CSIS261-8
WAN DATA LInk
Encapsulation
-High level
dalat link control(HDLC)
--Cisco default
encapsilation typically used between routers running cisco IOS;replaced SDLC
--Streamlinde:no
windowin or flow control.
--may not be
compatible with differnt vendors becaseu of the way each vendor has chosen to
implement it.
--HDLC Support
both point-to-point and multipoint configuration with minimal overhead
-Frame Relay
--Uses high
quality digital facilities;
--Uses
simplified frame with no error correction mechanisms (!!!CONNECTIONLESS!!!!)
--It can send
Layer 2 imformation much more rapidly than other WAN protocols
-PPP(Point to
Point Protocol
--Develope by
IETF;replaced SLIP
--Contains a
field to identify the network lyaer protocl
--PPP can check
for link quality during connection establishment
--Supports
PAP(Pasword Authentication Protocols)and CHAP(Challengae Handshake
Authentication Protocol)
WAN
TECHNOLOGIES
Dedicated
-T1,E1,T3,E3
-xDSL
-SONET
Analog
SWITHCED
Circuit Switched
-POTS
-ISDN
DEDICATTED
DIcatial SErvices PRovice FUll Time connectivity throught a point to point
link.
-T sericse in
US. And E series in Europe
-- USee time
divison multiplexing to 'slice up' data and assign time slots for transmission
---T1=1.544
Mbps
---T3=44.736
Mbps
---E1(T1)=2.048
Mbs
---E3(T3)=34.368Mbs
^These types
use twisted pair & Fiber. Extremely popluar. Moderate coast.
-DSL/Digital
Subsciber lines; the xstands for a
fiamily of technologies.
--NEw WAN
TEchnology frohome uses; decreasein bandwithc with increasing distance from the
phone cmpanies co.
--Data raste
hias as 51.84 Mbs bur more comm to be in the 100s of Kbps
--Cariteies
include HSDSL, SDSL, ADSL. VDSL
--Moderate
expense and getting cheaper.
-Synchonouse
Optical Network(SONET)
--Speciallized
high bandwithc technology for use at various optical carrier speeds(OC) range
form 51.84Mbs (OC-1) to 9,952 Mbps(OC-192)
--USES Lasers
to divide the wavelenght of th light into sections that can carry large amounts
of data(Wave Division Multiplexing)
--Very
expensive; used by lager ISPs and orthe Internet Backbone entities.
ANALOG SERVICES
-Dial-UP
Modemes (Swtiched analog)
--Limited to
56kbs
--Works with
existing phone network
--Low Cost and
widespread usage
-Cable Modems
(shared Analog)
--Puts data
signal on the same cabel as televicso siganlas
--Increaseing
in popularity
--Maximum
Bandwidth can be 10 mbs, though this degrades as more useres attach to a given
netowk segment (behaveing like an unswitched LAN)
--Coast is
relatively low; usage is small but increasing; the medium is RG-6 coaxial cable
WIRELESS
--Terrestraial
---Bandwiths
Typically in the 11Mbs range-Anntannas=Unidirectional Dipol
---Cost
relatively low
---Line Of site
is useually required
---Usage is
moderate
--Satellite
---Can serve
mobile users and remote useres
---Usage is
widespread
---Cost is high
SWITCHED
-POTS Plain old
telephone systems
--Not a
computer data service but
---Pots is an
important componieent of our communication sinfrastructure and
---It is still
the standeard for reliable networks
-ISDN
Integraded SErvices Digital Network
--Historically
inmportanta--- first dial up digital service
--Cost is
moderate; max bandwidth = 128kbs for BRI(Basic Rate INterface)PRI Primary rate
INterface
---2B channesl
@ 64kps and 1 D channeld @ 16kps
---B channeds
are voice/dat channels ' dis is for signalling
PACKET SWITCHED
-X.25(Connection
Oriented)
--Older WAN
technology developed in the 1970
--Reliable--X.25
has been extensively debugged and is now very stable--literally no errowr in
modern X.25 networks
--Store &
Forward -- Since X.25 stores teh whole frame to error check it before
forwarding it on to the destination , it has an inherent delay (unlike Frame
Relay) and requires large, expensive memory buffering capabilities.
-FRAME
RELAY(Connectionless)
--More
Efficient and much fater than X.25
--Packet
wsitchend version of ISDN (Which is circuit switched); Data rates up to
44/736Mbs with 56kbps and 384kbps being the most popular
--Used mostly
to forward LANIP and IPX packets but can be used ot forward other types of
traffic
--Primay
comnpetitive advancetages is xDSL
CELL SWITCHED
SERVISE
-Asynchonous
Transfer Mode(ATM)
--Relatively
new WAN TEchonology related to broadband ISDN;MAX. Bandwitdth = 622Mbps
--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--coice, data, video
---Compartible
with current wiring infrastucture(cable palnt)
---Very
flexibel and scalable
---Simplifies
network management
-Switched
Multimegabit Data Service(SMDS)
--Closely
related to ATM; SMDSis the MAN (Metropolitan Area Network) implementation of
ATM
--High Cousta
with masx bandwitds 1.544Mbps to 44.736Mbps
ROUTER BASICS
Internal
componentes
-Ram,NVRAM,flash,ROM,COnsole,Auxiliary,Interfaces
RAM
-Temporary
Storage for touter confiuraton files
-RAM content is
lost on power down or resta
CSIS261-9
RAM
-Temporary
Storage for touter confiuraton files
-RAM content is
lost on power down or restart
-Sortes
--Routing
Tables
--ARP(Address
Resolution Protocol) Cach(MAC Address TAble)
--Fast
switching cahce
--Packet
bufferins
--And PAckjet
hold queues
NVRAM
-Non-Volatial
RAM
-Stores
Backup/Stasrtup Configuratoin Files
-COntaent is
not lost when router is powerd down or restarted
FLASH
-EEPROM(Electronically
Erasable Programmable Read-only Memeory)
-Holds THE
Cisco IOS(Internet Operateing System)
-Allows
updateing of osftare without replaceing the flash chip.
-Multiple
version of IOS can be stored
-Retained on
power down
ROM
-Contains
POST(Power on SElf Test)
-A Bootstrap
program(loads the Cisco IOS)
-And operatein
system sofware
--Backup,trimmed
down version of the IOS
--Upgerades
required installing new chip set
INTERFACES
-Network connection
sthrough which packets enter an exit the router
-Attached to
the mother board or as separte modules.
ROUTER USER
INTERFACE
User EXEC Modes
-User Mode
--Limited mode
used for checkin the routers status lookin at routing tables.
--You CANNOT
confiure the router.
--Onece you've
typoed teh password to enter user mode tyou will see the > prompt. Ther
word'Router' will be the name of the router.
Exp.
Passowrd:
Router> <---Means you're in user mode.
Privileged EXEC
Modes
-Priviled Mode
--Does everthing
user mode does
--Full power to
configure the router
--IN user mode,
you endter the command 'enable' the pthe privileged password
Exp.
Router>
enable
Password:
Router# <-----Means Your in Privileged Mode
COMMAND LIST
-To get the
list of cmmands available in eitehr user mode or pivileded mode, enter a ? at
the prompt.
Exp.
Router>
? <---All the commands availble
in User Mode
Router# ? <---All the commands available in
Privilage Mode
-Since the
avaiable command will be more than the screen caon hold, you will get th
--More-- maessage at the bottom.
-Hitting the
SPACE BAR will adavance the screen to show the next page. ENTER key will show
one line at a time.
GETTING HELP ON
A COMMAND
- the ? can be
used with a partial cmmand to learn all the available commands tahat match what
you entered.
-To tuse this
help feature, Enter the Partial Command Than tap the SPACE BAR, than type ?
-For
example....
Router# show ?
ip
flash:
interfaces <----Router Returned All the
available commands for 'Show'
ipx
version
parser
ERROR INDICATOR
-When you've
entered an error in the command string, a carat (^) symbol will indicate where
teh error occurred.
-For Exp.
Router# Show
runing-config
%Invalid input
detected at the '^' marker
Predicted
Encoding - looks at previous frame, current frame to determine if they have the
same pixels exist.
Bi-directional
Interpolations looks previous frame,
current frame, and next frame to determine if they have the same pixels exist.
Streaming
Playing an MPEG video file received over a network before the file is fully downloaded.
Unicast three separate transmission to reach
three transmissions to reach three speartea workstations
Broadcast- One broadcast to all workstation
regardless of who wants to receive it.
Multicasting One transmission to the receiving
groups only.
RSVP-Make sure
the workstations are ready before they send the transmission. 6mbs
To improve a
network for multimedia is to change HUBS into Switches!!!