Ch-1_OSI Model

1

By Tulsidas Chouhan

Exam 640-802Cisco Certified Network Associate ( CCNA )

2

•CISCO is a company. It create networking devices like Router, Switch & Firewall.•Developed by “San Jose” in 1984.•Cisco’s name is derived from the city San Francisco.

Tulsidas chouhan mob. 9990563983, 09179397108

3

Cisco Icons and Symbols

Workgroup Switch

Router

Access Point

WirelessRouter

WirelessConnectivity

Line: Serial Line: Ethernet

Home Office

SmallBusiness

Firewall

IP Phone Mobile Access Phone

Secure Router


4

CCIE

CCNP

CCNA

CCENT

Expert

Expand Your Professional Options, Advance Your Career

Entry Technicia

n

Recommended Training Through Cisco Learning Partners

Interconnecting Cisco Networking Devices Part 1


Cisco Certified Network Associate

Recommended Training Through Cisco Learning Partners


Cisco Certified Entry Network Technician

Professional

Associate

www.cisco.com/go/certifications

Cisco Career Certifications


5

• The OSI model defines the communications process between source to destination.

• Open Systems Interconnection (OSI) model is a reference model developed by ISO (International Organization for Standardization) in 1984.

• It consist of seven layers.

OSI Model


6

Seven layer of OSI Model


7

• It is a first layer of OSI model.• It provide the physical connectivity between the system or

network.• In physical layer data transmission form of “bit” and this

process is called Protocol Data Unit(PDU).• There are no protocols which work at the Physical layer.

– Some device are working on physical layer.

• Cable:- Coaxial cable – 185 meter Twisted pair cable – STP, UTP – 100 meter

Fiber Optic cable – mono mode – 100 K.M. multi mode – 2 K.M.

Physical Layer


8

• Media Convertor:- Connect to two or more media.


9

• Network Interface Card (NIC) :- – A NIC is a printed circuit board that provides network communication

capabilities to and from a personal computer. Also called a LAN adapter.


10

• Amplifier:-• Repeater:-

– Both are used for busting the signal & Extending the Network. • Hub:-

– It is centralized device used in start topology.– It is also known as multiport repeater.– It is work’s on half duplex.– In hub data transmission between source to destination form of bit

so work’s on Physical Layer.– It’s data transfer speed 10 Mbps.– It work’s on shared mode.– Port’s are 4, 8, 16, 24.


11

– It has single broadcast domain.• Uncast:- one source – one destination• Multicast:- one source - multiple destination/ group• Broadcast:- one source – all destination

– It doesn’t break the broadcast domain.– It is single collision domain.– It doesn’t understand the MAC address.– It also known as broadcasting device because always

communication via broadcast.– It fallow IEEE 802.3 standard.– Hub works on CSMA/CD technology.

Modem:- it is used to convert the signal.


12

Data Link Layer• It is second layer of OSI model.• It’s PDU is “FRAME”.• It’s two sub layer are available.

– MAC IEEE 802.3– LLC IEEE 802.2

1. MAC– MAC stand’s for Media Access Control.– It is 48 bit, 6 byte & 12 digit hexadecimal address.– Responsibility of MAC address.

• Check the physical topology.• Check the logical topology.• How to transmit data in media.• CRC/FCS

2. LLC• LLC stands for Logical Link Control.• It control the unwanted traffic.• It works same as trailer.


13

Some devices are working on DLL

• NIC:-• Bridge:-

– It is centralized device.– It is used to star topology.– It’s work’s on Data Link Layer.– It’s work’s on full duplex mode.

• There are no collisions in full-duplex mode. • Full-duplex Ethernet can be used in three situations:

– With a connection from a switch to a host – With a connection from a switch to a switch – With a connection from a host to a host using a crossover cable

– It has maximum ports available 8 port.– Each port have own speed.– It has one broadcast domain.– It has multiple collision domain.– It doesn’t break the broadcast domain.– It understand the MAC address.


14

– Communication:– • first time – broadcasting• second time – unicasting

– Manage the MAC table in bridge with the help of “Software”.

– Types of Bridge:-• Lenear Bridge:

– Mac address entry manually via network admin.– Secure Network because doesn’t communicate the other person.

• Transparent Bridge:– Automatic entry of MAC addresses.

» MAC Table Timer Update Time – 60 sec. False / Remove Time – 300 sec.


15

• Switch:– It is centralized device used in star topology.– It work’s on DLL Layer.– It work’s on full duplex mode.

• There are no collisions in full-duplex mode. • Full-duplex Ethernet can be used in three situations:

– With a connection from a switch to a host – With a connection from a switch to a switch – With a connection from a host to a host using a crossover cable

– Communication – first time – broadcastingsecond time – unicasting

– It understand the MAC address.– It has single broadcast domain.– It doesn’t break the broadcast domain.– It has available port’s are – 8, 12, 24, 32, 64, 128, 256, 512 etc.– It has known as multiport bridge.– Manage the MAC table in switch with the help of “Hardware” – IC – ASIC (Application

Specific Integrated Circuit).


16

Type's of switching method

• Cut Through: – In this method forwarding starts as soon as destination address of the frame is

received in header. Also known as WIRE SPEED. This method has following features:-

– Lowest latency.– Lowest error checking. – Highest frame forwarding speed.


admin

the amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network.

17

• Store & Forward: – In this method complete frame is received by the switch. CRC, source address and destination

address are checked. This method has following features:-– Highest latency (delay in forwarding of frame) but may vary depending upon the length of frame.– Highest error checking. – Lowest frame forwarding speed. – Catalyst 500 switch uses this method.


18

• Fragment Free (Modified Cut Through):– In this method forwarding starts as soon as first 64 bytes of the frame are received as

fragmentation occurs usually in first 64 bytes. This method has following features:-– Latency approx 60m Sec.– Sufficient error checking. – Moderate frame forwarding speed.

• Some Protocols are working on DLL.– HDLC:

• HDLC stands for High-Level Data Link Control protocol. Like the two other WAN protocols mentioned in this article, HDLC is a Layer 2 protocol . HDLC is a simple protocol used to connect point to point serial devices.


19

• HDLC is actually the default protocol on all Cisco serial interfaces. If you do a show running-config on a Cisco router, your serial interfaces (by default) won’t have any encapsulation. This is because they are configured to the default of HDLC. If you do a show interface serial 0/0, you’ll see that you are running HDLC. Here is an example:


admin

The process of adding a header or trailer to the PDU at each layer of the OSI is called encapsulation.

20

• Synchronous Data Link Control (SDLC):– The SDLC or the Synchronous Data Link Control was first developed

by IBM. It is basically a linked layer protocol which can be used with systems network architecture or the SNA environment. In 1974, IBM developed one of the first bit-oriented synchronous protocols, known as Synchronous Data Link Control (SDLC). After IBM submitted the protocol to the ISO for international standardization, the ISO adapted the protocol and renamed it HDLC.

• X.25• Frame Relay• PPP


21

Network Layer• It is third layer in OSI model• It’s PDU is - “packet”• Two types of packets are used at the Network layer: data and route updates.

– Data packets:- Transport user data across the internetwork. Protocols used to support data traffic are called routed protocols; examples of routed protocols are IP and IPv6.

– Route update packets :-Send updates to neighbor routers about all networks connected to that internetwork and are supported by routing protocols such as RIP, EIGRP, and OSPF.

• The Network layer (also called layer 3) manages device addressing, tracks the location of devices on the network, and determines the best way to move data, which means that the Network layer must transport traffic between devices that aren’t locally attached. Routers (layer 3 devices) are specified at the Network layer and provide the routing services within an internetwork.

• Network layer provide services such as assigning IP addresses and routing.– Routing:- routing is the process of selecting the best path.


22

• Devices:-– Router– B-Router– Layer 3 switch – There are two advantages of using routers in your network:

– They don’t forward broadcasts by default. – They can filter the network based on layer 3 (Network layer) information (e.g., IP address).

– Four router functions in your network can be listed as follows: • Packet switching • Packet filtering • Internetwork communication • Path selection

– It communication always different network. – Routing (define the route ).– It is called internetworking device because it communicate always different network. – It is packet filtering device.– It break the broadcast domain.

(reduce the traffic and fast communication.)– It is path selection device.


23

B-Router:- The combination of Router and bridge is called Brouter. Bridge router same as router but it have more security as compare to router.Layer 3 Switch:-

Layer 2 Switch• It work on Data Link Layer.• Data sending format “FRAME”.

• It is a centralize device.

• Security with the help of MAC address.

Layer 3 Switch• It work’s on network layer.• Data sending format “FRAME &

Packet”.• It is centralized device & routing

device. • Security with the help of MAC &

IP address.


24

Some protocols is working on Network Layer

• IP• IPX• ICMP• IGMP• ARP• RARP• Apple talk• Token talk


25

• IP:-– It is Internet Protocol.– It’s logical port no. is “0”.– It is used for identification of machine or pc.– It is also knows as routed protocol because it define the route.– Internet is working on IP address.– It is used on www.– It is called logical add on pc’s.

• ICMP:-– Internet Control Massage Protocol.– ICMP protocol work on background of PING command

• PING:- check the connectivity of pc.


26

• ARP:-– Address Resolution Protocol– Find source IP to destination MAC address.

• RARP:-– Reverse Address Resolution Protocol– Find source MAC to destination IP address.

• IGMP:-– Internetwork Group Massage Protocol– It is used for multicasting purpose.

(Generally user for ISP)


27

• IPX:-– Internetwork packet exchange– It is a propriety of novel– It is used for only novel network.– It is responsible for communicate between two node in Novel Network.

• Apple talk:- – It is propriety of Apple.– Communicate between two node in APPLE Network.

• Token talk:-– It is propriety of IBM.– It is responsible for communicate in token ring network.


28

Transport Layer• The Transport Layer is responsible for delivering messages between networked hosts.• As part of this, the Transport Layer is also responsible for fragmentation and

reassembly.• It is host to host layer.• Fourth layer of OSI model.• It’s PDU is “segment”.• By default data correction on transport layer & error detection Data Link Layer.

• Devices:-– Firewall:- A firewall is a device or set of devices designed to permit or deny

network transmissions based upon a set of rules and is frequently used to protect networks from un-authorized access while permitting legitimate communications to pass• Software Firewall – Antivirus• Hardware Firewall - Firewall Device


29

Hardware Firewall

Software Firewall

30

• We can apply security with the help of logical port no.– Port no. range “0 – 65535”

– There are three types of port’s• Well known or predefine or reserve port “0-1023”.• Registered port – for ISP “1024-49151”.• Private or Dynamic port – for LAN “49152-65535”.

• Protocol:-– TCP– UDP– SPX– Net BEUI– SCTP


31

• TCP:-– Transmission Control Protocol– Size – 20 & 24 byte.– It is connection oriented protocol.– It is reliable protocol.– It is open standard protocol because it communicate in multiple OS.– It is Universal protocol used in www.Disadvantage:-

• Heavy protocol because it’s more size & more bandwidth consume (Ack. Pass out).

There are three types of function on TCP.– Three way hand shacking.– Data flow control– TCP windowing.


32

• UDP:-– User Datagram Protocol– Size – 4 & 8 byteAdvantage:- – Open standard– Universal Protocol – It is a light protocol because –

less size as compare to TCP.No Ack. Pass out.

Disadvantage:-– Connection less protocol.– Unreliable because no Ack. Pass out.


33

• SPX:-– Sequence Packet Exchange– It is propriety of Novel– Used only Novel Network IPX/SPXAdvantage:-

• It is connection oriented protocol.• Reliable (Ack. Pass out).• Universal protocol

Disadvantage:-• Not open standard

• Net BEUI:-– Net BIOS Extended User Interface. Net BIOS/Net BEUI– It provide communication between two pc with the help of Net BIOS name or

computer name.– Max. 40 PC communicate to each other.


34

– Communication always –broadcasting.– Internet is not working. – With the help of Win Server we can use internet.– Win Server resolve -

• Net BIOS Name to IP Address• IP Address to Net BIOS Name

• SCTP:-– Stream Control Transfer Protocol– It is used for managing the Wireless Network.


35

Session Layer• Fifth layer of OSI model• The job of session layer stabilized & maintaining connection

between application to session layer.• This layer add Check point in data.• Decide to way between source to destination.

– Simplex– Half duplex– Full duplex

– First check in the destination network which centralized device use than data send.


36

• Protocol:-– NFS– RPC– Net BIOS– SQL

• NFS:-– Network File System– The job of NFS protocol transfer the file in different Operating System.

• RPC:-– Remote Procedure Call– RPC protocol pass out the Acknowledge between to PC.

• SQL:-– Structure Query Language– It maintain the SQL server database & program.


37

Presentation Layer• Sixth layer of OSI model• The job of presentation layer how to represent data in

application layer.• Data Translation:-

– Data Formatting– Data Encryption– Data Compression

– Data Formatting :- Easy to understanding – communication between different different programming database like ASCII, ANSI etc.

– Data Encryption :- For data security• Software - DES(Data Encryption Standard) - Encrypt data in 56 bit

AES(Advanced Encryption Standard) – Encrypt data in 128, 168, 192, 256, 512 bit.


38

• Data Compretion:-– Fist communicate data in network.Software-

Win zipWin rar

• Protocol:-– NFS– NCP:-

• Network Control Protocol• It support multiple routed protocol.


39

Application Layer• Seventh layer of OSI model• In Application layer user do interaction, communication &

work. • It is also responsible for provide Networking service for user

like telnet, http, ftp etc.• It is called desktop layer.• Identification of services is done using port number.• Note:- protocol’s port no. work’s on Transport layer and

service work’s on Application layer.


40Tulsidas chouhan mob. 9990563983, 09179397108

41Tulsidas chouhan mob. 9990563983, 09179397108

42

• Protocol– TFTP– FTP– Telnet– SSH– HTTP– HTTPS– Kerberos– SMTP– IMAP– POP3– DNS– DHCP Request– DHCP Replay– SNMP– NNTP

• Port number’s– 69– 21– 23– 22– 80– 443– 88– 25– 143– 110– 53– 67– 68– 161– 119


43

• TFTP (Trivial File Transfer Protocol)-• FTP (File Transfer Protocol)-

– Both are used for file upload & download in the network– When we want to heavy data upload & download to create TFTP &

FTP Server.– How to access TFTP & FTP Server

• TFTP <TFTP server IP> -It don’t authentication, directly access• FTP <FTP server IP > - It do authentication, ask user name and password &

than access.

• Kerberos:– It worked on background of Radius server. Doing

authentication.


44

• Telnet (Terminal Emulation Network Protocol)• SSH (Secure shell )

– Both are used for remotely access the device. Like Router, Switch & Firewall.

– How to access devices:-• c:\>Telnet <Device IP> - Ask – username, password • Telnet username and password verification in plane text formats

• C:\>SSH -l <user name> <Device IP>• SSH username and password verification in encrypted formats


45

• HTTP (Hyper Text Transfer Protocol)• HTTPS

– Both are used for provide plate form open .HTML pages.

– HTTP - always open plane text pages.– HTTPS – it open both pages plane & encrypted pages.

• DNS (Domain Name System)– The job of DNS Server resolving Domain to IP and IP to Domain.– TCP port No. 6 & UDP port No. 17

• Both protocol work in DNS server background.


46

• SMTP (Simple Mail Transfer Protocol)• PoP-3 (Post Office Protocol)• IMAP (Internetwork Message Access Protocol)

– In this all protocol’s use sending & receiving the mail.

– SMTP – Mail send – POP-3 – Mail receive– IMAP – Mail receive – only selected mail open used for

Exchange Server.• DHCP (Dynamic Host Configuration Protocol)

– The job of DHCP server assign the automatically temporary IP address in the network.


47

• SNMP (Simple Network Management Protocol)– It is used for managing networking devices like-

• Port no. LED’s proper working or not.

• NNTP (Network News Transfer Protocol)– It is mainly used for transfer the news in over all network.– Ex. Net meeting.

• Encapsulation :- Attaches, add the information our side this process is called encapsulation.

• De-encapsulation :- Open the header.• Left the Physical layer all layer’s add the header.• DLL add header & trailer


48

Some protocol worked on same as TCP & UDP

• TCP– FTP– SMTP– HTTP– Telnet– DNS

UDPDHCPTFTPSNMPDNS

TCP & UDPDNS DNS query send =UDPDNS zone transfer= TCP


49

The EndTulsidas chouhan mob. 9990563983,

09179397108

Date post:	02-May-2017
Category:	Documents
Upload:	arif-pasha
View:	212 times
Download:	0 times

Ch-1_OSI Model

Documents