CCNA in Short

8/12/2019 CCNA in Short

1/51

CCNA(640-607)

2003 Certificationsuccess.com

Your Free Certification Portal

CCNACisco Certified Network Associate

Study Guide for the

640-607 Exam

2003

Certificationsuccess.com


2/51

CCNA(640-607)



Please read carefully

. This study guide has been created to cover the MAIN objectives of CCNA exam(640-607).

. The topics of this study guide have been compiled to help readers to clarify &illustrate the majority objectives of CCNA (640-607) exam based on Cisco 's officialweb site (not in the same order):

http://www.cisco.com/warp/public/10/wwtraining/certprog/testing/current_exams/640-607.html

. You MUST have at least a modest background in networking basics knowledge.

. The CCNA ( 640-607 ) study guide is designed to be a succinct, an exam reviewguide that has to be used in conjunction with the links revealed on it.

. Don't just rely on what is written without pointing your web browser at thementioned links that are stated on this study guide. In other words, when you see

(Point your browser at the following link :); that means pointing your browser is aMUST.

. Further Informationlinks have been compiled to provide you excessive, deep, &comprehensive details on particular topics (sometimes beyond the scope of CCNA

exam objectives).However, you are not obliged to point your browser at such a link; unless you areinterested.


3/51

CCNA(640-607)



Table of Content

Please read carefully1

Definitions4OSI model...4Cisco IOS...4

Windowing..4Acknowledgement...4Flow Control...5

Connection-Oriented transport.....5Connectionless transport..5Half duplex communication..5Full duplex communication...5LLC...5

MAC address.....................................................................................................5-6

Unicast address...6Multicast address....6Broadcast address..6Broadband..6

Baseband6Collision..6

Collision domain...6Broadcast domain7

Frame..7

Packet..7Data Encapsulation7

CSMA/CD8LAN..8WAN.8

Hub...9Repeater....................................................................................................................9Bridge........................................................................................................................9Brouter...9Handshake....9

Three-way handshake....9DCE.9

DTE..9CSU10

DSU10T1..10IEEE 802 series...10

PAP.....10CHAP..10Port.10

OSI reference model & layered communication..11Why using layered network model? ...........................................................................11OSI layers functions11-12


4/51

CCNA(640-607)



TCP/IP.13DoD model..13

FTP..14

HTTP14

SMTP14DNS..14

DHCP..14-15SNMP...15Telnet.15TCP.15-16

UDP..16

IP..16ICMP16

ARP...16How information is packaged?.................................................................................17Cisco model layers.17-18

IP addressing & Subnetting......19-22Ethernet networking........23

What is Ethernet?........................................................................................................23

Ethernet connection media (802.3 standards).23-24Ethernet types....25

Ethernet cables types..25Half-and-Full duplex Ethernet.26

Icons used for networking devices27

Icons used for networks & network connections...27

Bridging/Switching28What is a switch?.....................................................................................................28Switches vs. Bridges...28

Switch function..28-29

Switch vs. hub29STP...30Switching modes..30-31

Cisco Catalyst switch series31VLAN..32-33

Link types..33ISL34

VTP...34

Router..35-40WAN protocols...41-44

Cisco router & switch configurations.46-48Useful Links.49


5/51

CCNA(640-607)



:Def initions

Note: you MUST understand all the definitions that are stated below.

-------------------------------------

OSI model: Open System Interconnection- a system for organizing the exchange ofdata across networks that is based on a seven layers model:7. Application layer.6. Presentation layer.

5. Session layer.4. Transport layer.

3. Network layer.2. Data Link layer.

1. Physical layer.

Cisco IOS: Cisco Internetwork Operating System which runs Cisco routers & someCisco switches but doesn't allow devices configurations.

Windowing: Windowing is when a receiving host tells the sending host how manydata segments it can receive between Acknowledgements. This amount of data iscalled a window . Windowing can adjust its size of data depending on Networkresources. That means it's a maximum amount of data (in bytes) that the sending host

allows to send without expecting an acknowledgement from a receiving host (seeFig.1).

Acknowledgement: (Cisco states that) notification sent from one network device toanother to acknowledge that some event occurred (for example, the receipt of amessage ). Sometimes abbreviatedACK.


6/51

CCNA(640-607)



Flow Control: when a host receives a flood of data too quickly for it to process, itstores it in a memory section called a buffer. This buffering action solves the problemonly if the data bursts are small & don't last long. However, if the data burst continues

it will eventually exhaust the memory of the receiving host & that will result in the

arriving data being discarded or lost. Flow control prevents a sending host fromoverflowing the buffers in the receiving host.

Connection-Oriented transport: it uses acknowledgements & responses toestablish connections between sending & receiving hosts. When a receiving host

successfully receives a packet sent by the sending host, the receiving host sends anacknowledgement back to the original sender to indicate to the sender that the packet

was successfully received at the receiving host. TCP & SPX are examples ofconnection-oriented protocols.

Connectionless transport: Communication type that doesn't maintain active linksbetween senders & receivers. Messages are transmitted without acknowledgement

about the receiver being online.For example, when you send an e-mail, your sending host assumes that the messagehas been delivered to the receiving host without getting an acknowledgement from the

receiving host. IP, IPX, & UDP are examples of connectionless protocols.

Half Duplex Communication: It allows only a single node to transmit at a time.There's always a dedicated sender & receiver, & when the sender is done the receivercan switch roles in order to transmit. Both entities can't transmit at the same time.

Data travels in only one direction at a time, & it uses the same transmissionfrequency.

Full Duplex Communication: it is more like a telephone conversation.Communication happens in both directions at the same time. With type of networking,a host can send data in one direction while acknowledgement of previously sent data

may be return to the same host at the same time. For example, when you are using atelephone, it's possible for you to speak to a caller while he's talking to you.

LLC: Logical Link Control- it's responsible for identifying the Network layerprotocols & encapsulating them. The logic used on the Data Link layer includes

where data is meant to go, which computer sent data, & checking the overall validityof the bytes sent. After a data frame was sent, the data link sends a frame & then waits

for a positiveACK. If one is not received, or if the frame was damaged, it sendsanother one.

LLC provides a jumping point for going directly to upper levels in the OSI model. Butthe common method of packet communication is still to move up through the layersone at a time.

MAC Address: Media Access Control- every network interface card has an address,which's usually assigned at the factory. This address is protocol-independent & isoften called the hardware address. The MAC address exists at the MAC sub-layer ofthe OSI model.


7/51

CCNA(640-607)



The MAC address is used on the Data Link layer where it identifies network devices& computers. The MAC address itself is a 12 digit hexadecimal number burnedintothe network card. 00-A0-24-34-8D-9C is an example of MAC address.

Unicast Address: One of the MAC addresses types that is unique to a single host.When one host wants to send a message to a specific host, a unicast address is used.

For example, 00-A0-24-34-8D-9C is a unicast address.

Multicast Address: One of the MAC addresses types that is meant for multiplehosts, but not all hosts, on a LAN. Multicast addresses are used in lieu of sendingmultiple unicast messages that would take unnecessary LAN resources & broadcast

messages that would take unnecessary host resources.

Broadcast Address: One of the MAC addresses types that is used when a host wantsto send a message to every host on a LAN. The broadcast MAC address is representedby 48 binary ones or 12 hex Fs (0xFFFFFFFFFFFF). A message sent to the broadcast

address is processed by every host that receives it.

Broadband: it is type of signaling that shares the cable with other signals on thesame cable. (Cisco states that) broadband describes facilities or services that operateat the DS3 rate and above. For example, a Broadband DCS makes cross-connections

at the DS3, STS-1, and STS-Nc levels. Similarly, Broadband ISDN provides about150 Mb/s per channel of usable bandwidth.

1. Transmission system that multiplexes multiple independent signals onto one cable.

2. Telecommunications terminology: Any channel having a bandwidth greater than a

voice-grade channel (4 kHz).

3. LAN terminology: A coaxial cable on which analog signaling is used. An RFsystem with a constant data rate at or above 1.5 Mbps. Also called wideband.

Baseband: It's type of signaling in a digital form that uses the entire cable. In otherwords, no other signals can be on (share) the same cable during a baseband

transmission. This's opposite of broadband, where multiple signals can be on (share) asingle cable at the same time.

Collision : (Cisco states that) inEthernet( I'll explain it later), the result of two nodestransmitting simultaneously. The frames from each device impact & are damaged

when they meet on the physical media.

Collision Domain : In Ethernet term is when a particular device on a segment sendsa packet & enforces each device on the same segment to pay attention to its sendingpacket. Repeaters & hubs propagate collisions; but LAN switches, bridges, & routersdo not.


8/51

CCNA(640-607)



Broadcast Domain: (Cisco states that) set of all devices that receive broadcastframes originating from any device within the set. Broadcast domains typically arebounded by routers because routers do not forward broadcast frames.

Frame : it's a logical grouping of information sent as a Data Link layer unit over atransmission medium. Often refers to the header and the trailer, used forsynchronization and error control that surround the user data contained in the unit.

Packet: It's a Logical grouping of information that includes a header containingcontrol information & usually user data. Packets most often are used to refer to

network layer units of data. Packet consists of a certain number of data bytes.

Data Encapsulation: Encapsulation is the process of adding headers to data at eachlayer of a stack. Data that is to be sent over a network starts at the Application layerand moves down a protocol stack until it leaves a host at the Physical layer. At each

layer of a host's stack, a header is placed in front of the data. Your data combined with

a header or headers is a datagram. A datagram at layer 3 is called a packet; a packetstarts with a layer-3 header. A datagram at layer 2 is a frame; a frame starts with alayer-2 header (frame header). (See Fig.2)

A datagram header provides a path up a stack toward an application. A header mustcontain a data field that indicates the type of data encapsulated at the layer

immediately above the layer that adde d the header. For example, when your computerreceives web page from a web server, the header that immediately precedes the web-

page data must contain a field that indicates to your computer that the data beingreceived is meant for your web browser. Another example occurs when a host isencapsulating a packet with a frame header at layer 2, the frame header must contain a

value that indicates what protocol is being spoken; this value could indicate what typeof layer-3 header immediately follows the layer-2 header in the frame.


9/51

CCNA(640-607)



CSMA/CD: Carrier Sense Multiple Access/Collision Detection is defined in IEEEstandard 802.3. This standard specifies how multiple computers can send messages

when they sense a live wire. If the messages hit each other, collision detection occurs,& each node realizes that the message have been turned into gibberish. A random

amount of time is then allowed to pass before each node attempts a retransmission.This standard is commonly known as Ethernet.In other words, it's a media-access mechanism wherein devices ready to transmit data

first check the channel for a carrier. If no carrier is sensed for a specific period oftime, a device can transmit.

LAN: Local Area Network- a LAN is a network limited to a specific area, usually thesize of an office. LAN can't go outside the bound Aries of a single building. If thenetwork spans more than a single location, it becomes a WAN. LAN can be dividedinto small logical areas called workgroup (see Fig. 3).

WAN: Wide Area Network- it's a computer network that can span severalbuildings,cities, nations, or countries. The Internet is actually a specific type of WAN.Some of WAN features are:- Greater distance than LAN.

- Speeds are slower than LAN.- Several choices of how the data can be transported.- Possible to connect on demand or have a permanent connection.


10/51

CCNA(640-607)



Hub: It's a device that operates on the Physical layer to distribute an inbound networksignal to many outbound connections. Hub broadcasts what it receives on one port toall other ports (provides one broadcast domain). It can be active or passive.

Repeater: It's a device that regenerates the electrical signal coming from one port &sends it out to another port. The repeater enables the cable length to be extended.

For example, with a repeater in a 100BaseT (its length=100 meters) network, you canconnect a second 100BaseT cable & extend the total allowable distance to 200 meters.

Bridge : It's a device that operates at the Data Link layer & is used to extend themaximum reach of a network. A bridge makes two physical segments appear as one

network to the upper layers of the OSI model. Bridge permits communication thatwould otherwise be stopped by aRouter( I'll explain it later). In other words, if twosites for instance on the same network use a protocol that's stopped by a router, then

the use of a bridge is warranted instead.Bridges can connect dissimilar network types (Token Ring & Ethernet for instance) as

long as the bridge operates on the LLC sub-layer of the Data Link layer. If the bridgeoperates at the MAC sub-layer (lower layer), in this case the bridge can only connectsimilar network types (Token Ring with Token Ring, & Ethernet with Ethernet for

instance). Bridge provides one broadcast domain. Bridge looks up the framedestination in its address table & sends the frame towards the destination.

Brouter: It's a device that has the characteristics of both a bridge & a router. Itoperates on both the Data Link layer & Network layer. Brouter are mainly used to

connect different network topologies & bridge between them when the protocol beingused is NOT routable (for example, NetBEUI).

Handshake : (Cisco states that) It's a Sequence of messages exchanged between twoor more network devices to ensure transmission synchronization.

Three-way handshake : A TCP/IP connection is established when a client requeststhe connection by sending a SYN packet to the server. Once the server receives therequest, it will respond with a SYN-ACKacknowledging the clients SYN packet.Finally, the connection is established when the client sends anACKback to the servercompleting the three-way handshake.

DCE: (Cisco states that) Data Circuit-terminating Equipment (ITU-T expansion).Devices & connections of a communications network that comprise the network endof the user-to-network interface. The DCE provides a physical connection to the

network, forwards traffic, & provides a clocking signal used to synchronize datatransmission between DCE & DTE devices. Modems & interface cards are exam plesof DCE.

DTE: (Cisco states that) Data Terminal Equipment. Device at the user end of a user-network interface that serves as a data source, destination, or both. DTE connects to adata network through a DCE device (for example, a modem) and typically usesclocking signals generated by the DCE. DTE includes such devices as computers,protocol translators, & multiplexers.


11/51

CCNA(640-607)



CSU: (Cisco states that ) Channel Service Unit- digital interface device that connectsend-user equipment to the local digital telephone loop. Often referred to together with

DSU, as CSU/DSU.

DSU: (Cisco states that) Data Service Unit- device used in digital transmission thatadapts the physical interface on a DTE device to a transmission facility, such as T1 orE1. The DSU also is responsible for such functions as signal timing. Often referred to

together with CSU, as CSU/DSU.

T1 : (Cisco states that) Digital WAN carrier facility. T1 transmits DS1 (DigitalService 1) formatted data at 1.544 Mbps through the telephone-switching network,using AMI (Alternate Mark Inversion) or B8ZS coding.

IEEE 802 series: Institute of Electrical Engineers 802 subcommittees- it definesdifferent network communication protocols. The 802 subcommittees that define

networks & their traffic are the most well known. There are twelve 802 standards. Forexample, 802.2 is the logical control; 802.3 uses CSMA/CD; 802.5 is Token Ring.Using these protocols, & depending on their MAC addresses, packets are directed totheir destinations.

PAP:Password Authentication Protocoluses plaintext (unencrypted) passwords & isthe least sophisticated authentication protocol. PAP is typically used if your

connection & the server cannot negotiate a more secure form of validation.

CHAP: The Challenge Handshake Authentication Protocolnegotiates a secure formof encrypted authentication by using Message Digest 5 (MD5). A hashing scheme is amethod for transforming data (for example, a password) in such a way that the result

is unique & can't be changed back to its original form. CHAP uses challenge-responsewith one-way MD 5 hashing on the response. In this way, you can prove to the server

that you know the password without actually sending the password over the network.

Port : (Cisco states that) in IP terminology, an upper-layer process that receivesinformation from lower layers. Ports are numbered, and each numbered port isassociated with a specific process. For example, SMTP is associated with port 25. A

port number is also called a well-known address .

(Point your browser at the following link :)http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212811,00.html


12/51

CCNA(640-607)



OSI Reference Model & Layered Communication

1. Why using Layer ed Networ k Model ?

- Reduces complexity.

- Standardized interfaces.

- Facilitates modular engineering.

- Allows various types of network (hardware & software) to communicate with each

other.

- Accelerates evolution.

- Allows multiple vendors development.

- Prevents changes in one layer from affecting the other layer.

- Simplifies teaching & learning.

2. Descr ibe the funct ions of each the seven l ayer s ofOSI model ?

Layer 7

The Applications layer is where all network applications run. These are theapplications that you use to send information, data, across the network, for example,web browsers and servers & e-mail clients & servers.

Layer 6

The Presentation layer controls the formatting of data for your applications use. For

example, if the data is sound from a radio broadcast to which you are listening acrossthe Internet, the Presentation layer formats the data for the application that youre

using to receive the broadcast.

Layer 5

The Session layer handles the establishment & termination of communicationsessions. For example, when you login to your companys mainframe, a session must

be established for you to be able to talk to the mainframe, & when you logout, yoursession is terminated.


13/51

CCNA(640-607)



Layer 4

The Transport layer provides source-to-destination connection establishment for datatransfer. Over the connection, the Transport layer can provide multiplexing for upper

layer applications, hiding details from the higher layers, & establishing sessions.

Layer 3

The Network layer is the most important layer in r outing. The network layer contains

the address that routing software examines to determine where to route a messageacross a network. Router & Brouter are layer 3 devices.

Layer 2

The Data Link layer is dependent on the medium to which a host is attached. The

Data Link layer links the data from the network protocol to the physical medium on

which it is to be transmitted. Data Link layer can provide flow control & errornotification. The IEEE Ethernet Data Link layer has two sub-layers: (MAC) 802.3 &(LLC) 802.2. Switch ( I'll explain it later) & Bridge are layer 2 devices.

Layer 1

The Physical layer defines the characteristics that belong to the type of physical

network connection on a host, for example, the cable type, the connector type, thesignal frequenc y, the signal level, & the maximum cable length. The Physical layerdetermines exactly how bits (binary ones and zeroes) are transmitted and received on

a network. Active Hub & Repeater are layer 1 devices.

Layer

number

Layer Protocols or Connection

media used at this layer

7 Application HTTP, FTP, Telnet, SMTP,DHCP, DNS,etc

6 Presentation NetBIOS, XNS, & NCP

5 Session LDAP, NetBEUI,.etc

4 Transport TCP, UDP, NetBEUI, &SPX

3 Network IP, IPX, SLIP ,..etc2 Data Link ISDN, Ethernet, CSMA/CD,

Frame Relay, Token Ring,

FDDI, PPP, PPTP,..etc1 Physical ISDN, 10Base(T, F, 5, 2),

100Base(T, X), UTP, STP,Frame Relay.....etc (thoseare connection media )

3. Def ine & expl ain TCP/ IP Inter net pr otocol s?


14/51


15/51

CCNA(640-607)



5.Fig

FTP: File Transfer Protocol- it is both a protocol & program. It transfers files betweentwo computers using the TCP/IP protocol. FTP is a simple protocol that transfers

complete files from an FTP server to an FTP client. It can't perform browsingfunctions. Users must know the URL of the FTP server to which they wish to attach.

FTP is associated with port 21.ftp.mysite.com:21For example,

HTTP: Hypertext Transfer Protocol- an important protocol used when a browser isconnected to a web server. It governs the transfer of files, both text & multimedia,across the web. It's based on the idea that files can contain links to other files which in

turn link to other files. Servers make requests, wait for the response, & then processthe received file using HTTP. HTTP is associated with port 80.

SMTP: Simple Mail Transfer Protocol- it sends e-mails. Server to server transmissionuses SMTP. When you send a message from your client to server, SMTP is also used.

Dissimilar operating systems work with SMTP e-mail protocol, which originates fromTCP/IP suite. SMTP is associated with port 25.

DNS : Domain Name System- it resolves Internet domain names to IP address & viceversa.

For example, www.certificationsuccess.comis resolved to 216.168.60.68 via a DNSserver. DNS resolvesFully Qualified Domain Name(FQDN); the mentioned URL

here is FQDN. Users & computers access servers & their shared folders via domainnames. DNS is associated with port 53.

TFTP uses port 69.http://www.webopedia.com/TERM/T/TFTP.htmlTFTP :

DHCP: (Microsoft states that) Dynamic Host Configuration Protocol (DHCP) is aTCP/IP standard for simplifying ma nagement of host IP configuration. The DHCPstandard provides for the use of DHCP servers as a way to manage dynamic allocation

of IP addresses & other related configuration details to DHCP-enabled clients on yournetwork.


16/51

CCNA(640-607)



Every computer on a TCP/IP network must have a unique computer name & IPaddress. The IP address (together with its related subnet mask) identifies both the hostcomputer and the subnet to which it is attached. When you move a computer to a

different subnet, the IP address must be changed. DHCP allows you to dynamically

assign an IP address to a client from a DHCP server IP address database on your localnetwork (see Fig.6):

Fig.6

For TCP/IP-based networks, DHCP reduces the complexity & amount ofadministrator work involved in reconfiguring computers.

SNMP: Simple Network Management Protocol- it's a network management standardwidely used in TCP/IP & IPX networks. SNMP provides a method of managing

network hosts such as workstation or server computers, routers, bridges, & hubs froma centrally -located computer running network management software. SNMP isassociated with port 161. SNMP can be used to:

- Configure remote devic es.- Monitor network performance.

- Detect network faults or inappropriate access.

Telnet: (Cisco states that) it's a standard terminal emulation protocol in the TCP/IPprotocol stack. Telnet is used for remote terminal connection, enabling users to log into remote systems and use resources as if they were connected to a local system.Telnet is associated with port 23.

:)SPoint your browser at the following link(:TCP

TCP Overview

http://www.netfor 2.com/tcp.htm

TCP Header Formathttp://www.freesoft.org/CIE/Course/Section4/8.htm

Further Information

http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc1379.html

http://www.ee.siue.edu/~rwalden/networking/tcp.html


17/51

CCNA(640-607)



http://ironbark.bendigo.latrobe.edu.au/subjects/bitcne/1997/lectures/Lect03.html

UDP: User Datagram Protocol- it's a connectionless transport protocol in the TCP/IPprotocol stack. UDP is a simple protocol that exchanges datagrams, withoutacknowledgments, windowing, or guaranteed delivery, requiring that error processing& retransmission be handled by other protocols; therefore it lacks the reliable

delivery.For example, if you were to send data across an Internetwork, it doesn't matter in what

order the pieces of your message arrive as long as it all arrives.( Point your browser at the following link :)

http://www.erg.abdn.ac.uk/users/gorry/course /inet-pages/udp.html

the protocol that hides the underlying physical network byit's-Internet Protocol:IPcreating a virtual network view. It is an unreliable, best -effort, & connectionlesspacket delivery protocol. Note that best-effort means that the packets sent by IP may

be lost, arrive out of order, or even be duplicated.(Point your browser at the following link :)

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ ip.htm

ICMP : Internet Control Message Protocol- it is used to send control &troubleshooting packets over an IP-based network.For example, ICMP is used onPingcommand, if you ping any station with an IPaddress (ICMP echo request), the ICMP that is a part of the host's TCP /IP stack willrespond to the request (ICMP echo reply).

ARP: Address Resolution Protocol- it is used only on a LAN. Every transmission onthe LAN contains the local network, or MAC address of the source & destinationhosts. Routing can't be performed using the MAC address.

When a source does not know the MAC address of a non-local router, the sourceissues an ARP request. A router that is connected to the same network as the sourcepicks up the ARP request. This router issues an ARP reply to the device that

originated the ARP request. The reply contains the MAC address of the non-localrouter. Without the ARP request ever going beyond the local network, the source is

able to obtain the addressing information it needs in order to send data to deviceslocated on distant networks. In other words, ARP resolves IP address to Ethernet

address (MAC address).


18/51

CCNA(640-607)



4. Expl ain how the inf or mation is packaged at the OSImodel ?

The information is packaged in this order:

. Data (at Application/Presentation /Session layers)

. Segment (at Transport layer)

. Packet (at Network layer)

. Frame (at Data Link layer)

. Bits (at Physical layer)

The OSI model defines layers, interfaces between layers, Protocol Data Units (PDUs)for each layer, & protocols for each layer. Each layer of communication, on the

source computer, communicates with a layer-specific PDU, & with its peer layer onthe destination computer.

Data packets on a network originate at a source & are then sent to a destination. Each

layer depends on the service function of the OSI layer below it. To provide thisservice, the lower layer uses encapsulation to put the PDU from the upper layer into

its data field; then it adds whatever headers & trailers the layer needs to perform itsfunction. Next, as the data moves down through the layers of the OSI model, headers

& trailers are added. After Layers 7, 6, and 5 have added their information, Layer 4

adds more information. This grouping of data, the Layer 4 PDU, is called a Segment.

The Network layer has the task of moving the data through the Internetwork. Itaccomplishes this task by encapsulating the data within a header. This header contains

information required to complete the transfer, such as source & destination logicaladdresses. The Network layer provides a service to the Transport layer by

encapsulating the data within a header & creating a Packet (the Layer 3 PDU.)

The Data Link layer provides a service to the Network layer. It encapsulates the

Network layer information in a Frame (the Layer 2 PDU); the frame header contains

information (such as, physical addresses) required to complete the data link functions.The Physical layer also provides a service to the Data L ink layer. The Physical layer

encodes the data link frame into a pattern of ones & zeros (B its) for transmission on

the connection medium (usually a wire) at Layer 1. (See also Data Encapsulationexplained earlier.)

5. Expl ain each of the thr ee l ayer s of Cisco model ?

Core layerRouters connect to other core routers providing multiple paths over the backbonebetween destinations. These routers carry the bulk of WAN traffic between thedistribution routers. Core routers are usually configured with several high speed

interfaces.


19/51


20/51


21/51

CCNA(640-607)



2. Suppose you were provided the following IP address : 136.28.92.55?

- This's a c lass B (136 falls within its Decimal Range 128-191).

- Network address: 136.28(based on the Default Subnet Mask 255.255.0.0, thus itsformat isNetwork .Network.Host.Host).

- Host address: 92.55

---------------------------------------------------------------------------

3. Suppose you were provided the following IP address : 192.168.24.18?

- This's a c lass C (192 falls within its Decimal Range 192-223).

- Network address: 192 .168.92 (based on the Default Subnet Mask 255.255.255.0,thus its format is Network .Network.Network.Host).

- Host address: 18

inary& Bexadecimal,Hecimal,DbetweeningConvert

Note: You have to understand & memorize the powers of 2 for use with IP subnetting

(I replaced "to the power" w ith ** mark).

2**0 = 12**1 = 22**2 = 42**3 = 8

2**4 = 162**5 = 322**6 = 64

2**7 = 128

- Convert the decimal number 24032 to a hexadecimal number:

24032 / 16 = 16 into 24032 is 1502, with a remainder of 01503 / 16 = 16 into 1502 is 93, with a remainder of 14 or E

93 / 16 = 16 into 93 is 5, with a remainder of 13 or D

13 / 16 = 16 into 13 is 0, with a remainder of 3

By collecting all the remainders backward, we have the hexadecimal number 3DE0.


22/51

CCNA(640-607)



-Convert the binary number 11000000 to a decimal number:

11000000 (Work from right hand side to left)

1 1 0 0 0 0 0 0

128 64 32 16 8 4 2 1

In this example, there are 0 values of 1, 0 values of 2 , 0 values of 4 , 0 values of 8, 0

values of 16 , 0 values of 32, 1 value of 64, & 1 value of 128. There are no 1s, no

2s, no 4s, no 8s, no 16s, no 32s, one 64, & one 128. Added together, the values equal192, therefore, the binary number 11000000 equals the decimal num ber 192.

- Convert the binary IP address 10101010.11111111.00000000.11001101 to a

decimal number:

1 0 1 0 1 0 1 0

128 + 32 + 8 + 2 = 170128 6432 16 8 4 2 1

To convert this IP address, start with the bit that is on the far left side in the first octet.

It is 1. You should know that the value of a bit in that position is 128; therefore thedecimal number starts with a value of 128. The next value is 0, so skip it; the thirdvalue is 1. Any bit in that position has a value of 32; therefore you must add 32 to

128, which then equals a new value of 160. The fourth bit is 0; the fifth bit is 1, whichmeans that now you must add 8 to the current value of 160, giving you a total of 168.

The sixth bit is also 0, the seventh bit is 1, which means add 2 to the current value of168. The last bit is 0, so you can skip it. The value for the first octet, after all thenumbers have been added, is 170.

The second bit from the left side equals 255 (give it a try!).

- Convert the first octet of 192.57.30.224 to a binary format :

128 64 32 16 8 4 2 1 = 192

1 1 0 0 0 0 0 0 = 11000000

The first step is to select the octet on the far left and determine whether the value isgreater than 128. In this instance (192), it is. Then place a 1 in that bit and subtract128 from 192. The remainder is 64. The value of the next bit is 64, which is equal to

the value of the remainder, so that bit would be 1 as well. Subtract 64 from 64. Theremainder is 0; therefore the remaining bits would all be 0. The binary number for thefirst octet would be 11000000.

57= 111001, 30= 11110 & 224= 11100000.


23/51

CCNA(640-607)



Private IP addresses

These types of addresses were designated to solve the explosive growth of theInternet. Each device connected to the Internet needs its own "public " IP address. But,

what if there are several devices in your LAN that DON'T need to be connected

directly to the Internet?, thus, instead of assigning a public IP address for each ofthese devices; InterNIC & IANA designated some IP address range asprivateaddresses (they can't directly access the Internet or receive data from the Internet).

10.0.0.0 - 10.255.255.255 with a subnet mask 255.0.0.0



Subnetting

Network administrators sometimes need to divide networks, particularly largenetworks, into smaller networks, called subnetworks, in order to provide extraflexibility. Most of the time subnetworks are simply referred to as subnets.

Similar to the host number portion of class A, class B, & class C addresses, subnetaddresses are assigned locally, usually by the network administrator. Moreover, like

other IP addresses, each subnet address is unique. It is possible to break a class B IPaddress into many subnets for instance.

(Point your browser at one ormore the following link S :)

http://www.learntosubnet.com

http://subnetting.tcp-ip.nu

http://www.ralphb.net/IPSubnet

http://compnetworking.about.com/library/weekly/aa043000a.htm

(Free Subnetting exams )

http://www.2000trainers.com/exams/subnetting


24/51

CCNA(640-607)



Ethernet Networking

1. What is Ether net?

(Cisco states that) it's a baseband LAN specification invented by Xerox Corporation& developed jointly by Xerox, Intel, & DEC. Ethernet networks use CSMA/CD & run

over a variety of cable types at 10 Mbps. Ethernet is similar to the IEEE 802.3 seriesof standards.

2. List & descr ibe the Ether net connect ion media types(802.3standar ds) at Physical l ayer?

Before starting to list, you have to know some specifications for cabling system:

- The Ethernet naming convention is #BaseN(where #refers to the speed in Mbps,Base refers to Baseband, & Nrefers to the type of cable).For example, 100BaseT100: 100 Mbps

Base: BasebandT: stands for Twisted pair, which means it can go to 100 meters.

- RJ: Registered Jack- (Cisco states that) standard connectors originally used toconnect telephone lines. RJ connectors are now used for telephone connections & for

10BaseT & other types of network connections. RJ-11 (telephone connector ), RJ-12,& RJ-45 (Ethernet connectors) are popular types of RJ connectors (see Fig.7).

7.Fig

- UTP: Unshielded Twisted Pair sheathing type - it is used for Category 3 & Category5 w ires. The most common use for Unshielded Twisted Pair cable is Ethernet (seeFig.8).

- Category 3 : It's a data grade physical medium. Category 3 consists of four twistedpairs, with three twists per foot. It rates up to 10Mbps.

- Category 5 : It's the current standard of wire that's run from wire closets to desktops .

It consists of four twisted pairs & is rated for up to 100Mbps.

- Fiber Optic cables: The highest performing structured cabling systems use fiberoptics. These systems offer many advantages over copper-based systems. Since fiber


25/51

CCNA(640-607)



optics use light pulses instead of electrical signals for transmitting information, thereis no concern for EMI (Electromagnetic Interference) or RFI (Radio FrequencyInterference).

Transmission distances are greater because light pulses lose energy much more slowly

than electrical signals. Fiber also offers a much greater bandwidth than copper cables(see Fig.8).

- Coaxial cable : It's a thick cabling that's commonly housed in a black sheath (seeFig.8). There are thinnetversion (10Base2) & thicknetversion (10Base5).

8.Fig

Ethernet media types

Maximum Length

(meters )

CategoryTypeIEEE 802.3

standards

1003UTP10BaseT

185UTP10Base2

500UTP10Base51003, 4, or 5UTP (Fast

Ethernet)100BaseT4

1005, 6, or 7UTP100BaseTX

100UTP100BaseVGAnylan

412Fiber cabling100BaseFX

25Copper shieldedtwisted pair

1000BaseCX

10000Fiber cabling

(Laser)

1000BaseLX

260MMF1000BaseSX

1005UTP1000BaseT

Note: 100BaseVGAnylan is very rarely used now.


26/51

CCNA(640-607)



3. What ar e the types of Ether net f r ames at Data Linkl ayer ?

. Ethernet_| |

. IEEE 802.2

. IEEE 802.3

. SNAP(Point your browser at the following link :)

http://www.yale.edu/pclt/COMM/ETHER.HTM

4. State Ether net cabl es types?

Crossover cable : Four wires are used in this type to connect devices (see Fig.9). You

use this type of Ethernet cabling if you want to connect:- Hub to another hub.- Hub to a switch.

- Switch to another switch (uplinks).- Router interface to another router interface.

- Host to host w ithout using a hub or a switch.

Straight-Through cable : Four wires are used in this type to connect devices (seeFig.9). You use this type of Ethernet cabling if you want to connect:- Host to hub or switch.

- Server to hub or switch.

- Router to hub or switch.

9.Fig

Rolled cable : Eight wires are used in this type to connect serial devices. You use thistype of Ethernet cabling if you want to connect:

- Host to a router console serial communication (com) port.


27/51

CCNA(640-607)



5. What is the dif f er ence between Hal f - dupl ex & Ful l -Dupl ex Et her net?

Half-duplex Ethernet:- It uses one wire pair with digital signal running in both directions.- It uses CSMA/CD.- You use this type if you want to connect a hub to a switch (10BaseT).

Full-duplex Ethernet:- It uses two wires pairs.

- It uses point-to-point connection between sendin g host & receiving host.- There are no collisions.- You use this type if you want to connect:

. Host to a switch.

. Switch to a switch.

. Host to host (by using crossover cable).

Further Information

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ethernet.htm

http://www.techfest.com/networking/lan/ethernet.htm

http://www.networkuptime.com/faqs/ethernet


28/51

CCNA(640-607)



):10.see Fig(Icons used for networking devices.

10.Fig

see(used for networks & network connectionssIcon.):11.Fig

11.Fig


29/51

CCNA(640-607)



witchingS/Bridging

1. What is a switch?

A switch is a layer 2 device that directs (looks up) frames according to their MACaddresses.

2. State the simil ar ities & contr asts between switches& br idges?

- Switches & bridges make forwarding decision based on layer 2 addresses.

- Switches & bridges don't break up broadcast domains by default.- Switches & bridges forward layer 2 broadcasts.

- Switches are hardware based (use the MAC address ), while bridges are softwarebased.- Switches have higher number of ports than most bridges.

- Switches can have many STPs (Spanning Tree Protocols), while bridges have oneonly.

3. How does l ayer 2 switch function?When you turn on the layer 2 switch at the first time, its MAC address table is empty.Now consider four hosts connected to a layer 2 switch as shown in Fig. 12:

- Address learning.

- Forward/Filter decisions.- Loop avoidance.


30/51

CCNA(640-607)



12.Fig

1) Host A sends a frame to host C.2) Switch's MAC address table was empty before host A sends that frame. But now ithas the MAC address of host A .

3) Switch has no idea about the MAC address of host C (it doesn't have thedestination's MAC address in its MAC address table) in order to forward that frame.

4) Switch broadcasts that frame to all hosts within its segment asking the destination'sMAC address.5) Host C receives that frame & replies with its MAC address. Switch's MAC address

table places the destination's MAC address.6) Frames now will be received by both host A & C only as point-to-point connection.Other hosts will not be able to see the frames (collision domain). As well as, theirMAC addresses are not placed in the switch's MAC address table yet because theydidn't send a frame to the switch.

4. Why is l ayer 2 switch better than the hub inEther net LAN networ ks?

Switch provides one broadcast domain with multiple collision domains which meansa network segment with several Ethernet devices sharing the same bandwidth (seeFig.13). Each port of a switch has its own separate collision domain , which means

more network segments & bandwidth increasing for each host. Unlike hub whichprovides one broadcast domain only without collision domains .

13.Fig


31/51

CCNA(640-607)



5. Define & expl ain STP operation?

Spanning Tree Protocolwhich is used to stop an infinite network loops & shut down

any redundant links from occurring on bridges & layer 2 switches which can cause abroadcast storm (an undesirable network event in which many broadcasts are sent

simultaneously across all network segments. A broadcast storm uses substantialnetwork bandwidth & typically causes network time-outs).

(Cisco states that) bridge protocol that uses the spanning-tree algorithm, enabling alearning bridge to dynamically work around loops in a network topology by creating aspanning tree. Bridges exchange BPDU (Bridge Protocol Data Unit) messages with

other bridges to detect loops, & then remove the loops by shutting down selectedbridge interfaces.

:Function

- Selecting the Root Bridge: The bridge ID is selected based on the default priority ofthe device (= 32,768). Otherwise, the lowest device's MAC address will be taken into

consideration in case the two devices having the same priority.

- Selecting the Designated Port: If there's more than one link connected to the rootport, a port cost will be taken into consideration to determine which port will be theroot port. However, each direct connection to the root bridge will be a root port.

- Selecting the Blocked port: it must be done by shutting down the redundant link toavoid infinite network loops based on bridge ID as well. (For example, if there are

two switches D & E, one of them must be shut down, & referring to the Blocking Portmode, switch E would be blocked).

:STP modes

- Blocking: A blocked port doesn't send frames, but can listen to the BPDUs.- Listening: Port listens to the BPDUs in order to make sure that there are no infinite

network loops occur.- Learning: Port learns all the paths in the switched network.- Forwarding: Port sends & receives data.

- Disabled: Port doesn't participate in the frame forwarding or STP.

6. Distinguish between cut-thr ough, f r agmentf r ee, &stor e-and-f or war dLAN switc hing?

LAN switching types determine how the frame is handled when it's received on theswitch port. Switching modes are:


32/51

CCNA(640-607)



Cut-through: (Cisco states that) a packet switching approach that streams datathrough a switch so the leading edge of a packet exits the switch at the output port

before the packet finishes entering the input port. A device using cut-through packet

switching reads, processes, & forwards packets as soon as the destination address islooked up & the outgoing port is determined.

FragmentFree : Also called modified cut-through. A switch checks the first 64 bytesof a frame before forwarding it for fragmentation. This mode is a default mode forCatalyst 1900 switch.

Store -and-forward : (Cisco states that) packet-switching technique in which framesare completely processed before being forwarded out the appropriate port. This

processing includes calculating the CRC (Cyclic Redundancy Check) & checking thedestination address. In addition, frames must be stored temporarily until networkresources (such as an unused link) are available to forward the message.

7. Name some of Cisco Catal yst switc h pr oducts ser ies?

- Cisco 1548 Micro switch 10/100.- Catalyst 1900/2820 series.- Catalyst 2900 series XL.

- Catalyst 3000 series.- Catalyst 2900 series.- Catalyst 5000 series.

- Catalyst 6500 series.- Catalyst 8500 series.


33/51

CCNA(640-607)



8. Descr ibe the oper ation & benef its of VLANs?

Virtual LAN. (Cisco states that) it's a group of devices on one or more LANs that are

configured (using management software) so that they can communicate as if theywere attached to the same wire, when in fact they are located on a number of differentLAN segments. Because VLANs are based on logical instead of physical connections,they are extremely flexible.

(Cisco states that) A VLAN is defined as a broadcast domain within a switched

network. Broadcast domains describe the extent that a network propagates a broadcastframe generated by a station. Some switches may be configured to support a single or

multiple VLANs.Whenever a switch supports multiple VLANs, broadcasts within one VLAN neverappear in another VLAN. Switch ports configured as a member of one VLAN belong

to a different broadcast domain, as compared to switch ports configured as members

of a different VLAN. Creating VLANs enables administrators to build broadcastdomains with fewer users in each broadcast domain.This increases the bandwidth available to users because fewer users will contend forthe bandwidth. Routers also maintain broadcast domain isolation by blockingbroadcast frames. Therefore , traffic can pass from one VLAN to another only througha router. Normally, each subnet belongs to a different VLAN. Therefore, a network

with many subnets will probably have many VLANs. Switches & VLANs enable anetwork administrator to assign users to broadcast domains based upon the user's jobneed. This provides a high level of deployment flexibility for a network administrator .

Advantages of VLANs include the following:

. Segmentation of broadcast domains to create more bandwidth.

. Additional secur ity by isolating users with bridge technologies.

. Deployment flexibility based upon job function rather than physical placement.

. Increasing the number of broadcast domains while decreasing their size.

Now, after you knew that VLAN breaks up a broadcast domain which's provided by alayer 2 switch into several small broadcast domains & that would increase security &bandwidth.

For example, suppose you have created two VLANs for two departments as shown inFig.14.

Network address /subnet

mask

DepartmentVLAN number

192.168.10.0/24Engineering1

192.168.40.0/24I.T2.

Note: Instead of writing subnet mask as 255.255.255.0, Cisco developed a for mat ofwriting any subnet mask by counting the 1s of it (after converting the subnet mask toa binary number), so in this case the subnet mask would be 24 (since the subnet mask


34/51

CCNA(640-607)



contains 24 ones). Another example, convert the subnet mask 255.255.224.0 to aCisco format, after converting this subnet mask to a binary number, the result will be:11111111.11111111.11111111.11100000, so when you count the number of 1s in

here you will get 19 which's the default subnet mask in Cisco format.

14.Fig

Now, if you want to add a new user to an I.T department (VLAN 2), & this new useris physically located in the Sales depa rtment for instance, you can assign the neededport of this user in VLAN 2 (logically) without needing to shift him (physically) tothe I.T department. But, correct IP address information must be taken into account inorder to logically assign a device to a VLAN's port. For our example, the IP address

information of the new user must be in the same range as network address of VLAN 2(192.168.40.0/24), as well as, each host in VLAN 2 must be configured into the192.168.40.0/24 network. However, this applies to every VLAN in the network.

In our case, the new user can be assigned 192.168.40.5/24 for instance.

9. State the two dif f er ent types of l inks in a switchednetwor k?

- Access link.- Trunk link: It's a 100 or 1000Mbps (10Mbps is not an option) point-to-point link

between:

. Switch & a server.

. Switch & another switch.

. Switch & a router.

(Point your browser at the following link :)ftp://ftp.netlab.ohio-state.edu/pub/jain/courses/cis788-

97/virtual_lans/index.htm#Connections


35/51

CCNA(640-607)



10. How can hosts communicate between dif f er entVLANs?

As in our previous example (Fig.14), VLAN 1 can communicate with VLAN 2 byusing a layer 3 device (Router ). You can use a router with multiple interfaces for each

VLAN (in our example, two interfaces are needed) with 10BaseT or Fast Ethernetconnections.

But, what if we have dozens of VLANs, & they are more than router interfacesavailable for instance?!. We can use a router that supports ISL (Inter Switch Link)routing on one Fast Ethernet or Gigabit Ethernet links only. ISL routing is supported

in the 2600 series router or higher (1600, 1700, & 2500 series don't support it ).Otherwise, you may buy a RSM (Route Switch Module) for a 5000 series switch.

Note: ISL is proprietary to Cisco switches.

11. Expl ain VTP (V L A N T r u n k P r o t o c o l )?

(Point your browser at the following link :)http://www.cisco.com/warp/public/473/21.html

Further Information

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/lanswtch.htm

ftp://ftp.netlab.ohio-state.edu/pub/jain/courses/cis788-97/virtual_lans/ index.htm

http://net21.ucdavis.edu/newvlan.htm


36/51

CCNA(640-607)



Router

1. What is a router ?

In networking, there are two addressing schemes: one uses the MAC address, a datalink (Layer 2) address; & the other uses an address located at the network layer (Layer3) of the OSI model. An example of a Layer 3 address is an IP address. A router is a

type of internetworking device that passes data packets between networks, based onLayer 3 addresses. A router has the ability to make intelligent decisions regarding thebest path for delivery of data on the network.(Cisco states that) it's a Network layer device that uses one or more metrics (low cost)to determine the optimal path along which network traffic should be forwarded.

Routers forward packets from one network to another based on network layerinformation. Occasionally called a gateway (although this definition of gateway is

becoming increasingly outdated).

2. What is a router interf ace?

A routers attachment to a network is called an interface (network connection); it may

also be referred to as a port. In IP routing, each interface must have a separate, uniquenetwork (or subnetwork) address. (See Fig.15)- S0 (Serial interface, 0 is an interface number).- E0 (Ethernet interface, 0 is an interface number).- F0/0 (Fast Ethernet interface).


37/51

CCNA(640-607)



15.Fig

3. Def ine Consol e por t & Auxil iar y por t on a Ciscor outer ?

- Console port : It's an RJ-45 connection port on the back of a Cisco router (usually)

& switch that allows CLI (Command Line Interface).

- Auxiliary port: It can be the Console port as well on the back of Cisco router that

allows dialing the router by configuring modem commands & make consoleconfiguration settings if the router is down.

(Point your browser at the following link :)

http://www.cisco.com/warp/public/779/smbiz/service/knowledge /pinouts/ios_conaux.htm

------------------------------------------------------------------------------

4. What ar e the r outer modes?

- User mode : It is used to view statistics. However, after you press Enter in the CLI,the Router>prompt will appear, which means you are in the User mode.

- Privileged mode : It is used to view & change a Cisco router configuration.However, when Router#prompt appears, that means you are in the Privileged mode.

- Global configuration mode : It is used to change the whole router running-configuration. However, when you type config t ( configure terminal) in the privilegedmode (Router#config t ), the Router(config)# prompt appears, which means you are in

the Global configuration mode.

5.Dif f er entiate between r outedand routingpr otocol s?

You know that protocols are like languages. IP is a network layer protocol, however,

IPs can also provide fragmentation, & reassembly. Because IP is routed over anInternetwork, it is called a routed protocol. Examples of other types of routed

protocols:

.IPX

.Appletalk

Routers use routing protocols to exchange routing tables & share routing information.In other words, routing protocols are protocols that determine how routed protocols

get routed. Examples of routing protocols:

(Routing Information Protocol)RIP.


38/51

CCNA(640-607)



(Interior Gateway Routing Protocol)IGRP.

(Enhanced Interior Gateway Routing Protocol)EIGRP.

(Open Shortest Path First)OSPF.

Routing protocols enable routers to draw a map, internally, of the entire Internet forthe purposes of routing. Such maps become part of each router's routing table.

6. Descr ibe the Administr ative Distance f or r outingpr otocol s?

(Cisco states that) rating of the trustworthiness of a routing information source.Administrative distance often is expressed as a numerical value between 0 and 255.

The higher the value, the lower the trustworthiness rating. Administrative DistanceabbreviatedAD.Default AD

Default ADRoute Source

0Connected interface

1Static route

90EIGRP100IGRP

110OSPF

120RIP

255Unknown

7. Descr ibe the cl asses of r outing pr otocol s?

- Distance Vector: (Point your browser at the following link :)

http://www.firewall.cx/distance_vector.php

- Link State : For example, OSPF. It creates three separate tables:

. A table that keeps track of directly attached neighbors to the router.

. A table that determines the entire Internetwork topology.

. A table that is used as a routing table.

- Hybrid: It uses both Distance Vector & Link State protocols (for example, EIGRP).


39/51

CCNA(640-607)



8. Descr ibe RIP (r outing inf or mation pr otocol )f eatur es?

- Distance Vector routing protocol.- Only metric is number of hops.

- Maximum number of hops is 15.- Updates every 30 seconds.- Doesn't always select fastest path for packets.

- Generates lots of network traffic with updates.

Note: (C isco states that) a hop is a Passage of a data packet between two networknodes (for example, between two routers). Hop countis a Routing metric used tomeasure the distance between a source & a destination. RIP uses hop count as its solemetric. Routing metric is a method by which a routing algorithm determines that oneroute is better than another. This information is stored in routing tables. Metrics

include bandwidth, communication cost, delay, hop count, load, MTU (MaximumTransmission Unit), path cost, & reliability. Sometimes referred to simply as a metric .

9. Descr ibe IGRP (In t e r io r G a t ew a y R o u t i n g P r o t o c o l )f eatur es?

IGRP was developed specifically to address problems, associated with routing inlarger networks that were beyond the scope of protocols such as RIP (maximum hopcount is 15). Like RIP, IGRP is a distance vector protocol; however, whendetermining the best path, it also takes into consideration such things as bandwidth,load, delay, MTU, & reliability. The maximum hop count of IGRP is 255.

10. Def ine Conver gence?

It's the time it takes a router to recognize a network topology change, calculate thechange within its own table & then distribute the table to adjacent routers. The

adjacent routers then perform the same functions. The total time it takes for the

routers to begin using the new calculated route is called the convergence time. Thetime for convergence is critical for time-sensitive traffic. If a router takes too long to

detect, recalculate & then distribute the new route, the time-sensitive traffic mayexperience poor performance or the end nodes of the connection may then drop.

11. How can we avoid r outing l oops?



40/51

CCNA(640-607)



http://www.firewall.cx/distance_vector.php

12. Descr ibe the basic Cisco r outer components?

BootstrapThe main purpose of Bootstrap is to boot the router & then load IOS.

POST(Power-On Self Test) is used to check the basic router functions of the routerhardware & determines the presented interfaces.

Memory

All computers have memory of some type. Cisco routers have four main types ofmemory:

(Read-Only Memory)ROMFlash Memory

(Random-Access Memory)RAM(Non-Volatile RAM)NVRAM

Of each of these types, RAM is the only one that loses its contents when the router is

booted or power-cycled. The following sections briefly describe the primary purposeof each memory type on Cisco routers:

ROM

ROM is where a routers bootstrap software is normally stored. The bootstrapsoftware is the first software that runs; it has the responsibility of getting the routergoing.

FlashFlash memorys primary purpose is to store the IOS software that the router is to run.If a router has flash memory, then flash memory is the default location of the IOSsoftware used to boot the router. With enough flash memory, multiple IOS images can

be stored to provide multiple boot options.

RAMRAM is used for too many things to list, but two of the things are IOS system tables& buffers. The IOS uses RAM for all of its normal, operational storage requirements.

NVRAMThe primary purpose of NVRAM is to store the configuration that the IOS reads when

a router boots. This configuration is called the startup conf iguration.

Configuration register


41/51

CCNA(640-607)



It is used to control how the router boots up. It can be noticed by typing show versioncommand in CLI (0x2102). However, this tells the router to load IOS from flashmemory.

13. Descr ibe r outer star t-up sequence?

1) POST.2) Bootstrap.

3) IOS software looks for a valid configuration file stored in NVRAM.4) If startup-config file in NVRAM, the router loads. However, if not, the router starts

the setup mode configuration.

Further Information

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/rip.htm

http://www.cisco.com/warp/public/103/5.html

http://www.firewall.cx/link_state.php

http://www.idir.net/~adrian/ip_tutor/trouble/RtLoop.html

http://www.networkcomputing.com/715/715wsrip.html


42/51

CCNA(640-607)



WAN Protocols

1. Def ine WAN terms?

- CPE- Demarc- Local loop

- CO(Point your browser at the following link :)

http://personal.hartfordschools.org/~stephen/library/network_primer/appendix_c.html

2. Expl ain key Fr ame Rel ay terms and f eatures?

Frame relay is based on a packet-switched data network. The differential of frame

relay to previous packet-switched networks like X.25 is that frame relay switches aframe versus a packet. Frame relay has considerable low overhead & its speed

through the network is in part to not insuring delivery of data. Frame relay as a WANnetwork solution grew due to the low cost for acceptable performance as compared to

leased-line WAN solutions. An optimal frame relay network design is based on thefollowing:

. Balancing the cost savings of using a public network with the business performancerequirements.

. A scalable WAN design founded in a manageable environment.

. Utilizes a hierarchical design.

Components for creating a scalable frame relay network designs are:

.The adherence to the three-layer router model of Core, Distribution & Access

layers.

. Overall hierarchical design.

. Implementing various mesh topology design.

. Addressing protocol broadcast issues.

. Addressing performance concerns.


43/51

CCNA(640-607)



Frame relay design is based on permanent virtual connections (PVCs). A PVC isidentified using a Data Connection Link Identifier (DLCI) number. Multiple PVCs are

possible over a single physical communication link. Using this ability, a single link

can communicate with multiple locations.Due to the nature of frame relay services through PVCs, hierarchical designs are more

logical than physical in definition. Each PVC may be guaranteed bandwidthparameters called committed information rate (CIR). The CIR is an agreement withthe frame relay provider for a minimum throughput for the PVC.

3. Dif f er entiate between the f ol l owing WAN ser vices:LAPB, Fr ame Rel ay, ISDN/ LAPD, HDLC, PPP, and DDR?


http://www.geocities.com/ciscosite/ccna/wanprotocols.html# 8

- LAPB : (Cisco states that)Link Access Procedure, Balanced. Data Link layer

protocol in the X.25 protocol stack. LAPB is a connection-oriented protocol derivedfrom HDLC.

- Frame Relay : (Cisco states that) Industry-standard, switched Data Link layerprotocol that handles multiple virtual circuits using HDLC encapsulation between

connected devices. Frame Relay is more efficient than X.25, the protocol for which itgenerally is considered a replacement.

- ISDN/LAPD: (Cisco states that)Integrated Services Digital Network.

Communication protocol offered by telephone companies that permits telephonenetworks to carry data, voice, & other source traffic. LAPD is aLink Access

Procedure on the D channel. ISDN data link layer protocol for the D channel. LAPD

was derived from the LAPB protocol & is designed primarily to satisfy the signalingrequirements of ISDN basic access.

- HDLC: (Cisco states that)High-Level Data Link Control. Connection-orientedsynchronous data link layer protocol developed by ISO. Derived from SDLC, HDLC

specifies a data encapsulation method on synchronous serial links using framecharacters & checksums.

- PPP: (Cisco states that)Point-to-Point Protocol. Successor to SLIP that providesrouter-to-router & host-to-network connections over synchronous & asynchronous

circuits. Whereas SLIP was designed to work with IP, PPP was designed to work withseveral network layer protocols, such as IP, IPX, & ARA. PPP also has built-insecurity mechanisms, such as CHAP & PAP. PPP relies on two protocols: LCP (Link

Control Protocol) & NCP (Network Control Program).


44/51

CCNA(640-607)



- DDR:Dial-on-Demand Routing uses switched circuit connections through publictelephone networks. Using these switched circuits allows Cisco routers to providereliable backup and bandwidth optimization between locations. The features

supported by Cisco DDR include:

. POTS via an external modem

. SW56 via an external CSU

. ISDN (BRI and PRI) via integrated ISDN interfaces or external terminal adapters

. Dial backup

. Supplementary bandwidth

. Bandwidth-on-demand

. Snapshot routing. Multiprotocol routing & transparent bridging over switched circuits

. ISDN fast switching

. Asynchronous ISDN access

(Cisco states that)Dial-on-Demand Routing. Technique whereby a router canautomatically initiate & close a circuit-switched session as transmitting stationsdemand. The router spoofs keepalives so that end stations treat the session as active .DDR permits routing over ISDN or telephone lines using an external ISDN terminaladaptor or modem.

4. Identif y PPP operations to encapsul ate WAN data onCisco r outer s?

PPP was designed to be used over point-to-point links. In fact, it's the prevalent IPencapsulation scheme for dedicated Internet access as well as dial-up access. One ofthe significant strengths of PPP is its ability to negotiate a number of things upon

initial connection, including passwords, IP addresses, compression schemes, &encryption schemes. In addition, PPP provides support for simulta neous multipleprotocols over a single connection, an important consideration in those environments

where dial-up users can employ either IP or another network Layer protocol. Finally,in environments such as ISDN, PPP supports inverse multiplexing & dynamic

bandwidth allocation via the Multilink-PPP .

The operation of PPP is basically as follows:

1) After the link is physically established, each host sends LCP (Link Control

Protocol) packets to configure & test the data link. It's here where the maximumframe length, authentication protocol PAP (Password Authentication Protocol), or


45/51

CCNA(640-607)



CHAP (Challenge-Handshake Authentication Protocol), & other configurationparameters are negotiated. Authentication, if it used, will occur after the link has beenestablished.

2) After the link is established, one or more Network Layer Protocol connections areconfigured using the appropriate NCP . Once each of the Network Layer Protocols has

been configured, datagrams from those protocols can be sent over the link. Controlprotocols may be used for IP, IPX, DDP (AppleTalk), DECnet, & more.

3) The link will remain configured for communications until LCP &/or NCP packetsclose the link down.

5. Identif y ISDN pr otocol s, f unction gr oups, r ef er encepoints, & channel s?

(Point your browser at the following link :)http://www.cicprep.com/WebHelp/ccna/ccna_obj_ 14.htm

6. Descr ibe br ief l y some of wan technol ogies & theiruses?

Typical UsesWAN Technology

Analog modems are typically used fortemporary dial-up connections or forbackup of another type of link. The

bandwidth is typically 9.6bps - 56 Kbps

Analog modem

Leased lines have been the traditionaltechnology for implementing WANs.

These are links "leased" fromcommunications services companies forexclusive use by the corporation

Leased line

ISDN is a dial-up solution for temporaryaccess to the WAN but adds theadvantage of supporting voice/video/fax

on the same physical connection. As aWAN technology, ISDN is typically usedfor dial-backup support at 56, 64 or 128

Kbps bandwidth

Integrated Services Digital Network(ISDN)

X.25 can provide a reliable WAN circuithowever does not provide the high

bandwidth requirements as a backbonetechnology

X.25

WAN ATM (Asynchronous Transfer

Mode) is used as the high bandwidthbackbone for supporting multiservicerequirements. The ATM architecture

WAN ATM


46/51

CCNA(640-607)



supports multiple QoS (Quality ofService) classes for differing applicationrequirements delay & loss

er InformationFurth

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/isdn.htm

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/introwan.htm#xtocid13

http://www.protocols.com/protoc.shtml#Protocols

http://www.rhyshaden.com/routing.htm

http://jhunix.hcf.jhu.edu/~tnaugler/770.512/Common_files/WANs/ScanTechnologies/scan04.html

http://www.microsoft.com/technet/treeview /default.asp?url=/TechNet/prodtechnol/winxppro/reskit/prcg_cnd_gvfb.asp


47/51

CCNA(640-607)



CCiissccooRRoouutteerr&&sswwiittcchhccoonnffiigguurraattiioonnss

. Basic Cisco IOS CLI (Command Li ne I nterface):

(Point your browser at the following linkS :)

http://www.cisco.com/warp/cpropub/45/tutorial.htm

http://www.tele.sunyit.edu/DND/Cisco_Router_Basics/icnecontent/ioscmdrefindex.ht

m

.Configure IP addresses:


.Verify IP addresses: (Point your browser at the following link :)

http://www.cicprep.com/WebHelp/ccna/ccna_obj_ 32.htm

.Monitor Novell IPX operation on the router:



.Enable the Novell IPX protocol & configure interfaces:



48/51

CCNA(640-607)



.Add the RIP routing protocol to your configuration:


.Add the IGRP routing protocol to your configuration:



.List commands to configure Frame Relay LMIs, maps, & subinterfaces:



.List commands to monitor Frame Relay operation in the router:


.Identify PPP operations to encapsulate WAN data on Cisco routers:


.Configure standard & extended access lists to filter IP traffic :


.Configure IPX access lists & SAP filters to control basic Novell traffic: (Point your browser at the following link :)


.Monitor & verify selected access list operations on the router:


49/51

CCNA(640-607)




.Copy & manipulate configuration files:



.List the commands to load Cisco IOS software from: flash memory, a TFTPserver, or ROM:



.Prepare to backup, upgrade, & load a backup Cisco IOS software image:

(Point your browser at the following link :)http://www.cicprep.com/WebHelp/ccna/ccna_obj_26.htm

.Manage configuration files from the Privileged exec mode :


. Configuring VLAN & VTP on Cisco Catalyst switch:

(Point your browser at the following linkS :)

http://netcert.tripod.com/ccna /switches/confvlan.html

http://www.mislab.com/lab_sample_vlan.htm

http://www.cs.rpi.edu/~kotfid/compnet1/labs/lab3-switch-vlan-rip-lab-2-even.html

Note: If purchasing a Cisco equipment (at least a router) is not an option, try topurchase (or arrange) Router Simulator(such as, Sybex, Boson etc) for CCNA


50/51

CCNA(640-607)



exam. Otherwise, make sure that you "understand & memorize" the Cisco CLIfundamentals from the provided links above precisely.

UUsseeffuullLLiinnkkss

(Comprehensive VLAN configurations details)

http://www.cisco.com/univercd/cc/td/doc/product/lan/28201900/1928v8x/eecli8x/clip

art2.htm#25568-----------------------------------------------------

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ita/index.htm

http://www.firewall.cx

http://www.geocities.com/ciscosite /ccna

http://www.cicprep.com/WebHelp/toclist.htm

http://www.delmar.edu/Courses/ITSC1391

http://www.celticrover.com/tig/ccna/ccnareviews.asp

http://www.aiinet.com/documents/aiscout2/m/111/sc2111bk.htm

http://www.ethermanage.com/ethernet/ethernet.html

http://searchnetworking.techtarget.com

Best of Luck.


51/51

CCNA in Short

Documents

Transcript of CCNA in Short