640-821: The CCNA in Two-Parts
Proving your expertise in internetworking doesn't have to be hard. Cisco's latest exam
combination will let you obtain your CCNA credential in two steps.
A new path to Cisco Systems' CCNA, 640-821 allows you to achieve certification in two
small steps instead of one giant leap. You can now choose which path to take in obtaining
your CCNA. You can pass a single exam, 640-801. Or you can tackle two tests: 640-811,
the new ICND (Interconnecting Cisco Networking Devices) exam and 640-821, INTRO.
The first of the two that Cisco suggests you tackle, and received 50 questions in 90
minutes with a passing score of 867. Even though this was the beta version of this exam,
a screen appeared prior to the test, which said, "This beta exam is in the late stages of
development and a score report will be provided." I received a traditional score report,
unlike any other beta I've ever taken.
I had three router simulators, many
multiple choice questions and a few drag-
#640-821: Introduction to
and-drop items on my exam. Having
Exam Cisco Technologies
taken the CCNA 407, 507, 607 and 801
(INTRO)
exams, I found this exam much easier. It
includes all my favorite topics; cable
Vendor Cisco
types, IOS commands, the OSI model and
subnetting.
Status Current
The exam engine is slow when it comes to
"This new exam will test
switching between the simulator-based
your knowledge of basic
questions and the standard multiple choice
Reviewer's router configuration, cable
questions. Patience is a must! For most
Rating types, IOS commands, the
simulator-based questions, you're OSI model and
subnetting."
presented with a router requirement and
required to configure one or more routers
55 to 65 questions, 60
and save and verify your work. The
Test
minute time limit. Cost:
Information
simulator behaves very much like the real
$100 (U.S.).
thing and includes limited support for
abbreviated, editing and help commands.
Who Should Candidates for CCNA;
Take This must take in conjuction
Exam? with 640-811 ICND exam.
The main topics from the objectives list
are: Design and Support, Implementation
and Operation and Technology. Exam
Test
topics include: Network Types, Network
Click here
Objectives
Media, Switching Fundamentals, TCP/IP,
IP Addressing and Routing, WAN
Technologies, Operating and Configuring
IOS Devices, and Managing Network Environments. In this article, I address many of
these topics under their main headings to help you prepare for this exam.
Design and Support
Under this general heading you'll find these topics: Use a subset of Cisco IOS commands
to analyze and report network problems; use embedded layer 3 through layer 7 protocols
to establish, test, suspend or disconnect connectivity to remote devices from the router
console; and determine IP addresses.
Knowing the basic Cisco Internetworking Operating System commands has traditionally
been up to one-third of the required knowledge for the aspiring CCNA. You should
become conversant with the commands listed in Table 1.
Table 1. Basic IOS commands used to establish, test, suspend or disconnect connectivity
to remote devices from the router console.
Show version
Display the IOS version and
configuration register value
Show ip
Display the IP address and subnet
interface
mask for an interface
Show running- Display the contents of RAM
config
Show startup- Display the contents of NVRAM
config
Resume
Connect to an existing telnet session
session
from the router's console
Exit
Leave a remote or local telnet or
console session
Ping ip
Test connectivity
address
Traceroute ip
Test path connectivity
address
Telnet ip
Create remote connection
address
Tip: When interpreting the output of the ping command, exclamation points (!!!!!)
represent echo replies and good connectivity.
Remember your OSI layer assignments for this exam. Ping and tracert are Network
layer (3) commands; telnet operates at the Application layer (7).
Implementation and Operation
Under this general heading you'll find these topics listed: establish communication
between a terminal device and the router IOS and use the IOS for system analysis;
manipulate system image and device configuration files; perform an initial configuration
on a router and save the resultant configuration file; use commands incorporated within
the IOS to analyze and report network problems; assign IP addresses; describe and install
the hardware and software required to be able to communicate via a network; and finally,
use embedded data link functionality to perform network neighbor discovery and analysis
from the router. Sounds like it's time for another table of commands!
To establish connectivity between a terminal device and the router's IOS, use an ASCII-
compliant terminal-emulation program such as HyperTerminal or Telnet.
Type the console or VTY line password for user access or enable and the enable
password for executive access.
See Table 2 below for IOS commands needed to manage connections, images and CDP.
Table 2. IOS commands for system analysis, manipulating system image and device
configuration files, performing an initial configuration on a router and saving the
resultant configuration file, use commands incorporated within IOS to analyze and report
network problems and assigning IP addresses.
Display a list of connected users or open
Show users or sessions
sessions to the router's IOS
Manipulate the system image (IOS) in flash
Copy TFTP Flash
memory
Allow changes to the configuration file stored
Config terminal
in RAM
Line VTY 0 4, password
Configures telnet password
password
Line console 0,
Configures console line password
password password
Copy running-config
Save those changes to NVRAM
startup-config
Interface interface
Assign IP address and mask to a router's
name address mask
interface
Display Cisco Discovery Protocol (a layer 2
Show CDP
protocol) running configuration.
Tip: The boot system flash command configures the router's IOS to look for the
IOS image in flash memory.
Technology
Under the final heading of Technology in the exam guide, you'll find a multitude of
topics. Let me address them by providing my list of "things to know."
First, binary, hex and decimal are all numbering systems you should be intimately
familiar with for this exam. Table 3 provides a conversion chart.
Table 3. Binary, hex and decimal conversions.
Binary Hex Decimal
0000 0 0
0001 1 1
0010 2 2
0011 3 3
0100 4 4
0101 5 5
0110 6 6
0111 7 7
1000 8 8
1001 9 9
1010 A 10
1011 B 11
1100 C 12
1101 D 13
1110 E 14
1111 F 15
Computer network LAN topologies consist of bus, star and ring. In a bus and star
network topology, data travels from end to end. In a ring topology, data travels in a ring.
WAN topologies cover greater geographic distances and all data travels in a bit-by-bit
serial fashion.
Tip: Data transmission flow control occurs with the help of buffering, windowing and
congestion avoidance.
In token ring networks, a token is passed around the network from device to device.
When a device has data to send, it must wait until it has the token before sending its data.
Tip: To connect a network device to any one of these network types, you need at a
minimum a compatible network interface card and a connecting cable and protocol.
Network media includes wireless, twisted-pair and optical. Wireless uses no physical
connectors. Twisted-pair is still the most common. UTP (Unshielded Twisted Pair)
includes eight wires in four twisted pairs. Optical media includes fiber, which offers the
greatest distance of the three types. Table 4, below, shows the most common of the
twisted-pair wiring configurations.
Table 4. Common wiring configurations.
Type Use Pin-Out
Straight- workstations connecting to 1-----1
thru hubs, switches, routers 2-----2
3-----3
4-----4
5-----5
6-----6
7-----7
8-----8
Crossover workstation to workstation or 1-----3
hub to hub and switch to switch 2-----6
3-----1
4-----4
5-----5
6-----2
7-----7
8-----8
Rolled workstation's serial port to router 1-----8
console port 2-----7
3-----6
4-----5
5-----4
6-----3
7-----2
8-----1
Tip: Routers are responsible for switching and
routing of data packets.
Additional Information
Loads of resources on the market will
help you prepare and practice for
passing the CCNA exams. One such
favorite resource of mine is free,
authoritative and recommended by
many others: Cisco.com.
Once at Cisco.com, you'll want to
spend time with the reference guides
and technology white papers available
in the documentation site or CCO
(Cisco Connection Online) found here.
For the first set of exam objectives, I
recommend the "Internetworking
Technology Handbook" chapters 1-7
found here. Honestly, how much easier
and cheaper can it get? This resource
will help you keep the costs of your
studies down (along with many other
recommendations in the "IT
Certification on the Cheap" guide sold
Cisco routers include the following hardware
here).
and software components: CPU (Central
Processing Unit), RAM (Random Access
When deciding which study guides will
Memory), ROM (Read Only Memory),
prepare you for the new CCNA 640-821
exam, keep in mind that the exam
NVRAM (Non-Volatile RAM), IOS, mini-IOS
objectives are only a subset of the
and configuration files. A router startup process
exam. If you've already started your
is like this:
studying using one of the many popular
607 study guides on the market, you
1. Bootstrap loads from ROM.
should be able to match the objectives
from this exam to chapters in your
2. Router finds IOS, usually from flash, and
book. For example, in Cisco Press'
loads it.
Cisco CCNA Exam #640-607
3. Router finds and loads configuration file,
Certification Guide (ISBN 1-58720-055-
usually from NVRAM.
4), you should study chapters 1-6 for
this exam and the remainder (7-13) for
the companion ICND 640-811 exam.
Ethernet uses CSMA/CD for error detection and
correction. It includes the following:
You should also pick up a router
simulator or real router to prepare for
" Carrier sense. Each station
the router simulator questions. Cisco
continuously listens for traffic on the
uses a router simulator in their exams
wire to determine when gaps between
developed by the Cisco Networking
Academy program. It also offers a
frames occur.
sample on its Web site. Many third-
" Multiple accesses. Stations may begin
party products on the market are
transmitting any time they detect that the
similar. You can view and even demo a
network is quiet.
copy of the official Cisco exam
" Collision detect. If two or more stations
simulator here.
begin transmitting at the same time, the
bits from the transmitting stations will
collide with each other and both
transmissions will be unreadable. If that
happens, each transmitting station must be capable of detecting that a collision
has occurred before it has finished sending its frame. Each must stop transmitting
as soon as it has detected the collision and then must wait a random length of time
(determined by a back-off algorithm) before attempting to retransmit the frame.
Tip: Routers divide networks into different broadcast domains for controlling
client and server network broadcast traffic. Switches and bridges create or divide
collision domains.
How could any network student understand networking without knowing the OSI model?
The OSI 7 layer reference model includes these layers, taking it from the top:
Application, Presentation, Session, Transport, Network, Data Link, and Physical. The
numbering starts from the bottom (physical layer is number 1). Knowing the layer names
and their order is crucial. Some people like to use an anagram to help. One of my
favorites (from the bottom up): Please Do Not Throw Sausage Pizza Away.
Knowing where the most common network devices operate in the OSI model is also a
must. At the physical layer there is the cabling of the network, repeaters and hubs. The
data link layer includes bridges and switches, and routers operate at the network layer.
Tip: A switch is really nothing more than a multi-port bridge.
Understanding protocol operation and at which layer each functions is an exam
requirement. This exam focuses only on TCP/IP. From the physical layer up, there are
protocols that define the physical connection and signaling on the wire such as V.35 and
RS-232. At the data link layer there are also protocols responsible for defining the
network topology and data communication standards such as ethernet, token-ring, and
FDDI.
At the network layer, there's IP, ICMP, ARP. At the transport layer, there's TCP and
UDP. UDP is fast and efficient but doesn't provide guaranteed delivery and
retransmission like TCP. TCP is more commonly used at this layer by many upper-layer
protocols and applications.
The Internet protocol suite includes many application-layer protocols that represent a
wide variety of applications, including the following:
" FTP (File Transfer Protocol) -- moves files between devices.
" SNMP (Simple Network-Management Protocol) -- reports network conditions
and sets network threshold values.
" Telnet -- serves as a terminal emulation protocol.
" SMTP (Simple Mail Transfer Protocol) -- provides electronic mail services.
" DNS (Domain Name System) -- translates the names of network nodes into
network addresses.
" TFTP (Trivial File Transfer Protocol) -- allows for transfer of router files to
and from a network workstation.
Table 5, below, lists the common application-layer protocols, their use of TCP or UDP
and port number assignments.
Table 5. Common application-layer protocols, TCP or UDP, and port numbers.
Protocol TCP or UDP Port Number
FTP TCP 20 and 21
SNMP UDP 161
SMTP TCP 25
DNS TCP and UDP 53
TFTP UDP 69
Cisco requires you to know how to plan, assign, configure, subnet and troubleshoot IP
addresses.
For this exam, you must have an understanding of the classes of IP addresses, their
starting and ending ranges, default subnet masks, the minus-2 rule, how to figure and
identify the first host, last host and broadcast address of any subnet, along with
calculating the mask for a required number of networks or hosts or both.
Tip: Here's a technique to help calculate the subnet: 256 minus the subnet mask. For
example; the address 192.168.0.22 255.255.255.240, is on the 192.168.0.16 subnet with
subnets of 16, 32, 48, and so on. The first assignable address is 17, and the broadcast is
31.