CCNA-Day1

Communications and Services Certifications

CCNA ExamExam Number - 640-801Total Marks - 1000Duration 90 MtsPassing score 849Questions -45-55Multiple ChoiceSimulationsDrag and Drop

BenefitsPeer ValidationPersonalPotential EmployerCareer advancement

Cisco Icons and Symbols

Data NetworksSharing data through the use of floppy disks is not an efficient or cost-effective manner.

Businesses needed a solution that would successfully address the following three problems: How to avoid duplication of equipment and resources How to communicate efficiently How to set up and manage a network

Businesses realized that networking technology could increase productivity while saving money.

Networking DevicesEquipment that connects directly to a network segment is referred to as a device.

These devices are broken up into two classifications. End-user devices Network devices

End-user devices include computers, printers, scanners, and other devices that provide services directly to the user.

Network devices include all the devices that connect the end-user devices together to allow them to communicate.

Network Interface CardA network interface card (NIC) is a printed circuit board that provides network communication capabilities to and from a personal computer. Also called a LAN adapter.

HubConnects a group of Hosts

SwitchSwitches add more intelligence to data transfer management.

RouterRouters are used to connect networks together Route packets of data from one network to another Cisco became the de facto standard of routers because of their high-quality router products Routers, by default, break up a broadcast domain

Network TopologiesNetwork topology defines the structure of the network.

One part of the topology definition is the physical topology, which is the actual layout of the wire or media.

The other part is the logical topology,which defines how the media is accessed by the hosts for sending data.

Bus TopologyA bus topology uses a single backbone cable that is terminated at both ends.

All the hosts connect directly to this backbone.

Ring TopologyA ring topology connects one host to the next and the last host to the first.

This creates a physical ring of cable.

Star TopologyA star topology connects all cables to a central point of concentration.

Extended Star TopologyAn extended star topology links individual stars together by connecting the hubs and/or switches.This topology can extend the scope and coverage of the network.

Mesh TopologyA mesh topology is implemented to provide as much protection as possible from interruption of service. Each host has its own connections to all other hosts. Although the Internet has multiple paths to any one location, it does not adopt the full mesh topology.

Physical and Logical Topology

LANs, MANs, & WANsOne early solution was the creation of local-area network (LAN) standards which provided an open set of guidelines for creating network hardware and software, making equipment from different companies compatible.

What was needed was a way for information to move efficiently and quickly, not only within a company, but also from one business to another.

The solution was the creation of metropolitan-area networks (MANs) and wide-area networks (WANs).

Virtual Private NetworkA VPN is a private network that is constructed within a public network infrastructure such as the global Internet. Using VPN, a telecommuter can access the network of the company headquarters through the Internet by building a secure tunnel between the telecommuters PC and a VPN router in the headquarters.

Bandwidth

Measuring Bandwidth

Internetworking Devices

What Are The Components Of A Network ?Main OfficeBranch Office Home Office Mobile UsersInternet

Network Structure & HierarchyDistribution LayerCore LayerAccessLayer

Institute of Electrical and Electronics Engineers (IEEE) 802 StandardsIEEE 802.1: Standards related to network management.

IEEE 802.2: General standard for the data link layer in the OSI Reference Model. The IEEE divides this layer into two sublayers -- the logical link control (LLC) layer and the media access control (MAC) layer.

IEEE 802.3: Defines the MAC layer for bus networks that use CSMA/CD. This is the basis of the Ethernet standard.

IEEE 802.4: Defines the MAC layer for bus networks that use a token-passing mechanism (token bus networks).

IEEE 802.5: Defines the MAC layer for token-ring networks.

IEEE 802.6: Standard for Metropolitan Area Networks (MANs)

Why do we need the OSI Model?To address the problem of networks increasing in size and in number, the International Organization for Standardization (ISO) researched many network schemes and recognized that there was a need to create a network model

This would help network builders implement networks that could communicate and work together

ISO therefore, released the OSI reference model in 1984.

Dont Get Confused.ISO - International Organization for Standardization

OSI - Open System Interconnection

IOS - Internetwork Operating SystemTo avoid confusion, some people say International Standard Organization.

The OSI Reference Model7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 PhysicalThe OSI Model will be used throughout your entire networking career!

Memorize it!

OSI ModelData Flow LayersTransportData-Link NetworkPhysical

Layer 7 - The Application Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 PhysicalEach of the layers have Protocol Data Unit (PDU)

Layer 6 - The Presentation Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Layer 5 - The Session Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Half DuplexIt uses only one wire pair with a digital signal running in both directions on the wire.

It also uses the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a collision does occur.

If a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions.

Half-duplex Ethernettypically 10BaseTis only about 30 to 40 percent efficient because a large 10BaseT network will usually only give you 3 to 4Mbpsat most.

Full DuplexIn a network that uses twisted-pair cabling, one pair is used to carry the transmitted signal from one node to the other node. A separate pair is used for the return or received signal. It is possible for signals to pass through both pairs simultaneously. The capability of communication in both directions at once is known as full duplex.

Layer 4 - The Transport Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Layer 3 - The Network Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Layer 2 - The Data Link Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Layer 1 - The Physical Layer7 Application6 Presentation5 Session4 Transport3 Network2 Data Link1 Physical

Data EncapsulationTransport Data-LinkPhysical Network Upper-Layer DataUpper-Layer DataTCP HeaderDataIP HeaderDataLLC Header0101110101001000010DataMAC HeaderPresentationApplicationSessionSegmentPacketBitsFramePDU

Data Encapsulation

OSI Model Analogy Application Layer - Source HostAfter riding your new bicycle a few times in Bangalore, you decide that you want to give it to a friend who lives in DADAR, Mumbai.

OSI Model Analogy Presentation Layer - Source HostMake sure you have the proper directions to disassemble and reassemble the bicycle.

OSI Model Analogy Session Layer - Source HostCall your friend and make sure you have his correct address.

OSI Model Analogy Transport Layer - Source HostDisassemble the bicycle and put different pieces in different boxes. The boxes are labeled 1 of 3, 2 of 3, and 3 of 3.

OSI Model Analogy Network Layer - Source HostPut your friend's complete mailing address (and yours) on each box.Since the packages are too big for your mailbox (and since you dont have enough stamps) you determine that you need to go to the post office.

OSI Model Analogy Data Link Layer Source HostBangalore post office takes possession of the boxes.

OSI Model Analogy Physical Layer - MediaThe boxes are flown from Bangalore to Mumbai.

OSI Model Analogy Data Link Layer - DestinationDadar post office receives your boxes.

OSI Model Analogy Network Layer - DestinationUpon examining the destination address, Dadar post office determines that your boxes should be delivered to your written home address.

OSI Model Analogy Transport Layer - DestinationYour friend calls you and tells you he got all 3 boxes and he is having another friend named BOB reassemble the bicycle.

OSI Model Analogy Session Layer - DestinationYour friend hangs up because he is done talking to you.

OSI Model Analogy Presentation Layer - DestinationBOB is finished and presents the bicycle to your friend. Another way to say it is that your friend is finally getting him present.

OSI Model Analogy Application Layer - DestinationYour friend enjoys riding his new bicycle in Dadar.

Data Flow Through a Network

Type of TransmissionUnicastMulticastBroadcast

Type of Transmission

Broadcast DomainA group of devices receiving broadcast frames initiating from any device within the group

Routers do not forward broadcast frames, broadcast domains are not forwarded from one broadcast to another.

CollisionThe effect of two nodes sending transmissions simultaneously in Ethernet. When they meet on the physical media, the frames from each node collide and are damaged.

Collision DomainThe network area in Ethernet over which frames that have collided will be detected. Collisions are propagated by hubs and repeatersCollisions are Not propagated by switches, routers, or bridges

Physical LayerDefinesMedia type Connector type Signaling typeEthernet802.3V.35PhysicalEIA/TIA-232802.3 is responsible for LANs based on the carrier sense multiple access collision detect (CSMA/CD) access methodology. Ethernet is an example of a CSMA/CD network.

Physical Layer: Ethernet/802.3HubHostsHost10Base2Thin Ethernet 10Base5Thick Ethernet10BaseTTwisted Pair

Device Used At Layer 1Physical All devices are in the same collision domain.All devices are in the same broadcast domain.Devices share the same bandwidth.

Hubs & Collision DomainsMore end stations means more collisions.CSMA/CD is used.

Layer 2DataSource AddressFCSLengthDestination AddressVariable26640000.0C xx.xxxxVendor AssignedIEEE AssignedMAC Layer802.3PreambleEthernet II uses Type here and does not use 802.2.MAC Address8Number of Bytessynchronize senders and receivers

Devices On Layer 2(Switches & Bridges)Each segment has its own collision domain.All segments are in the same broadcast domain.Data-LinkOR12312

SwitchesEach segment is its own collision domain.Broadcasts are forwarded to all segments.MemorySwitch

Layer 3 : Network Layer

Defines logical source and destination addresses associated with a specific protocolDefines paths through networkNetworkIP, IPXData-LinkPhysicalEIA/TIA-232V.35EthernetFrame RelayHDLC802.2802.3

Layer 3 : (cont.)DataSource AddressDestination AddressIPHeader172.15.1.1NodeNetworkLogical AddressNetwork Layer End-Station PacketRoute determination occurs at this layer, so a packet must include a source and destination address.Network-layer addresses have two components: a network component for internetwork routing, and a node number for a device-specific address. The example in the figure is an example of an IP packet and address.

Layer 3 (cont.) 11111111 11111111 00000000 00000000 10101100 00010000 01111010 11001100Binary MaskBinary Address172.16.122.204 255.255.0.017216122204255AddressMask25500NetworkHost

Device On Layer 3RouterBroadcast controlMulticast controlOptimal path determinationTraffic managementLogical addressingConnects to WAN services

Layer 4 : Transport LayerDistinguishes between upper-layer applicationsEstablishes end-to-end connectivity between applicationsDefines flow control Provides reliable or unreliable services for data transfer

NetworkIPXIPTransportSPXTCPUDP

Reliable ServiceSynchronizeAcknowledge, SynchronizeAcknowledgeData Transfer(Send Segments)SenderReceiverConnection Established

How They OperateHubBridgeSwitchRouterCollision Domains:1 4 4 4 Broadcast Domains:1 1 1 4

Why Another Model?Although the OSI reference model is universally recognized, the historical and technical open standard of the Internet is Transmission Control Protocol / Internet Protocol (TCP/IP). The TCP/IP reference model and the TCP/IP protocol stack make data communication possible between any two computers, anywhere in the world, at nearly the speed of light.The U.S. Department of Defense (DoD) created the TCP/IP reference model because it wanted a network that could survive any conditions, even a nuclear war.

TCP/IP Protocol Stack7654325432ApplicationPresentationSessionTransportNetworkData-LinkPhysical1ApplicationTransportInternetData-LinkPhysical1

Application Layer Overview*Used by the RouterApplicationTransportInternetData-LinkPhysicalFile Transfer- TFTP*- FTP*- NFSE-Mail- SMTPRemote Login- Telnet*- rlogin*Network Management- SNMP*Name Management- DNS*

Transport Layer OverviewTransmission ControlProtocol (TCP)

User Datagram Protocol (UDP)ApplicationTransportInternetData-LinkPhysicalConnection-Oriented Connectionless

TCP Segment FormatSource Port (16)Destination Port (16)Sequence Number (32)Header Length (4)Acknowledgment Number (32)Reserved (6)Code Bits (6)Window (16)Checksum (16)Urgent (16)Options (0 or 32 if Any)Data (Varies)20 BytesBit 0Bit 15Bit 16Bit 31

Port NumbersTCPPort NumbersF T PTransport LayerT E L N E TD N SS N M PT F T PS M T PUDPApplication Layer2123255369161R I P520

TCP Port NumbersSourcePortDestinationPortHost A102823SPDPHost ZTelnet ZDestination port = 23. Send packet to my Telnet application.

TCP Port Numbers

TCP Three-Way Handshake/Open ConnectionSend SYN (seq = 100 ctl = SYN)SYN ReceivedSend SYN, ACK (seq = 300 ack = 101 ctl = syn,ack)Established(seq = 101 ack = 301 ctl = ack)Host AHost BSYN Received

Opening & Closing Connection

WindowingWindowing in networking means the quantity of data segments which is measured in bytes that a machine can transmit/send on the network without receiving an acknowledgement

TCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2Receive ACK 3Send ACK 3Send 3Receive 3Receive ACK 4Send ACK 4

TCP Sequence and Acknowledgment NumbersSourcePortDestinationPortSequence

Acknowledgment

102823SourceDest.11Seq.101Ack.102823SourceDest.10Seq.100Ack.102823SourceDest.11Seq.100Ack.102823SourceDest.12Seq.101Ack.I just got number11, now I need number 12.I justsent number11.

Windowing

There are two window sizesone set to 1 and one set to 3. When youve configured a window size of 1, the sending machine waits for an acknowledgment for each data segment it transmits before transmitting anotherIf youve configured a window size of 3, its allowed to transmit three data segments before an acknowledgment is received.

Windowing

Transport Layer Reliable Delivery

Flow ControlAnother function of the transport layer is to provide optional flow control.

Flow control is used to ensure that networking devices dont send too much information to the destination, overflowing its receiving buffer space, and causing it to drop the sent information

The purpose of flow control is to ensure the destination doesn't get overrun by too much information sent by the source

Flow ControlSEQ 1024SEQ 2048SEQ 3072AB30723Ack 3073 Win 0Ack 3073 Win 3072

User Datagram Protocol (UDP)User Datagram Protocol (UDP) is the connectionless transport protocol in the TCP/IP protocol stack.

UDP is a simple protocol that exchanges datagrams, without acknowledgments or guaranteed delivery. Error processing and retransmission must be handled by higher layer protocols.

UDP is designed for applications that do not need to put sequences of segments together.

The protocols that use UDP include: TFTP (Trivial File Transfer Protocol) SNMP (Simple Network Management Protocol) DHCP (Dynamic Host Control Protocol) DNS (Domain Name System)

UDP Segment FormatNo sequence or acknowledgment fieldsSource Port (16)Destination Port (16)Length (16)Data (if Any)1Bit 0Bit 15Bit 16Bit 31Checksum (16)8 Bytes

TCP vs UDP

Internet Layer OverviewIn the OSI reference model, the network layer corresponds to the TCP/IP Internet layer.Internet Protocol (IP)

Internet Control MessageProtocol (ICMP)

Address ResolutionProtocol (ARP)

Reverse AddressResolution Protocol (RARP)ApplicationTransportInternetData-LinkPhysical

IP DatagramVersion (4)Destination IP Address (32)Options (0 or 32 if Any)Data (Varies if Any)1Bit 0Bit 15Bit 16Bit 31Header Length (4)Priority &Type of Service (8)Total Length (16)Identification (16)Flags (3)Fragment Offset (13)Time-to-Live (8)Protocol (8)Header Checksum (16)Source IP Address (32)20 Bytes

Protocol FieldDetermines destination upper-layer protocol Transport LayerInternet LayerTCPUDPProtocol NumbersIP176

Internet Control Message ProtocolApplicationTransportInternetData-LinkPhysicalDestination Unreachable

Echo (Ping)

OtherICMP1

Address Resolution ProtocolMap IP MAC Local ARP172.16.3.1IP: 172.16.3.2 Ethernet: 0800.0020.1111 172.16.3.2IP: 172.16.3.2 = ???

Reverse ARP Map MAC IP

Ethernet: 0800.0020.1111IP: 172.16.3.25Ethernet: 0800.0020.1111 IP = ???What is my IP address?I heard that broadcast. Your IP address is 172.16.3.25.

Found by Xerox Palo Alto Research Center (PARC) in 1975Original designed as a 2.94 Mbps system to connect 100 computers on a 1 km cableLater, Xerox, Intel and DEC drew up a standard support 10 Mbps Ethernet IIBasis for the IEEEs 802.3 specificationMost widely used LAN technology in the worldOrigin of Ethernet

10 Mbps IEEE Standards - 10BaseT 10BaseT 10 Mbps, baseband, over Twisted-pair cable Running Ethernet over twisted-pair wiring as specified by IEEE 802.3Configure in a star patternTwisting the wires reduces EMIFiber Optic has no EMIUnshielded twisted-pair RJ-45 Plug and Socket

Unshielded Twisted Pair Cable (UTP)most popularmaximum length 100 mprone to noiseTwisted Pair Cables

Category 1

Category 2

Category 3

Category 4

Category 5

Category 6

Voice transmission of traditional telephone

For data up to 4 Mbps, 4 pairs full-duplex





Baseband TransmissionEntire channel is used to transmit a single digital signalComplete bandwidth of the cable is used by a single signalThe transmission distance is shorterThe electrical interference is lower

Broadband TransmissionUse analog signaling and a range of frequenciesContinuous signals flow in the form of wavesSupport multiple analog transmission (channels)ModemBroadband TransmissionNetwork CardBaseband TransmissionBaseband VS Broadband

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Sheet2

Sheet3

Straight-through cable

Straight-through cable pinout

Crossover cable

Rollover cable

Rollover cable pinout

Straight-Thru or CrossoverUse straight-through cables for the following cabling: Switch to router Switch to PC or server Hub to PC or server

Use crossover cables for the following cabling: Switch to switch Switch to hub Hub to hub Router to router PC to PC Router to PC

Decimal to Binary100 = 1101 = 10102 = 100103 = 10001101001000172 Base 10124816326412810101100 Base 220 = 121 = 222 = 423 = 824 = 1625 = 3226 = 6427 = 12810101100172270100

17200480320128

172

Base 2 Number System101102 = (1 x 24 = 16) + (0 x 23 = 0) + (1 x 22 = 4) + (1 x 21 = 2) + (0 x 20 = 0) = 22

Converting Decimal to BinaryConvert 20110 to binary: 201 / 2 = 100 remainder 1 100 / 2 = 50 remainder 0 50 / 2 = 25 remainder 0 25 / 2 = 12 remainder 1 12 / 2 = 6 remainder 0 6 / 2 = 3 remainder 0 3 / 2 = 1 remainder 1 1 / 2 = 0 remainder 1When the quotient is 0, take all the remainders in reverse order for your answer: 20110 = 110010012

Binary to Decimal Chart

Hex to Binary to Decimal Chart

Introduction to TCP/IP AddressesUnique addressing allows communication between end stations.Path choice is based on destination address.Location is represented by an address172.18.0.2172.18.0.1172.17.0.2172.17.0.1172.16.0.2172.16.0.1SADAHDRDATA10.13.0.0192.168.1.010.13.0.1192.168.1.1

IP Addressing 255255 255 255Dotted DecimalMaximumNetworkHost128 64 32 16 8 4 2 1 11111111 11111111 11111111 11111111 10101100 00010000 01111010 11001100Binary32 Bits 172 16 122 204Example DecimalExample Binary1891617242532128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1

IP Address ClassesClass A: Class B: Class C: Class D: Multicast Class E: Research8 Bits8 Bits8 Bits8 Bits

IP Address Classes1Class A:Bits:0NNNNNNNHostHostHost891617242532Range (1-126)1Class B:Bits:10NNNNNNNetworkHostHost891617242532Range (128-191)1Class C:Bits:110NNNNNNetworkNetworkHost891617242532Range (192-223)1Class D:Bits:1110MMMMMulticast GroupMulticast GroupMulticast Group891617242532Range (224-239)

Host Addresses172.16.2.2172.16.3.10172.16.12.1210.1.1.110.250.8.1110.180.30.118E1172.161212NetworkHost..NetworkInterface172.16.0.010.0.0.0E0E1Routing Table172.16.2.110.6.24.2E0

Classless Inter-Domain Routing (CIDR)Basically the method that ISPs (Internet Service Providers) use to allocate an amount of addresses to a company, a home Ex : 192.168.10.32/28 The slash notation (/) means how many bits are turned on (1s)

CIDR Values

Determining Available Host Addresses 11111111 172 16 0 0 10101100 00010000 00000000 0000000016 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 NetworkHost 00000000 00000001 11111111 11111111 11111111 11111110...... 00000000 00000011 11111101123655346553565536...265534N2N 2 = 216 2 = 65534

IP Address Classes ExerciseAddressClassNetworkHost10.2.1.1128.63.2.100201.222.5.64192.6.141.2130.113.64.16256.241.201.10

IP Address Classes Exercise AnswersAddressClassNetworkHost10.2.1.1128.63.2.100201.222.5.64192.6.141.2130.113.64.16256.241.201.10ABCCBNonexistent10.0.0.0128.63.0.0201.222.5.0192.6.141.0130.113.0.00.2.1.10.0.2.1000.0.0.640.0.0.20.0.64.16

SubnettingSubnetting is logically dividing the network by extending the 1s used in SNMAdvantageCan divide network in smaller partsRestrict Broadcast trafficSecuritySimplified Administration

FormulaNumber of subnets 2x-2Where X = number of bits borrowed

Number of Hosts 2y-2Where y = number of 0s

Block Size = Total number of AddressBlock Size = 256-Mask

SubnettingClassful IP Addressing SNM are a set of 255s and 0s.In Binary its contiguous 1s and 0s.SNM cannot be any value as it wont follow the rule of contiguous 1s and 0s.Possible subnet mask values0128192224240248252254255

Addressing Without SubnetsNetwork 172.16.0.0172.16.0.0172.16.0.1172.16.0.2172.16.0.3...172.16.255.253172.16.255.254

Addressing with SubnetsNetwork 172.16.0.0172.16.1.0172.16.2.0172.16.3.0172.16.4.0

Subnet Addressing172.16.2.200172.16.2.2172.16.2.160172.16.2.1172.16.3.5172.16.3.100172.16.3.150E0172.16NetworkNetworkInterface172.16.0.0172.16.0.0E0E1New Routing Table 2160Host..172.16.3.1E1

Subnet Addressing172.16.2.200172.16.2.2172.16.2.160172.16.2.1172.16.3.5172.16.3.100172.16.3.150172.16.3.1E0E1172.162160NetworkHost..NetworkInterface172.16.2.0172.16.3.0E0E1New Routing TableSubnet

Subnet Mask25525500IP AddressDefault Subnet Mask8-Bit Subnet MaskNetworkHostNetworkHostNetworkSubnetHostAlso written as /16, where 16 represents the number of 1s in the maskAlso written as /24, where 24 represents the number of 1s in the mask

11111111 111111110000000000000000

Decimal Equivalents of Bit Patterns00000000=010000000=12811000000=19211100000=22411110000=24011111000=24811111100=25211111110=25411111111=255128 6432168421

Subnet Mask Without SubnetsSubnets not in usethe default16NetworkHost17200101011001111111110101100000100001111111100010000000000000000000010100000000000000000000000000010172.16.2.160 255.255.0.0Network Number

Subnet Mask with SubnetsNetwork number extended by eight bits16NetworkHost172.16.2.160 255.255.255.017220101011001111111110101100000100001111111100010000111111110000001010100000000000000000000000000010SubnetNetwork Number128192224240248252254255

Subnet Mask with Subnets (cont.)Network number extended by ten bitsNetworkHost172.16.2.160 255.255.255.192101011001111111110101100000100001111111100010000111111110000001010100000110000001000000000000010Subnet161722128Network Number128192224240248252254255128192224240248252254255

Subnet Mask ExerciseAddressSubnet MaskClassSubnet172.16.2.1010.6.24.2010.30.36.12255.255.255.0255.255.240.0255.255.255.0

Subnet Mask Exercise AnswersAddressSubnet MaskClassSubnet172.16.2.1010.6.24.2010.30.36.12255.255.255.0255.255.240.0255.255.255.0BAA172.16.2.010.6.16.010.30.36.0

Broadcast Addresses172.16.1.0172.16.2.0172.16.3.0172.16.4.0172.16.3.255(Directed Broadcast)255.255.255.255(Local Network Broadcast)X172.16.255.255(All Subnets Broadcast)

Addressing Summary Example101011001111111110101100000100001111111100010000111111110000001010100000110000001000000000000010101011000001000000000010101111111010110000010000000000101000000110101100000100000000001010111110HostMaskSubnetBroadcastLastFirst172.16.2.160255.255.255.192172.16.2.128172.16.2.191172.16.2.129172.16.2.190123456789161722160

Class B Subnet ExampleSubnet Address = 172.16.2.0Host Addresses = 172.16.2.1172.16.2.254Broadcast Address = 172.16.2.255Eight Bits of SubnettingIP Host Address:172.16.2.121Subnet Mask: 255.255.255.0NetworkSubnetHost10101100000100000000001011111111172.16.2.121:255.255.255.0:1010110011111111Subnet:1010110000010000000100001111111100000010000000101111111101111001 0000000000000000Broadcast:Network

Subnet PlanningOther Subnets192.168.5.16192.168.5.32192.168.5.4820 Subnets5 Hosts per SubnetClass C Address: 192.168.5.0

Class C Subnet Planning ExampleSubnet Address = 192.168.5.120Host Addresses = 192.168.5.121192.168.5.126Broadcast Address = 192.168.5.127Five Bits of Subnetting11111000IP Host Address:192.168.5.121Subnet Mask: 255.255.255.248NetworkSubnetHost192.168.5.121:1100000011111111Subnet:1100000010101000101010001111111100000101000001011111111101111001 01111000255.255.255.248:Broadcast:NetworkNetwork11000000101010000000010101111111

Exercise192.168.10.0/27

? SNM? Block Size?- Subnets

Exercise/27

? SNM 224? Block Size = 256-224 = 32?- Subnets

Exercise192.168.10.0/30

? SNM? Block Size?- Subnets

Exercise/30

? SNM 252? Block Size = 256-252 = 4?- Subnets

Exercise

Exam QuestionFind Subnet and Broadcast address192.168.0.100/27

Exercise192.168.10.54 /29Mask ?Subnet ?Broadcast ?

Class B172.16.0.0 /19Subnets ?Hosts ?Block Size ?

Class B172.16.0.0 /19Subnets 23 -2 = 6Hosts 213 -2 = 8190Block Size 256-224 = 32

Find out Subnet and Broadcast Address172.16.85.30/20

ExerciseFind out the mask which gives 100 subnets for class B

ExerciseFind out the Mask which gives 100 hosts for Class B

Class A10.0.0.0 /10Subnets ?Hosts ?Block Size ?

Class A10.0.0.0 /10Subnets 22 -2 = 2Hosts 222 -2 = 4194302Block Size 256-192 = 64

Class A10.0.0.0 /18Subnets ?Hosts ?Block Size ?

Class A10.0.0.0 /18Subnets 210 -2 = 1022Hosts 214 -2 = 16382Block Size 256-192 = 64

Broadcast Addresses ExerciseAddressClassSubnetBroadcast201.222.10.60 255.255.255.248Subnet Mask15.16.193.6 255.255.248.0128.16.32.13 255.255.255.252153.50.6.27 255.255.255.128

Broadcast Addresses Exercise Answers153.50.6.127AddressClassSubnetBroadcast201.222.10.60 255.255.255.248C201.222.10.63201.222.10.56Subnet Mask15.16.193.6 255.255.248.0A15.16.199.25515.16.192.0128.16.32.13 255.255.255.252B128.16.32.15128.16.32.12153.50.6.27 255.255.255.128B153.50.6.0

VLSMVLSM is a method of designating a different subnet mask for the same network number on different subnets

Can use a long mask on networks with few hosts and a shorter mask on subnets with many hosts

With VLSMs we can have different subnet masks for different subnets.

Variable Length SubnettingVLSM allows us to use one class C address to design a networking scheme to meet the following requirements:Bangalore60 HostsMumbai 28 HostsSydney12 HostsSingapore12 HostsWAN 1 2 HostsWAN 2 2 HostsWAN 3 2 Hosts

Networking RequirementsBangalore 60Mumbai 60Sydney 60Singapore 60WAN 1WAN 2WAN 3In the example above, a /26 was used to provide the 60 addresses for Bangalore and the other LANs. There are no addresses left for WAN links

Networking Scheme Mumbai 192.168.10.64/27Bangalore 192.168.10.0/26Sydney 192.168.10.96/28Singapore 192.168.10.112/28WAN 192.168.10.129 and 130WAN 192.198.10.133 and 134WAN 192.198.10.137 and 13860121228222192.168.10.128/30192.168.10.136/30192.168.10.132/30

VLSM Exercise222402512192.168.1.0

VLSM Exercise222402512192.168.1.0192.168.1.4/30192.168.1.8/30192.168.1.12/30192.168.1.16/28192.168.1.32/27192.168.1.64/26

VLSM Exercise228155192.168.1.02235

SummarizationSummarization, also called route aggregation, allows routing protocols to advertise many networks as one address. The purpose of this is to reduce the size of routing tables on routers to save memoryRoute summarization (also called route aggregation or supernetting) can reduce the number of routes that a router must maintainRoute summarization is possible only when a proper addressing plan is in placeRoute summarization is most effective within a subnetted environment when the network addresses are in contiguous blocks

Summarization

SupernettingNetworkSubnet172.16.12.0110000001111111110101000111111110000110011111111255.255.255.0NetworkNetwork000000000000000016 8 4 2 1172.16.13.011000000101010000000110100000000172.16.14.011000000101010000000111000000000172.16.15.011000000101010000000111100000000

SupernettingNetworkSubnet172.16.12.0110000001111111110101000111111110000110011111100255.255.252.0NetworkNetwork000000000000000016 8 4 2 1172.16.13.011000000101010000000110100000000172.16.14.011000000101010000000111000000000172.16.15.011000000101010000000111100000000172.16.12.0/24172.16.13.0/24172.16.14.0/24172.16.15.0/24

172.16.12.0/22

Supernetting QuestionWhat is the most efficient summarization that TK1 can use to advertise its networks to TK2?

A. 172.1.4.0/24172.1.5.0/24172.1.6.0/24172.1.7.0/24B. 172.1.0.0/22C. 172.1.4.0/25172.1.4.128/25172.1.5.0/24172.1.6.0/24172.1.7.0/24D. 172.1.0.0/21E. 172.1.4.0/22172.1.7.0/24172.1.6.0/24172.1.5.0/24172.1.4.128/25172.1.4.128/25

True/FalseMultiple ChoiceSelect the Correct AnswerSelect the Three Correct AnswersSelect All That ApplyType the command for viewing routes learned from an IP routing protocol. SimulationsPeer Validation u understanding where u stand in the industryPersonal - For knowledge gainPotential Employer During the interview the company will filter by the certificationCareer Advancement CCNA, CCNP, CCIE You can progress ur carrer in ur company

When you are cabling up your computers and networking devices, various types of topologies can be used. A topology defines how the devices are connected. Metropolitan Area NetworksA metropolitan area network (MAN) is a hybrid between a LAN and a WAN. Like a WAN, it connects two or more LANs in the same geographic area. A MAN, for example, might connect two different buildings or offices in the same city. However, whereas WANs typically provide low- to medium-speed access, MANs provide high-speed connections, such as T1 (1.544Mbps) and optical services.The optical services provided include SONET (the Synchronous Optical Network standard) and SDH (the Synchronous Digital Hierarchy standard). With these optical services, carriers can provide high-speed services, including ATM and Gigabit Ethernet. These two optical services (covered in Chapter 2) provide speeds ranging into the hundreds or thousands of megabits per second (Mbps). Devices used to provide connections for MANs include high-end routers, ATM switches, and optical switches.A VPN typically provides authentication, confidentiality, and integrity to create a secure connection between two sites or devices. Authentication is provided to validate the identities of the two peers. Confidentiality provides encryption of the data to keep it private from prying eyes. And integrity is used to ensure that the data sent between the two devices or sites has not been tampered with. When you looked at Figure 1.1, did you notice that the router is found at center stage, and that it connects each physical network together? We have to use this layout because of the older technologies involvedbridges and hubs. Once we have only switches in our network, things change a lot! The LAN switches would then be placed at the center of the network world and the routers would be found connecting only logical networks together. If Ive implemented this kind of setup, Ive created virtual LANs (VLANs). On the top network in Figure 1.1, youll notice that a bridge was used to connect the hubs to a router. The bridge breaks up collision domains, but all the hosts connected to both hubs are still crammed into the same broadcast domain. Also, the bridge only created two collision domains, so each device connected to a hub is in the same collision domain as every other device connected to that same hub. This is pretty lame, but its still better than having one collision domain for all hosts.Notice something else: the three hubs at the bottom that are connected also connect to the router, creating one humongous collision domain and one humongous broadcast domain. This makes the bridged network look much better indeed!Core Layer BackboneDist Layer- to connect Access layer to Core LayerAccess Layer is the layer where all the end users reside

Core LayerThe core layer, as its name suggests, is the backbone of the network. It provides a high speed connection between the different distribution layer devices. Because of the need for high-speed connections, the core consists of high-speed switches and will not, typically, perform any type of packet or frame manipulations, Because switches are used at the core, the core is referred to as a layer-2 coreExam Watch The core provides a high-speed layer-2 switching infrastructure and typically does not manipulate packet contents.

Distribution LayerOf the three layers, the distribution layer performs most of the connectivity tasks. In larger networks, routers are used at the distribution layer to connect the access layers to the core. For smaller networks, sometimes switches are used.

Functions :-Containing broadcasts between the layers

Securing traffic between the layers

Providing a hierarchy through layer-3 logical addressing and route summarization

Translating between different media types

Access LayerThe bottom layer of the three-layer hierarchical model is the access layer. Actually, the access layer is at the periphery of your campus network, separated from the core layer by the distribution layer. The main function of the access layer is to provide the users initial connection to your network. Typically, this connection is provided by a switch, or sometimes, a hub. Sometimes if the user works at a small branch office or home office, this device can also be a router. But in most cases, the connection is provided by a switch.

IEEE is an organization composed of engineers, scientists, and students. The IEEE is best known for developing standards for the computer and electronics industryBefore OSI it was difficult for the vendors to create network products OSI, why U need to study, its a structured approach to troubleshoot

Each has independent modelBefore considering how to configure Cisco routers and switches, you must be introduced to basic networking concepts youll need to understand in order to grasp the advanced concepts discussed in later chapters

ISO developed the seven-layer top (seventh) layer of the OSI Reference Model is the application layer. It provides the user interface. Examples of TCP/IP applications include telnet, FTP, HTTP, and SMTP. The Presentation layer gets its name from its purpose: It presents data to the Application layer and is responsible for data translation and code formattingExam WatchThe presentation layer determines how data is represented to the user. Examples of presentation layer protocols and standards include ASCII, BMP, GIF, JPEG, WAV, AVI, and MPEG.ASCII (the American Standard Code for Information Interchange, used by most devices today) uses seven bits to represent characters. EBCDIC (Extended Binary-Coded Decimal Interchange Code, developed by IBM)

PICT A picture format used by Macintosh programs for transferring QuickDraw graphics.TIFF Tagged Image File Format; a standard graphics format for high-resolution, bitmapped images.JPEG Photo standards brought to us by the Joint Photographic Experts Group. Other standards guide movies and sound:MIDI Musical Instrument Digital Interface (sometimes called Musical Instrument Device Interface), used for digitized music.MPEG Increasingly popular Moving Picture Experts Group standard for the compression and coding of motion video for CDs. It provides digital storage and bit rates up to 1.5Mbps.QuickTime For use with Macintosh programs; manages audio and video applications.RTF Rich Text Format, a file format that lets you exchange text files between different word processors, even in different operating systems.

Categorize as file type

Exam WatchThe session layer is responsible for setting up and tearing down network connections. Examples include RPCs and NFS.The actual mechanics of this process, however, are implemented at the transport layer. To set up connections or tear down connections, the session layer communicates with the transport layer. Remote Procedure Call (RPC) is an example of an IP session protocol; the Network File System (NFS), which uses RPC, is an example application at this layer.Full duplex means you can send and receive at the same time. This was impossible on coax, the original Ethernet media since it had only 1 conductor and Ethernet uses baseband signaling. However, 10BaseT and 100BaseT use a cable with 4 conductors. (Actually, there are typically 8 conductors but only 4 are used.) 1 pair of conductors is used to send data and the other to receive data. Each pair are also twisted around each other to help eliminate noise, hence the name unshielded twisted pair. With the right hardware you can theoretically double the speed of your network by sending and receiving simultaneously. Of course its a rare environment that has so much data to send in both directions but full duplex will give you a performance boost because you no longer have to wait for 1 host to finish sending before you start to send your data, i.e. a deferral Protocol Data Unit. The term used to describe data as it moves from one layer of the OSI model to another. Preamble is sequence of 1s and 0s signifies the beginning of a frameDataLen decides the length of Data, can be 64 to 1500 Bytes is called as MTUFCS is used for error detectionCRC run on the data field and and the values is kept in FCS

The data is in Bits bits are converted to signals known as encodingThe physical layer is also responsible for how binary information is converted to a physical layer signal. For example, if the cable uses copper as a transport medium, the physical layer defines how binary 1s and 0s are converted into an electrical signal by using different voltage levels. If the cable uses fiber, the physical layer defines how 1s and 0s are represented using an LED or laser with different light frequenciesExam WatchMake sure you understand the mechanics of Ethernet: CSMA/CD. No device has priority over another device. If two devices transmit simultaneously, a collision occurs. When this happens, a jam signal is generated and the devices try to retransmit after waiting a random period.If two or more machines simultaneously sense the wire and see no frame, and each places its frame on the wire, a collision will occur. In this situation, the voltage levels on a copper wire or the light frequencies on a piece of fiber get messed up. For example, if two NICs attempt to put the same voltage on an electrical piece of wire, the voltage level will be different than if only one device does so. Basically, the two original frames become unintelligible (or undecipherable). The NICs, when they place a frame on the wire, examine the status of the wire to ensure that a collision does not occur: this is the collision detection mechanism of CSMA/CD.If the NICs see a collision for their transmitted frames, they have to resend the frames. In this instance, each NIC that was transmitting a frame when a collision occurred creates a special signal, called a jam signal, on the wire, waits a small random time period, and senses the wire again. If no frame is currently on the wire, the NIC will then retransmit its original frame. The time period that the NIC waits is measured in microseconds, a delay that cant be detected by a human. Likewise, the time period the NICs wait is random to help ensure a collision wont occur again when these NICs retransmit their frames.The more devices you place on a segment, the more likely you are to experience collisions. If you put too many devices on the segment, too many collisions will occur, seriously affecting your throughput. Therefore, you need to monitor the number of collisions on each of your network segments. The more collisions you experience, the less throughput youll get. Normally, if your collisions are less than one percent of your total traffic, you are okay. This is not to say that collisions are badthey are just one part of how Ethernet functions.Tk-10-7IEEEs Version of EthernetThere are actually two variants of Ethernet: IEEEs implementation and the DIX implementation. Ethernet was developed by three different companies in the early 1980s: Digital, Intel, and Xerox, or DIX for short. This implementation of Ethernet has evolved over time; its current version is called Ethernet II. Devices running TCP/IP typically use the Ethernet II implementation.The second version of Ethernet was developed by IEEE and is standardized in the IEEE 802.2 and 802.3 standards. IEEE has split the data link layer into two components: MAC and LLC. These components are described in Table 2-5. The top part of the data link layer is the LLC, and its function is performed in software. The bottom part of the data link layer is the MAC, and its function is performed in hardware.

Logical Link Control (LLC) 802.2 Defines how to multiplex multiple network layer protocols in the data link layer frame. LLC is performed in software.

MAC 802.3 Defines how information is transmitted in an Ethernet environment, and defines the framing, MAC addressing, and mechanics as to how Ethernet works. MAC is performed in hardware TK16-15Logical Addressing scenario ExplainAnother function of the transport layer is to set up and maintain connections for the session layer. The information transferred to devices at the transport layer is called a segment. Because multiple connections may be established from one device to another device or devices, some type of multiplexing function is needed to differentiate between the various connections. This ensures that the transport layer can send data from a particular application to the correct destination and, when receiving data from a destination, get it to the right application.To accomplish this feat, the transport layer assigns a unique set of numbers for each connection. These numbers are called port or socket numbers. There is a source port number and a destination port number for each connection. The destination port numbers assigned by the source device are referred to as well-known port numbers. The source device uses an appropriate port number in the destination port field to indicate to the destination which application it is trying to access. For example, the TCP/IP protocol stack gives each application a unique port number. A DNS query is a good example where using a connection-oriented service doesnt make sense. With a DNS query, a device is trying to resolve a fully qualified domain name to an IP address. The device sends the single query to a DNS server and waits for the servers response. In this process, only two messages are generated: the clients query and the servers response. Because of the minimal amount of information shared between these two devices, it makes no sense to establish a reliable connection first before sending the query. Instead, the device should just send its information and wait for a response. If a response doesnt come back, the application can send the information again or the user can get involved. Again, with DNS, you can configure two DNS servers in the Microsoft Windows operating system. If you dont get a reply from the first server, the application can use the second configured server. Purpose: This figure shows the protocol layers and compares them with the layers of the OSI reference model.Emphasize: This figure shows the TCP/IP conceptual layer titles. The protocol stack is used several times in this chapter, and the lower two layers may be sometimes called the network interface layer.The terms packet and datagram are nearly interchangeable. However, a datagram is a unit of data, while a packet is a physical entity that appears on a network. In most cases, a packet contains a datagram. In some protocols, however, a datagram is divided into a number of packets to accommodate a requirement for smaller, transmittable pieces.Note: Creation and documentation of the Internet protocols closely resembles an academic research project. The protocols are specified in documents called RFCs. RFCs are published, reviewed, and analyzed by the Internet community.

Purpose: This figure discusses application-layer protocols. Emphasize: The common network applications today include file transfer, remote login, network management, and e-mail.We focus on TCP/IP in this course for several reasons: TCP/IP is a universally available protocol and you will use it at work. TCP/IP is a useful reference for understanding other protocols, because it includes elements that are representative of other protocols. TCP/IP is important because the router uses it as a configuration tool. The router uses Telnet for remote configuration, TFTP to transfer configuration files and operating system images, and SNMP for network management. Transition: The next section moves down the model to discuss the transport layer.

Purpose: This figure introduces the protocols used at the transport layer.Emphasize: TCP is one protocol within the protocol suite of TCP/IP. TCP is an acknowledged transport-layer protocol. However, TCP has a large header so there is much overhead.UDP is unacknowledged. By eliminating all of the acknowledgement mechanisms, UDP is fast and efficient. UDP does not divide application data into pieces. Reliability is assumed to be handled by the upper-layer protocols, by a reliable lower-layer protocol, or by an error-tolerant application. UDP does have a smaller header and less overhead.

Purpose: This figure explains what is contained in a TCP segment. Emphasize: Source Port and Destination Port are the connections to the upper-layer protocol.Sequence and Acknowledgment numbers are the position in the users byte stream of this segment. Sequence numbers are used for establishing reliability.HLEN is the header length. It tells us where the data begins.Six bits are reserved for future use.Code Bits distinguish session management messages from data.Window is a term we will come back to in a few slides. For now, consider it to be the size of the receivers buffers.Checksum is a cyclic redundancy check (CRC). It verifies that the datagram arrived intact.Urgent Pointer is used to signify urgent data.- To deal with situations where a certain part of a data stream needs to be sent with a higher priority than the rest, TCP incorporates an urgent function. When critical data needs to be sent, the application signals this to its TCP layer, which transmits it with the URG bit set in the TCP segment, bypassing any lower-priority data that may have already been queued for transmissionOptions are used by vendors to enhance their protocol offering.The data portion of the frame contains the upper-layer protocol data.Purpose: This figure explains how TCP uses port numbers to connect applications. Emphasize: These port numbers were standardized in RFC 1340. This RFC has been obsoleted by RFC 1700. However, many of the port numbers outlined in RFC 1340 are still being used as standards. It is possible to filter on TCP port numbers.The TCP port number, combined with other information, is what UNIX C language developers call a socket. However, work sockets have different meanings in XNS and Novell, where they are service access point abstractions or programming interfaces rather than service access point identifiers.

Purpose: This figure continues to explain how TCP uses port numbers. Emphasize: In most cases, the TCP port number on one side of a conversation is the same on the other side. For example, when a file transfer takes place, the software on one host is communicating with a peer application on another host.In this example we see a Telnet (TCP port 23) session. It is possible to have multiple Telnet sessions running simultaneously on a host or router. Telnet selects an unused port number above 1023 to represent the source port for each independent session. Notice that the destination port is still 23. Port numbering is important to understand in order to configure IP extended access lists. The lack of symmetry in port number use is a critical factor in establishing effective security.

If more than one device is involved, things become more complicated. In the example shown PC-B also has a connection to the server. This connection has a source port number of 2,000 and a destination port number of 23another telnet connection. This brings up an interesting dilemma. How does the server differentiate between PC-As connection that has port numbers 2,000/23 and PC-Bs, which has the same? Actually, the server uses not only the port numbers at the transport layer to multiplex connections, but also the layer-3 addresses of the devices connected to these connections. In this example, notice that PC-A and PC-B have different layer-3 addresses: 1.1.1.1 and 1.1.1.2 respectively.

Syn Can I Talk to you?Syn (Can I talk to you?), ACK (Yes)Ack (Yes)

Emphasize: In the next segment, host A sends some data. Note that the sequence number of the segment in step 3 is the same as as the ACK in Step 2. This sequence is like two people talking. The first person wants to talk to the second, and says, I would like to talk with you. (SYN) The second person responds, Good. I want to talk with you. (SYN, ACK) The first person then says, Finelet us talk. Here is what I have to say. (SYN, ACK, DATA)At this point, either side can begin communicating and either side can break the connection. TCP is a peer-to-peer (balanced) communication method (no primary/secondary). Note: This figure explains TCP connection establishment. For more information regarding the three-way handshake in establishing a TCP connection, refer to RFC 793.

Forward Ack

Emphasize: ACK for message 3. (Send ACK 4, Receive ACK 4)This sequence helps to convey the delay associated with a window size of one.Note: TCP acknowledgments are expectational and are sometimes called forward referenced, which means that they refer to the segment they are expecting to receive, not the one just sent.Acknowledgment field sizes can become an issue when transmitting data at FDDI and ATM speeds.Layer 4 of 4Emphasize: Layer 4 shows the acknowledgment number is 12. The sequence and acknowledgment numbers are directional. The slide highlights the communication going in one direction. The sequence and acknowledgments take place with the sender on the right. TCP provides full-duplex communication.

Forward AckDelayed ACKFlow Control

Another function of the transport layer is to provide optional flow control. Flow control is used to ensure that networking devices dont send too much information to the destination, overflowing its receiving buffer space, and causing it to drop the sent information. Overflow is not good because the source will have to resend all of the information that was dropped. The transport layer can use two basic flow control methods:

Exam Watch The purpose of flow control is to ensure the destination doesn't get overrun by too much information sent by the source.

Ready/not ready signals

Windowing

Ready/not ready signals and windowing are used to implement flow control. Ready/not ready signals are not efficient, causing drops in unnecessary traffic and delays in the transmission of traffic. Windowing addresses these issues. With windowing, a window size is established, which defines the number of segments that can be transferred before waiting for an acknowledgment from the destination.Windows size 3 Delayed AckPurpose: This graphic explains the format of UDP. Emphasize: UDP is simple and efficient but not reliable. The UDP segment format includes a source port, a destination port, a length field, and an optional checksum field. It has no sequencing, acknowledgments, or windowing.Example: TFTP uses a checksum. At the end of the transfer, if the checksum does not match, then the file did not make it. The user is notified and must enter the command again. As a result, the user has become the reliability mechanism.Transition: The next section discusses the network layer of the OSI model and how it corresponds to the TCP/IP Internet layer.

IP is the main protocolIt is connection lessIP will carry the data packetsData packets are IP Packets

IP

Version IP version current 4TTL How many HOPS packet can withstandProtocol to determine whether TCP or UDP

Purpose: This figure explains the use of the protocol field.Emphasize: Protocol numbers connect, or multiplex, IP to the transport layer. These numbers are standardized in RFC 1700. Cisco uses these numbers in filtering with extended access lists.

Purpose: This figure explains which messages are ICMP messages.Emphasize: Describe ICMP messages and ping.

Layer 4 of 4Emphasize: In layer 4, the bulleted items at the bottom of the slide appear.ARP provides translation between network and data link layers.Discuss why it is necessary to have a mechanism like ARP.Describe ARP operation.Not all protocols use ARP. Some use other methods for address translation.Note: For the message to be transmitted uniquely to a single interface on the multiaccess link, it is necessary to build a frame with the unique MAC address of the interface.

Layer 4 of 4Emphasize: In layer 4, the bu

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