cost is relatively low Line-of-sight is usually required Usage is moderate

Satellite Can

serve mobile users and remote users Usage is widespread Cost is very high

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

Circuit Switched Services Plain

Old Telephone System (POTS) Not

a computer data service but...

POTS

is an important component of our communication infrastructure and It is still the standard for designing reliable networks

Circuit Switched Services Integrated

Services Digital Network (ISDN) Historically

important--first dial-up digital service Cost is moderate; max. bandwidth = 128 kbps for BRI (Basic Rate Interface) 2

B channels @ 64kps and 1 D channel @ B16kps DB channels are voice/data channels; D for  Bsignaling

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

Packet Switched Services X.25

(Connection-oriented)

Older

WAN technology developed in

1970s Reliable--X.25 has been extensively debugged and is now very stable-literally no errors in modern X.25 networks Store & Forward--Since X.25 stores the whole frame to error check it before forwarding it on to the destination, it has an inherent delay

Packet Switched Services Frame More

Relay (Connectionless)

efficient and much faster than

X.25 Packet switched version of ISDN (which is circuit switched); data rates up to 44.736Mbps with 56kbps and 384kbps being the most popular Used mostly to forward LAN IP and IPX packets but can be used to forward other types of traffic

WAN Technologies Overview Dedicated • T1, E1, T3, E3 • xDSL • SONET Circuit Switch ed • POTS • ISDN

Switche d

Packet Switch ed • X.25 • Frame Relay

Analog • Dial-up modems • Cable modems • Wireless Cell Switch ed • ATM • SMDS

Cell Switched Services Asynchronous

(ATM)

Transfer Mode

Relatively

new WAN Technology related to broadband ISDN; max. bandwidth = 622 Mbps Developed in order to provide one technology for both WANs and LANs to transport data, video, and voice. (High Cost) Key Benefits: One

network for all traffic--voice, data, video

Cell Switched Services Switched

Multimegabit Data Service (SMDS) Closely

related to ATM; SMDS is the MAN (Metropolitan Area Network) implementation of ATM High Cost with max. bandwidth 44.736 Mbps

WAN T ech nolog ies Review

Acronym Name Dedicated Digital Services T1, T3 T1, T3 xDSL Digital Subscriber Line Synchronous Optical SONET Network AnalogServices Dial-up Modem Modem

Max. Bandwidth

Comments

1.544 &44.736 Mbps Widelyused telecommunications 384 kbps Newtechnologyover phone lines 9,992 Mbps

Veryfastoptical fiber transmission

56 kbps

Mature technologyover phone lines

10 Mbps

Newtechnologyusing cable TV

Terrestrial Wireless Wireless

11 Mbps

Microwave and laser links

Satellite Wireless Wireless CircuitSwitchedServices Plain Old Telephone POTS Service Integrated Services ISDN Digital Network PacketSwitchedServices X.25 X.25 Frame Relay Frame Relay Cell SwitchedServices Asynchronous ATM Transfer Mode Switched Multimegabit SMDS Data Service

2 Mbps

Microwave and laser links

4 kHz Analog

The Standard for Reliability

128 kbps

Data and Voice Together

up to 44.736 Mbps

An Old Reliable, Workhorse A flexible newworkhorse; son ofISDN

622 Mbps

High powered Networks

Cable Modem

Cable Modem

1.544 &44.736 Mbps MAN variantofATM

Router Basics

Table of Contents

Internal Components

RAM Console Auxiliary

NVRAM Flash Interfaces

ROM

RAM Temporary

storage for router configuration files RAM content is lost on power down or restart Stores... Routing

tables ARP cache Fast switching cache Packet buffering

NVRAM Non-volatile

RAM Stores backup/startup configuration files Content is not lost when router is powered down or restarted.

Flash EEPROM

(Electronically Erasable Programmable Read-Only Memory) Holds the Cisco IOS (Internet Operating System) Allows updating of software without replacing the Flash chip Multiple versions of IOS can be stored Retained on power down

ROM Contains

POST (Power On Self Test) A bootstrap program (loads the Cisco IOS) And operating system software Backup,

trimmed down version of the

IOS Upgrades require installing new chip set

Interfaces Network

connections through which packets enter and exit the router Attached to the motherboard or as separate modules.

Labs Before

moving on to Ch. 3, make sure you have done both of the required labs for Ch. 2 Lab

2.2.2 Lab 2.2.3.2

Router User Interface

Table of Contents

User EXEC Modes User

mode

Limited

mode used for checking the routers status, looking at routing tables, etc. You cannot configure the router Once you’ve typed the password to enter user mode, you will see the > prompt. The word “Router” will be the name of the router. Means you’re in Password:

user mode

Privileged EXEC Modes Privileged

mode

Does

everything User mode does Full power to configure the router In user mode, you enter the command “enable” and then the privileged password Router> enable Password: Router#

Means you’re in privileged mode

Command Lists To

get a list of commands available in either user mode or privileged mode, enter a ? at the prompt.

Router> ? Router# ? Since

the available commands will be more than the screen can hold, you will get the --More-- message at the bottom. Hitting the space bar will advance

Getting Help on a Command The

? can be used with a partial command to learn all the available commands that match what you entered. To use this help feature, enter the partial command, Router# show ? then tap the space bar,ipthen type ? For flash: example... The Router returned all interfaces ipx version parser

the available commands for “show”

Error Indicator When

you’ve entered an error in the command string, a carat (^) symbol will indicate where the error occurred. For example...

Router# show runing-config ^ % Invalid input detected at the ‘^’ marker

Labs Before

taking the Ch. 2/3 test, make sure you have done both of the required labs for Ch. 3 Lab

3.2.1 Lab 3.2.2

End Slide Show

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