Semester 2 Chapter 1
WAN’s and Routers
Study Guide
Note to instructors: Please do not post these study guides on the Internet where anyone may access them. I choose to give my students
study guides without the answers so they can actually do the work themselves. However, there are so many schools that have study guides
with the answers posted for easy access my students do not have to look hard to get out of doing the work themselves. Please delete the
answers before posting the study guides for public access. Thank you!
WAN –
List 3 characteristics of WAN’s
WAN operates at what layers
1.1.1
Data communications network spanning a large
geographic area such as a state, province, or
country
1. Connect devices over wide geo area
2. Use service carriers (RBOC’s)
3. Use serial connections to access Bandwidth
1 (physical), 2(data link)
•
•
List and describe 4 WAN devices
WAN data link protocols describe –
Router – internetworking and WAN interfaces
Switches – connectivity for voice, data, and
video
• Modems – CSU/DSU’s interface T-1 and
TA/NT1’s interface ISDN
• Comm Srv – dial-in/out user communication
How frames are carried between systems on a single
data link
How is a router similar to a desktop
PC?
Has same basic components, CPU, memory, system
bus, input/output interfaces
How is a router different from a
desktop PC?
Provide connection BTW 2 networks and determines
best path for data through networks
What do configuration files contain?
Instructions & parameters that control traffic flow in
and out of routers
How do routers make decisions
regarding the best path for packets?
Using routing protocols the build routing tables to
choose the best path
•
1.1.2
•
•
List and describe the 5 main internal
components of the router.
•
•
1.1.3
RAM – stores routing tables, fast-switching
cache, running configuration file, looses
content when router powered down
NVRAM – storage for startup-config file,
retains content when router powered down
Flash – holds IOS/operating system, update
software w/out changing chips on the
processor
ROM – POST test, bootstrap program, basic
IOS image
Interfaces – connect router to network for
frame entry and exit, can be on motherboard
or a separate module
Routers operate at Layer _____.
3
Routers make decisions based on
________.
Network addresses, logical address
List 2 functions of the router:
Best path selection & switching the frames
How do routers accomplish
functions?
List 5 characteristics of an
internetwork:
1.1.4
Build routing tables and exchange info w/ other
routers
1.
2.
3.
4.
5.
consistent end-to-end addressing
addresses that represent network topologies
best path selection
dynamic or static routing
switching
At what layers of the OSI model
does a WAN operate?
L1 and L2
What does the WAN physical layer
describes?
Interface between DTE and DCE
Define DCE and give an example of
a DCE device.
Service provider – modem or CSU/DSU
Define DTE and give an example of
a DTE device.
Attached device/user’s side – router
What is the primary WAN role of a
router?
Provide connections to and between WAN L1 & L2
starndards
List some WAN layer 1 standards.
V.35, v.24, ISDN, T1, T3, E1, E3
List some WAN layer 2 standards.
HDLC, Frame Relay, PPP, X.25, LAPB, LAPD
Describe each component of the router and how to upgrade where applicable.
CPU –
RAM –
Flash –
NVRAM –
1.2.1
Buses –
ROM –
Interfaces (LAN, WAN, and
Console/AUX) –
Power Supply –
Executes instructions in OS
Running-config
Routing tables
Fast-switching cache
Upgraded by replacing/adding DIMM’s
Full IOS image
Upgraded by replacing/adding SIMM’s or PCMCIA
cards
Startup/backup-config
System bus – communication BTW CPU and
interfaces
CPU bus – communication BTW specified memory
addresses
ROM monitor
Basic IOS image
Upgraded by replacing chips in sockets
• LAN – fixed or modular, connects router to
network
• WAN – serial, ISDN, integrated CSU’s – fixed
or modular
• Console/AUX – initial config of router, not
networking ports, terminal sessions
Multiple or modular
1.2.3
1.2.4
What do LAN interfaces connect?
Router to LAN media
What does the WAN interface
connect?
Through service provider connects local site to
distant site or Internet
What are the management ports?
Console and AUX
What does the management port
provide?
Connection for configuration and troubleshooting
What kind of port is the
management port?
Asynchronous serial ports
The console and auxiliary ports are
designed as asynchronous serial
ports and not designed as what?
What type of configuration is
entered through the management
ports?
Why is the console port the
preferred port for troubleshooting?
What is needed for a connection to
the console interface?
1.2.5
1.2.6
What hyperterminal options are set
to allow a connection to the console
port?
How does a router communicate
with the LAN?
List 3 WAN connection types.
1.2.7
Networking ports
Initial configuration
Displays router startup, debugging and error mssg
by default, used when networking services not
available, used for disaster and password recovery
Rollover cable
RJ-45 to DB-9 adapter
Terminal emulation software
9600 baud
8 data bits
No parity
1 stop bit
no flow control
Via a hub or switch w/ straight-through cable
1. Leased line
2. Circuit-switched
3. Packet-switched
What does CPE stand for?
Customer Premises Equipment
What is an example of a DTE
device?
Router
What is an example of a DCE
device?
Modem or CSU/DSU
What does the DCE do?
Convert data from DTE to acceptable form for WAN
connection