CCNA Complete Guide 2nd Edition - Amazon Web Services

334 Pages·2010·6.46 MB·English

CCNA Complete Guide
2nd Edition

Yap Chin Hoong
CCNA Complete Guide 2nd Edition covers the syllabus of the latest CCNA 640-802 Exam.
Written with the mindset to become the best CCNA self-study guide ever, it contains all the
theory and practical knowledge that an accomplished CCNA must obtain to ace both the
CCNA exam and the challenging real-life working environments.

If you have just begun your CCNA journey, CCNA Complete Guide 2nd Edition will save you
hours of research and trial-and-error learning. If you are well into your CCNA preparation,
CCNA Complete Guide 2nd Edition will provide you with an excellent baseline on how well
you are progressing, and fill all the gaps in your knowledge holes.

CCNA Complete Guide 2nd Edition includes all the lab setups built using the Dynamips,
the Cisco router emulation software. Practical knowledge is vital for a CCNA candidate and
you can horn this invaluable skill by launching the pseudo-real-devices in seconds and
proceed to the lab guides.

How to be sure whether something works as it claimed to be? Prove it!
The companion CD-ROM includes all the detailed outputs of the important configuration and
debug commands, as well as packet dump captures that verify all the concepts and facts
presented in the main text. This ensures the information provided in the main text is as
precise as possible!

Last but not least, obtaining and reading the CCNA Complete Study Guide 2nd Edition is the
best investment you will ever make to become an accomplished network engineer!
CCNA Complete Guide
2nd Edition
Copyright © 2008 Yap Chin Hoong
[email protected]

Chapter Title Page
Chapter 1 Introduction to Computer Networking (Lecture) 1
Chapter 2 Transport and Network Layers (Lecture) 7
Chapter 3 Data Link and Physical Layers featuring The Ethernet (Lecture) 17
Chapter 4 Introduction to Cisco IOS (Lab) 31
Chapter 5 Spanning Tree Protocol (Lecture) 39
Chapter 6 Spanning Tree Protocol Lab (Lab) 45
Chapter 7 Virtual LAN and VLAN Trunking Protocol (Lecture) 51
Chapter 8 Virtual LAN and VLAN Trunking Protocol Lab (Lab) 57
Chapter 9 IP Addressing and Subnetting (Lecture) 61
Chapter 10 Managing a Cisco Internetwork (Lab) 67
Chapter 11 Distance-Vector Routing Protocols – RIP and IGRP (Lecture) 75
Chapter 12 Static Routing, Default Routing, RIP, and IGRP Lab (Lab) 81
Chapter 13 OSPF and EIGRP (Lecture) 91
Chapter 14 OSPF and EIGRP Lab (Lab) 99
Chapter 15 Variable-Length Subnet Masks and Route Summarization (Lecture + Lab) 111
Chapter 16 Classful and Classless Routing, and MISC TCP/IP Topics (Lecture + Lab) 117
Chapter 17 Scaling the Internet with CIDR and NAT (Lecture) 123
Chapter 18 Network Address Translation Lab (Lab) 131
Chapter 19 IP Access Control Lists (Lecture) 135
Chapter 20 IP Access Control Lists Lab (Lab) 139
Chapter 21 WAN Basics, Remote Access Technologies, and Serial PPP (Lecture) 143
Chapter 22 Serial PPP Connections Lab (Lab) 153
Chapter 23 Frame Relay (Lecture) 157
Chapter 24 Frame Relay Lab (Lab) 165
Chapter 25 Wireless Networking (Lecture + Lab) 173
Bonus Chapters
Chapter 26 ISDN 187
Chapter 27 ISDN and Dial-on-Demand Routing Lab 193
Chapter 28 Route Redistribution 203
Appendix 1 Cisco IOS Upgrade and Password Recovery Procedures 207
Appendix 2 Frame Relay Switch Configuration 219
Appendix 3 The IP Routing Process 225
Appendix 4 Dissecting the Windows Routing Table 229
Appendix 5 Decimal-Hex-Binary Conversion Chart 231
Appendix 6 CCNA Extra Knowledge 235

Download the companion CD-ROM at http://tinyurl.com/CCNA-CD02.

About the Author
Yap Chin Hoong is a senior engineer with the Managed Services team for Datacraft Advanced Network
Services, Malaysia. He found great satisfaction when conveyed complex networking concepts to his peers.
Yap holds a bachelor’s degree in Information Technology from Universiti Tenaga Nasional.

When not sitting in front of computers, Yap enjoying playing various types of musical instruments.
Visit his YouTube channel during your study breaks.

Facebook: http://tinyurl.com/yapch-facebook
Website: http://itcertguides.blogspot.com/
YouTube: http://www.youtube.com/user/yapchinhoong
Chapter 1
Introduction to Computer Networking

- Welcome to the exciting world of computer networking and Cisco certification!

- There are 3 levels of Cisco certification:
Associate level
CCNA Cisco Certified Network Associate
CCDA Cisco Certified Design Associate
Professional level
CCNP Cisco Certified Network Professional
CCDP Cisco Certified Design Professional
CCSP Cisco Certified Security Professional
CCIP Cisco Certified Internetwork Professional
CCVP Cisco Certified Voice Professional
Expert level
CCIE Cisco Certified Internetwork Expert
- Routing and Switching
- Security
- Service Provider
- Voice
- Storage Networking
- Wireless

- Below are the available paths to become a CCNA:
1 One exam: CCNA (640-802), 50-60 questions, 90 minutes, USD$250.

2 Two exams: ICND1 (640-822), 50-60 questions, 90 minutes, USD$125.
.ICND2 (640-816), 45-55 questions, 75 minute, USD$125.

Router Switch
Ethernet
WAN Cloud Serial
Figure 1-1: Icons and Symbols

- The 2 most common Internetworking Models are OSI Reference Model and TCP/IP Model.
Note: OSI – Open Systems Interconnection.

- Below are the benefits of layered architecture:
i) Reduces complexity and accelerates evolution. A vendor may concentrate its research
and development works on a single layer without worrying the details of other layers,
because changes made in one layer will not affect other layers.
ii) Ensures interoperability among multiple vendors’ products, as vendors develop and
manufacture their products based on open standards.

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Application
Process /
Upper Layers Presentation Application
Application
Session
Transport Transport Host-to-Host
Network Network Internet
Lower Layers
Data Link Data Link Network
Physical Physical Access
OSI Reference Model TCP/IP Model DoD Model
Figure 1-2: OSI Reference Model, TCP/IP Model, and DoD (Department of Defense) Model

- The upper 3 layers define the communication between applications running at different end
systems and the communication between an application and its users.
The lower 4 layers define how data is transmitted between end systems.

- Below describes the roles and functions of every layer in the OSI reference model:
Application Acts as the interface between applications and the presentation layer.
Applications such as web browsers are not reside in this layer. In fact they use
this interface for communication with remote applications at the other end.
Ex. Protocols: HTTP, FTP, SMTP, Telnet, SNMP.

Presentation Defines data formats, presents data, and handles compression and encryption.
As an example, the FTP ASCII and binary transfer modes define how FTP
transfer data between 2 end systems. The receiving end will reassemble data
according to the format used and pass them back to the application layer.
Ex. Formats: ASCII, EBCDIC, JPEG, GIF, TIFF, MPEG, WAV, MIDI.

Session Defines how to setup / establish, control / manage, and end / terminate the
presentation layer sessions between 2 end systems. Uses port numbers to keep
different application data separated from each other.
Ex: SQL, NFS, RPC, X Window, NetBIOS, Winsock, BSD socket.

Transport Provides reliable (TCP) and unreliable (UDP) application data delivery
services, as well as segmentation and reassembly of applications data.
Important concepts are connection-oriented, connectionless, error recovery,
acknowledgment, flow control, and windowing.
Ex. Protocols: TCP, UDP, SPX (Sequenced Packet Exchange).

Network Defines end-to-end packet delivery and tracking of end system locations
with logical addressing – IP addresses. Determines the best path to transfer
data within an internetwork through the routes learning via routing protocols.
Allows communication between end systems from different networks.
There are 2 types of packets – data packets and routing update packets.
Ex. Protocols: IP, IPX, AppleTalk.

Data Link Defines how to transmit data over a network media (how to place network layer
packets onto the network media – cable or wireless) with physical addressing.
Allows communication between end systems within the same network.
Ex. Protocols: LAN – Ethernet, WAN – HDLC, PPP, Frame Relay, ATM.

Physical Defines specifications for communication between end systems and the physical
media (how to place data link layer frames onto the media).
Defines connector shapes, number of pins, pin usages or assignments, electrical
current levels, and signal encoding schemes. Ex: Ethernet, RS-232, V.35.

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- Below lists some comparison points between common network devices:
Routers They are Network layer (L3) devices.
Their main concern is locating specific networks – Where is it? Which is the
shortest path or best way to reach there?
They create separate broadcast domains.

Switches and They are Data Link layer (L2) devices.
Bridges Their main role is locating specific hosts within the same network.
Devices connected to a switch do not receive data that is meant only for
devices connected to other ports.
They create separate collision domains for devices connected to them
(segmentation) but the devices are still reside in the same broadcast domain.
Note: VLAN technology found in enterprise-class switches are able to create
separate broadcast domains (multiple networks).

Hubs They are Physical layer (L1) devices.
Hubs are not smart devices. They send all the bits received from one port to all
other ports; hence all devices connected via a hub receive everything the other
devices send. This is like being in a room with many people – everyone hear if
someone speaks. If there is more than one person speaks at a time, there is only
noise. Repeaters also fall under the category of L1 devices. All devices
connected to a hub reside in the same collision and broadcast domains.

Note: A collision domain is an area of an Ethernet network where collisions can occur. If an end
system can prevent another from using the network when it is using the network, these systems
are considered reside in the same collision domain.

- Data encapsulation is the process of wrapping data from upper layer with a particular layer’s
header (and trailer), which creates PDU for that particular layer (for adjacent-layer interaction).

- A Protocol Data Unit (PDU) consists of the layer n control information and layer n+1
encapsulated data for each layer (for same-layer interaction). Ex: L7PDU, L6PDU, … L2PDU.
Application Da t a D a t a
Transport TCP Data Segment
Network IP Data Packet or Datagram
Data Link LH Data LT Frame
Physical 10101010101010 Bits
LH – Link Header
LT – Link Trailer
.
Figure 1-3: Data Encapsulation

- Below list the 2 types of interactions between layers:
Same-layer interaction Each layer uses its own header (and trailer) to communicate
between the same layer on different computers.

Adjacent-layer interaction A particular layer provides services to its upper layer while
requests its next lower layer to perform other functions. Take
place on the same computer.

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Cisco Hierarchical Model

- Defined by Cisco to simplify the design, implementation, and maintenance of responsive,
scalable, reliable, and cost-effective networks.

- The 3 layers are logical and not physical – there may be many devices in a single layer,
or a single device may perform the functions of 2 layers, eg: core and distribution.
Core layer
(Backbone)
Distribution layer
(Routing)
Access layer
(Switching)
Figure 1-4: The Cisco Hierarchical Model

- Below are the 3 layers in the Cisco Hierarchical Model:
Core layer Also referred to as the backbone layer. It is responsible for transferring large
amounts of traffic reliably and quickly – switches traffic as fast as possible. A
failure in the core can affect many users; hence fault tolerance is the main
concern in this layer. The core layer should be designed for high reliability,
high availability, high speed, and low convergence. Do not support
workgroup access, implement access lists, VLAN routing, and packet filtering
which can introduce latency to this layer.

Distribution Also referred to as the workgroup layer. Its primary functions are routing,
layer Inter-VLAN routing, defining or segmenting broadcast and multicast domains,
network security and filtering with firewalls and access lists, WAN access,
and determining (or filtering) how packets access across the core layer.

Access layer Also referred to as the desktop layer. Here is where end systems gain access to
the network. The access layer (switches) handles traffic for local services
(within a network) whereas the distribution layer (routers) handles traffic for
remote services. It mainly creates separate collision domains. It also defines the
access control policies for accessing the access and distribution layers.

- In a hierarchical network, traffic on a lower layer is only allowed to be forwarded to the upper
layer after it meets some clearly defined criteria. Filtering rules and operations restrict
unnecessary traffic from traversing the entire network, which results in a more responsive (lower
network congestion), scalable (easy to grow), and reliable (higher availability) network.

- A clear understanding of the traffic flow patterns of an organization helps to ensure the
placement of network devices and end systems within the organization.

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Application Layer

- Telnet is a TCP-based text-based terminal emulation application that allows a user to remote
access a machine through a Telnet session using a Telnet client which login into a Telnet server.
A user may execute applications and issue commands on the server via Telnet.

- HyperText Transfer Protocol (HTTP) is a TCP-based application protocol that is widely used
on the World Wide Web to publish and retrieve HTML (HyperText Markup Language) pages.

- File Transfer Protocol (FTP) is a TCP-based application protocol that allows users to perform
listing of files and directories, as well as transferring files between hosts. It cannot be used to
execute remote applications as with Telnet. FTP server authentication is normally implemented
by system administrators to restrict user access. Anonymous FTP is a common facility offered by
many FTP servers, where users do not require an account on the server.

- Trivial File Transfer Protocol (TFTP) is the stripped-down version of FTP (UDP-based).
It does not support directory browsing, and mainly used to send and receive files. It sends much
smaller block of data compared to FTP, and does not support authentication as in FTP (insecure).

- Network File System (NFS) is a UDP-based network file sharing protocol. It allows
interoperability between 2 different types of file systems or platforms, eg: UNIX and Windows.

- Simple Mail Transfer Protocol (SMTP) is a TCP-based protocol that provides email delivery
services. SMTP is used to send mails between SMTP mail servers; while Post Office Protocol 3
(POP3) is used to retrieve mails in the SMTP mail servers.

- X Window is a popular UNIX display protocol which has been designed for client-server
operations. It allows an X-based GUI application called an X client which running on one
computer to display its graphical screen output on an X server running on another computer.

- Simple Network Management Protocol (SNMP) is the de facto protocol used for network
management – fault, performance, security, configuration, and account management. It gathers
data by polling SNMP devices from a management station at defined intervals. SNMP agents can
also be configured to send SNMP Traps to the management station upon errors.

- Domain Name System (DNS) makes our life easier by providing name resolution services –
resolving hostnames into IP addresses. It is used to resolve Fully Qualified Domain Names
(FQDNs) into IP addresses. In DNS zone files, a FQDN is specified with a trailing dot, eg:
server.test.com., specifies an absolute domain name ends with an empty top level domain label.

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Chapter 2
Transport and Network Layers

Transport Layer

- Transport layer protocols provide reliable and unreliable application data delivery services.
The Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are the most
common transport layer protocols. There are many differences between them.
SYN, SEQ = 0
1 SPORT = 1024, DPORT = 80
SYN, ACK, SEQ = 0, ACK = 1
2 SPORT = 80, DPORT = 1024
ACK, SEQ = 1, ACK = 1
Web 3 SPORT = 1024, DPORT = 80 Web
Browser Server
Connection established.
Data transfer allowed.
4
Notes:
Source port numbers are greater than 1023 and dynamically
allocated by the operating system on the client side.
Figure 2-1: Connection-Oriented Session Establishment

- Connection-oriented communication is used in reliable transport service – TCP. Figure 2-1
shows the TCP connection establishment sequence (also known as three-way handshake) which
allows the systems to exchange information such as initial sequence number, window size, and
other TCP parameters for reliable data transfer between a web browser (client) and a web server.
These steps must be completed prior to data transmission in connection-oriented communication.

- The SYN and ACK flags are very important for the connection-oriented session establishment.
When SYN bit is set, it means synchronize the sequence numbers (during connection setup),
while ACK bit is used to indicate that the value in the acknowledgment field is valid. In step 2,
the ACK replied by the web server acknowledges the receipt of the web browser’s SYN message.

- Figure 2-2 shows the TCP connection termination sequence to gracefully shutdown a connection.
An additional flag – FIN flag, is being used in the four-way connection termination sequence.
Firstly, the web server sends a segment with the FIN bit set to 1 when the server application
decided to gracefully close the connection after finished sending data (Step 1). The client would
then reply with an ACK reply, which means it notices the connection termination request (Step 2).
After that, the server will still wait for FIN segment from the client (Step 3). Finally, the server
acknowledges the client’s FIN segment (Step 4).
1 FIN, ACK Server closing
2 ACK
3 Client closing FIN, ACK
Web Web
Browser 4 ACK Server
Figure 2-2: TCP Connection Termination

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