Network Addressing

Network AddressingNetworking for Home & Small Business

Objectives

IP Addresses

&

Subnet Masks

Purpose of an IP Address• Each host needs IP to communicate• Assigned to the NIC

– Computers, network printer, router interfaces• Remember

– Packet has source & destination IP

Everything is IP

IP Address Facts• Logical (not physical like MAC)• IPv4• 32 bits, 4 octets

– 8 bits in each octet– 11111111.10101010.11001100.00100101

• Written in decimal– 192.101.28.36

• Value in each octet from 0-255– That’s a total of 256 numbers.

Convert binary to decimal• Add up the values of the binary 1’s• 128 6432 16 8 4 2 1• 1 0 0 1 1 1 0 0

– 156

• 11100101– 229

Binary/Decimal Conversions

• How to Do Conversions Handout

• Binary & Decimal Conversions Practice

• Binary Game in Curriculum

Parts of an IP Address• Network portion

– Identifies network to the router– Router cares about this part

• Host portion– Identifies the specific host– Router doesn’t care about this part

• 192.175.36.9

Activity

IP & Subnet Mask• Subnet Mask

– Helps router decide which network packet is on– Helps show which part of IP is network & host– 32 bits– 192.168.6.5 255.255.255.0

• Binary 1’s - ID the network portion• Binary 0’s - ID the host portion

What network are these on?ANDing

ANDing- What network?• 199.81.210.17• 255.255.255.240

• What network does this belong to?

How many hosts- Unsubnetted?• SM helps tells us how many hosts are on

that network– 255.255.255.0– Binary 0= identifies # of hosts on that network– 28=256– Subtract 2 for useable number

• Unusable:– 00000000 (.0) is the network ID– 11111111 (.255) is the broadcast address for a network

• Total Useable is 254

How many total & useable hosts?

• SM 255.255.255.128– 128= 10000000– 27= 128-2 is 126 hosts

• SM 255.255.255.224– 224= 11100000– 25= 32-2 is 30 hosts

• SM 255.255.240.0– .240.0= 11110000.00000000– 212= 4096-2 is 4094 hosts

Figure It Out• One PC is 192.168.18.107 255.255.255.0

– What is network does it belong to?– How many useable hosts?– Give PC’s addresses.

Binary/Dec/Hex• Hex= MAC address• 0-9, A-F (10-15)• AB

Handout & Lab• 5.1.4 Lab (No Calculator)

• Homework- Decimal/Hex/Binary Conversion

Review1. Which version IP addresses are we

dealing with?– IPv4

2. How many bits in an IP address?– 32

3. How many octets in an IP address?– 4

4. Which part of this address is the host portion? 199.81.71.6

– 6

Review1. Which network does this belong on?

201.14.6.5 255.255.255.0– 201.14.6.0 network

2. How many total hosts can be on that network? Useable?

– 256– 254, why?

Types of

IP Addresses

IP Classes & Default SM• Class A

– Large organizations– 1-127– Default SM= 255.0.0.0

• One octet for network, 3 octets for hosts– How many hosts available?

• 224= over 16 million– 10.52.33.7– N.H.H.H– 255.0.0.0– 120.111.99.87

Class A Example• 15.7.92.5 255.0.0.0

• 15= Class A• Default SM for Class A= 255.0.0.0• Network portion of address= 15.• Host portion= .7.92.5• Network ID= 15.0.0.0

– All zero’s in the host portion• Broadcast address= 15.255.255.255

– All binary one’s in the host portion

IP Classes & Default SM• Class B

– Medium organizations– 128-191– Default SM= 255.255.0.0

• Two octets for network, 2 octets for hosts– How many hosts available?

• 216= over 65,000– 130.52.33.7– N.N.H.H– 255.255.0.0– 185.111.99.87

Class B Example• 167.101.52.36 255.255.0.0

• 167= Class B• Default SM for Class B= 255.255.0.0• Network portion of address= 167.101• Host portion= .52.36• Network ID= 167.101.0.0



IP Classes & Default SM• Class C

– Small organizations– 192-223– Default SM= 255.255.255.0

• Three octets for network, 1 octet for hosts– How many hosts available?

• 28= 256-2 (254 useable)– 199.52.33.7– N.N.N.H– 255.255.255.0– 220.111.99.87

Class C Example• 210.44.200.89 255.255.255.0

• 210= Class C• Default SM for Class C= 255.255.255.0• Network portion of address= 210.44.200• Host portion= .89• Network ID= 210.44.200.0



Other IP Classes & More• Class D & E not for commercial use

– D is multicast (one to a group)– 224.0.0.0- 239.255.255.255

• All 0’s in host portion(s) = network ID• All 1’s in host portion(s)= broadcast• CAN NOT USE THOSE FOR HOSTS!

• Activity on 5.2.1

IP Cheat Sheet

Handouts• Lots of Practice!

Public/Private IP’s• Some addresses are reserved & can not be routed

across Internet• You can have a public IP for network/servers &

private for hosts inside– Saves IP addresses

Address Class

Address Range

A 10.0.0.0- 10.255.255.255

B 172.16.0.0- 172.31.255.255C 192.168.0.0- 192.168.255.255

Private IP’s• If host does not connect DIRECTLY to

Internet, it can have a private IP

• Router BLOCKS private IP’s

• Security!!!– Private IP’s can not be seen from Internet

• 127.0.0.0 range is reserved for loopback testing

Private Nets- 5.2.2 Activity

Unicast Communication• One-to-one or Source to destination

Broadcast Communication• One-to-all or Source to all in segment• All hosts will look at it• All 1’s in host portion(s) of address• Broadcast IP & MAC• Default Broadcasts

– A- 10.255.255.255 255.0.0.0– B- 172.16.255.255 255.255.0.0– C- 192.168.1.255 255.255.255.0

Broadcast Communication

Multicast Communication• One-to-group• Class D 224.0.0.0- 239.255.255.255• Multicast MAC begins with 01-00-5E

• Where is it used?– Gaming– Distance learning

Multicast Communication

Which one?• Unicast• Multicast• Broadcast

Activity & Handout• 5.2.3.4• Handout• DOS

– Netstat –e– Do this every 10 seconds– Pay attention to non-unicast packets

Review1. 160.50.23.6 255.255.0.0; What network is this

on?– 160.50.0.0

2. Which default SM has the most hosts?– Class A 255.0.0.0– Over 16 million!

3. How many useable hosts in a Class C?– 254

4. 220.101.5.90 255.255.255.0; What network is this on?– 220.101.5.0

Review1. What are the private IP addresses?

– 10, 172.16-172.31, 192.168.2. What is the MAC broadcast frame in hex?

– FF-FF-FF-FF-FF-FF3. What is the MAC for a multicast?

– 01-00-5E4. One to one communication is…

– Unicast5. To send a unicast message, which addresses do

you need?– Source & dest. IP & MAC

How IP

Addresses Are

Obtained

Assigning IP Addresses• Static

– Manually type in IP Address

– Good for printers or servers• Devices people

access all the time• You wouldn’t want

their address changing!

– Good documentation!!!!

Assigning IP Addresses• Dynamic

– Assigned auto by DHCP server

– Assigns IP, SM, DG, more

– Good for larger networks or with mobile/new devices

– Leased addresses

Assigning IP Addresses• Admins have a pool of IP addresses

– DHCP assigns from the pool• SOHO routers usually have DHCP

• Medical field-– Legal requirement– Must track who is on machine– DHCP server assigns & keeps log of users

DHCP Servers• How you get on the net in a hotel, Starbucks, or BK• Either dedicated server or mixed in another device

– From ISP or on your ISR

How DHCP Works

Configuring DHCP on Linksys• 192.168.1.1• PacketTracer Lab5.3.3.3

Review1. Which addresses does a host use to

discover a DHCP server?– 255.255.255.255– FF-FF-FF-FF-FF-FF

2. Who sees that? Who responds?– All on the segment– The DHCP server

3. What happens to a PC’s IP when you shut down?

– Goes back to the DHCP pool of addresses

Address

Management

Network Boundaries

The Network In & Out

How to Connect to the ISP• Directly

– 1 PC to a modem– PC gets address from ISP

• ISR– Modem to ISR– Internal PC’s get addresses from ISR

• Gateway Device– ISR & Modem in one– Internal gets private IP’s

How to Connect to the ISP

NAT• Translates private into public addresses• Prevents external from seeing internal

NAT Translation• A private (local) source IP address is

translated to a public (global) address. – The process is reversed for incoming packets.– The integrated router is able to translate many

internal IP addresses to the same public address, by using NAT.

NAT Example

Packet Tracer• 5.4.3.2

Review

1. Which address does the PC need to access the Internet?

– Default gateway address of the ISR2. Which devices translates NAT?

– ISR

Review

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Network AddressingNetworking for Home & Small Business

Documents

Network Addressing