TestKing 640-607 Cisco CCNA 3.0

TestKing 640-607 Cisco CCNA 3.0

(Parte 1 de 11)

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OSI Model4
Upper Layer5
Lower Layers5
Data Link Layer Tasks6
Network Layer Tasks7
Transport Layer Tasks8
LAN Physical Layer Implementations8
Command Modes10
Basis Switch Commands1
Switch Configuration using the Command Line1
Basic Router Information12
Common CLI Error Messages12
Basic Router Commands13
Advance Router Configuration14
CDP Related Commands16
Telnet Application17
Router Basics18
Router components18
Frame Decisions21
Avoiding Loops21
Spanning Tree Protocol2
Spanning Tree Path Cost23
Spanning Tree Protocol elections23
Spanning Tree States24
How Frame Are Sent24
Switch communication25
Catalyst 1900 Switch Configuration25
Configuration commands26
Virtual LANs27
TCP Connection Establishment29
TCP/IP Internet Layer29

IP Addressing Basics .................................................................................................... 30 w.testking.com -3-

Address Classes31
Configuring IP Addresses35
Route Selection36
Routing Protocols37
Administrative Distance37
Routing Protocol Classes37
Access List Types42
Access List Guidelines42
Standard IP Access List43
Extended IP Access Lists45
Verifying and Monitoring Access Lists46
Encapsulation Types48
WAN Connection Types50
WAN Layer 2 Encapsulation50
Subinterface Connection Types5
Obtain Frame Relay Information56
Lab 1 – Configure a name and passwords for a router57
Lab 2 – Configuring Router Interfaces59
Lab 3 – Configuring Static Routes61
Lab 4 – Configuring RIP and Restoring Configuration62
Lab 5 – Configuring IGRP63

NOVELL INTERNETWORK PACKET EXCHANGE (IPX) PROTOCOL SUITE Lab 6 – Access List....................................................................................................... 64 w.testking.com -4-

CCNA Foundations

OSI Model

One of the keys to understanding Cisco is the OSI model. The OSI model permits people to understand how internetwork works and it serves as a guideline or framework for creating and implementing network standards, devices, and internetworking schemes. Some of the advantages of the OSI model include:

• It allows for the breaking down of complex operation into simple elements;

• Enables engineers to specialize the design and development of modular elements; and

• It provides standards for plug and play and multivendor integration.

The OSI reference model has 7 layers:

To assist in remembering the OSI model layers in the proper area you might want to try either of the following sentences:

All Application People Presentation Seem Session To Transport Need Network Data Data Link Processing Physical

Appliction (Upper) Layers

Application Presentation Session Transport Layer Network Layer Data Link Layer

Presentation Layer

Data Flow Layers Media Access Control (MAC) Sublayer

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Or from the bottom of the OSI model to the top Please Do Not Throw Sausage Pizza Away.

Upper Layer

Upper Layers – The upper layers of the OSI model deal with user interface, data formatting, and application access. Specifically these layers do the following:

Application Layer – this is where the user/applications access the network. Presentation layer – determines how data is presented and special processing such as encryption. Session Layer – controls the establishment the establishing, managing and terminating communications sessions between presentation layers.

Lower Layers

The four lower layers are in charge of how data is transferred across a physical wire, through internetwork devices, to desired end station, and finally to the application on the other side. Specifically these layers do the following:

Transport – provides for both reliable and unreliable delivery and error correction before retransmit. Network – provides logical addressing which device us for path destinations Data Link – Combines bits into bytes and bytes into frames, provided access to media using MAC addresses, and error detection. Physical – responsible to move bits between devices and specifies voltage, wire speed and pin-out cables.


The method of passing data down the stack and adding headers and trailers is called encapsulation. For the each of the lower four layers the unit are as follows:

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Collision vs Broadcast Domains

Collision domain is a group of devices connected to the same physical media such that if two devices access the media at the same time, the result is a collision of the two signals.

Broadcast Domains is a group of devices in the network that receive one another’s broadcast messages.

Data Link Layer Tasks

The data link layer provides network traffic with information on where it is to go and what it is to do once it gets there. In order to provide this functions the IEEE data link layer is defined into two sublayers:

1. Media Access Control (MAC) Sublayer (802.3) – This sublayers is responsible for how the data is transported over the physical wire. This is the part of the data link layer that communicates downward to the physical layer.

The MAC address is a 48-bit address expressed as 12 hexadecimal digits. The first 24 bits or 6 hexadecimal digits of the MAC address contain a manufacturer identification or vendor code. This can also be called the Organizationally Unique Identifier (OUI). The last 24 bits or 6 hexadecimal are administered by each vendor and often represents the interface serial number.

2. Logical Link Control (LLC) Sublayer (802.2) – This sublayer is responsible for logically identifying different protocol types and then encapsulating them in the order to be transmitted across the network.

The data link layer has two types of devices: bridges and Layer 2 switches. Layer 2 switching is hardware-based bridging. When a bridge hears a frame on the network it must decide to filter, flood or copy the frame onto another segment.

This is decided as follows:

frameThat is, it is sent to all other segment other than the originating one.

1. If the destination in on the same segment it is filtered. That is, if the frame is from the same segment then it is blocked from going onto segments. 2. If the destination is on another segment it is forwarded to the proper segment. 3. If the destination is not known to the bridge then the bridge will flood the

Bridged/switched networks have the following characteristics: 1. Each segment is a collision domain.

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2. All devices connected to the same bridge/switch are part of the same broadcast domain. 3. All segments must use the same data link layer implementation: Ethernet and all Token Ring. 4. In switched environment, there can be one device per segment, and each device can send frames at the same time, thus allowing the primary pathway to be shared.

Network Layer Tasks

The network layer defines how to transport traffic between devices that are not locally attached in the same broadcast domain. In order for this to occur the following is required:

1. A logical address associated with the source and destination stations. 2. A path through the network to reach the desired destination.

The logical network address consists of two parts: one part to identify the network and the other to uniquely identify the host.

Routers work at the network level. The router performs the following tasks:

• Routers identify networks and provide connectivity. • Router do not forward Layer 2 broadcast or multicast frames.

• Routers attempt to determine the optimal path through a routed network based on routing algorithms.

• Routers strip Layer 2 frames and forward packets based on Layer 3 destination address.

(Parte 1 de 11)