ccna 1 module 9: tcp/ip protocol suite and ip addressing

CCNA 1Module 9: TCP/IP Protocol Suite and IP Addressing

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TCP/IP – History and Future Created by US

DoD as a model able to withstand intense military attack and not fail.

Data transmission was possible to any destination on the network under any circumstances.

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TCP/IP – History and Future Standardized in

1981 The TCP/IP model

is now the standard on which the Internet is based.

There are similarities and differences between the TCP/IP model and the nine layer OSI model.

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Ensures that the data is properly packaged before being passed on.

Handles high-level protocols, representation, encoding, and dialog control.

Simple Network Management Protocol (SNMP) – allows network managers to manage configurations, statistics, performance, and security.

Domain Name System (DNS) – used to translate domain names into IP addresses.

TCP/IP Application Layer

Application

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Has protocols to support file transfer, e-mail, and remote login:

File Transfer: Trivial File Transfer Protocol (TFTP)

– unreliable, connectionless User Datagram Protocol (UDP) service used to transfer configuration files, Cisco IOS images, and to transfer files in a LAN.

File Transfer Protocol (FTP) – reliable, connection-oriented service that uses TCP to transfer files between systems

Network File System (NFS) – allows file access to a remote storage device such as a hard disk


Application

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E-mail: Simple Mail Transfer Protocol

(SMTP) – administers the transmission of plain text e-mail over computer networks.

Remote access: Telnet –remotely access a

computer, enabling a user to log into an Internet host and execute commands. A Telnet client is called a local host. A Telnet server is called a remote host.


Application

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Provides a logical connection between a source host and a destination host.

Transport Layer protocols segment and reassemble data sent by applications, into the same data stream, between end points.

Provides end-to-end control and reliability as data travels through the cloud, accomplished through: sequence numbers, acknowledgments

and sliding windows.

Transport

TCP/IP Transport Layer

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Transport


I just sent #10 I just received #10Now I need #11

This shows sequence numbers and acknowledgements.

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Transport


I just sent #11, 12 and 13 I just received #12

Now I need #13

This indicates that packet 13 either did not arrive, or arrived with errors, and needs retransmission.

Sliding Windows

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Transport


I just sent #13 and 14 I just received #14

Now I need #15

The sliding window has worked as the last packet sent has arrived.

Sliding Windows

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The only Transport layer protocols are TCP and UDP. Transmission Control Protocol

(TCP) Connection-oriented protocol End-to-end operation Flow control – sliding windows Reliability – sequence numbers and

acknowledgments User Datagram Protocol (UDP)

Connectionless Unreliable (no acknowledgments or

error checking)

Transport


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Two purposes are determining the best path and packet-switching.

No error checking or correction Protocols:

Internet Protocol (IP) - connectionless, best-effort delivery routing of packets; determines best path to destination

Internet Control Message Protocol (ICMP) – control and messaging

Address Resolution Protocol (ARP) - determines the MAC address, for a known IP address.

Reverse Address Resolution Protocol (RARP) - determines the IP address for a known MAC address.

Internet

TCP/IP Internet Layer

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Allows an IP packet to make a physical link to the network media

Maps IP addresses to MAC addresses Encapsulates IP packets into frames Drivers for software applications,

modem cards, and other devices operate at the network access layer.

Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) provide network access.

ARP and RARP also work at this layer.

Network Access

TCP/IP Network Access Layer

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Comparing TCP/IP and OSI

TCP/IP Model OSI Model

Application7

1

2

3

4

5

6Application

Network Access

Internet

Transport

Physical

Data Link

Network

Transport

Session

Presentation Application Layers

Data Flow Layers

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Comparing TCP/IP and OSI Similarities

Both have layers. Both have

application layers, though they include different services.

Both have comparable transport and network layers.

Both use packet-switched instead of circuit-switched technology.

Differences TCP/IP combines the

OSI application, presentation, and session layers into its application layer.

TCP/IP combines the OSI data link and physical layers into its network access layer.

TCP/IP appears simpler as it has fewer layers.

The TCP/IP transport layer uses UDP (not reliable) delivery of packets. The transport layer in the OSI model is always reliable.

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Internet Architecture The Internet is based on the

principle of network layer interconnection.

This means that it is independent of the lower layers and the upper layers.

This functionality allows for different Layer 1 and 2 LAN technologies (media; protocols; LAN design, etc.)

It also allows for a diversity of applications at Layers 5, 6, and 7.

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This means that one network with one set of Layer 1 and 2 LAN media, design etc. and its own upper layer Applications can communicate with a very different LAN.

This capability means that the Internet is scalable; now with over 90,000 core routers and 300 million users, and growing.

Internet Architecture

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X and Y represent computers that are connected and that can communicate with each other from across the world.

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Internetworking- building network of networks. A network of networks is called “internet”.

Internetworking must have the following characteristics. Scalable Handle the transport of data across vast

distances Flexible Adjust to dynamic conditions on the

network Cost-effective Permits anytime, anywhere data

communications to anyone.

An uppercase I is used to refer to the networks that grew out of the DoD on which the WWW runs, and to refer to the Internet.

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Two routers connect three physical networks. Because all the users on all the networks want to communicate with each other, even without being directly connected to one another, the router must have some way of dealing with this.

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The router needs to keep a list of all user computers and the paths to them. The router would decide whether and where to forward data packets based on this table of all users, forwarding based on the destination computer.

This is not scalable system

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Solution Two computers, anywhere in the world,

following certain hardware, software, and protocol specifications, can communicate reliably (“anyplace/anytime/anyone”). Even when they are not directly connected ( or even not close to being directly connected).

IP Addressing

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IP Addressing Each computer (computer interface)

in a TCP/IP network must have two addresses: An IP (logical, layer 3) address, is a

combination of the network address and the host address creating a unique address for each device on a network. This address is needed to deliver the packet to the correct network.

A unique MAC (physical, layer 2) address. Once the data (packet) has arrived at the network, this address is needed to deliver it to the destination device.

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IP Addressing

An IP address is a 32-bit sequence of ones and zeros.

It is commonly represented in dotted decimal format, as it is easier to understand and less prone to error.

11000000.10101000.00000001.00001000

192.168.1.8

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Decimal and Binary Conversion Review the binary to decimal and

the decimal to binary conversions in 9.2.2

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Address Classes A router uses the IP address of the

destination network to deliver a packet to the correct network.

Every IP address has two parts The first part identifies the network

where the device is connected and the second part identifies the device.

There are four octets, each ranging from 0-255, representing 256 possible addresses.

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Address Classes

An IP address is always divided up into a network portion and a host portion.

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IP Address as a 32-Bit Binary Number

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Binary and Decimal Conversion

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IP addresses are hierarchical, meaning an address can be referenced back to a particular group address.

Address Classes

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There are five address classes: Class A – for very large networks Class B – for medium networks Class C – for small networks Class D – for multicast groups; no

need for network and host parts Class E – for research purposes

Address Classes

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Address Classes

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Address Classes

Learn these tables!

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Address Classes

One network octet and three host octets. The first bit of a Class A address is 0. The lowest number that can be

represented is 00000000, decimal 0. The highest number that can be

represented is 01111111, decimal 127. Usable 1st octet addresses: 1 126

(0 and 127 are reserved addresses)

Class A:

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Address Classes

Two network octets and two host octets. The first two bits of a Class B address

are 10. The lowest number that can be

represented is 10000000, decimal 128. The highest number that can be

represented is 10111111, decimal 191. Usable 1st octet addresses: 128 191

Class B:

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Address Classes

Three network octets and one host octet.

The first three bits of a Class C address are 110.

The lowest number that can be represented is 11000000, decimal 192.

The highest number that can be represented is 11011111, decimal 223.

Usable 1st octet addresses: 192 223

Class C:

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Address Classes

Created to enable multicasting. A destination address is a group of addresses.

The first four bits of a Class D address must be 1110.

The first octet range for Class D addresses is 11100000 to 11101111, or 224 to 239.

Class D:

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Address Classes

Reserved for IETF research. Not used on the Internet. The first four bits of a Class E address

are always 1111. The first octet range for Class E

addresses is 11110000 to 11111111, or 240 to 255.

Class E:

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1. 176.186.14.112 176 = 10110000 = 2. 197.76.210.100 197 = 11000101 = 3. 129.118.32.189 129 = 10000001 = 4. 113.26.172.106 113 = 01110001 = 5. 201.200.100.90 201 = 11001001 = 6. 47.145.148.211 47 = 00101111 =

What is the Address Class?

A

B

C

B

C

A

What do you notice about each of the Class addresses?

What is common with the Class A addresses?

What is common with the Class B addresses?

What is common with the Class C addresses?

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This is a very important table. Copy it into your journal. MEMORISE IT!

Address Classes

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Reserved addresses Two addresses on any network

cannot be used by hosts. Network address – Used to

identify the network itself Broadcast address – Used for

broadcasting packets to all the devices on a network

The HOST bits of a network address are all 0s.

The HOST bits of a broadcast address are all 1s.

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Reserved addresses

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IP Address –10.18.127.100 Subnet Mask – Network address = Broadcast address =

Reserved addresses

255.0.0.0

10.0.0.0

10.255.255.255

The first question to ask is, ‘What class is this address?’

Class A

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Reserved addresses

255.255.0.0

131.234.0.0

131.234.255.255

What class is this address?

Class B

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Reserved addresses

255.255.255.0

199.218.4.0

199.218.4.255


Class C

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IP Address – 210.189.137.100 Subnet Mask – 255.255.255.240 Network address = Broadcast address =

Reserved addresses

210.189.137.96

210.189.137.111


Class C

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IP Address – 180.43.120.39 Subnet Mask – 255.255.255.192 Network address = Broadcast address =

Reserved addresses

180.43.120.0

180.43.120.63


Class B

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Network and Host Addressing

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Network Address Host portion all zeros

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Broadcast Address

Host portion all ones

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Public and Private Addresses No two devices on the Internet can

have the same IP address. Ensuring this does not happen is

handled by the Internet Assigned Numbers Authority (IANA).

With the growth of the Internet, available Internet addresses have nearly run out.

To help deal with this problem, RFC 1918 sets aside three blocks of IP addresses for private, internal use.

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Required Unique Address A packet can only be sent out onto the

Internet if it has a unique address

Both networks have a network

address 198.150.11.0.

when data transmissions

reach the router, which network

would it forward to???

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One Class A, a range of Class B addresses, and a range of Class C addresses are not routed on the Internet. 10.0.0.0 – 10.255.255.255 172.16.0.0 – 172.31.255.255 192.168.0.0 – 192.168.255.255

A router uses Network Address Translation (NAT) to translate private addresses to public addresses.

Public and Private Addresses

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Public and Private Addresses

If you are addressing a test lab or a home network, these private addresses can be used instead of globally unique addresses. Private addresses can be

intermixed with public IP addresses as shown in the figure.

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Subnets

Subnetting a network means to use the subnet mask to divide a up a network into smaller, segments, or subnets.

Subnetting has prevented the wasting of usable host addresses.

To create a subnet address, some bits from the host field are borrowed, and designated as subnet bits.

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The following figure shows a Class B network (131.108.0.0) divided into three subnetworks.

131.108.1.0

131.108.3.0

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Subnetworks

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Subnet Mask

Determines which part of an IP address is the network field and which part is the host field

Follow these steps to determine the subnet mask:1. Express the subnetwork IP address in

binary form.2. Replace the network and subnet

portion of the address with all 1s.3. Replace the host portion of the address

with all 0s.4. Convert the binary expression back to

dotted-decimal notation.

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Subnet mask in decimal = 255.255.240.0

Subnet Mask

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AND is like multiplication. OR is like addition. NOT changes 1 to 0, and 0 to 1.

Boolean Operations: AND, OR, and NOT

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Performing the AND Function

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Range of Bits Needed to Create Subnets

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Subnet Addresses

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Decimal Equivalents of 8-Bit Patterns

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Creating a Subnet Determining subnet mask size Computing subnet mask and IP

address Computing hosts per subnetwork Boolean AND operation IP configuration on a network diagram Host and subnet schemes Private addresses

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Class B address with 8 bits borrowed for the subnet

130.5.2.144 (8 bits borrowed for subnetting) routes to subnet 130.5.2.0 rather than just to network 130.5.0.0.

Determining Subnet Mask Size

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The address 197.15.22.131 would be on the subnet 197.15.22.128.

11000101 00001111 00010110 100 00011

Network Field SNHost Field

Class C address 197.15.22.131 with a subnet mask of 255.255.255.224 (3 bits borrowed)

Determining Subnet Mask Size

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Subnetting Example with AND Operation

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The router connects subnetworks and networks.

IP Configuration on a Network Diagram

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IPv4 vs IPv6

Class A and Class B addresses make up three quarters of the four billion possible addresses. These are virtually used up.

Class C addresses only allow 254 hosts, too small for many organisations.

In 1992 the Internet Engineering Task Force (IETF) began work on IP version 6.

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IPv4 addresses are 32 bits long. IPv6 addresses are 128 bits long. IPv6 addresses are assigned to

interfaces, not nodes. IPv6 addresses are written in

hexadecimal, and separated by colons.

IPv4 vs IPv6

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IPv4 vs IPv6

Obtaining an IP Address

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Obtaining an IP Address IP addresses can be assigned

statically or dynamically. Static addressing is manually

done by a system administrator. Best on small, infrequently

changing networks. Good record-keeping is essential. Servers, printers and routers

should be given static addresses. Static addressing is NOT

scalable.

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Reverse Address Resolution Protocol (RARP) associates a known MAC addresses with an IP addresses.

IP source addresses are needed for the address field in all IP packets.

A RARP server must be present. RARP requests are broadcast onto

the LAN and are responded to by the RARP server, usually a router.

RARP IP Addressing

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RARP Example

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ARP/RARP Message Structure

Return to Page 400 in the Book for more details

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BOOTP IP Addressing Operates in a Client-Server

environment. Unlike BOOTP was not designed for

dynamic address assignment. The administrator must maintain the

BOOTP database with profiles for each host.

BOOTP is used when a device starts up. BOOTP uses UDP to carry messages. BOOTP sends a broadcast IP packet. A BOOTP server receives the broadcast

and then sends back a broadcast.

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DHCP IP Addressing DHCP has replaced BOOTP. DHCP allows a host to obtain an IP

address dynamically without needing an individual profile for each device.

All that is needed is a defined range of IP addresses on a DHCP server.

Information sent includes the subnet mask and the leased address.

Users can be mobile and keep the same address.

DHCP offers a one to many ratio of IP addresses, and that an address is available to anyone who connects to the network.

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Address resolution

A datagram on a LAN must contain both a destination MAC address and a destination IP address.

These addresses must be correct and match the destination MAC and IP addresses of the host device.

If it does not match, the datagram will be discarded by the destination host.

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ARP – Address Resolution Protocol ARP tables store MAC and IP

addresses of other LAN devices. Maintained automatically Stored in RAM

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Two ways to gather MAC addresses: Monitor traffic and record the addresses Broadcast an ARP request

An ARP request is used if a device needs an IP and MAC address pair. The broadcast is sent If the device exists and is on line, it will

reply. If the device does not exist or is turned

off, there is no response to the ARP request. In this situation, the source device reports an error.

ARP – Address Resolution Protocol

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Proxy ARP

A router sends an ARP response with the MAC address of the interface on which the request was received, to the requesting host.

This is done for addresses not in local subnet.

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Default Gateway The IP address of the router interface is

stored in the network configuration of the host.

The source host compares the destination IP address and its own IP address to determine if the two IP addresses are located on the same segment.

If the receiving host is not on the same segment, the source host sends the data using the actual IP address of the destination and the MAC address of the router.

Either Proxy ARP or the Default Gateway must be configured, or no traffic can leave the LAN.

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Do lab 9.2.7 Do lab 9.3.7 at home

Good luck on the exam……..

ccna 1 module 9: tcp/ip protocol suite and ip addressing

Documents

tcpip model

tcpip protocol suite

windows slide

tcpip history

layer osi model

ip addressing slide

file access

remote host